Volume 44,Issue 6,2016 Table of Contents
2016, 44(6):855-859.
Abstract:
Accurate measurement of differential reflectivity (〖WTBX〗Z〖WTBZ〗DR) of meteorological targets is an important part in the upgrade of the operational China New Generation Weather Radar with dualpolarization capability. The principles of ZDRcalibration methods using external instrument, internal test signal, sun and drizzle are introduced respectively. Key factors that affect 〖WTBX〗Z〖WTBZ〗DRmeasurement accuracy are analyzed, which include drifting biases induced by transmitter, receiver and azimuth rotary joint. In addition, advantages and disadvantages of various calibration methods are compared. Taking the Cband dualpolarization radar operated by Nanjing University as an example, 〖WTBX〗Z〖WTBZ〗DR bias measurements by using external instrument, sun and drizzle methods are presented and analyzed. It is found that the measurements of the three methods have good consistency. Besides, it is also shown that 〖WTBX〗Z〖WTBZ〗DR measurement result changes with azimuth regularly. Therefore, with the long term operation of dualpolarization weather radar, the effect of azimuth rotary joint should not be neglected. The results have a certain reference value for the operation and network observation of dual polarization radar in China in future.
Accurate measurement of differential reflectivity (〖WTBX〗Z〖WTBZ〗DR) of meteorological targets is an important part in the upgrade of the operational China New Generation Weather Radar with dualpolarization capability. The principles of ZDRcalibration methods using external instrument, internal test signal, sun and drizzle are introduced respectively. Key factors that affect 〖WTBX〗Z〖WTBZ〗DRmeasurement accuracy are analyzed, which include drifting biases induced by transmitter, receiver and azimuth rotary joint. In addition, advantages and disadvantages of various calibration methods are compared. Taking the Cband dualpolarization radar operated by Nanjing University as an example, 〖WTBX〗Z〖WTBZ〗DR bias measurements by using external instrument, sun and drizzle methods are presented and analyzed. It is found that the measurements of the three methods have good consistency. Besides, it is also shown that 〖WTBX〗Z〖WTBZ〗DR measurement result changes with azimuth regularly. Therefore, with the long term operation of dualpolarization weather radar, the effect of azimuth rotary joint should not be neglected. The results have a certain reference value for the operation and network observation of dual polarization radar in China in future.
2016, 44(6):860-866.
Abstract:
The analysis is based on the data collected continually by WSIRCMS at Beijing Meteorological Observatory in November 2011. The analysis aims to evaluate preliminarily the detectability of WSIRCMS on total cloud cover, cloud base height, and sky types. The results indicate: (1) The instrument can conduct continuous automatic detection day and night towards cloud height, cloud cover (includes high, medium, low and total cloud cover) as well as sky types. (2) Samples whose difference from the reference standards is within ±10%, account for 72.5% of the total sample. The detection capability towards medium and high clouds is weaker when haze happens, which leads to great differences among observations of cloud covers. (3) When there is no cloud, the data consistency of results from WSIRCMS and ceilometers reaches 94.9%. The observed results conform fairly well under the condition of low or medium clouds. But towards high clouds, the observed results from WSIRCMS are higher than those from ceilometers. (4) Samples that conform with results of sky types under manual classification account for 82.63% of the total sample, but WSIRCMS does not show high identification capability towards undulates clouds, cumuliform clouds, and mixed clouds.
The analysis is based on the data collected continually by WSIRCMS at Beijing Meteorological Observatory in November 2011. The analysis aims to evaluate preliminarily the detectability of WSIRCMS on total cloud cover, cloud base height, and sky types. The results indicate: (1) The instrument can conduct continuous automatic detection day and night towards cloud height, cloud cover (includes high, medium, low and total cloud cover) as well as sky types. (2) Samples whose difference from the reference standards is within ±10%, account for 72.5% of the total sample. The detection capability towards medium and high clouds is weaker when haze happens, which leads to great differences among observations of cloud covers. (3) When there is no cloud, the data consistency of results from WSIRCMS and ceilometers reaches 94.9%. The observed results conform fairly well under the condition of low or medium clouds. But towards high clouds, the observed results from WSIRCMS are higher than those from ceilometers. (4) Samples that conform with results of sky types under manual classification account for 82.63% of the total sample, but WSIRCMS does not show high identification capability towards undulates clouds, cumuliform clouds, and mixed clouds.
2016, 44(6):867-874.
Abstract:
To evaluate the consistency between different products, 8 datasets of soil moisture products from the multisatellite estimation data of the European Space Agency Climate Change Initiative (ECV CCI), different versions of the Global Land Data Assimilation System (GLDAS/CLM, NOAH2.7, NOAH3.3, VIC, MOSAIC) and reanalysis datasets (ERAInterim, NCEP/DOE) are compared with the observed data in mainland China in the temporal and spatial distribution during the period of 1995 to 2010. Results show that all datasets can simulate the spatial distribution of soil moisture in different regions of China. GLDASNOAH and European Centre for MediumRange Weather Forecasts (ECMWF) reanalysis data (ERAInterim) have a bias of lessthan 0.05, the rootmeansquare deviation (RMSE) less than 0.1, and the correlation coefficient morethan 0.4. All datasets perform well in the north eastern region, but they have relatively poor representation in the south, southwest and northwestern parts of China. The ERAInterim successfully captured the interannual variability of soil moisture.
To evaluate the consistency between different products, 8 datasets of soil moisture products from the multisatellite estimation data of the European Space Agency Climate Change Initiative (ECV CCI), different versions of the Global Land Data Assimilation System (GLDAS/CLM, NOAH2.7, NOAH3.3, VIC, MOSAIC) and reanalysis datasets (ERAInterim, NCEP/DOE) are compared with the observed data in mainland China in the temporal and spatial distribution during the period of 1995 to 2010. Results show that all datasets can simulate the spatial distribution of soil moisture in different regions of China. GLDASNOAH and European Centre for MediumRange Weather Forecasts (ECMWF) reanalysis data (ERAInterim) have a bias of lessthan 0.05, the rootmeansquare deviation (RMSE) less than 0.1, and the correlation coefficient morethan 0.4. All datasets perform well in the north eastern region, but they have relatively poor representation in the south, southwest and northwestern parts of China. The ERAInterim successfully captured the interannual variability of soil moisture.
2016, 44(6):875-881.
Abstract:
Combined with new generation Doppler weather radar, the temperature and liquid water path data from the 14channel parallel groundbased microwave radiometer of German RPGHATPROG3, and the ground precipitation data obtained from THIES CLIMA LNM ground laser raindrop spectrometer, the nearsurface inversion layer distribution, liquid water path changes and raindrop spectrum distribution of a shorttime strong precipitation weather process on 3 August 2015 in Jinan are analyzed. It is concluded that due to the latent heat effect of warming in the strong convective precipitation process, there existed strong nearsurface inversion layer in the surface layer. Liquid water content showed strong shortterm accumulation phenomenon. Liquid water content path goes up and down quickly, and larger jump increased very significantly prior to precipitation. With the weakening of the intensity of precipitation, the liquid water path fluctuation decreased. In the whole process of precipitation, the early rain spectrum presents the bimodal distribution, but the heavy rain and late precipitation is unimodal spectrum. The Gamma fitting accuracy is higher.
Combined with new generation Doppler weather radar, the temperature and liquid water path data from the 14channel parallel groundbased microwave radiometer of German RPGHATPROG3, and the ground precipitation data obtained from THIES CLIMA LNM ground laser raindrop spectrometer, the nearsurface inversion layer distribution, liquid water path changes and raindrop spectrum distribution of a shorttime strong precipitation weather process on 3 August 2015 in Jinan are analyzed. It is concluded that due to the latent heat effect of warming in the strong convective precipitation process, there existed strong nearsurface inversion layer in the surface layer. Liquid water content showed strong shortterm accumulation phenomenon. Liquid water content path goes up and down quickly, and larger jump increased very significantly prior to precipitation. With the weakening of the intensity of precipitation, the liquid water path fluctuation decreased. In the whole process of precipitation, the early rain spectrum presents the bimodal distribution, but the heavy rain and late precipitation is unimodal spectrum. The Gamma fitting accuracy is higher.
