近30年京津风沙源区气候干湿变化分析

Dry /Wet variation of Beijing- Tianjin dust and sandstorm source region during 1981- 2010

基于近30a(1981-2010)中国区域高时空分辨率地面气象要素数据,通过Thornthwaite方法计算获得京津风沙源区的湿润指数,采用Mann-Kendall趋势性检验的方法对研究区的降水、气温以及气候干湿变化趋势进行了分析。结果表明:近30a年,京津风沙源区气温呈现显著上升趋势,降水和湿润指数总体均呈现下降趋势,但变化趋势并不显著,显著下降区域分别只占到18.8%和28.0%;导致土地干湿变化的主导因素是潜在蒸散量的变化,降水也起到了一定的影响作用,但是不如潜在蒸散量所起作用明显;干旱区和干旱亚湿润区的界限逐步向东推进。

Mainly based on the method of Mann- Kendall test,the annual precipitation,annual average temperature and dry /wet variation were analyzed by using the China meteorological forcing dataset from 1981 to 2010 in Beijing- Tianjin dust and sandstorms source regions. Results show that in the past 30 years,the annual average temperature in most areas of the study regions increased significantly,annual precipitation and annual moisture index both decreased,but not significant,the significantly decreased areas accounted for 18. 8% and 28. 0%.The dominant factor for dry /wet variation was the potential evapotranspiration,and annual precipitation also played a certain role,but not as obvious as potential evapotranspiration; arid and dry sub- humid regions boundaries were moving gradually eastward in the nearly past 10 years.