摘要
从中国气象局信息中心提供的全国地面台站逐日观测资料中选取黄河中上游流域66个台站资料,结合NCEP/NCAR再分析资料,运用小波分析等统计方法,对黄河中上游流域夏季降水异常的变化特征、周期分布及影响降水的因子进行分析,研究结果表明:(1)流域旱涝年夏季降水空间分布上差异显著,易涝区位于河套平原,易旱区位于黄土高原东北部;(2)1960-2008年,流域夏季降水量线性趋势变化不明显,但年际间波动较大,多雨年少雨年相间出现,近50 a中降水整体呈现平稳—少雨—多雨—平稳—多雨—少雨的过程;(3)黄河中上游流域降水变化周期复杂多样,总体以2 a周期振荡为主,异常少雨年多表现为9 a周期振荡,异常多雨年多表现为15 a周期振荡,且流域主周期的空间分布可能与地形地貌、海拔高度及流域分布等地理因素有关;(4)丰、枯雨年环流形式差异显著,影响流域降水的环流系统有季风,西太平洋副高,温带气旋及贝加尔湖低压。
The purpose of this study is to analyze the variation of precipitation and the reasons for drought and flood in summer in the upper and middle reaches of the Yellow River basin. Based on the daily precipitation data of 66 stations in the region provided by the China Meteorological Administration Information Center, combining with the NCAR/NCEP reanalysis data, using wavelets analysis and statistical methods, the temporal characteristics, periodic variation and circulation characteristics of summer precipitation are analyzed. The results are as follows ： （ ! ） There is significant northeast to southwest distribution of summer precipitation in drought and flood years in the Yellow River basin. However,the Hetao Plain where the mean annual precipitation is more than 327 mm, with the spatial anomaly percentage of 27.6% ,is the most sensitive flood region in the area, while the northeast of the Loess Plat- eau where the mean annual precipitation is less than 184 mm, with the spatial anomaly percentage of -27.2% ,is the most sensitive drought region; （2） In the recent 50 years, there is no significant linear trend change of summer precipitation in the reaches, but there are annual rainfall＇s obvious interannual fluctuations. In a word, the precipi- tation is with following fluctuation process： ＇normal - partial less - partial more - normal - partial more - partial less＇; （3）In terms of the wavelet analysis result, basically the summer precipitation＇s quasi-biennial oscillation is significant, abnormal little rain years performance with nine-year fluctuations, unusually much rain years perform- ance with 15-year fluctuations. Moreover,both the quasi-two year period and the quasi-nine year period at negative phase mean obviously rainy, while the quasi-two year period and the quasi-fifteen year period at positive phase de- termine obviously arid. Spatial distribution differences of main period of the Yellow River basin are due to its topog- raphy, geomorphology, altitude and distribution; （4）There are dramatic variations in circulation patterns of the flood and the drought years in the Yellow River basin where precipitation characteristics result from monsoon, west pacific subtropical high, extra tropical cyclone and Baikal cyclone in the northwest area. In the. flood years, the warm moist air from the Bay of Bengal and South China Sea upwellings with the strong meridional monsoon action, combining with the dry cold air mass carried by Baikal cyclone, produces abundant rainfall in the Hetao Plain which locates in the front of long-wave trough
出处
《干旱区地理》
CSCD
北大核心
2012年第5期754-763,共10页
Arid Land Geography
基金
2010气象行业专项(编号:GYHY201006038)
国家自然科学基金(编号:40805009)
关键词
黄河中上游流域
夏季降水异常
小波周期分析
环流形式
middle and upper reache of the Yellow River
drought and flood of summer precipitation
wavelet a-nalysis
circulation pattern
