近期黄河上游气候变化对龙羊峡入库水量的影响

根据1956年以来气候资料,统计分析了黄河上游龙羊峡以上地区气温、降水分布规律及变化特点,并以各站气温、降水与唐乃亥站天然径流量关系为基础,建立天然径流量计算公式,计算分析了唐乃亥以上地区20世纪90年代(近期)以来气候变化对龙羊峡入库径流量的影响,以及唐乃亥站径流量对气候变化的敏感性.结果表明:①近期唐乃亥以上各区年平均气温均较常年平均偏高0.5℃左右,而比前期升温达0.7~0.8℃;降水量不仅较多年均值偏少,更比前期显著减少,其中玛曲一带最大减幅达15.8%;②平均天然年径流量与前期相比,近期减少了43.7亿m3,表明气候变化所引起的减幅达20.2%;③龙羊峡入库径流量对降水变化的响应要比气温更为显著.

Climate variation in upper Yellow River in 1990s and its influences on inflow of Longyangxia Reservoir

Distribution laws and variation characteristics of the precipitation and temperature in the area above the Longyangxia Reservoir on the upper Yellow River were analyzed with the climate data obtained since 1956. Based on the relationships between the natural runoff at the Tangnaihai Station and the temperature and precipitation at each gauging station, a natural runoff calculation formula was established. With the formula, the influence of climate variation in the upper Tangnaihai region since the 1990s on the inflow of the Longyangxia Reservoir was calculated, and the sensitivity of runoff at the Tangnaihai Station to climate variation was analyzed. The results show that the average annual temperature in the 1990s is about 0.5 higher than the perennial average value,and increases by 0.7-0.8 as compared with that of previous decades,that the annual rainfall of this region is much less than the long-term average value,and especially, the maximum reduction of rainfall is up to 15.8% in Maqu district, that the natural annual runoff in the 1990s decreases by 43.710~8?m~3 as compared with that of previous decades, and 20.2% of which is induced by climate variation, and that the variation of rainfall is of great influences on the inflow of the Longyangxia Reservoir as compared with the variation of temperature.