2016, 44(6):882-888.
Abstract:
Quality control （QC） methods for Automatic Weather Stations （AWS） precipitation data are combined to design a fast and realtime QC Algorithm. Abnormal precipitation data are classified firstly. The Grubbs test is then used to screen out suspicious stations in a local and finite space preliminarily. Three factors are considered in the second step of the QC procedure, which are the spatial distribution of precipitation per hour, the timehistory equation of precipitation per minute, and the related characteristics between temperature and humidity. Practical test shows that the integrated quality control algorithm has a better balance between performance and accuracy, which is especially effective in summer.
Quality control （QC） methods for Automatic Weather Stations （AWS） precipitation data are combined to design a fast and realtime QC Algorithm. Abnormal precipitation data are classified firstly. The Grubbs test is then used to screen out suspicious stations in a local and finite space preliminarily. Three factors are considered in the second step of the QC procedure, which are the spatial distribution of precipitation per hour, the timehistory equation of precipitation per minute, and the related characteristics between temperature and humidity. Practical test shows that the integrated quality control algorithm has a better balance between performance and accuracy, which is especially effective in summer.
2016, 44(6):889-895.
Abstract:
The radiosonde temperature observation data collected at the Sheyang station throughout 2014 are analyzed，and it is discovered that the detection errors caused by air moisture are very common．When temperature sensors transferring from high humidity area to low humidity area，the observed temperature will become lower than environmental temperature due to water evaporation． Inconsistent air temperature, moisture distribution， and phase states of water in the atmosphere result in disparate errors in the collected data. Several practical cases, as examples, are selected to perform simple experiments，and the potential influences of air moisture on radiosonde temperature observations are discussed．
The radiosonde temperature observation data collected at the Sheyang station throughout 2014 are analyzed，and it is discovered that the detection errors caused by air moisture are very common．When temperature sensors transferring from high humidity area to low humidity area，the observed temperature will become lower than environmental temperature due to water evaporation． Inconsistent air temperature, moisture distribution， and phase states of water in the atmosphere result in disparate errors in the collected data. Several practical cases, as examples, are selected to perform simple experiments，and the potential influences of air moisture on radiosonde temperature observations are discussed．
2016, 44(6):896-901.
Abstract:
As the test and maintenance of weather radar is based on abundant technical experiences and knowledge, it needs a great deal of information and specialty. Taking for example of CINRAD SA/SB, the development of test and maintenance for weather radar is introduced, and the 2step experience database, hierarchical database， faults case database, fault tree diagram, and so on for weather radar are described. The compatibility, expansibility, and building target for test and maintenance are pointed out. According to practice, the test and maintenance database is a helpful tool for daily technical support in different level users of CINRAD SA/SB. The test and maintenance of weather radar should be paid enough attention and continually be enriched and perfected.
As the test and maintenance of weather radar is based on abundant technical experiences and knowledge, it needs a great deal of information and specialty. Taking for example of CINRAD SA/SB, the development of test and maintenance for weather radar is introduced, and the 2step experience database, hierarchical database， faults case database, fault tree diagram, and so on for weather radar are described. The compatibility, expansibility, and building target for test and maintenance are pointed out. According to practice, the test and maintenance database is a helpful tool for daily technical support in different level users of CINRAD SA/SB. The test and maintenance of weather radar should be paid enough attention and continually be enriched and perfected.
2016, 44(6):902-906.
Abstract:
Wind sensors of automatic meteorological station are frequently frozen and fail to work. To resolve the problem, an automatic malfunction detecting device based on the ZQZTF wind sensor is designed for the realtime detection of freezing faults. By detecting working voltage and current, the proposed device is able to keep the sensors under surveillance. In addition, combined with the specific diagnosis algorithm, it is quick to distinguish whether the wind sensors are frozen or not. The hardware circuit and software algorithm of the design can be integrated in the wind speed data acquisition circuit and the embedded software of the automatic meteorological station respectively. It allows for compact structure and simplified operation. It has been demonstrated that the device is competent for the realtime detection of frozen sensors, and it works stably with high detection precision as well.
Wind sensors of automatic meteorological station are frequently frozen and fail to work. To resolve the problem, an automatic malfunction detecting device based on the ZQZTF wind sensor is designed for the realtime detection of freezing faults. By detecting working voltage and current, the proposed device is able to keep the sensors under surveillance. In addition, combined with the specific diagnosis algorithm, it is quick to distinguish whether the wind sensors are frozen or not. The hardware circuit and software algorithm of the design can be integrated in the wind speed data acquisition circuit and the embedded software of the automatic meteorological station respectively. It allows for compact structure and simplified operation. It has been demonstrated that the device is competent for the realtime detection of frozen sensors, and it works stably with high detection precision as well.
2016, 44(6):907-912.
Abstract:
The method for designing a key SMS monitoring platform of Fengyun3 meteorological satellite data processing system is proposed. The selection of key monitoring positions, the intelligent identification of orbits, the processing of alarming messages, and the way to guarantee high realtime performance are discussed. Based on the detailed analysis of orbit characters, two orbitsidentification algorithms are proposed and discussed. Besides, a SMS filter logic and high efficiency software architecture is adopted to guarantee realtime performance. The operation statistic results are given.
The method for designing a key SMS monitoring platform of Fengyun3 meteorological satellite data processing system is proposed. The selection of key monitoring positions, the intelligent identification of orbits, the processing of alarming messages, and the way to guarantee high realtime performance are discussed. Based on the detailed analysis of orbit characters, two orbitsidentification algorithms are proposed and discussed. Besides, a SMS filter logic and high efficiency software architecture is adopted to guarantee realtime performance. The operation statistic results are given.
2016, 44(6):913-917.
Abstract:
Based on the natural conditions of the South China Sea and Hainan Province, considering the usage of the Island AWS equipment under high temperature, high humidity, high salt spray, strong radiation, gale and other harsh environment in South China Sea in recent years, the failure reasons of the island AWS through statistics and analysis of failures and failure modes on the island station for many years are discussed. According to the Island AWS construction and protection requirements and the experiences accumulated by the site meteorological equipment maintenance staff for many years, some effective protection methods and measures are proposed by using highquality materials, advanced technology, a variety mature and key electronic equipment protection technology on the market, to improve the marine environmental adaptability of the Island AWS equipment and extend equipment service life.
Based on the natural conditions of the South China Sea and Hainan Province, considering the usage of the Island AWS equipment under high temperature, high humidity, high salt spray, strong radiation, gale and other harsh environment in South China Sea in recent years, the failure reasons of the island AWS through statistics and analysis of failures and failure modes on the island station for many years are discussed. According to the Island AWS construction and protection requirements and the experiences accumulated by the site meteorological equipment maintenance staff for many years, some effective protection methods and measures are proposed by using highquality materials, advanced technology, a variety mature and key electronic equipment protection technology on the market, to improve the marine environmental adaptability of the Island AWS equipment and extend equipment service life.
2016, 44(6):918-922.
Abstract:
The system uses the Japanese Mitsubishi PLC as the main control core and the intermediate relay system for signal acquisition and conversion, mainly composed of the data processing module, grid monitoring module, wireless communication module, remote controller, the speech recognition module, display module, sensors, switching output module, and the UPS power supply. It can be achieved when power outages occur, the system automatically enables the generator for power supply, and when the power supply returns to normal, it can restore the function of the mains power supply automatically. In order to improve the stability of the system, there are the functions of fault alarm, remote reset, and remote query, etc., which can realize seamless switching between the mains and the generator and effectively avoid the data loss, data delay, network interruption, etc., resulted from the instability of the mains power supply, and solve the power supply problem for base stations, especially at night.
