Volume 38,Issue 4,2010 Table of Contents
2010, 38(4):403-408.
Abstract:
Accurate description of the cloud vertical layer structure is of primary importance for the Numerical Weather Prediction Model to get accurate parameters like longwave, shortwave radiation fluxes, radiation heating rate profile, cloud reflection, cloud radiation effect. However, the cloud vertical structure can not be validated by the data observed on the ground. The occurrence frequencies of high, middle, low clouds and cloud top pressure retrieved from a uptodate algorithm (classifying cloud vertical layer structure), applied with MODIS cloud product MOD06 (Collection 5), are used to evaluate the results from the NCEP North American Mesoscale model (NAM). The evaluation results from the scope of (153° to 48°W, 12° to 62°N), July to October, 2006 show: (1) The distribution patterns of high, middle, and low clouds retrieved from satellite products and model are similar, especially for high clouds. Over the tropical Pacific, the model shows greater high cloud amount than the satellite scene. The model data shows much more low cloud cover over Mexico, the North American continent, and the Atlantic Ocean, and the middle cloud cover is less than high cloud cover. (2) There is the least difference in the occurrence frequencies of middle clouds between satellite retrieval and model results. Peaks for high and low clouds seen in NAM outputs are sharper and higher than those from the satellite retrieval. (3) The latitudemean middle and low cloud amounts from the model are greater than those generated form the satellite retrieval and more noticeably for low clouds. The cloud parameterization in NCEP NAM needs to be improved.
Accurate description of the cloud vertical layer structure is of primary importance for the Numerical Weather Prediction Model to get accurate parameters like longwave, shortwave radiation fluxes, radiation heating rate profile, cloud reflection, cloud radiation effect. However, the cloud vertical structure can not be validated by the data observed on the ground. The occurrence frequencies of high, middle, low clouds and cloud top pressure retrieved from a uptodate algorithm (classifying cloud vertical layer structure), applied with MODIS cloud product MOD06 (Collection 5), are used to evaluate the results from the NCEP North American Mesoscale model (NAM). The evaluation results from the scope of (153° to 48°W, 12° to 62°N), July to October, 2006 show: (1) The distribution patterns of high, middle, and low clouds retrieved from satellite products and model are similar, especially for high clouds. Over the tropical Pacific, the model shows greater high cloud amount than the satellite scene. The model data shows much more low cloud cover over Mexico, the North American continent, and the Atlantic Ocean, and the middle cloud cover is less than high cloud cover. (2) There is the least difference in the occurrence frequencies of middle clouds between satellite retrieval and model results. Peaks for high and low clouds seen in NAM outputs are sharper and higher than those from the satellite retrieval. (3) The latitudemean middle and low cloud amounts from the model are greater than those generated form the satellite retrieval and more noticeably for low clouds. The cloud parameterization in NCEP NAM needs to be improved.
2010, 38(4):409-412.
Abstract:
With the data of wind profile Radar in Tangshan, the stratiform precipitation occurred on 12 February 2009 is analyzed. The results show that windprofiler radar can observe the disturbance of cold or warm shearing and the downward expanding of a jet stream. These small disturbances and downward expanding would enhance and maintain the precipitation. The enhancing of the vertical shear and the strong sinking air indicate the beginning of precipitation. The invasion of northerly winds at lower levels and the disappearance of the strong sinking air indicate the ending of precipitation.
With the data of wind profile Radar in Tangshan, the stratiform precipitation occurred on 12 February 2009 is analyzed. The results show that windprofiler radar can observe the disturbance of cold or warm shearing and the downward expanding of a jet stream. These small disturbances and downward expanding would enhance and maintain the precipitation. The enhancing of the vertical shear and the strong sinking air indicate the beginning of precipitation. The invasion of northerly winds at lower levels and the disappearance of the strong sinking air indicate the ending of precipitation.
2010, 38(4):413-417.
Abstract:
The basic detection performance of four wind profiler radar sets of Beijing Meteorological Bureau is introduced. The application of newtype observation data in meteorological forecast service is discussed, with emphases on the secondary development of profiler data according to the atmospheric physics equations, taking two weather processes occurred on August 2009 as examples. In comparison with the base data of wind profiler, the redeveloped data derived from base data are more indicative in describing the occurrence and development of weather systems, can help improve the accuracy of shortterm weather forecasting and nowcasting.
The basic detection performance of four wind profiler radar sets of Beijing Meteorological Bureau is introduced. The application of newtype observation data in meteorological forecast service is discussed, with emphases on the secondary development of profiler data according to the atmospheric physics equations, taking two weather processes occurred on August 2009 as examples. In comparison with the base data of wind profiler, the redeveloped data derived from base data are more indicative in describing the occurrence and development of weather systems, can help improve the accuracy of shortterm weather forecasting and nowcasting.
2010, 38(4):418-422.
