中国西南纵向岭谷区近百年降水的时空变化特征

对纵向岭谷地区近百年来降水的时空变化特征进行分析,结果表明:纵向岭谷区年降水量、夏季降水量和冬季降水量第一种主要分布型式呈现出一致偏多(或偏少)的特征。由于受地形阻隔、通道及地形抬升影响,岭谷地区年和夏季降水量以元江-红河流域为界,东部降水量空间分布减小,西部年降水量空间分布增加,其中心在澜沧江、怒江流域摆动,具有经向分布特征;冬季岭谷地区雨量具有纬向分布特征。近百年的降水量变化,年际变化最显著,周期变化主要集中在3.5年以下的高频振荡时域内,其次是年代际变化,最后是气候态的变化,但冬季的气候态变化并不明显;年降水分布第二模态的气候态变化是3个不同时段中最明显的,其次是夏季降水分布的第二种模态。

The Spatio-temporal Variations of the Longitudinal Range-Gorge Region (LRGR) Precipitation in Recent 100 Years in Southeast China

Located in north-south directed mountains and valleys in Southwest China,mainly in Yunnan Province,the Longitudinal Range-Gorge Region(LRGR) is a very important ecological corridor between South China and Southeast Asia.Ecological changes in this region directly influence Chinese trans-boundary ecological security and resources security.In this paper,the spatio-temporal variations of annual precipitation and precipitation in winter and summer over the LRGR are studied using many statistical methods with 1901-2002 precipitation data at 13 stations scattered in LRGR.The results show that the first type of principal distribution pattern of the precipitation is consistently high or consistently low.The distribution of both annual and summer precipitation shows meridionality while longitudinal for winter precipitation.Because of the "corridor-barrier" and orographic lifting function,it is higher in the west of the LRGR while lower in the east of the LRGR for annual and summer precipitation,bounded by Yuanjiang-Honghe river.The center of the distribution is located on the Lancang River for annual and summer precipitation,while that on the Nujiang River for winter precipitation.It is higher(lower)in the northwest of the LRGR while lower(higher) in the southeast of the LRGR for the second type of principal distribution pattern of annual precipitation and precipitation in summer and winter.The variation of the precipitation in the LRGR is characteristic by interannual scale,interdecadal scale and the climate base state for both annual and summer precipitation.For the winter case,the variation of the precipitation in the LRGR is characteristic by interannual scale and interdecadal scale.The significant variation of precipitation concentrates in a high frequency band less than a 3.5-yr period.The climate base state of the time series of the second principal component of annual precipitation is significant and the next is the second principal component of summer precipitation.