The system uses the Japanese Mitsubishi PLC as the main control core and the intermediate relay system for signal acquisition and conversion, mainly composed of the data processing module, grid monitoring module, wireless communication module, remote controller, the speech recognition module, display module, sensors, switching output module, and the UPS power supply. It can be achieved when power outages occur, the system automatically enables the generator for power supply, and when the power supply returns to normal, it can restore the function of the mains power supply automatically. In order to improve the stability of the system, there are the functions of fault alarm, remote reset, and remote query, etc., which can realize seamless switching between the mains and the generator and effectively avoid the data loss, data delay, network interruption, etc., resulted from the instability of the mains power supply, and solve the power supply problem for base stations, especially at night.
2016, 44(6):923-927.
Abstract:
The field calibration values of wind speed from automatic meteorological stations cannot be traced back, so that the accuracy and reliability of the field calibration data cannot be guaranteed. A investigate is conducted on the causes, which are determined by the current field calibration methods and the working principles of field calibration equipment. In order to solve this problem, the value transfer of wind speed sensors and the impeller wind meters are used to carry on the intermediate data transmission. In calibration, the impeller wind meter is used as the standard equipment. Using the linear characteristics of threecup type wind speed sensors, the field calibration values of wind speed sensors are traced to the largescale wind tunnel pitot tube, and through a great number of experiments, the validity of the method is proved, so as to solve this technical problem. The method provides a theoretical reference for making new specifications for the field calibration for wind speed from automatic meteorological stations and for perfecting of calibration equipment.
The field calibration values of wind speed from automatic meteorological stations cannot be traced back, so that the accuracy and reliability of the field calibration data cannot be guaranteed. A investigate is conducted on the causes, which are determined by the current field calibration methods and the working principles of field calibration equipment. In order to solve this problem, the value transfer of wind speed sensors and the impeller wind meters are used to carry on the intermediate data transmission. In calibration, the impeller wind meter is used as the standard equipment. Using the linear characteristics of threecup type wind speed sensors, the field calibration values of wind speed sensors are traced to the largescale wind tunnel pitot tube, and through a great number of experiments, the validity of the method is proved, so as to solve this technical problem. The method provides a theoretical reference for making new specifications for the field calibration for wind speed from automatic meteorological stations and for perfecting of calibration equipment.
2016, 44(6):928-936.
Abstract:
The sea fog disasters in Taiwan Strait, which is a traffic artery, often lead to life and property losses. This review covers the main achievements of sea fog in the western side of Taiwan Strait and makes a comparison with sea fog research progress in other sea areas, mainly including sea fog synoptic and climatic characteristics, monitoring means, microphysics and numerical prediction researches. The results show that some achievements have been made in terms of sea fog synoptic climatology in the western side of Taiwan Strait. With the development of science and technology, the monitoring method is constantly improving, but the inversion of satellite remote sensing monitoring results still needs further study. The study on microphysical characteristics of sea fog helps to improve the sea fog model and the retrieval technology of satellite remote sensing sea fog, so it will be the next research focus. The numerical simulation of sea fogs in the Taiwan Strait is less reported. With the continuous improvement of observation technology and dynamic statistical method, the sea fog forecast ability for Taiwan Strait can be improved by combining the numerical prediction products with traditional synoptic methods.
The sea fog disasters in Taiwan Strait, which is a traffic artery, often lead to life and property losses. This review covers the main achievements of sea fog in the western side of Taiwan Strait and makes a comparison with sea fog research progress in other sea areas, mainly including sea fog synoptic and climatic characteristics, monitoring means, microphysics and numerical prediction researches. The results show that some achievements have been made in terms of sea fog synoptic climatology in the western side of Taiwan Strait. With the development of science and technology, the monitoring method is constantly improving, but the inversion of satellite remote sensing monitoring results still needs further study. The study on microphysical characteristics of sea fog helps to improve the sea fog model and the retrieval technology of satellite remote sensing sea fog, so it will be the next research focus. The numerical simulation of sea fogs in the Taiwan Strait is less reported. With the continuous improvement of observation technology and dynamic statistical method, the sea fog forecast ability for Taiwan Strait can be improved by combining the numerical prediction products with traditional synoptic methods.
2016, 44(6):937-948.
Abstract:
Tropical cyclone path forecast results are checked for 2012 to 2013 using the GRAPES_TYM model. The results show that the average distance errors of the model is 94.3, km, 143.7 km and 260.8 km, in 24 h， 48 h and, 72 h, respectively; there exist farthernorthern systematic biases for all types of TC forecast paths for the GRAPES_TYM model; for TC in the South China Sea, the TC moving direction prediction by GRAPES_TYM model slants to the right, and the moving speed error is less. The moving direction deviation is the main source of the path deviation. In addition, the statistic prediction model bias toward TC and TC environmental steering flow forecast bias are closely related. Taking the Typhoon “Kaitak” as an example, according to the moving direction error diagnosis equation, the environmental steering flow forecast deviations (including environment wind field deviation, the impacts of the environment directing flow radius deviation, and environmental steering flow thickness deviation) on the TC moving direction prediction error are investigated; however, the environmental steering flow forecasting error sources are related with the model forecasting errors of largescale weather systems and the size and strength of TCs.
Tropical cyclone path forecast results are checked for 2012 to 2013 using the GRAPES_TYM model. The results show that the average distance errors of the model is 94.3, km, 143.7 km and 260.8 km, in 24 h， 48 h and, 72 h, respectively; there exist farthernorthern systematic biases for all types of TC forecast paths for the GRAPES_TYM model; for TC in the South China Sea, the TC moving direction prediction by GRAPES_TYM model slants to the right, and the moving speed error is less. The moving direction deviation is the main source of the path deviation. In addition, the statistic prediction model bias toward TC and TC environmental steering flow forecast bias are closely related. Taking the Typhoon “Kaitak” as an example, according to the moving direction error diagnosis equation, the environmental steering flow forecast deviations (including environment wind field deviation, the impacts of the environment directing flow radius deviation, and environmental steering flow thickness deviation) on the TC moving direction prediction error are investigated; however, the environmental steering flow forecasting error sources are related with the model forecasting errors of largescale weather systems and the size and strength of TCs.
2016, 44(6):949-955.
Abstract:
Based on the surface meteorology observation data, weather phenomena records, and radiosonde data, the circulation backgrounds of freezing rainfall in Hubei from 1998 to 2014 are analyzed, and the characteristics of variations of meteorological elements and atmospheric stratifications are summarized. The discrimination criteria of freezing rain weather based on the relationships between positive and negative energy areas are given. The results show that the Urals blocking high and Lake Baikal blocking high are two major circulation patterns leading to the occurrence of freezing rainfall in Hubei Province. There are mainly three variation patterns of temperature stratification, in which the pattern of the transmission from warm rainfall to freezing rainfall then to solid precipitation has the longest duration and the largest influenced area. As for the discrimination criteria based on positive/negative energy for the occurrence of freezing rainfall: when there are the threelayer stratification, the positive energy area (ASP) is less than 80 ℃〖DK〗·hPa and negative energy area (ASN) is less than 400 ℃〖DK〗·hPa and there is the relationship between ASP and ASN of (5.71ASP-257.14)≤ASN≤(6.25ASP+200); when there is the twolayer stratification, ASP is 350 to 650 ℃〖DK〗·hPa, and ASN is 200 to 400 ℃〖DK〗·hPa, and there is the relationship between ASP and ASN of (ASP-350)≤ASN≤(ASP-100).