Abstract:
The Z index is widely used in flood statistics. Taking into account the temporal and spatial characteristics of flood disasters in small drainage areas, the 10day continuous rainfall proved to be more realistic and reasonable for calculating Z index. Through determining the flood disaster index of a single station and then compared with the traditional index, it is found that the new method can make up the deficiencies of the traditional one and describe the strength and starting and ending times of flood disasters. The flood disaster index computed by means of the new method can well fit the historical flood disaster cases over small drainage areas
The Z index is widely used in flood statistics. Taking into account the temporal and spatial characteristics of flood disasters in small drainage areas, the 10day continuous rainfall proved to be more realistic and reasonable for calculating Z index. Through determining the flood disaster index of a single station and then compared with the traditional index, it is found that the new method can make up the deficiencies of the traditional one and describe the strength and starting and ending times of flood disasters. The flood disaster index computed by means of the new method can well fit the historical flood disaster cases over small drainage areas
2010, 38(4):423-426.
Abstract:
Electric field instruments were used to measure the electric fields on the ground from June to October 2008 in Tianjin. The variations of the electric fields under such weather conditions as clear sky, stable rainfall, squall line, and heavy rainfall are discussed and analyzed. Combining with Doppler radar and lightning positioning data, the squall line process on 4 September 2008 and the rainstorm process on 14 July 2008 are analyzed. It is found that the atmospheric electric field data, which exhibit a jitter 15 to 45 minutes before the occurring of a thunderstorm, are highly indicative in strong convective weather monitoring and early warning; the combined use of radar and lightning positioning data can effectively improve the accuracy of thunder and lightning warning and forecasts; the multipoint atmospheric electric field detection can expand the monitoring range, and the electric field data can be used to determine the path of thunderstorms.
Electric field instruments were used to measure the electric fields on the ground from June to October 2008 in Tianjin. The variations of the electric fields under such weather conditions as clear sky, stable rainfall, squall line, and heavy rainfall are discussed and analyzed. Combining with Doppler radar and lightning positioning data, the squall line process on 4 September 2008 and the rainstorm process on 14 July 2008 are analyzed. It is found that the atmospheric electric field data, which exhibit a jitter 15 to 45 minutes before the occurring of a thunderstorm, are highly indicative in strong convective weather monitoring and early warning; the combined use of radar and lightning positioning data can effectively improve the accuracy of thunder and lightning warning and forecasts; the multipoint atmospheric electric field detection can expand the monitoring range, and the electric field data can be used to determine the path of thunderstorms.
2010, 38(4):427-431.
Abstract:
Two heavy fog processes occurred in March and June 2008 in Dalian and the coastal areas are analyzed by using the sounding data from GTS1 digital radiosondes, conventional observation data, and automatically observed visibility data. The structural features of ABL temperature and wind fields are analyzed. The results show that both radiative fog and advective fog usually form under the conditions of zonal circulation, abundant water vapor and appropriate thermal state supplied by the middlelevel southeast wind. However, there is obvious difference between them. The advection cooling near the surface by the northeasterly wind is an important condition for the formation of radiation fog, leading to the dispersion of advection fog. The surface southeast wind is a condition for the generation of advection fog, but it contributes to the disappearance of radiation fogs. The inversion in the radiation fog is thick and strong, but weaker or no inversion in advection fogs. Radiation fogs evolve from occurrence to dispersion while the stratification varies from stable to unstable, but from unstable to stable for advection fogs.
Two heavy fog processes occurred in March and June 2008 in Dalian and the coastal areas are analyzed by using the sounding data from GTS1 digital radiosondes, conventional observation data, and automatically observed visibility data. The structural features of ABL temperature and wind fields are analyzed. The results show that both radiative fog and advective fog usually form under the conditions of zonal circulation, abundant water vapor and appropriate thermal state supplied by the middlelevel southeast wind. However, there is obvious difference between them. The advection cooling near the surface by the northeasterly wind is an important condition for the formation of radiation fog, leading to the dispersion of advection fog. The surface southeast wind is a condition for the generation of advection fog, but it contributes to the disappearance of radiation fogs. The inversion in the radiation fog is thick and strong, but weaker or no inversion in advection fogs. Radiation fogs evolve from occurrence to dispersion while the stratification varies from stable to unstable, but from unstable to stable for advection fogs.
2010, 38(4):432-436.
Abstract:
A wholeprovince range thunderstorm occurred in Zhejiang Province on 26 June 2009, and the occurrence frequency of cloudtoground lightning in this thunderstorm is the highest since the establishment of the lightning position system in 2006. By means of the observation data from the lightning position system, the intensive rainfall observation system, and Doppler radar, the characteristics of the cloudtoground lightning process are analyzed. The results indicate that lightning strokes were mainly negative; in the lightning echo image, negative strokes were mostly distributed in the area of 25 dBz to 55 dBz, and positive strokes were usually in the area of 25 dBz to 35 dBz; lightning strokes occurred mostly on the side of echo development or advancement, distributed around the area with maximum gradients, and there seldom appeared lightning strokes around a strong echo center; the frequency of cloudtoground lightning was correlated closely with the accumulated precipitation of the whole province during the thunderstorm. The peak value of precipitation lagged more than 0.5 hour behind the peak value of the frequency of cloudtoground lightning, and the accumulated precipitation of the whole province occurred 1 to 2 hours behind the peak value of the frequency of cloudtoground lightning. Therefore, the cloudtoground lightning data can be used as a basis in shortrange severe precipitation forecasting.
