库姆塔格沙漠大尺度风场特征分析

A Study of Wind System in Kumtag Desert

利用美国NCEP/NCAR1979—2006年27 a地面10 m高度的日平均风场再分析-2资料以及46 a的地面常规气象站观测资料和1 a的沙漠中自动气象站观测资料,对库姆塔格沙漠地区风场进行了统计与诊断分析。结果表明:沙漠地区,一年四季北风和东北风为近地面主要存在的风向,春季风速最强,夏季次之,秋冬季最弱;在夏秋冬季节,由于北风的逐渐减弱,加上受到南侧阿尔金山和青藏高原风场的影响,南下的气流在沙漠南侧分为三支,分别流入新疆、青海和甘肃。春夏季节在沙漠北侧基本都是以东北风或者西北风吹向库姆塔格沙漠,秋冬季节,沙漠地区出现西南风。根据沙漠周围6个气象站风场风速显示,库姆塔格沙漠地区风速存在明显的周期变化,在过去的10多年中库姆塔格沙漠周围风场风速处于一个低谷期,但最近几年风速有不断加强的趋势。

Based on the dataset of NCEP （National center of environment prediction, USA） and NCAR （National center of atmosphere research） reanalysis-2 daily average wind data 10 m from surface in 27 years from 1979 to 2006 and the observations of ground weather stations, some statistic characteristics of wind system in Kumtag desert were analyzed. The conclusions are as follows： In spring, summer, autumn and winter, north and northeast wind directions are dominant in the desert; Wind is stronger in spring and sum- mer than in autumn and winter; The southward airflow evolved into three branches due to decreasing north wind strength combined with effect of uplifting landforms of Qinghai-Xizang Plateau; There is northeast wind in mid-west of the desert and southwest wind in the mid-east, and the southwest wind is weaker in spring and summer but stronger in autumn and winter. Analysis on the wind system according to observations of 6 stations around the desert suggests that the wind speed in Kumtag desert existed obvious periodic change, being in trough period in the past 10 years and appearing increasing trend in recent years.