陇东黄土高原气候变化及其对水资源的影响

Climate change and their impact on water resources in the Loess Plateau of east Gansu

选取甘肃陇东8个气象观测站的月平均气温、月降水量和月蒸发量及水文资料，分析陇东气候变化历史演变趋势及其对水资源的影响。结果指出：1971～2009年陇东年降水量总的变化呈减少趋势，平均每10a减少9．3mm，尤以近20a减少最为明显；年平均气温总的变化呈上升趋势，气温每10a升高0．41℃。年蒸发量总体呈增加趋势，平均每10a增加9．3mm。分析的结果还指出：年降水量500mm等值线和年蒸发量1550mm等值线南移。半干旱区面积增大。陇东整体暖干化导致董志塬地下水水位下降了30m；使水资源分布不均匀，地表水利用率低；每年水蚀表土0．2—1．0m3，严重的达2cm以上。所以应正确评估陇东水资源的脆弱性和干旱灾害程度，提出科学的抗旱对策。

On the basis of the daily average temperature, monthly precipitation, monthly evaporation and the hydro- logical＇ data from 8 weather stations in east Gansu, the trend of historical evolution of climate change and its impact on water resources were analyzed. The results showed that the annual precipitation in the area demonstrated a decreasing trend from 1971 - 2009, and the decreasing slope was 9.3 mm/10a, which was more severe in recent 20 years. The an- nual average temperature showed an increasing trend, and the increasing slope was 0.41/10a. The annual evaporation showed an increasing trend, and the increasing slope is 9.3 mm/10a. The contour with 500 mm annual precipitation and the contour with 1 550 mm annual evaporation both move towards south. The area of semi-arid increased obviously. The groundwater-level of Dongzhiyuan fell 30 meters and the water resources distributed unevenly, which were mainly caused by warm-dry climate tendency. The utilization rate of the 0.2 - 1.0 m3 every year or even up to 2 cm in some area. source water was low. The soil of water erosion decreased by So in order to deal with the challenge of the climatic change, the vulnerability of water resources and the extent of the arid meteorological disaster should be evaluated correctly, and some scientific countermeasures for drought should be proposed.