A wholeprovince range thunderstorm occurred in Zhejiang Province on 26 June 2009, and the occurrence frequency of cloudtoground lightning in this thunderstorm is the highest since the establishment of the lightning position system in 2006. By means of the observation data from the lightning position system, the intensive rainfall observation system, and Doppler radar, the characteristics of the cloudtoground lightning process are analyzed. The results indicate that lightning strokes were mainly negative; in the lightning echo image, negative strokes were mostly distributed in the area of 25 dBz to 55 dBz, and positive strokes were usually in the area of 25 dBz to 35 dBz; lightning strokes occurred mostly on the side of echo development or advancement, distributed around the area with maximum gradients, and there seldom appeared lightning strokes around a strong echo center; the frequency of cloudtoground lightning was correlated closely with the accumulated precipitation of the whole province during the thunderstorm. The peak value of precipitation lagged more than 0.5 hour behind the peak value of the frequency of cloudtoground lightning, and the accumulated precipitation of the whole province occurred 1 to 2 hours behind the peak value of the frequency of cloudtoground lightning. Therefore, the cloudtoground lightning data can be used as a basis in shortrange severe precipitation forecasting.
2010, 38(4):437-443.
Abstract:
Based on the monthly NCEP/NCAR reanalysis data of 1950 to 2005, by using the rotated empirical orthogonal function, the leading mode of the lowerlevel Asiapacific atmosphere is extracted, putting emphasis on the interdecade variation characteristics of the coupled mode of the lowerlevel atmosphere and the relation with the interdecade variation of East Asian Summer Monsoon. It is found that there was a remarkable zonal geopotential gradient in the lower troposphere over East Asia and the subtropical Pacific. The first mode of REOF (REOF1) shows that there was a positive center at the midhigh latitudes of East Asia and a negative center in the subtropical Pacific. Corresponding to it, there was a low pressure around Mongolia and a high pressure in the subtropical Pacific during summer, their coupling variation evidently influencing East Asian Summer Monsoon. It can be seen from the time coefficients of REOF1 that there was a remarkable interdecade variation at the negative phase from 1950 to the middle 1960s, corresponding to a stronger low pressure around Mongolia and stronger high pressure over the subtropical Pacific; the coupled mode was at positive phase after the middle 1970s, corresponding to a weaker low pressure around Mongolia and a weaker high pressure over the subtropical Pacific, and at the alternate positive and negative phases from the middle 1960s to the middle 1970s. There was rather close negative correlation between REOF1 and East Asian subtropical summer monsoon, including zonal and meridional winds, especially meridional wind. The composite analyses show that when REOF1 was at the negative phase (from 1950 to the middle 1960s), there was southerly wind anomalies in the lower troposphere over the subtropics and middle latitudes of East Asia, corresponding to the stronger East Asian subtropical summer monsoon; when the REOF1 at the positive phase (from the middle 1970s to 2005), there was northerly wind anomalies in the lower troposphere over the subtropics and middle latitudes of East Asia, corresponding to the weaker East Asian subtropical summer monsoon.
Based on the monthly NCEP/NCAR reanalysis data of 1950 to 2005, by using the rotated empirical orthogonal function, the leading mode of the lowerlevel Asiapacific atmosphere is extracted, putting emphasis on the interdecade variation characteristics of the coupled mode of the lowerlevel atmosphere and the relation with the interdecade variation of East Asian Summer Monsoon. It is found that there was a remarkable zonal geopotential gradient in the lower troposphere over East Asia and the subtropical Pacific. The first mode of REOF (REOF1) shows that there was a positive center at the midhigh latitudes of East Asia and a negative center in the subtropical Pacific. Corresponding to it, there was a low pressure around Mongolia and a high pressure in the subtropical Pacific during summer, their coupling variation evidently influencing East Asian Summer Monsoon. It can be seen from the time coefficients of REOF1 that there was a remarkable interdecade variation at the negative phase from 1950 to the middle 1960s, corresponding to a stronger low pressure around Mongolia and stronger high pressure over the subtropical Pacific; the coupled mode was at positive phase after the middle 1970s, corresponding to a weaker low pressure around Mongolia and a weaker high pressure over the subtropical Pacific, and at the alternate positive and negative phases from the middle 1960s to the middle 1970s. There was rather close negative correlation between REOF1 and East Asian subtropical summer monsoon, including zonal and meridional winds, especially meridional wind. The composite analyses show that when REOF1 was at the negative phase (from 1950 to the middle 1960s), there was southerly wind anomalies in the lower troposphere over the subtropics and middle latitudes of East Asia, corresponding to the stronger East Asian subtropical summer monsoon; when the REOF1 at the positive phase (from the middle 1970s to 2005), there was northerly wind anomalies in the lower troposphere over the subtropics and middle latitudes of East Asia, corresponding to the weaker East Asian subtropical summer monsoon.