Based on the surface meteorology observation data, weather phenomena records, and radiosonde data, the circulation backgrounds of freezing rainfall in Hubei from 1998 to 2014 are analyzed, and the characteristics of variations of meteorological elements and atmospheric stratifications are summarized. The discrimination criteria of freezing rain weather based on the relationships between positive and negative energy areas are given. The results show that the Urals blocking high and Lake Baikal blocking high are two major circulation patterns leading to the occurrence of freezing rainfall in Hubei Province. There are mainly three variation patterns of temperature stratification, in which the pattern of the transmission from warm rainfall to freezing rainfall then to solid precipitation has the longest duration and the largest influenced area. As for the discrimination criteria based on positive/negative energy for the occurrence of freezing rainfall: when there are the threelayer stratification, the positive energy area (ASP) is less than 80 ℃〖DK〗·hPa and negative energy area (ASN) is less than 400 ℃〖DK〗·hPa and there is the relationship between ASP and ASN of (5.71ASP-257.14)≤ASN≤(6.25ASP+200); when there is the twolayer stratification, ASP is 350 to 650 ℃〖DK〗·hPa, and ASN is 200 to 400 ℃〖DK〗·hPa, and there is the relationship between ASP and ASN of (ASP-350)≤ASN≤(ASP-100).
2016, 44(6):956-964.
Abstract:
Based on the observed data from 1960 to 2011, the Heating Degree Days (HDD) and Cooling Degree Days (CDD) in China are calculated and analyzed by using the MannKendall test. The results show that an abrupt change of winter temperature in the northern China and its adjacent plateau region occurred at around 1987, along with the decreasing HDD on the background of climate warming. The summer temperature in the southern China changed abruptly around 1997, with CDD increasing after that. The circulation characteristics before and after the climate warming are further analyzed by using the NCEP/NCAR reanalysis data and the circulation index data. It is found that the Arctic Oscillation (AO) index is negatively correlated with HDD in the northern China and its adjacent plateau region. When the AO index is stronger (weaker) than normal, the heavy cold air events decrease (increase), along with the decreasing (increasing) HDD. On the other hand, the Subtropical High Area (SHA) index has a significantly positive correlation with CDD in southern China. When the SHA index is stronger (weaker) than normal, the fair weather with high temperature will increase (decrease), along with the increasing (decreasing) CDD.
Based on the observed data from 1960 to 2011, the Heating Degree Days (HDD) and Cooling Degree Days (CDD) in China are calculated and analyzed by using the MannKendall test. The results show that an abrupt change of winter temperature in the northern China and its adjacent plateau region occurred at around 1987, along with the decreasing HDD on the background of climate warming. The summer temperature in the southern China changed abruptly around 1997, with CDD increasing after that. The circulation characteristics before and after the climate warming are further analyzed by using the NCEP/NCAR reanalysis data and the circulation index data. It is found that the Arctic Oscillation (AO) index is negatively correlated with HDD in the northern China and its adjacent plateau region. When the AO index is stronger (weaker) than normal, the heavy cold air events decrease (increase), along with the decreasing (increasing) HDD. On the other hand, the Subtropical High Area (SHA) index has a significantly positive correlation with CDD in southern China. When the SHA index is stronger (weaker) than normal, the fair weather with high temperature will increase (decrease), along with the increasing (decreasing) CDD.
Li Zonghao
,
Fang Yihe
,
Xu Fangshu
,
Xi Xiaotong
,
Wang Xiuying
,
Zhou Xiaoyu
,
Xu Hong
,
Cai Bing
,
Ma Fanshu
2016, 44(6):965-971.
Abstract:
Based on the monthly temperature data of 53 observational stations in Northeast China from 1961 to 2010 and the NCEP/NCAR monthly reanalysis data of the wind field, geopotential height field, sea level pressure field, and specific humidity field, the impact factors of large scale circulation characteristics on summer temperature in Northeast China are analyzed. The 200 hPa zonal wind shear index, which is suitable for describing the summer temperature in Northeast China is defined, and the predict method of the index are provided. Results show that there is close relationship between summer temperature in Northeast China and the dipole of the Okhotsk blocking high in the sea level pressure (SLP) in the central North Pacific. The 500 hPa geopotential height field over Northeast China is abnormally high, corresponding to the summer temperature in Northeast China abnormally high, and vice versa corresponding to the summer temperature in Northeast China abnormally low. The 850 hPa vector wind field, the whole layer moisture flux field, and the 200 hPa vector wind field present a cyclonic circulation over Northeast China, corresponding to the summer temperature in Northeast China abnormally low, and vice versa corresponding to the summer temperature in Northeast China abnormally high. At the same time, water vapor from the Bay of Bengal is also an impact factor of summer temperatures in Northeast China. There is a significant positive correlation between 200 hPa zonal wind shear index and temperature in Northeast China. Large index corresponds to high summer temperature in Northeast China, and vice versa corresponding to the summer temperature in Northeast China abnormally low. There is a close relationship between the tropical Indian Ocean and the Pacific SST from April to May and the 200 hPa zonal wind shear index.
Based on the monthly temperature data of 53 observational stations in Northeast China from 1961 to 2010 and the NCEP/NCAR monthly reanalysis data of the wind field, geopotential height field, sea level pressure field, and specific humidity field, the impact factors of large scale circulation characteristics on summer temperature in Northeast China are analyzed. The 200 hPa zonal wind shear index, which is suitable for describing the summer temperature in Northeast China is defined, and the predict method of the index are provided. Results show that there is close relationship between summer temperature in Northeast China and the dipole of the Okhotsk blocking high in the sea level pressure (SLP) in the central North Pacific. The 500 hPa geopotential height field over Northeast China is abnormally high, corresponding to the summer temperature in Northeast China abnormally high, and vice versa corresponding to the summer temperature in Northeast China abnormally low. The 850 hPa vector wind field, the whole layer moisture flux field, and the 200 hPa vector wind field present a cyclonic circulation over Northeast China, corresponding to the summer temperature in Northeast China abnormally low, and vice versa corresponding to the summer temperature in Northeast China abnormally high. At the same time, water vapor from the Bay of Bengal is also an impact factor of summer temperatures in Northeast China. There is a significant positive correlation between 200 hPa zonal wind shear index and temperature in Northeast China. Large index corresponds to high summer temperature in Northeast China, and vice versa corresponding to the summer temperature in Northeast China abnormally low. There is a close relationship between the tropical Indian Ocean and the Pacific SST from April to May and the 200 hPa zonal wind shear index.
2016, 44(6):972-978.
Abstract:
By means of the percentile method to determine the extreme temperature events in Zhejiang Province, using the ttest and the climatic trend rate method, the interdecadal and interannual characteristics of extreme temperature events are analyzed. Base on the Kernel density estimation method, the extreme temperature event decadal variation characteristics in four seasons are discussed and the differences between urban and rural areas are compared. Results show that the extreme high and low temperature days have opposite characteristics, increase and decrease respectively, and the trend strengthens along with time, especially in the eastern coastal area of Zhejiang Province. The number of extreme hot days increases, the increment is the greatest in summer and the least in winter. The strength of extreme hot weather becomes stronger, especially in spring and winter. The number of extreme cold days decreases, especially in winter. The intensity of extreme cold events becomes weaker, especially in spring. The interannual variability of Zhejiang extreme temperature events in the western region is weaker than that in the eastern region. Urban areas show the stronger strength in extreme high temperature and the weaker strength in extreme low temperature.
