Spatial distribution and temporal trends in precipitation extremes over the Hengduan Mountains region, China, from 1961 to 2012

Extreme precipitation events will cause serious disasters, and their changing trends require thorough evaluation. Spatial distribution and temporal trends of extreme precipitation events were analyzed based on the daily precipitation data of 27 meteorological stations in the Hengduan Mountains region from 1961 to 2012. Twelve indices of precipitation extreme were studied. The results were as follows: except for consecutive dry days, consecutive wet days and maximum 5-day precipitation, other indices of precipitation extreme demonstrated non-significant increasing trends, and most indices fluctuated from 1961 to 2012. Increasing trends in precipitation indices were greater than those in precipitation days. The spatial distribution for precipitation extremes exhibited a declining trend from southwest to northeast, which reflected regional differences and the influence of topography in the Hengduan Mountains region. Furthermore, the relationship between precipitation extremes and elevation indicated that precipitation extreme events decreased with altitude. The extreme precipitation indexes had positive correlations with the annual total precipitation, and their correlation coefficients were statistically significant at the 1% significance level, except for consecutive dry days. Continuous wavelet transform analysis presented significant periodic variations with periods of 2-4 year, 5-year, and 10-year in the extreme precipitation, and there was a 2-4 year resonance cycle with the South/East Asian summer monsoon index. The South/East Asian Summer Monsoon was an important influence on precipitation extremes in the Hengduan Mountains region. (C) 2014 Elsevier Ltd and INQUA. All rights reserved.