2010, 38(4):444-449.
Abstract:
With the 57year Tropical Cyclone (TC) data from 1950 to 2006, the climatic characteristics of TCs influencing Zhejiang are analyzed. The results indicate that since the 1990s, the TCs influencing or landing Zhejiang show a increasing trend, which is different from the decreasing trend of TCs influencing or landing on the whole China. In TCs both influencing and landing on Zhejiang there exist variation with the long periods being quasi15 years and quasi25 years, and the short periods being the quasi5 years and quasi8 years, respectively. The average source region is more northward and eastward for TCs influencing Zhejiang than those influencing China, which is more westward and northward than normal from the 1990s. In addition, the East Asian circulation factors during July and September are analyzed, and the results show that the structure of the circulation system in the years with more TCs influencing Zhejiang is much different from the years with less TCs influencing Zhejiang.
With the 57year Tropical Cyclone (TC) data from 1950 to 2006, the climatic characteristics of TCs influencing Zhejiang are analyzed. The results indicate that since the 1990s, the TCs influencing or landing Zhejiang show a increasing trend, which is different from the decreasing trend of TCs influencing or landing on the whole China. In TCs both influencing and landing on Zhejiang there exist variation with the long periods being quasi15 years and quasi25 years, and the short periods being the quasi5 years and quasi8 years, respectively. The average source region is more northward and eastward for TCs influencing Zhejiang than those influencing China, which is more westward and northward than normal from the 1990s. In addition, the East Asian circulation factors during July and September are analyzed, and the results show that the structure of the circulation system in the years with more TCs influencing Zhejiang is much different from the years with less TCs influencing Zhejiang.
2010, 38(4):450-455.
Abstract:
An introduction is made to two different instruments for measuring ground surface temperature. Based on the ground surface temperature data observed by the two instruments in the Xilinhaote National Climate Observatory from January 2007 to February 2008， the differences between the two observed data in different weather conditions are analyzed and compared. The results show that the difference was mainly influenced by solar radiation and the conditions of the underlying surface. At high temperature in Summer, the difference, affected greatly by solar radiation, was considerable large in daytime， and relatively small in night. At low temperature in winter, the difference was small and the data were of good comparability. The results also show that the two sets of measurements tend to be close when it rains. However, the difference increases with the depth of the snow.
An introduction is made to two different instruments for measuring ground surface temperature. Based on the ground surface temperature data observed by the two instruments in the Xilinhaote National Climate Observatory from January 2007 to February 2008， the differences between the two observed data in different weather conditions are analyzed and compared. The results show that the difference was mainly influenced by solar radiation and the conditions of the underlying surface. At high temperature in Summer, the difference, affected greatly by solar radiation, was considerable large in daytime， and relatively small in night. At low temperature in winter, the difference was small and the data were of good comparability. The results also show that the two sets of measurements tend to be close when it rains. However, the difference increases with the depth of the snow.
2010, 38(4):456-462.
Abstract:
The variation features of GPSretrieved atmospheric Precipitable Water Vapor (PWV) are analyzed, and a comparison is conducted on the radiosonde observations and the retrieved precipitation (PWV) in Yunnan. The results show that PWV can be used to reflect the seasonal characteristics of precipitation, and the values of PWV from lower elevation stations are generally higher than those of higher elevation stations in the same period; the changing trends of PWV and radiosonde observations are basically the same, and the correlation coefficient is approximately 0.89; the variation periods of PWV and precipitation are also identical, with the precipitation starting mostly following the peak after a consecutive increasing of PWV; the large increasing amplitude (or keeping at high level) of PWV can be used as an indicator for forecasting continuous heavy precipitation, but when the peak value of PWV is used as a forecasting indicator, seasonal factors should be considered also.
The variation features of GPSretrieved atmospheric Precipitable Water Vapor (PWV) are analyzed, and a comparison is conducted on the radiosonde observations and the retrieved precipitation (PWV) in Yunnan. The results show that PWV can be used to reflect the seasonal characteristics of precipitation, and the values of PWV from lower elevation stations are generally higher than those of higher elevation stations in the same period; the changing trends of PWV and radiosonde observations are basically the same, and the correlation coefficient is approximately 0.89; the variation periods of PWV and precipitation are also identical, with the precipitation starting mostly following the peak after a consecutive increasing of PWV; the large increasing amplitude (or keeping at high level) of PWV can be used as an indicator for forecasting continuous heavy precipitation, but when the peak value of PWV is used as a forecasting indicator, seasonal factors should be considered also.
