LOCAL PRECIPITATION CHANGES INDUCED BY THE THREE GORGES RESERVOIR BASED ON TRMM OBSERVATIONS
LOCAL PRECIPITATION CHANGES INDUCED BY THE THREE GORGES RESERVOIR BASED ON TRMM OBSERVATIONS
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基于TRMM观测的三峡水库引起局地降水变化
DOI：
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发表时间：
2014
期刊：
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通讯作者：
B. Li
中科院分区：
文献类型：
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作者：
B. Li
三峡水库引起的水体增加可能对局地气候和大尺度气候变化背景，特别是对气象灾害的频率和特征产生重大影响。如何区分自然气候变化和人为气候变化是当前水科学和气象学共同关注的热点和研究热点。为了揭示三峡水库对局地气候的影响，对2003年（三峡工程）前后TRMM 3b42卫星降水资料进行了分析。结果表明：三峡蓄水后，三峡库区西北地区年累积降水量增加，东南地区年累积降水量减少，反映了大尺度的降水变化；TRMM 3b42的年累积降水量变化与雨量计数据具有较好的一致性，空间相关系数为0.72（p0.01）。三峡库区对坝区降水的影响较小，干流站点间的差异随着时间的推移而增大，但TRMM 3b42和实测降水对坝区年平均降水量的影响均不显著。水库建成后降水变化呈现季节差异。冬天几乎整个地区的降雨量都增加了。春季，上游部分降水增强，下游大部分降水增强，中游降水减弱。夏季除部分下游地区外，大部分库区降水增加。秋季降水呈现上下游增加、下游减少的趋势。区域平均季节降水年际变化趋势不显著。综合分析表明，三峡水库对局地降水变化的影响仅局限于坝区附近，对整个大三峡地区的影响几乎可以忽略不计。目前TRMM 3b42的数据长度只能反映三峡水库建成前后的降水变化。这些变化是否直接由储层引起的答案将需要更长的观测与数值模拟相结合的验证。
The increased water body caused by the Three Gorges Reservoir might bring substantial influences on the local climate and the background of large-scale climate change,especially on the frequency and characteristics of meteorological disasters.How to distinguish the natural and the human-induced climate changes is a hot common concern and a study focus of the current water science and the meteorology.In order to reveal the impact of the Three Gorges Reservoir on the local climate,the TRMM 3B42satellite precipitation dataset was analyzed before and after 2003(The Three Gorges Reservoir Project).The results showed that,the accumulated annual precipitation was enhanced over the northwestern parts and reduced over the southeastern area of the Three Gorges after the impoundment,which reflects the large-scale precipitation changes.The cumulative annual precipitation amount changes in TRMM 3B42and the rain-gauged data were in good coherence and the spatial correlation coefficient was 0.72(p0.01).The Three Gorges Reservoir produced a minor influence on the precipitation over the regions near the dam,and the differences among the trunk stream sites were increasing as time,but no significant changes were observed for the area mean yearly rainfall amount in both TRMM 3B42and the raingauged observations.The precipitation change after building the reservoir exhibited seasonal differences.The rainfall increased over almost the whole region in winter.In spring,the precipitation was enhanced over parts of the upstream and most parts of the downstream,while was reduced over the midstream.Precipitation increased over most of the reservoir regions except for some downstream regions in summer.In autumn,precipitation increased in the upstream and the midstream and decreased in the downstream.The regional averaged seasonal rainfall had no significant inter-annual trends.Overall,the analysis implies that the impacts of the Three Gorges Reservoir on the local precipitation change are only confined in the near dam area,and the impacts on the entire large Three Gorges Region is nearly negligible.The current data length of TRMM 3B42can only reflect the precipitation changes before and after the Three Gorges Reservoir was built.Answers to whether these variations are induced directly by the reservoir will need combined verifications of longer observations with numerical simulations.