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利用洞庭湖流域1999年1月-2008年12月间的TRMM3B43月降水量资料,通过区域综合Z指数的构建,旱涝等级的划分以及降水变差系数的计算,对洞庭湖流域近10年来的旱涝发生特点进行了分析,并通过与流域实测降水数据分析结果的对比,验证了TRMM数据在流域旱涝监测中具有很好的可行性和较高可信度。另外,研究结果显示:①在区域综合Z指数构建过程中,由于考虑了区域降水空间分布的不均匀性,文中的计算方法比通常采用的面积平均法更加符合实际;②TRMM数据格点在流域内均匀分布,可有效刻画流域降水的空间分布。其监测的流域旱涝结果较有限气象站点的监测结果更加真实、可靠;③受季节性季风降水及区内复杂地貌特征的影响,洞庭湖流域旱涝发生较为频繁,平均一年内大约有2.8个月和2.4个月,分别表现为流域性的洪涝和干旱。且总体上,流域性洪涝发生的频率和等级要高于干旱;④洞庭湖流域洪涝发生具有持续时间长的特征。在过去10年间,常常有持续2～3个月,甚至更长的洪涝或干旱发生;⑤洞庭湖流域西北部、西南部以及东南部的旱涝发生几率相对较高,而中部和东部的几率相对较低,尤其是北部湖区的几率最低。
Based on the TRMM3B43 monthly rainfall data collected from January 1999 to December 2008 in the Dongting Lake basin, through the construction of the Z-index, the division of drought and flood level and the calculation of precipitation variation coefficient, The characteristics of drought and flood were analyzed, and compared with the results of precipitation data analysis in the basin, it was verified that the TRMM data had good feasibility and high credibility in the monitoring of drought and flood in the basin. In addition, the results show that: ①In the process of constructing the Z-index of regional integrated Z-index, considering the nonuniformity of spatial distribution of regional precipitation, the calculation method in this article is more realistic than the commonly used area average method; Uniform distribution, which can effectively describe the spatial distribution of precipitation in the basin. The monitoring result of drought and flood in the basin is more realistic and reliable than the monitoring result of the limited meteorological station. (3) Due to the seasonal monsoon precipitation and the complex landscape features in the region, droughts and floods occur frequently in Dongting Lake basin, with an average of about 2.8 Month and 2.4 months, respectively, as a basin of floods and droughts. In general, the frequency and level of flooding in the basin are higher than those in the drought. (4) Flooding in the Dongting Lake basin has the characteristics of long duration. In the past 10 years, floods and droughts lasting 2 ~ 3 months or more often occurred. ⑤ Drought / flood in the northwest, southwest and southeast of Dongting Lake basin is relatively high, while the probability of drought and flood in central and eastern China Relatively low, especially in the northern lakes, the lowest probability.