By means of the percentile method to determine the extreme temperature events in Zhejiang Province, using the ttest and the climatic trend rate method, the interdecadal and interannual characteristics of extreme temperature events are analyzed. Base on the Kernel density estimation method, the extreme temperature event decadal variation characteristics in four seasons are discussed and the differences between urban and rural areas are compared. Results show that the extreme high and low temperature days have opposite characteristics, increase and decrease respectively, and the trend strengthens along with time, especially in the eastern coastal area of Zhejiang Province. The number of extreme hot days increases, the increment is the greatest in summer and the least in winter. The strength of extreme hot weather becomes stronger, especially in spring and winter. The number of extreme cold days decreases, especially in winter. The intensity of extreme cold events becomes weaker, especially in spring. The interannual variability of Zhejiang extreme temperature events in the western region is weaker than that in the eastern region. Urban areas show the stronger strength in extreme high temperature and the weaker strength in extreme low temperature.
2016, 44(6):979-984.
Abstract:
Using the ground and sounding data of 21 years in Tongliao and Chifeng stations in the southeastern Inner Mongolia, the precipitation phases such as rain, sleet and snow of two stations are analyzed. As a result, the temperature characteristics at 850 hPa are relatively close when it sleets or snows at Tongliao Station. The temperature characteristics of the 850 hPa are relatively close when rains and sleets in Chifeng Station; the thickness between 850 and 700 hPa is similar when sleets or snows in Tongliao Station and so it is when rains or sleets in Chifeng Station. In the boxplot, the thickness between 850 and 700 hPa and the temperature of 850 hPa exhibits opposite superposition corresponding to three phase. The temperature discrimination indexes of 850 and 925 hPa for Chifeng are higher than those for Tongliao Station: 1.5 ℃ and 1.7 ℃ higher when it rains, and 2.4 ℃ and 3.8 ℃ higher when snows. Temperature statistical results show that the ground temperatures is 4.0 or more in Tongliao and 6.0 ℃ or more in Chifeng Station when it rains, and less than 0.0 ℃ for both stations when snows. The temperature is 0.0 to 4 ℃ in Tongliao (0.0 to 6 ℃ in Chifeng) when it rains, sleets, and snows simultaneously. Although there are large differences between the thresholds of two stations, the three kinds of precipitation phases are closely related to the thickness of the lower layer and the temperature of middle and lower layers, but have little relation to the temperature of the middle layer. It is showed that the thickness of the mid/low layers and the temperature of the lower layer determine ground precipitation.
Using the ground and sounding data of 21 years in Tongliao and Chifeng stations in the southeastern Inner Mongolia, the precipitation phases such as rain, sleet and snow of two stations are analyzed. As a result, the temperature characteristics at 850 hPa are relatively close when it sleets or snows at Tongliao Station. The temperature characteristics of the 850 hPa are relatively close when rains and sleets in Chifeng Station; the thickness between 850 and 700 hPa is similar when sleets or snows in Tongliao Station and so it is when rains or sleets in Chifeng Station. In the boxplot, the thickness between 850 and 700 hPa and the temperature of 850 hPa exhibits opposite superposition corresponding to three phase. The temperature discrimination indexes of 850 and 925 hPa for Chifeng are higher than those for Tongliao Station: 1.5 ℃ and 1.7 ℃ higher when it rains, and 2.4 ℃ and 3.8 ℃ higher when snows. Temperature statistical results show that the ground temperatures is 4.0 or more in Tongliao and 6.0 ℃ or more in Chifeng Station when it rains, and less than 0.0 ℃ for both stations when snows. The temperature is 0.0 to 4 ℃ in Tongliao (0.0 to 6 ℃ in Chifeng) when it rains, sleets, and snows simultaneously. Although there are large differences between the thresholds of two stations, the three kinds of precipitation phases are closely related to the thickness of the lower layer and the temperature of middle and lower layers, but have little relation to the temperature of the middle layer. It is showed that the thickness of the mid/low layers and the temperature of the lower layer determine ground precipitation.
20 TemporalSpatial Distribution Characteristics of Temperature and Precipitation in Northern Henan
2016, 44(6):985-990.
Abstract:
This paper analyzes the temporal and spatial distribution characteristics of temperature and precipitation changes in the north part of Henan Province based on GIS technology, using the temperature and precipitation data of 28 observation stations in “Homogenization Dataset of China National Ground Meteorological Station” from 1971 to 2010 in the northern Henan. The results show that the temperature of the northern Henan showed an increasing trend and significant warming in winter and spring. The spatial distribution of temperature variation shows that larger in the northern and central parts and smaller in the eastern and western parts. Seasonal variation of precipitation was relatively large, and precipitation in spring showed increasing trend overall and fluctuated in other seasons. The spatial variation distribution characteristics of precipitation show that precipitation decreased obviously in the western mountain area along the Taihang Mountain and increased slightly in the eastern region. From the overall changes, the interregional differences in climate change increased in the northern Henan, and local changes were not stable. This paper analyzes the drought occurrence tend by means of temperature and precipitation ratio, and the results show that the drought trend along the Taihang Mountains is obvious, and on the contrary in the region of the Yellow River. The Taihang Mountain and the Yellow River are the main terrain factors caused climate regional distribution in the northern Henan.
This paper analyzes the temporal and spatial distribution characteristics of temperature and precipitation changes in the north part of Henan Province based on GIS technology, using the temperature and precipitation data of 28 observation stations in “Homogenization Dataset of China National Ground Meteorological Station” from 1971 to 2010 in the northern Henan. The results show that the temperature of the northern Henan showed an increasing trend and significant warming in winter and spring. The spatial distribution of temperature variation shows that larger in the northern and central parts and smaller in the eastern and western parts. Seasonal variation of precipitation was relatively large, and precipitation in spring showed increasing trend overall and fluctuated in other seasons. The spatial variation distribution characteristics of precipitation show that precipitation decreased obviously in the western mountain area along the Taihang Mountain and increased slightly in the eastern region. From the overall changes, the interregional differences in climate change increased in the northern Henan, and local changes were not stable. This paper analyzes the drought occurrence tend by means of temperature and precipitation ratio, and the results show that the drought trend along the Taihang Mountains is obvious, and on the contrary in the region of the Yellow River. The Taihang Mountain and the Yellow River are the main terrain factors caused climate regional distribution in the northern Henan.
2016, 44(6):991-997.
Abstract:
Based on the daily maximum temperature data from the Mapoling weather station in Changsha in recent 64 years, with the criteria for recognizing heat wave events, a statistical analysis is conducted on the characteristics of heat wave events over Changsha, so as to strengthen the people’s awareness of heat wave events, and make scientific emergency plans in advance. The study shows that: (1) The numbers of annual averaged high temperature days and heat wave events are 30.6 and 2.16, respectively; high temperature days are more common between June and September than other months; and July is the hottest month. (2) The frequency and intensity of heat wave show a stepwise variation characteristic in the last 64 years: the frequency is basically stable or slightly increasing (strengthening) from the 1950s to the middle 1960s, followed by a decreasing (weakening) from the 1970s to the late 1990s years, and after 2000, significantly increasing; the intensity is also strengthening. (3) The study also found that the urban heat island effect has intensified the heat wave intensity to some extent after 2000.
Based on the daily maximum temperature data from the Mapoling weather station in Changsha in recent 64 years, with the criteria for recognizing heat wave events, a statistical analysis is conducted on the characteristics of heat wave events over Changsha, so as to strengthen the people’s awareness of heat wave events, and make scientific emergency plans in advance. The study shows that: (1) The numbers of annual averaged high temperature days and heat wave events are 30.6 and 2.16, respectively; high temperature days are more common between June and September than other months; and July is the hottest month. (2) The frequency and intensity of heat wave show a stepwise variation characteristic in the last 64 years: the frequency is basically stable or slightly increasing (strengthening) from the 1950s to the middle 1960s, followed by a decreasing (weakening) from the 1970s to the late 1990s years, and after 2000, significantly increasing; the intensity is also strengthening. (3) The study also found that the urban heat island effect has intensified the heat wave intensity to some extent after 2000.
