21世纪初中国北方沙尘天气特征及其与地面风速和植被的关系研究

Characteristics of Sand-dust Weather in Northern China from 2002 to 2010and Its Relationship with Surface Wind Speed and NDVI

利用2002—2010年气象站点观测资料,结合同期归一化植被指数(NDVI)资料,分析了中国北方地区2002—2010年的沙尘天气特征,以及沙尘天气与地面风速和NDVI的关系。结果表明,2002年和2006年是21世纪初的沙尘天气强年,中国北方的沙尘天气总站日数明显偏多;中国北方的沙尘天气与NDVI的0.2等值线位置的变化有关,当其向东进时,沙尘天气也频发,向西退时,沙尘天气也减弱;在植被很少,靠近沙漠的地区,沙尘天气日数和强风日数有很好的正相关性,在沙漠与草原的过渡地带,沙尘天气日数与NDVI有很好的负相关性;当植被指数减小,地表面植被覆盖减少,强风也增强,中国北方的沙尘天气就很可能增强。

The characteristics of sand-dust weather in northern China from 2002 to 2010 were analyzed based on meteorological observation data and normalized difference vegetation index（NDVI）,and the relationships between sand-dust weather and wind speed or NDVI were explored.Results show that the sand-dust weather days increased significantly in northern China in 2002 and 2006 compared with that during 2003-2005 and 2007-2010.The sand-dust weather variation was related with the change of the isoline of NDVI 0.2.When the isoline of NDVI 0.2 advanced eastward,the sand-dust weather days increased;when it retreated westward,the sand-dust weather days decreased.Sand-dust weather frequency was positively correlated with strong wind days near desert regions,and the negative correlation between the NDVI and sand-dust weather days was identified in the desert-steppe ecotone.If the strong wind frequency increases and NDVI reduces,sand-dust weather is likely to become active in northern China.