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.