2016, 44(6):998-1003.
Abstract:
The climate characteristics of summer precipitation anomaly in Funshun is investigated by using the monthly NCEP/NCAR reanalysis data and the monthly precipitation observations from the Zhangdang observation station from 1951 to 2012. Using the statistical methods and through the analysis of the characteristics of the atmospheric circulation, the climate characteristics of the summer precipitation anomaly in Fushun are discussed. The results show that summer precipitation in Fushun has obvious interannual scale periodic characteristics, and the more northern (the stronger) the western Pacific subtropical high north border (intensity) is, the stronger the rainfall intensity of the summer precipitation in Fushun area is. In the strong (weak) rainfall years in Fushun, in the 500 hPa height field, Fushun is at the front of the low vortex (high pressure) area; in the 850 hPa wind field, Fushun is controlled by the southwest (north) airflow; in the sea level pressure field, Fushun is located in the front of the bottom of the Mongolia cyclone (anticyclone); in the specific humidity field， Fushun is located in the positive (negative) specific humidity anomaly zone. In strong precipitation years, low temperature anomaly center behind the 500 hPa height field lowvalue centers, conducive to the development of the upper trough, is advantageous to keep strengthening the precipitation; while in weak precipitation years, low temperature anomaly center matching with the 500 hPa height field low center has no obvious influence on the development of upper troughs and ridges.
The climate characteristics of summer precipitation anomaly in Funshun is investigated by using the monthly NCEP/NCAR reanalysis data and the monthly precipitation observations from the Zhangdang observation station from 1951 to 2012. Using the statistical methods and through the analysis of the characteristics of the atmospheric circulation, the climate characteristics of the summer precipitation anomaly in Fushun are discussed. The results show that summer precipitation in Fushun has obvious interannual scale periodic characteristics, and the more northern (the stronger) the western Pacific subtropical high north border (intensity) is, the stronger the rainfall intensity of the summer precipitation in Fushun area is. In the strong (weak) rainfall years in Fushun, in the 500 hPa height field, Fushun is at the front of the low vortex (high pressure) area; in the 850 hPa wind field, Fushun is controlled by the southwest (north) airflow; in the sea level pressure field, Fushun is located in the front of the bottom of the Mongolia cyclone (anticyclone); in the specific humidity field， Fushun is located in the positive (negative) specific humidity anomaly zone. In strong precipitation years, low temperature anomaly center behind the 500 hPa height field lowvalue centers, conducive to the development of the upper trough, is advantageous to keep strengthening the precipitation; while in weak precipitation years, low temperature anomaly center matching with the 500 hPa height field low center has no obvious influence on the development of upper troughs and ridges.
2016, 44(6):1004-1008.
Abstract:
Based on the monthly sunshine dataset from the Lishui observation station from 1953 to 2014, the trend analysis method is used to analyze the interannual, decadal and seasonal trends of sunshine duration, and then the Morlet wavelet transform and MTM (MultiTaper Method) are applied to study the periodic characteristics of sunshine duration, and the significant periodic signals are reconstructed by MTM, to further study the lesssignificant periods on different time scales with the oscillation time of evolution. The results show that sunshine duration exhibits very significant decline trend in Lishui, with a rate of 3.5 percent per 10 years. The maximum sunshine duration is in summer, followed by that in autumn. The Morlet wavelet and MTM analysis results show that quasi12year cycle is the most significant in the whole time domain, with regular alternating positive and negative oscillations and the maximum spectral density; in addition, the cycles of 6 years and 2 to 4 years cycle are also apparent. The MTM reconstruction analysis indicates that the amplitudes of quasi12year periodic signals vary with time, and there are three distinct and slowly varying envelopes.
Based on the monthly sunshine dataset from the Lishui observation station from 1953 to 2014, the trend analysis method is used to analyze the interannual, decadal and seasonal trends of sunshine duration, and then the Morlet wavelet transform and MTM (MultiTaper Method) are applied to study the periodic characteristics of sunshine duration, and the significant periodic signals are reconstructed by MTM, to further study the lesssignificant periods on different time scales with the oscillation time of evolution. The results show that sunshine duration exhibits very significant decline trend in Lishui, with a rate of 3.5 percent per 10 years. The maximum sunshine duration is in summer, followed by that in autumn. The Morlet wavelet and MTM analysis results show that quasi12year cycle is the most significant in the whole time domain, with regular alternating positive and negative oscillations and the maximum spectral density; in addition, the cycles of 6 years and 2 to 4 years cycle are also apparent. The MTM reconstruction analysis indicates that the amplitudes of quasi12year periodic signals vary with time, and there are three distinct and slowly varying envelopes.
24 Diagnostic Analysis of a Meiyu Heavy Rain in Northeast HubeiProvince by Using Divergence Equation
2016, 44(6):1009-1015.
Abstract:
By using the 0.5°×0.5° GFS and conventional observational data, a Meiyu heavy rain took place from 5 to 7 in July 2013 over the northeastern Hubei Province is analyzed.The results show: (1) The rainfall has obvious diurnal variations: increased at night and decreased in the day time; the convergence at low levels had the same tendency with that of the rainfall.(2) Positive divergence variability at upper levels and negative divergence variability at middle and low levels were favorable to rainfall increase. These changes were ahead of the heavy rainfall. Negative divergence variability at low levels began in the evening, which was helpful to the convergence increase at low levels at night.(3) By the divergence equation with twoitem combination, it is found that although the deviation of the nonlinear balance equation is the main item of divergence variability, the remainder is the only item whose value became obviously negative in the beginning stage of the heavy rain. (4) By the divergence equation with fouritem combination, it is found that the convergence in the boundary layer was one of the rain trigger factor; the ageostrophic equilibrium item with large positive value in the near surface indicated the weakening of the rain well; and item in connection with upward motion had large negative values at the middle levels in the peak rain stage.
By using the 0.5°×0.5° GFS and conventional observational data, a Meiyu heavy rain took place from 5 to 7 in July 2013 over the northeastern Hubei Province is analyzed.The results show: (1) The rainfall has obvious diurnal variations: increased at night and decreased in the day time; the convergence at low levels had the same tendency with that of the rainfall.(2) Positive divergence variability at upper levels and negative divergence variability at middle and low levels were favorable to rainfall increase. These changes were ahead of the heavy rainfall. Negative divergence variability at low levels began in the evening, which was helpful to the convergence increase at low levels at night.(3) By the divergence equation with twoitem combination, it is found that although the deviation of the nonlinear balance equation is the main item of divergence variability, the remainder is the only item whose value became obviously negative in the beginning stage of the heavy rain. (4) By the divergence equation with fouritem combination, it is found that the convergence in the boundary layer was one of the rain trigger factor; the ageostrophic equilibrium item with large positive value in the near surface indicated the weakening of the rain well; and item in connection with upward motion had large negative values at the middle levels in the peak rain stage.
2016, 44(6):1016-1023.
Abstract:
Using theconventional meteorological data, NCEP reanalysis data (horizontal resolution 1°×1°), FY2E satellite images and TBB data, the heavy rain process happened on 7 and 8 July 2014 is studied in detail from the meteorological diagnostic analysis angle, which was caused by Northeast Cold Vortex and produced an effect on the northeast of Inner Mongolia. The main results are: (1) The main water vapor were carried by the Low level jet stream. Different regions had different formation mechanisms of heavy rainfall. The Eastern Xingan Meng and Hulun Beir are found to be located at front of trough and nearby the surface warm front in the south of the shear line, where were the high incidence area of severe weather caused by the instability energy release of strong convergence uplifting. However, the heavy rain happed at the southwest of Hulun Beir was closely associated with the germination and development of the cold vortex and the dynamic effect of the ground low pressure system. (2) The distribution of moist potential vorticity (MPV) is of very good instructive significance for heavy rain occurrence and precipitation area. The heavy rainfall occurred in the superimposed region of the area of anomalously dense isopleths of 700 hPa and the area of MPV2 ≥ 0 at 850 hPa. (3) The maximum rainfall intensity appeared 1 or 2 hours behind the minimum TBB, and the maximum TBB and rainfall intensity did not occur in the same time.
