三峡库首典型区2001—2010年局地气象因子变化趋势分析

Variations of Local Meteorological Factors from 2001 to 2010 in Typical Area of Head Part of Three Gorges Reservoir

三峡工程对库区气候变化的影响一直是备受关注的科学问题，通过对库首秭归典型区2001-2010年10年期间地气象因子的连续观测，分析各气象要素的动态变化趋势。根据现有观测资料，三峡库首典型区蓄水前后的温度、降水、气压日照等主要气象因子虽有一定程度年际波动，但未见较大显著变化。与蓄水前棚比，秭归典型区在蓄水后年平均气温降低了0．3℃，年均最高气温降低了约0．7℃，年均最低气温升高了约013℃；蓄水后的4月、5月和12月平均气温升幅约为0．8℃～1．0℃，其余月份降幅约为0．4℃～2．0℃；蓄水后，多年平均≥10℃有效积温降低幅度约为116．6℃。10年期间，除极端最高地断温度有一定降低外，平均地面温度、平均最高最低地面温度和极端最低地温均无明显变化：每年4—8月份为雨日最集中时期，10年期间平均降雨量为939．7mm，其中以2008年的降雨量最高为1148．7mm，而2009年降雨量最低为742．8mm；10年平均年蒸发量为937．0mm，各年份中5—9月份平均蒸发量为668．5mm，占年度蒸发量的71．3％；10年期间平均气压有升高趋势，其中2010年平均气压为101．0kPa，比2001年平均气压升高了约1．2％；10年期间，日照时数存在波动，但总体有降低趋势，其中2004年日照时数最长达1384．9h，2005年日照时数最短为981．8h。

The effects of the Three Gorges Project on climate change have been widely concerned as a scientific question. Meteorological factors of Zigui country in typical area of the head part of the Three Gorges Reservoir were continuously observed and analyzed from 2001 to 2010. According to the existing observation data, main meteorological factors such as temperature, rainfall, air pressure and sunshine showed a certain degree of annual fluctuations, but no significant change was found. Compared with before water storage, annual average temperature in Zigui typical area decreased by about 0.3℃, annual average highest temperature decreased by about 0.7℃, annual average lowest temperature increased by about 0.3℃; average temperature in April, May and December after water storage increased by 0.8℃-1.0℃, the other month dropped by about 0.4℃-2.0 ℃; average ≥I0℃ effective accumulated temperature dropped by about 116.6℃ after water storage. During the 10 years, except for a few decrease of extreme highest ground temperature, no significant change was observed in average ground temperature, the average highest ground temperature and extreme minimum temperature. April to August of every year was the most concentrated raining period. The annual average rainfall was 939.7mm from 2001 to 2010, and the highest rainfall was 1 148.7 mm in 2008, and the lowest rainfall was 742.8 mm in 2009. The annual average evaporation was 937.0 mm; average evaporation from May to September in different years was 668.5 mm, which accounting for 71.3% of the annual evaporation. Average air pressure showed an increase trend, which was 101.0 kPa in 2010 and increased by about 1.2% compared with 2001. Sunshine fluctuated and showed a general decreasing trend. The highest sunshine was 1 384.9 h in 2004 and the lowest was 981.8 h in 2005.