2010, 38(4):463-466.
Abstract:
The structure and format of 713model radar data, Plain Position Indicator (PPI) and Range Height Indicator (RHI), are introduced briefly. After fully analyzing, the interpretation of radar data is completed accurately by using Visual Basic.NET 2005. Selecting MapX as the secondary development components, the geovisualization of radar data by both line and region is realized under the polar coordinate system, including PPI and RHI, by means of the traditional algorithms of creating radar images. The method can recover, to the utmost, the echo information of radar data and provide an accurate analysis basis for regional precipitation.
The structure and format of 713model radar data, Plain Position Indicator (PPI) and Range Height Indicator (RHI), are introduced briefly. After fully analyzing, the interpretation of radar data is completed accurately by using Visual Basic.NET 2005. Selecting MapX as the secondary development components, the geovisualization of radar data by both line and region is realized under the polar coordinate system, including PPI and RHI, by means of the traditional algorithms of creating radar images. The method can recover, to the utmost, the echo information of radar data and provide an accurate analysis basis for regional precipitation.
2010, 38(4):467-471.
Abstract:
On the basis of the detection principles of the new generation Lwave radar, the difficulties existing in the detection of strong wind weather with Lwave radar at lower altitudes and low elevation angles in island observation stations are discussed. Particularly， the phenomenon of balloon loss and sidelobe balloon at lower altitudes and low elevation angles are analyzed. A solution for balloon loss at lower altitudes and low elevation angles under strong surface winds, identifying the appropriate elevation range by means of downstream winds, is presented. Some experiences are also given, which can be used as reference for better use of Lwave radar
On the basis of the detection principles of the new generation Lwave radar, the difficulties existing in the detection of strong wind weather with Lwave radar at lower altitudes and low elevation angles in island observation stations are discussed. Particularly， the phenomenon of balloon loss and sidelobe balloon at lower altitudes and low elevation angles are analyzed. A solution for balloon loss at lower altitudes and low elevation angles under strong surface winds, identifying the appropriate elevation range by means of downstream winds, is presented. Some experiences are also given, which can be used as reference for better use of Lwave radar
2010, 38(4):472-477.
Abstract:
To satisfy the sustainable operation development, the establishment of newgeneration data centers has becoming a common sense. According to the definition of the Uptime Institute (UI), the availability and reliability of data centers will be improved obviously when they evolve from basic, component redundancy level to the concurrently maintainable and faulttolerant level. To meet the increasing demands on the time effectiveness for the large volume of remote sensing data transmission and processing and the fast growing requirements for system computing and storage capabilities, the six key technologies for the Newgeneration Data Center (NDC) are investigated. Based on these technologies, the application and practice put their emphases on the dynamic resource deployment automation, resource effective usage optimization, unified infrastructure and facilities management, solid resource and data protection mechanism, scalable information technical architecture, energy conservative or green computing technologies, product adoption, etc, which will facilitate the successful construction and operation of a newgeneration remote sensing data center. In combination with the implementation of the FY3A ground application system, the best practice is presented for the implementation of six key technologies to set up a newgeneration remote sensing data center.
To satisfy the sustainable operation development, the establishment of newgeneration data centers has becoming a common sense. According to the definition of the Uptime Institute (UI), the availability and reliability of data centers will be improved obviously when they evolve from basic, component redundancy level to the concurrently maintainable and faulttolerant level. To meet the increasing demands on the time effectiveness for the large volume of remote sensing data transmission and processing and the fast growing requirements for system computing and storage capabilities, the six key technologies for the Newgeneration Data Center (NDC) are investigated. Based on these technologies, the application and practice put their emphases on the dynamic resource deployment automation, resource effective usage optimization, unified infrastructure and facilities management, solid resource and data protection mechanism, scalable information technical architecture, energy conservative or green computing technologies, product adoption, etc, which will facilitate the successful construction and operation of a newgeneration remote sensing data center. In combination with the implementation of the FY3A ground application system, the best practice is presented for the implementation of six key technologies to set up a newgeneration remote sensing data center.
2010, 38(4):478-483.
Abstract:
Contour mas are an effective tool to show the spatial distribution of a variable, which is used widely in many fields including meteorology. A contourrelated algorithm class library named “wContour.dll” was developed using VB.NET, which has such functions as interpolation, contour generation, smoothing, clipping, and color filling. The algorithms have been tested with random data, and can be used flexibly in software development to realize contour functions. The contour filling algorithm is based on topology relationship, so vector polygon shapes can be generated. The class library (wContour.dll) could be downloaded and used for free.
