The spatial-temporal evaluation and variability study on the aridity of the Northern China using ESDA

摘要

The arid and semiarid region of northern China is one of the most fragile regions in ecological environment. Humidity index that was proposed and recommended by UNCCD (United Nations Convention to Combat Desertification) was utilized to investigate the aridity tread and its variations from 1960 to 2000 in northern China by means of the daily observed datasets of 3 82 meteorological stations in China Spatial-temporal changing principles and zonation variations of aridity trend of the region were quantitatively analyzed from spatial-temporal attribution, the severity, and the significant level test by using the ESDA (Exploring Spatial Data Analyst) and Mann-Kendall rank statistical test. The results indicated that: 1) the extent and severity of extreme arid, arid, semi-arid, arid sub-humid and humid climate zones in northern China fluctuated dramatically from 1960 to 2000; 2) the west part of northeast China, north part of northern China and mostly part of northwestern China tended to be wet;; 3) In 1960s and 1970s, the aridity trend in northern China was significant But since 1980s, the humid extent increased distinctly, especially in the middle and west part of western China, where the humid tread in some part of the region was so evident that it exceeds the significant level test of 99%.