Abstract:

Based on the daily precipitation data of the 46 meteorological stations in Inner Mongolia from 1960 to 2012, the inhomogeneity characteristics of annual precipitation and its trend during 1960-2012 in Inner Mongolia was analyzed by applying the Precipitation Concentration Degree (PCD) and Precipitation Concentration Period (PCP). The result showed that: (1)In recent 53 a, the mean PCD of Inner Mongolia was 0.7, with an apparent decreasing trend in Inner Mongolia; while the PCP in Inner Mongolia was 194.65°, showing an insignificant declined trend. (2) The area of high PCD value was mainly distributed in Alxa Plateau, the eastern part of XilinGol Plateau, Hulunbuir upland plain and the eastern areas of Greater Hinggan, while the low value centers lay in the northern areas of Greater Hinggan, Wulanchabu plateau and Ordos Plateau. Divided by the PCP contour line of 192°, the PCP in the whole area showed an obvious spatial difference, and the west is high while the east is low. (3) The PCD in Inner Mongolia showed a decreasing trend, especially in Hulunbuir upland plain and Ulanchap plateau. The PCP also showed a decreasing trend, indicating that the PCP appears earlier in the east of Helan Mountain and Ulan Buh Desert line.(4) PCD of all stations had a highly positive correlation with annual precipitation, and 60.8% of the stations passed statistically significant test, while PCP of all stations had low positive correlation with annual precipitation, merely with the area of 34.7% passed significant test.

Key words: Inner Mongolia, spatio-temporal variations, precipitation concentration degree, precipitation concentration period