Dryland expansion in northern China from 1948 to 2008

This study examined the expansions of drylands and regional climate change in northern China, by analyzing the variations in aridity index, monthly mean surface air temperature and precipitation developed by the Climate Prediction Center (CPC), from 1948 to 2008. The results show the drylands in northern China have remarkably expanded during the last 61 years, which are 0.65×106 km2 (12%) larger than those in the 1948-1962. The expansion of semi-arid regions is the most severe, and the areal change is nearly 10 times higher than those in arid and subhumid regions. The boundary of drylands has been moving eastward over Northeast China by about 2 degrees of longitude, and southward along middle-lower reaches of Yellow River by about 1 degree of latitude. The expansions of semi-arid regions occur over Northeast China in a zonal band, stretching from western Heilongjiang to southern Gansu provinces, while the expansions of dry subhumid regions occur to the east of semi-arid regions.