ANALYSIS OF CLIMATE VARIABILITY IN THE JINSHA RIVER VALLEY

Monthly mean surface air temperatures and precipitation at 20 meteorological stations in the Jinsha River Valley (JRV) of southwest China were analyzed for temporal-spatial variation patterns during the period 1961-2010. The magnitude of a trend was estimated using Sen’s Nonparametric Estimator of Slope approach. The statistical significance of a trend was assessed by the MK test. The results showed that mean annual air temperature has been increasing by 0.08°C /decade during the past 50 years as a whole. The climate change trend in air temperature was more significant in the winter (0.13°C/decade) than in the summer (0.03°C/decade). Annual precipitation tended to increase slightly thereafter and the increasing was mainly during the crop-growing season. Both the greatest variation of the annual mean temperature and annual precipitation were observed at the dry-hot valley area of middle reaches. Significant warming rates were found in the upper reaches whereas the dry-hot basins of middle reaches experienced a cooling trend during the past decades. Despite of the overall increasing in precipitation, more obvious upward-trends were found in the dry-hot basins of middle reaches whereas the upper reaches had a drought trend during the past decades.