横断山区季风期水分盈亏量时空变化特征及其与若干气候指数的相关性分析

基于横断山区27 个气象台站1961-2012 年的实测数据,应用Penman-Monteith 模型、气候倾向率空间插值、交叉小波和相干小波变换等方法分析横断山区季风期水分盈亏量的时空变化趋势及其与若干气候指数之间的相互关系。结果表明:近52 a 来,横断山区季风期水分盈亏量在波动中呈增加趋势,其增加速率为5.87 mm/10 a;且在整个时段内,横断山区季风期水分盈亏量均呈盈余状态。该区季风期水分盈亏量空间差异也较为明显,水分盈亏量从南到北逐渐降低,但其增加趋势却从南到北逐渐增大。季风期水分盈亏量与海拔呈现负相关,即水分盈亏量随着海拔的升高而降低;在海拔相对较低的区域,水分盈亏量较高;反之,水分盈亏量较低。此外,该区域季风期水分盈亏量与北极涛动(AO)、太平洋年代际振荡(PDO)和厄尔尼诺-南方涛动(ENSO)气候指数等存在多尺度的显著相关性。

Variation of Water Deficit and Its Association with Climate Indices in Summer Monsoon in Hengduan Mountains

The cognition and awareness of water deficit which is computed as the difference between precipitation and potential evaporation has an important role to understand the supplydemand situation and rational utilization of water resources. Based on the daily precipitation, mean temperature, maximum and minimum temperature, wind speed, sunshine hours, average related humidity data of 27 meteorological stations in the Hengduan Mountains region during the period of 1961-2012 and using the methods of climate tendency rate, Penman- Monteith model, Inverse Distance Weighted interpolation, the temporal-spatial variations of water deficit and the relationship between the water deficit and PDO, AO and ENSO by the cross wavelet and wavelet coherence techniques were analyzed in terms of summer monsoon in the Hengduan Mountains region. The results are as follows: 1) The annual mean value of water deficit changed and increased obviously in fluctuation and the increasing rate was 5.87 mm/10 a in the summer monsoon during the recent 52 years. The amount of water deficit was positive in the summer monsoon over the study area. 2) The mean value of water deficit existed obvious differences in the space and presented decreasing trends from south to north. However, the changing trends increased gradually from south to north. The water deficit had increasing trends at rate of 7.96 mm/10 a, 7.54 mm/10 a and 2.16 mm/10 a in the northern, central and southern over the study area, respectively. 3) The relationship between the water deficit and elevation indicated that precipitation extreme events decreased with the altitude. Furthermore, the relationship between the water deficit and PDO, AO and ENSO presented significant periodic variations with water deficit. In general, the increase of water deficit will relieve the contradiction between water supply and demand, decrease climate drought and improve ecological environment in the Hengduan Mountains region.