Contour mas are an effective tool to show the spatial distribution of a variable, which is used widely in many fields including meteorology. A contourrelated algorithm class library named “wContour.dll” was developed using VB.NET, which has such functions as interpolation, contour generation, smoothing, clipping, and color filling. The algorithms have been tested with random data, and can be used flexibly in software development to realize contour functions. The contour filling algorithm is based on topology relationship, so vector polygon shapes can be generated. The class library (wContour.dll) could be downloaded and used for free.
2010, 38(4):484-487.
Abstract:
The Meteorological Service Information System for Sichuan Province, using the WebGIS model, integrated with the GeoBeans platform, possesses such functions as map browsing, weather information query, information query, rainfall and temperature curve drawing, and so on. The system is designed in B/S mode, using the partial refresh achieved by JavaScript and ASP, which is faster and more stable. The application indicates that the GIS and meteorological data can be perfectly combined in the system, which makes meteorological data more applicable, with the scope of application expanded greatly.
The Meteorological Service Information System for Sichuan Province, using the WebGIS model, integrated with the GeoBeans platform, possesses such functions as map browsing, weather information query, information query, rainfall and temperature curve drawing, and so on. The system is designed in B/S mode, using the partial refresh achieved by JavaScript and ASP, which is faster and more stable. The application indicates that the GIS and meteorological data can be perfectly combined in the system, which makes meteorological data more applicable, with the scope of application expanded greatly.
2010, 38(4):488-491.
Abstract:
Since weather conditions may affect astronomical observation greatly, it is necessary to build a meteorological observation station near a telescope, but conventional meteorological stations usually adopt the wired data transfer mode, which is of many disadvantages, such as complexity in the wiring system and installation. The characteristics of ZigBee technology and the design of a wireless meteorological observation based on the ZigBee JN5139 Module are introduced. The system has been tested for several times. The results indicate that the meteorological observation system is easy to use, maintain, and expand, and performed well in various kinds of weather, such as raining, snowing, and high winds.
Since weather conditions may affect astronomical observation greatly, it is necessary to build a meteorological observation station near a telescope, but conventional meteorological stations usually adopt the wired data transfer mode, which is of many disadvantages, such as complexity in the wiring system and installation. The characteristics of ZigBee technology and the design of a wireless meteorological observation based on the ZigBee JN5139 Module are introduced. The system has been tested for several times. The results indicate that the meteorological observation system is easy to use, maintain, and expand, and performed well in various kinds of weather, such as raining, snowing, and high winds.
2010, 38(4):492-494.
Abstract:
2010, 38(4):495-499.
Abstract:
Most parts of the Tibetan Plateau belong to the region frequently attacked by droughts or heavy droughts， which is one of most serious disasters influencing agriculture and pasturing production in Tibet. Using NDVI (Normalized Difference Vegetation Index) and ST (Surface Temperature) gained from MODIS (Moderate Resolution Imaging Spectroradiometer) at the Lhasa receiving station， the STINDVI characteristic space is constructed and a drought discriminating method is devised according to TVDI (TemperatureVegetation Dryness Index) as the drought guideline， along with the satellite datasets for the same periods (June and July) from 2005 to 2008， and the monitoring results of meteorological droughts and soil moisture observation indicate that the TVDI method is applicable in the Tibetan Plateau for monitoring droughts with satellite datasets.
Most parts of the Tibetan Plateau belong to the region frequently attacked by droughts or heavy droughts， which is one of most serious disasters influencing agriculture and pasturing production in Tibet. Using NDVI (Normalized Difference Vegetation Index) and ST (Surface Temperature) gained from MODIS (Moderate Resolution Imaging Spectroradiometer) at the Lhasa receiving station， the STINDVI characteristic space is constructed and a drought discriminating method is devised according to TVDI (TemperatureVegetation Dryness Index) as the drought guideline， along with the satellite datasets for the same periods (June and July) from 2005 to 2008， and the monitoring results of meteorological droughts and soil moisture observation indicate that the TVDI method is applicable in the Tibetan Plateau for monitoring droughts with satellite datasets.
2010, 38(4):500-503.
Abstract:
According to the fact that late rice responses to droughts most sensitively after booting stage, five drought indexes are designed in the tests: the numbers of drought days after booting stage being 7, 10, 13, 16 days and till plant death, respectively. The results show that there exist significant negative correlations between the number of drought days and the number of grains per spike,the number of filled grains per spike. The correlation coefficients are －0.956 and －0.959. Soil moisture decreases rapidly and yield reduction rate rises with the increasing number of drought days. When the number of drought days is up to 18, the plants go dead at a critical soil moisture of 5.57%. The linear and nonlinear regression methods are applied in establishing the equations among the number of drought days, soil moisture, and yield reduction rate. It is concluded that there is slight influence in the first 6 to 7 days of droughts, moderate influence in 8 to 11 days, severe influence over 12 days.