Using theconventional meteorological data, NCEP reanalysis data (horizontal resolution 1°×1°), FY2E satellite images and TBB data, the heavy rain process happened on 7 and 8 July 2014 is studied in detail from the meteorological diagnostic analysis angle, which was caused by Northeast Cold Vortex and produced an effect on the northeast of Inner Mongolia. The main results are: (1) The main water vapor were carried by the Low level jet stream. Different regions had different formation mechanisms of heavy rainfall. The Eastern Xingan Meng and Hulun Beir are found to be located at front of trough and nearby the surface warm front in the south of the shear line, where were the high incidence area of severe weather caused by the instability energy release of strong convergence uplifting. However, the heavy rain happed at the southwest of Hulun Beir was closely associated with the germination and development of the cold vortex and the dynamic effect of the ground low pressure system. (2) The distribution of moist potential vorticity (MPV) is of very good instructive significance for heavy rain occurrence and precipitation area. The heavy rainfall occurred in the superimposed region of the area of anomalously dense isopleths of 700 hPa and the area of MPV2 ≥ 0 at 850 hPa. (3) The maximum rainfall intensity appeared 1 or 2 hours behind the minimum TBB, and the maximum TBB and rainfall intensity did not occur in the same time.
2016, 44(6):1024-1029.
Abstract:
The synoptic situation, formation and disappearance causes, and correlation between visibility and meteorological elements are analyzed in detail for a drizzlelike fog occurred in Tai’an in the summer of 2011, by using the data collected by traffic meteorological observation stations, the surface meteorological observation stations, and GFS from 2011 to 2014. As a result, the following conclusions are reported: (1) In Tai’an, drizzlelike fogs mostly occur at night and early morning in summer and autumn during 2011-2014. All drizzlelike fogs had a duration of less than 3 hours, and the lowest visibility is generally above 500 m. (2) As for the drizzlelike fog on 22 June 2011, the convergence and lifting of the southerly airstream on the south side of Taishan Mountain are important contributors of the drizzlelike fog, and the evaporation is the primary cause of the drizzlelike fog. The weaker precipitation supported its maintaining. (3) The inverse correlation of humidity and visibility is stronger, but the humidity did not fluctuate with visibility. The very low wind speed, less than 2 m/s, the lower inversion layer, weaker temperature inversion, and the radiation cooling effect were found during the event.
The synoptic situation, formation and disappearance causes, and correlation between visibility and meteorological elements are analyzed in detail for a drizzlelike fog occurred in Tai’an in the summer of 2011, by using the data collected by traffic meteorological observation stations, the surface meteorological observation stations, and GFS from 2011 to 2014. As a result, the following conclusions are reported: (1) In Tai’an, drizzlelike fogs mostly occur at night and early morning in summer and autumn during 2011-2014. All drizzlelike fogs had a duration of less than 3 hours, and the lowest visibility is generally above 500 m. (2) As for the drizzlelike fog on 22 June 2011, the convergence and lifting of the southerly airstream on the south side of Taishan Mountain are important contributors of the drizzlelike fog, and the evaporation is the primary cause of the drizzlelike fog. The weaker precipitation supported its maintaining. (3) The inverse correlation of humidity and visibility is stronger, but the humidity did not fluctuate with visibility. The very low wind speed, less than 2 m/s, the lower inversion layer, weaker temperature inversion, and the radiation cooling effect were found during the event.
2016, 44(6):1030-1036.
Abstract:
Based on the equalization conception of basic public weather services, considering relevant research results, we selected the statistical data of 2013, summarizing 10 indicators, and divided into three categories with factor analysis. Then we build a multilevel evaluation index system of equalization of basic public weather services. According to AHP to construct the hierarchical graph, we quantitatively calculated the relative weights of the factors of the rule layer and the index layer by consulting the experts to obtain judgment matrix. Through the application of grey relational comprehensive evaluation model, we conducted an empirical analysis of the national 31 provincial equalization of basic public weather services in 2013. The results show that the overall level of the equalization of basic public weather services in China is low, and the unbalanced provincial development, ladder features from East, Central, and West China are found. Provinces can be divided into three levels: high, medium, and low. Besides, there is positive correlation between the level of the equalization and the provincial economic strength, financial revenue scale, and comprehensive development capacity.
Based on the equalization conception of basic public weather services, considering relevant research results, we selected the statistical data of 2013, summarizing 10 indicators, and divided into three categories with factor analysis. Then we build a multilevel evaluation index system of equalization of basic public weather services. According to AHP to construct the hierarchical graph, we quantitatively calculated the relative weights of the factors of the rule layer and the index layer by consulting the experts to obtain judgment matrix. Through the application of grey relational comprehensive evaluation model, we conducted an empirical analysis of the national 31 provincial equalization of basic public weather services in 2013. The results show that the overall level of the equalization of basic public weather services in China is low, and the unbalanced provincial development, ladder features from East, Central, and West China are found. Provinces can be divided into three levels: high, medium, and low. Besides, there is positive correlation between the level of the equalization and the provincial economic strength, financial revenue scale, and comprehensive development capacity.
2016, 44(6):1037-1042.
Abstract:
In order to study the probability distribution characteristics of lightning peak current and the fitting effectiveness of cumulative probability for peak current, and the demands of lightning protection engineering design and lightning risk assessment, this article utilizes the peak current data observed by the LLS (Lightning Location System) from 2007 to 2013 to analyze the distribution characteristics of probability and density for peak current. The results show that there is a big difference in the cumulative probabilities for different polar peak currents; the distribution of negative lightning is more concentrated than that of positive lightning; the distribution curve of peak current cumulative probability for negative lightning is basically the same with the total one; and the peak currents of lightning are concentrated mostly in 10 to 50 kA. According to the distribution expression suggested by IEEE for cumulative probability of peak currents, this article fits the distribution expression of cumulative probability for different polar peak currents. The statistical analysis shows that when the peak current is less than 110 kA, the relative error between fitting cumulative probability calculated by the fitting expression of IEEE and the actual one is small, but when the peak current is above 110 kA, the error increases with the peak current. According to the segment revision expression given by this article, with the peak current being above 110 kA, the error between calculated cumulative probability and the actual one is less than 2%. When use the expression suggested by IEEE to fit the cumulative probability and density of peak currents, the fitting effectiveness for negative lightning and total one is better than the positive one. The reason seems to be connected with the distribution characteristics of positive lightning.
In order to study the probability distribution characteristics of lightning peak current and the fitting effectiveness of cumulative probability for peak current, and the demands of lightning protection engineering design and lightning risk assessment, this article utilizes the peak current data observed by the LLS (Lightning Location System) from 2007 to 2013 to analyze the distribution characteristics of probability and density for peak current. The results show that there is a big difference in the cumulative probabilities for different polar peak currents; the distribution of negative lightning is more concentrated than that of positive lightning; the distribution curve of peak current cumulative probability for negative lightning is basically the same with the total one; and the peak currents of lightning are concentrated mostly in 10 to 50 kA. According to the distribution expression suggested by IEEE for cumulative probability of peak currents, this article fits the distribution expression of cumulative probability for different polar peak currents. The statistical analysis shows that when the peak current is less than 110 kA, the relative error between fitting cumulative probability calculated by the fitting expression of IEEE and the actual one is small, but when the peak current is above 110 kA, the error increases with the peak current. According to the segment revision expression given by this article, with the peak current being above 110 kA, the error between calculated cumulative probability and the actual one is less than 2%. When use the expression suggested by IEEE to fit the cumulative probability and density of peak currents, the fitting effectiveness for negative lightning and total one is better than the positive one. The reason seems to be connected with the distribution characteristics of positive lightning.
