Correlation of precipitation to temperature variation in the Huanghe River (Yellow River) basin during 1957–2006

Based on the data of 88 meteorological observation stations distributed in nine provinces and autonomous regions in Huanghe River (Yellow River) basin of China, time series of annual precipitation and temperature, the frequency and quantity of extreme precipitation per year were analyzed to assess the correlation of precipitation to temperature increasing variation during a 50-year period from 1957 to 2006. The results showed trends of precipitation were constantly decreasing while temperature was increasing in the last five decades. The correlation coefficient between precipitation and temperature demonstrates a statistically significant rising trend over time (p < 0.01). In the upper reach of the basin, a typical arid zone with vulnerable ecosystem, extreme rain events including rainstorms and drought periods are significantly increasing. Compared with the lower reach in semi-humid zone, the precipitation in the arid zone is more responsive to temperature variation.