近20年中国气象灾害损失的初步分析

采用全国气象部门收集的县（区）域行政单元灾情普查资料，结合全国气象站点降水观测资料，分析了1984—2008年中国暴雨及其引发的洪涝灾害的时空演变特点及灾害损失情况，揭示了气候变化及人类活动双重作用下中国暴雨洪涝灾害变化趋势和演变特点，以及暴雨洪涝灾害影响的时空差异性。结果表明：近25 a来中国暴雨日数总体上稍有增加，暴雨强度和暴雨天数的空间分布均表现为南方高于北方，东部高于西部的特点，20世纪90年代中后期为中国暴雨高发期。研究时段内，中国暴雨洪涝灾害造成的直接经济损失呈增加趋势，但直接经济损失占当年GDP的比例则呈下降趋势，平均每年经济损失约为573亿元人民币，损失较高的地区主要集中在中国南方地区，县域年平均损失超过2 000万元的县约占15%，其中有34个县超过亿元。受灾人口呈增加趋势，但因灾死亡人口呈下降趋势；暴雨洪涝灾害对农作物受灾面积和绝收面积的影响均呈微弱上升趋势，年平均作物受灾面积近9.00×10⁶ hm²，作物绝收面积为1.27×10⁶ hm²。

Trends in total precipitation and frequency of daily precipitation extremes over China

Rainstorms have a high frequency and flood disaster is one of the major natural hazards in China. Extreme precipitation events are projected to increase in frequency and intensity in the future according to the results of global climate models. Based on survey data of floods at county-level and daily precipitation data at weather stations, the temporal-spatial variation of rainstorms and the consequences of floods caused by rainstorms were analyzed for last 25 years. Meanwhile, the change trend of the flood consequences and its regional difference were highlighted. The results suggest that the range of rainstorms was increasing on the scale of country. It shows a spatial pattern of greater in the Southeast than in the Northwest for the intensity of rainstorms. The mid-late 1990s was a high-frequent period during this research period. The direct economic loss of floods due to rainstorm floods had an increasing tendency, but the ratio of direct loss to the annual Gross Domestic Product (GDP) was decreasing. The loss amounts are evaluated at 57.3 billion Yuan per year over the period. These higher loss counties were mainly located in southern China because of higher frequency of rainstorms and more prosperous economy. In China, the counties where the per year loss amounts exceed 20 million Yuan got about 15% loss of the total. There were 34 counties at more expensive loss, which per year amounts exceed 100 million Yuan. During the period, the total population who suffered the flood caused by rainstorms was increased. However, the death toll was in decline.. It reflects the capacity to coping flood disasters has improved. Our results also show that agriculture was affected greatly by rainstorms and flood disasters, both the affected areas and devastated areas have slight increasing trends in the period. The annual mean areas of cultivated land influenced by rainstorm floods were nearly 9 million hm², and the fail areas were 1.3 million hm², which is consistent with the increasing trend of rainstorms. This research not only displays the impact of rainstorms and floods in the temporal-spatial patterns which have high consistency of the pattern of rainstorms, but also suggests climate change and human activities do have impact on the consequences of floods. More attention should be paid on climate change adaptation and disaster risk management of floods in the future.