2016, 44(6):1043-1052.
Abstract:
The key point of ground burner rain enhancement is the updrafts around the operation site. The layout conditions and operating conditions are analyzed with automatic meteorological station data from Bawangling of Changjiang, Yulongshan of Dongfang, Fuguang of Ledong, and Maoyang of Wuzhishan in Hainnan Province， as well as the Doppler radar data of Haikou, and the terrain characteristics of operation sites, and the catalyst diffusion is simulated using the Gaussian model. Results show that the four ground burners are on the highaltitude windward slope, where updrafts can take catalysts into clouds. By means of the comprehensive utilization of NCEP/NCAR reanalysis data, MICAPS data, and radar data to determine the operation time and to carry out the warm cloud seeding, the effectiveness of precipitation enhancement is obvious.
The key point of ground burner rain enhancement is the updrafts around the operation site. The layout conditions and operating conditions are analyzed with automatic meteorological station data from Bawangling of Changjiang, Yulongshan of Dongfang, Fuguang of Ledong, and Maoyang of Wuzhishan in Hainnan Province， as well as the Doppler radar data of Haikou, and the terrain characteristics of operation sites, and the catalyst diffusion is simulated using the Gaussian model. Results show that the four ground burners are on the highaltitude windward slope, where updrafts can take catalysts into clouds. By means of the comprehensive utilization of NCEP/NCAR reanalysis data, MICAPS data, and radar data to determine the operation time and to carry out the warm cloud seeding, the effectiveness of precipitation enhancement is obvious.
2016, 44(6):1053-1059.
Abstract:
A ground precipitation enhancement was conducted on 28 September 2014 in Shandong. By means of CINRA radar and radiosonde data and 10min automatic precipitation, using the methods of contrast clouds and radar tracking target clouds, the relation between radar responses and rainfall after the precipitation enhancement operation is discussed. The results indicate that the cloud top of the target cloud began to rise 13 min after seeding; the target cloud echo strengthened 3 dBz 19 min after seeding; the target cloud VIL increased from 2.5 kg/m2 to 3 kg/m2 25 min after seeding. The 10 min precipitation at three rainfall stations that the target cloud passed had the same increasing trend, and the analysis from the time and location indicates that these changes are associated with the rocket artificial precipitation.
A ground precipitation enhancement was conducted on 28 September 2014 in Shandong. By means of CINRA radar and radiosonde data and 10min automatic precipitation, using the methods of contrast clouds and radar tracking target clouds, the relation between radar responses and rainfall after the precipitation enhancement operation is discussed. The results indicate that the cloud top of the target cloud began to rise 13 min after seeding; the target cloud echo strengthened 3 dBz 19 min after seeding; the target cloud VIL increased from 2.5 kg/m2 to 3 kg/m2 25 min after seeding. The 10 min precipitation at three rainfall stations that the target cloud passed had the same increasing trend, and the analysis from the time and location indicates that these changes are associated with the rocket artificial precipitation.
2016, 44(6):1060-1065.
Abstract:
Based on the tea planting area of 78 counties from 1980 to 2014, the paper divided the tea base counties into three main growing areas in Anhui province. Using the data of daily minimum temperature from 1980 to 2014 in the tea base counties， the last frost dates， the spring frost days, and the occurrence frequency of different grade frosts are calculated and its distribution characteristics are analyzed. The results show that the averaged last frost dates in the south is earlier than those in north, with the earliest occurred on 21 March, the latest on 6 April. In the three main growing areas, the Dabie mountain area has the most spring frost days, and Xuancheng is the next, and then Huangshan. The dates of extremelate frost and late frosts in Xuancheng appear obviously later than that in the Dabie Mountain and Huangshan. The extremely late frost mainly occurred in the 1980’s, and occurred only once in 2000. The late frosts appeared mainly in the 1980’s and 1990’s, and occurred only once after 2000. In recent 35 years, mild spring frost had the highest frequency in the Dabie Mountain (Lu’an), while moderate and severe spring frost had the highest frequency in Xuancheng (Jixi). The occurring frequencies of mild, moderate and severe spring frost show a declining trend. The tea frost damage risk in the base counties is analyzed according to the theory of risk analysis and the spatial distribution features are obtained. The conclusion can be a reference for disaster prevention and reduction.
Based on the tea planting area of 78 counties from 1980 to 2014, the paper divided the tea base counties into three main growing areas in Anhui province. Using the data of daily minimum temperature from 1980 to 2014 in the tea base counties， the last frost dates， the spring frost days, and the occurrence frequency of different grade frosts are calculated and its distribution characteristics are analyzed. The results show that the averaged last frost dates in the south is earlier than those in north, with the earliest occurred on 21 March, the latest on 6 April. In the three main growing areas, the Dabie mountain area has the most spring frost days, and Xuancheng is the next, and then Huangshan. The dates of extremelate frost and late frosts in Xuancheng appear obviously later than that in the Dabie Mountain and Huangshan. The extremely late frost mainly occurred in the 1980’s, and occurred only once in 2000. The late frosts appeared mainly in the 1980’s and 1990’s, and occurred only once after 2000. In recent 35 years, mild spring frost had the highest frequency in the Dabie Mountain (Lu’an), while moderate and severe spring frost had the highest frequency in Xuancheng (Jixi). The occurring frequencies of mild, moderate and severe spring frost show a declining trend. The tea frost damage risk in the base counties is analyzed according to the theory of risk analysis and the spatial distribution features are obtained. The conclusion can be a reference for disaster prevention and reduction.
2016, 44(6):1066-1070.
Abstract:
Based on early spring (February to April) daily temperature from 7 county observation stations in the southern Zhejiang from 1971 to 2015, according to meteorological disaster indexes of early spring frost for tea, the multiscale trend method is used to analyze the temporal and spatial characteristics of early spring frost for spring tea in the southern Zhejiang and the MannKendall test is applied to verify the trend, mutations and turning of early spring frost weather. The results show that the probability of early spring frosts occurred in the southern Zhejiang is high with an annual mean of 16.8 d/a; the highest occurrence probability in February, mainly consisting of minor and severe frosts; as for the spatial distribution of early spring frost, the probability increases from southeast to northwest, the lowest in Qingtian, and the highest in Jinyun. The longterm trend of early spring frost days for spring tea shows a significant decreasing trend, and the extreme minimum temperature rose significantly, with the possibility of early spring frost reducing in the southern Zhejiang. The mutation of early spring frost reduction occurred in the 1980s and 1990s in the southern Zhejiang, and the decreasing trend was the most significant in the early 21th century.
Based on early spring (February to April) daily temperature from 7 county observation stations in the southern Zhejiang from 1971 to 2015, according to meteorological disaster indexes of early spring frost for tea, the multiscale trend method is used to analyze the temporal and spatial characteristics of early spring frost for spring tea in the southern Zhejiang and the MannKendall test is applied to verify the trend, mutations and turning of early spring frost weather. The results show that the probability of early spring frosts occurred in the southern Zhejiang is high with an annual mean of 16.8 d/a; the highest occurrence probability in February, mainly consisting of minor and severe frosts; as for the spatial distribution of early spring frost, the probability increases from southeast to northwest, the lowest in Qingtian, and the highest in Jinyun. The longterm trend of early spring frost days for spring tea shows a significant decreasing trend, and the extreme minimum temperature rose significantly, with the possibility of early spring frost reducing in the southern Zhejiang. The mutation of early spring frost reduction occurred in the 1980s and 1990s in the southern Zhejiang, and the decreasing trend was the most significant in the early 21th century.
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