关于伊塞克湖水位下降的原因

ON DECLINE OF ISSYK-KUL LAKE LEVEL

本文较为详细地分析了近半个世纪以来的伊塞克湖区实测水文和气象资料。指出流域内降水量的变化未出现减少趋势,相反在湖泊东部迎风坡上,降水有增大的趋势。这部分增加的降水量是由于气候趋暖造成蒸发量增加所致。同时气候趋暖也使冰川消融扩大,径流量增加。但由于沿河引水灌溉,使河川径流在滨湖地带显著减少。灌溉的实质是扩大蒸发面,使蒸发水量增加。蒸发形成的水量,部分以降水形式返回湖内,部分越过流域边界外逸,外逸水量的多少决定了湖水位的下降速度。

The sequence of some hydrological factors has been analyzed in detail since the mid century. The result shows that the precipitation has not shown any increase in the basin, but in the eastern zone against the wind the precipitation has been increasing. The reason is that the rise of temperature resulted in the increase of evaporation. In addition, glacier melting increase may be an another reason for the increase in precipitation. In fact ,the runoff feeding the lake has not increased since the amount of water was expanded under irrigation. The plough irrigation is responsible for the evaporating area and evaporation as well. Part of evaporating vapor has come back to the lake in the way of precipitation,the left has passed over the boundary of the basis to the outside ,leading to decline of the lake level.