青海湖周边地区沙丘移动监测及其气候驱动力分析

根据青海湖周边地区3个定点沙丘监测点近5 a沙丘移动监测资料,结合邻近气象局气象资料,分析了青海湖周边地区沙丘移动距离、方向和高度变化规律及其气候驱动力。结果显示,近年来青海湖湖东地区沙丘主要向ENE方向移动,移动速度减慢,沙丘高度降低;龙羊峡水库西北部的两个沙丘主要向偏SW方向移动,移动速度东部快西部慢,沙丘高度均有所降低。沙丘移动速度及方位主要受4～8 m·s-1风速级风向出现频率的影响。近年来兴海、海晏水热条件向暖湿化方向发展,兴海风速自1996年以来变化平稳,海晏近几年虽有所增加,但在2004年前经历了16 a较平稳的低风速阶段,气候条件对沙丘发展有一定的抑制作用;共和降水增幅较小,气温持续升高,且在2004年以前经历了13 a的高风速阶段,对沙漠化具有加剧作用。

Monitoring of Aeolian Dunes Movement in Surrounding Qinghai Lake Areas and Climate-Driven Forces Analysis

The evolution of sand dunes, including moving speed and direction and height changing, at three positional monitoring sites in surrounding Qinghai Lake areas was studied based on the observation data for five years. The climate-driven forces for the sand dunes evolution were further discussed by an integrated analysis on sand dunes dynamics and weather data of the adjacent stations. The results showed that the sand dunes to the east of Qinghai Lake mainly moved in direction of NNE, the speed slower and dunes height fall for recent years. The two sand dunes to the northwest of Long Yangxia Reservoir moved in SW direction principally, their speed are different but their height all became smaller. The moving speed and direction of sand dunes are mainly controlled by the blowing of 4~8 m·s-1 wind and its frequency. In recent years, the annual precipitation and temperature of Xinghai and Haiyan in study area increased obviously. The annual wind speed at Xinghai weather station changed little since 1996, and that at Haiyan station although increased, its speed were low for the 16 years before 2004. The climate factors in these two regions have limited the development of sand dunes to some degree. But the conditions in Gonghe have exacerbated desertification status, the annual precipitation increasing rate was small, the temperature increased continually, and the wind speed kept high in the 13 years before 2004.