| Based on the daily measured precipitation data during 1960 to 2013 from 60 meteorological stations in Shanxi, Shaanxi and Inner Mongolia, analyzed the spatial-temporal variation of average annual precipitation and the extreme precipitation in recent 54 years of these provinces. The results showed that: (1) The average annual precipitation was presentted a slow decrease trend in the fluctuation, but the decrease was not noteble. The decrease trend in Shanxi, Shaanxi and Inner Mongolia was 14.014 mm·10a-1, 10.706 mm·10a-1 and 0.76 mm·10a-1, respectively. In space the precipitation of Inner Mongolia presented the obvious differences between East and West and from 400 to 500 mm in East reduced to less than 200 mm in West.The yearly average precipitation in Shanxi was decreased from Southeast to Northwest. It was 500 to 800 mm in Southeast and 400 to 500 mm in Northwest. The yearly average precipitation in Shaanxi was presentted the characteristics more in South and less in North. It was more than 800mm in Southern Shaanxi and 400 to 500 mm in Northern Shaanxi. (2) From Southeast to Northwest, the precipitation appeared the change trend from decrease to increase. The precipitation in former rich area was tended to reduce and less area was tended to increase. The difference of internal precipitation in Shanxi, Shaanxi and Inner Mongolia was tended to decrease. The decrease was 0 to 1 mm·a-1 in Eastern Inner Mongolia and the increase was 0 to 1 mm·a-1 in Westen Inner Mongolia. The maximal decrease was 1 to 3 mm·a-1 in South Shanxi and was decreased above 3 mm·a-1 in Northeast Shanxi. The decrease was total less than 0 to 1 mm·a-1 in North and South Shaanxi. (3) The precipitation isoclines of 200 mm and 400 mm were obviously presented the decade fluctuation, in 1970s and 1990s were inclined to North and West, in 1980s and 2000s were inclined to East and South. In recent years, the impact range of summer monsoon was reduced, so the precipitation was tended to reduce in Inner Mongolia and slightly increase in southern Shanxi and Shaanxi. (4) The yearly average extreme precipitation was showed no significant increasing trend, most of the changes were 0 to 1 mm·a-1. In these periods, the extreme precipitation did not occur the mutations. The increase of the extreme precipitation, let the precipitation in these regions were presentted unstable situation. In the intensity of extreme precipitation, the intensity of Shanxi and Shaanxi was higher than in Inner Mongolia. The intensity of Shanxi and Shaanxi was decreased from south to north. In South Shaanxi was large than 50 mm·a-1, but in North Shaanxi was decreased to 30 to 40 mm·a-1. It was 40 to 50 mm·a-1 in most areas of Shanxi, only in north was 30 to 40 mm·a-1. The intensity of extreme precipitation in Inner Mongolia was gradually reduced from East to West, in East was 30 to 40 mm·a-1 and in West was less than 20 mm·a-1. The change trend of the intensity of extreme precipitation was not big for internal differences. The days for extreme precipitation were weakly increased, but the increasing level was not notable. The extreme precipitation days was not occurred the drastic change in this period. |