According to the fact that late rice responses to droughts most sensitively after booting stage, five drought indexes are designed in the tests: the numbers of drought days after booting stage being 7, 10, 13, 16 days and till plant death, respectively. The results show that there exist significant negative correlations between the number of drought days and the number of grains per spike,the number of filled grains per spike. The correlation coefficients are －0.956 and －0.959. Soil moisture decreases rapidly and yield reduction rate rises with the increasing number of drought days. When the number of drought days is up to 18, the plants go dead at a critical soil moisture of 5.57%. The linear and nonlinear regression methods are applied in establishing the equations among the number of drought days, soil moisture, and yield reduction rate. It is concluded that there is slight influence in the first 6 to 7 days of droughts, moderate influence in 8 to 11 days, severe influence over 12 days.
2010, 38(4):504-509.
Abstract:
Using the ArcGIS and computer servers as platforms, considering the local demands for weather modification, a WebGISbased command system of artificial rain enhancement was developed, bringing together operations on the provincial, city and county levels. Utilizing the new technologies of computer network, database, airland wireless transmission, GPS, GIS and text messaging, integrating meteorological products such radar, satellites, automatic weather station gauges, drought/flood indexes and numerical prediction, the system can issue in real time instructions and commands via the IE explorer for airplane and surface rain enhancement operations. The general outlines of design, system configuration, software functions and database design of the system are discussed.
Using the ArcGIS and computer servers as platforms, considering the local demands for weather modification, a WebGISbased command system of artificial rain enhancement was developed, bringing together operations on the provincial, city and county levels. Utilizing the new technologies of computer network, database, airland wireless transmission, GPS, GIS and text messaging, integrating meteorological products such radar, satellites, automatic weather station gauges, drought/flood indexes and numerical prediction, the system can issue in real time instructions and commands via the IE explorer for airplane and surface rain enhancement operations. The general outlines of design, system configuration, software functions and database design of the system are discussed.
2010, 38(4):510-514.
Abstract:
By using of a nonrandomized experiment scheme and the data of rainfall and inflow of Gutian Reservoir between 1960 and 2007, the effectiveness evaluation method of precipitation enhancement effectiveness for water storage was studied based on the drainage area rainfall, inflow and runoff coefficients of the reservoir. After the reasonable precipitation enhancement operation over the Gutian Reservoir drainage area of 1350 km2, the precipitation of drainage area increased by 18.87%, with absolute value increased 22.4 mm, total rainfall 30.24 million m3, runoff coefficient of the reservoir 9.31%，inflow 29.95%，absolute increment 5.17 m3/s，the total inflow 13.59395 million m3. The precipitation enhancement operation improved the ecoenvironment, heightened soil moisture, and enhanced the runoff coefficient. The relative increment of inflow is larger than that of area rainfall. The economic benefit of waterstorage precipitation enhancement operation is larger than that of droughtresistant precipitation enhancement operation.
By using of a nonrandomized experiment scheme and the data of rainfall and inflow of Gutian Reservoir between 1960 and 2007, the effectiveness evaluation method of precipitation enhancement effectiveness for water storage was studied based on the drainage area rainfall, inflow and runoff coefficients of the reservoir. After the reasonable precipitation enhancement operation over the Gutian Reservoir drainage area of 1350 km2, the precipitation of drainage area increased by 18.87%, with absolute value increased 22.4 mm, total rainfall 30.24 million m3, runoff coefficient of the reservoir 9.31%，inflow 29.95%，absolute increment 5.17 m3/s，the total inflow 13.59395 million m3. The precipitation enhancement operation improved the ecoenvironment, heightened soil moisture, and enhanced the runoff coefficient. The relative increment of inflow is larger than that of area rainfall. The economic benefit of waterstorage precipitation enhancement operation is larger than that of droughtresistant precipitation enhancement operation.
2010, 38(4):515-520.
Abstract:
Aerosol Optical Depth (AOD) in the Zhengzhou area is retrieved according to the BouguerLamber law with the measured data from CE318 photometers in 2008. The monthly and daily variations of AOD in the Zhengzhou area are analyzed, and the effect of whether condition on AOD is studied. The results reveal: In 2008, AOD in the Zhengzhou area was at the same level with that in 2007, but the wavelength index increased. There were evident seasonal characteristics in AOD, higher in spring and summer and lower in autumn and winter, with the lowest value in December. AOD in the Zhengzhou area was mainly affected by industrial dusts. The daily variation pattern of AOD on workdays was different from that on nonworkdays, with the biggest differences occurred in the morning and noon. Traffic contributed most to the differences. Thin fog and haze made AOD increase obviously, and the effect of thin fog on AOD was higher than that of haze. During the sandy/dusty weather process, AOD increased rapidly at first, then descended gradually, and returned to normal level, with a decreased aerosol wavelength index.
