摘要
利用卫星上携带的闪电探测仪所获取的 8年闪电资料 (1995～ 2 0 0 2 )对青藏高原闪电活动的时空分布以及高原季风期间闪电活动对地面热力学特征的响应进行了研究 .结果表明 ,高原上的平均闪电密度为3fl·a-1·km-2 ,并在高原中部 (32 °N ,88°E)出现闪电密度峰值 5 .1fl·a-1·km-2 .闪电活动主要发生在 6～ 8月 ,并在6月下旬至 7月中旬最为活跃 .大部分地区的闪电活动日变化峰值出现在 14 :0 0～ 16 :0 0LT ,在中西部的显著高山地区早于这一时刻 ,而在显著低海拔的塔里木和柴达木盆地晚于这一时刻 .夏季季风期间高原上的闪电活动明显依赖于地表的热力学特征 ,并与地表鲍恩比和感热通量呈明显的线性正相关 ,相关系数分别为 0 .7和 0 .6 。
We study the spatial and temporal distribution of lightning flash activity and its response to the thermodynamic characteristics over the Tibetan plateau by using the composite gridded lightning data from 1995 to 2002 observed by the satellite-based sensors, provided by NASA LIS/OTD Science Team in Marshall Space Flight Center. Our results show that the mean flash density over the Tibetan plateau is 3 fl·a -1·km -2, and the maximum flash activity is over the Central Plateau around (32°N, 88°E) with a peak value of 5.1 fl·a -1·km -2. The flash activity on the Plateau exhibited a seasonal variation and mainly occurs from June to August with a maximum flash activity period from late June to middle July. The diurnal variation of the maximum flash rate peaked during 14:00～16:00 LT with exceptions of the prominent high mountain region, which peaked earlier, and prominent low basins, which peaked later. The flash activity on the Plateau strongly depends on the ground thermodynamic characteristics, and positive correlations between lightning activity and Bowen ratio and ground sensitive heat flux are found during plateau monsoon season. Their correlation coefficients are 0.7 and 0.6, respectively, and the Bowen ratio could be an indicator of lightning producing efficiency.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2004年第6期997-1002,共6页
Chinese Journal of Geophysics
基金
国家自然科学基金委"十五"重点项目 ( 4 0 13 5 0 10 )
国家杰出青年科学基金项目 ( 4 0 3 2 5 0 13 )
中国科学院资源环境领域知识创新工程重要方向项目 (KZCX2 2 0 1)资助
关键词
青藏高原
闪电活动
时空分布
鲍恩比
感热通量
Flash activity, Tibetan Plateau, Temporal and spatial distribution, Bowen ratio, Sensitive heat flux.
