金沙江筑坝蓄水对近岸小气候的可能影响

THE POSSIBLE INFLUENCE ON THE COASTAL MICROCLIMATE OF THE JINSHA RIVER DAMS IMPOUNDMENT

为探讨金沙江河段筑坝蓄水对近岸小气候的影响,运用对比分析法对云南省大理州鹤庆县的龙开口水电站的库区蓄水前后气温、湿度、风速、风向、降水和蒸发的变化量进行研究。结果表明:库区蓄水后近岸相对年均气温上升0.2℃,年均相对湿度增大1.3%,年均风速增大0.3 m/s,风向频率由NE和SE,转向W、SSE和SE;冬夏季气温日较差分别减小2.7℃、2.6℃;相对湿度日较差冬增大14%、夏减小8.4%;冬最低气温上升3.0℃、夏最高气温下降1.4℃,最大湿度冬减小2.6%、夏增大2.7%,最小湿度冬夏分别增大1.4%和2.8%,其出现时间也发生变化;库区蓄水后其近岸年降雨量和蒸发量的变化不显著。

To explore the Jinsha river dam impoundment influence on the coastal microclimate, select the catchment areas of the Longkaikou Hydropower Station in Heqing County, Dali City in Yunnan Province as the research objection, set up the observation point respectively in the upriver and downriver of the dam and about 1 km away from the river bank, observe the temperature, humidity, wind speed, wind direction, rainfall, evaporation and meteorological elements for 4 years of parallel, analyze and compare the two observation points data before and after the impoundment. The result shows that after the reservoir relative annual temperature where close to the shore rises 0. 2℃, annual average relative humidity increases 1.3%, annual average wind speed increases 0. 3 m/s, and wind direction frequency by NE and SE, steering W, SSE and SE; winter and summer tempera- tures diurnal range reduced 2. 7℃, 2. 6℃ respectively; relative humidity winter of diurnal range increased by 14%, reduced 8.4% in the summer; winter minimum temperature increase of 3.0℃, the highest temperature drop in the summer of 1.4℃, winter maximum humidity decreases by 2. 6%, summer increase 2. 7%, summer and winter minimum humidity increase 1.4% and 1.4% respectively, the time can be change; the reservoir after the nearshore changes in annual rainfall and evaporation is also changing.