Aerosol Optical Depth (AOD) in the Zhengzhou area is retrieved according to the BouguerLamber law with the measured data from CE318 photometers in 2008. The monthly and daily variations of AOD in the Zhengzhou area are analyzed, and the effect of whether condition on AOD is studied. The results reveal: In 2008, AOD in the Zhengzhou area was at the same level with that in 2007, but the wavelength index increased. There were evident seasonal characteristics in AOD, higher in spring and summer and lower in autumn and winter, with the lowest value in December. AOD in the Zhengzhou area was mainly affected by industrial dusts. The daily variation pattern of AOD on workdays was different from that on nonworkdays, with the biggest differences occurred in the morning and noon. Traffic contributed most to the differences. Thin fog and haze made AOD increase obviously, and the effect of thin fog on AOD was higher than that of haze. During the sandy/dusty weather process, AOD increased rapidly at first, then descended gradually, and returned to normal level, with a decreased aerosol wavelength index.
2010, 38(4):521-525.
Abstract:
Based on the 30year wind data of basic observation stations from 1971 to 2000 and the wind data of automatic weather stations from 2006 to 2009 in Dalian, the wind speed, valid hours, mean wind power density, and effective wind power density are computed, and the spatial characteristics of wind power in Dalian are analyzed. The results show that the wind power resources are very abundant in Dalian, and the annual effective wind power density is greater than 80 W/m2 in most areas of Dalian, Lushun Station having the highest value of 191.7 W/m2; the values of Changhai, Dalian and Wafangdian are above 150 W/m2. The effective wind power density of Jinzhou is 104.2 W/m2, Zhuanghe and Pulandian less than 100 W/m2. Valid hours for most areas are above 4500 hours per year, above 6500 hours per year for Dalian and Changhai, and between 4800 and 5500 hours per year for Lushun, Wafangdian, and Changhai. The wind power resources in Dalian have the following spatial distribution features: more abundant in the coast and island areas than in the inland areas, in the south parts than in the north parts, and in the western coast than eastern coast.
Based on the 30year wind data of basic observation stations from 1971 to 2000 and the wind data of automatic weather stations from 2006 to 2009 in Dalian, the wind speed, valid hours, mean wind power density, and effective wind power density are computed, and the spatial characteristics of wind power in Dalian are analyzed. The results show that the wind power resources are very abundant in Dalian, and the annual effective wind power density is greater than 80 W/m2 in most areas of Dalian, Lushun Station having the highest value of 191.7 W/m2; the values of Changhai, Dalian and Wafangdian are above 150 W/m2. The effective wind power density of Jinzhou is 104.2 W/m2, Zhuanghe and Pulandian less than 100 W/m2. Valid hours for most areas are above 4500 hours per year, above 6500 hours per year for Dalian and Changhai, and between 4800 and 5500 hours per year for Lushun, Wafangdian, and Changhai. The wind power resources in Dalian have the following spatial distribution features: more abundant in the coast and island areas than in the inland areas, in the south parts than in the north parts, and in the western coast than eastern coast.
2010, 38(4):526-531.
Abstract:
By using the statistical data of meteorological disasters, the historical data of Tropical Cyclones (TCs) affecting Lishui, Zhejiang Province, and GDP ( Gross Domestic Product) data of Lishui in the past years, the characteristics of tropical cyclone disasters affecting Lishui from 1984 to 2007 are statistically analyzed. The risk assessment for tropical cyclone disasters affecting Lishui is conducted by use of the improved meteorological disaster grading standards. The results show that the tropical cyclone disaster was most serious among meteorological disasters in Lishui. In the recent 24 years, the occurrence frequency of disasterscausing tropical cyclones was 1.2 per year. The disastercausing tropical cyclones happened usually in the months of May, July, August, September, and October, with the maximum number and the severest impact in August. Although there was slight difference in different months, the tropical cyclone disasters presented an obvious mitigation from southeast to northwest. The largest risk is found in Qingtian County and the minimum in Songyang County with a huge difference.
By using the statistical data of meteorological disasters, the historical data of Tropical Cyclones (TCs) affecting Lishui, Zhejiang Province, and GDP ( Gross Domestic Product) data of Lishui in the past years, the characteristics of tropical cyclone disasters affecting Lishui from 1984 to 2007 are statistically analyzed. The risk assessment for tropical cyclone disasters affecting Lishui is conducted by use of the improved meteorological disaster grading standards. The results show that the tropical cyclone disaster was most serious among meteorological disasters in Lishui. In the recent 24 years, the occurrence frequency of disasterscausing tropical cyclones was 1.2 per year. The disastercausing tropical cyclones happened usually in the months of May, July, August, September, and October, with the maximum number and the severest impact in August. Although there was slight difference in different months, the tropical cyclone disasters presented an obvious mitigation from southeast to northwest. The largest risk is found in Qingtian County and the minimum in Songyang County with a huge difference.
External LinksChina Meteorological AdministrationCMA Meteorological Observation CentreChinese Academy of Meteorological SciencesBeijing Meteorological ServiceNational Satellite Meteorological Center
You are thevisitors
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
Supported by:Beijing E-Tiller Technology Development Co., Ltd.