近50a青藏高原东部夏半年强降水事件的气候特征  

Climatic characteristics of heavy precipitation events during summer half year over the Eastern Tibetan Plateau in recent 50 years

作　　者：赵雪雁[1] 王亚茹[1] 张钦[1] 雒丽[1] 

机构地区：[1]西北师范大学地理与环境科学学院,甘肃兰州730070

出　　处：《干旱区地理》2015年第4期675-683,共9页Arid Land Geography

基　　金：国家自然科学基金项目(41361106);教育部新世纪优秀人才支持计划(NCET-11-0910)

摘　　要：基于青藏高原东部47个站点1963-2012年的5-9月逐日降水资料,分析了近50 a该区夏半年强降水的时空分布特征和相对强度。结果表明：青藏高原东部夏半年强降水事件在7月出现的频次最多,以持续1 d的单站暴雨为主;强降水量和频次在近50 a呈弱增长趋势,其存在准12 a的年代际震荡,且在1978年之后,强降水量同时存在大致准3 a的演变周期,在各自然分带强降水量和频次的变化趋势存在差异;夏半年强降水量和频次呈现出自东南向西北阶梯性递减的分布特征;青藏高原东部夏半年强降水的相对强度与强降水量呈反向特征,其中以柴达木地区相对强度为最大,藏东川西区为最少;各自然分带的强降水量和频次与夏半年降水量有很好的相关关系,而强降水的相对强度与夏半年降水量表现出不同的正负相关性。Based on the daily precipitation data of 47 meteorological stations from May to September during1963-2012 in the eastern Tibetan Plateau,the methods of linear trend analysis,polynomial curve fitting analysis,wavelet transform,inverse distance weighted interpolation method etc. are employed to analyze the temporal and spatial distribution of heavy precipitation,frequencies and relative intensity in nearly 50 years and applying R/S method to predict the heavy precipitation variation in future. According to the actual precipitation during summer half year in the eastern Tibetan Plateau,more than 25 mm of daily precipitation are used as the standard of heavy precipitation. The climatic characteristics of heavy precipitation events in the eastern Tibetan Plateau have an important influence on global climate change and in order to better contrast the internal differences of heavy precipitation over the eastern Tibetan Plateau,the study region was divided into five different natural zones. The results are as follows：（1）Heavy precipitation events often occurred in July and dominated by 1 d single-station in summer half year over the eastern Tibetan Plateau.（2）In recent 50 years,the heavy precipitation and frequencies showed weak increasing trend,the linear trend rate is 0.25 mm·（10 a）-1and 0.01 d·（10 a）-1respectively and they will be increasing in the future. In the five natural zones,the linear trend rate is different,only Naquyushu area showed a decreasing trend and the increasing trend is the most notable in the Chaidamu area.（3）Heavy precipitation and frequencies existed a decadal oscillation cycle with quasi 12 years,as well as,after the 1978,the heavy precipitation had inter-annual oscillation cycle with 3 years during summer half year over the eastern Tibetan Plateau.（4）During summer half year,the spatial distribution patterns of heavy precipitation and frequencies was very similar to each other,which decreased from southeast to northwest,its highest and lowest value occurred in the eas

关 键 词：青藏高原东部 夏半年 强降水事件 气候特征 

分 类 号：P426.6[天文地球—大气科学及气象学]