Abstract:The radiation field characteristics of cloudtoground (CG) lightning flashes in the Daxing’an Mountain Range are analyzed and compared with those of other researches from home and abroad by using the data obtained from a broadband slow antenna system with a high time resolution. It is found that for 35 positive CG flashes, the average duration of the slowchange period and the 10% to 90% rising period for the first return strokes are 78 μs and 45 μs, respectively, in 11 of which the average crossing time and overshoot depth are 34 μs and 23%, respectively; for 76 negative CG flashes, those are 35 μs and 19 μs, respectively, in 15 of which the crossing time and overshoot depth are 51 μs and 52%, respectively. The average half peak width of first return strokes of positive CG flashes is larger than that of negative CG flashes, with the average values being 136 μs and 56 μs. Compared with other observations both from home and abroad, the characteristics of radiation fields of return strokes of CG flashes at the Daxing’an Mountain Range are similar with those in Sweden and Florida of America, but different from those on the QinghaiTibet plateau.