摘要
利用极端降水量集中度和集中期讨论西北地区东部夏季极端降水量的非均匀性分布特征。结果表明:西北地区东部夏季极端降水量集中度与集中期的空间差异并不大;西北地区东部夏季极端降水量的季节内分配状况同夏季极端降水量存在较好的相关性,极端降水量越集中、集中期越早,则极端降水量越少,反之亦然;东亚夏季风同西北地区东部夏季极端降水量、极端降水量集中期存在负相关,与极端降水量集中度存在正相关。
Based on 33 weather stations daily precipitation datasets in the east of Northwest China from 1960 to 2004, the extreme precipitation threshold of different stations are defined by centesimal value method, by introducing extreme precipitation concentration degree and period which reflects time distribution feature. Intra-seasonal inhomogeneity characteristics of extreme precipitation are analyzed by the new parameter in the east of Northwest China. The result show that the summer extreme precipitation shows increasing trend in the east of Northwest China. From long term tendency, it is found that the summer extreme precipitation displays clear inter-annual variability since 1980s. Moreover, it shows distinct inter-decadal change in the recent 45 years. It is proved that inconspicuous spatial difference is reflected by extreme precipitation concentration degree and period. It is also found that there is high relativity between summer extreme precipitation concentration degree and concentration period and summer extreme precipitation in the east of Northwest China. If the summer extreme precipitation concentration degree leans to high and concentration period leans to early date, the extreme precipitation leans to more amount, vice versa. It is proved that summer extreme precipitation concentration degree and period exhibit remarkable inter-decadal period vibration in recent 45 years. Despite summer total precipitation showing decreasing trend in the east of Northwest China, the summer extreme precipitation displays increasing trend, therefore it shows that there exist negative correlation between summer extreme precipitation, summer extreme precipitation concentration period and east Asian summer monsoon, but there is positive correlation between summer extreme precipitation concentration degree and east Asian summer monsoon, moreover its relativity is more remarkable between extreme precipitation.
出处
《应用气象学报》
CSCD
北大核心
2008年第1期111-115,共5页
Journal of Applied Meteorological Science
基金
国家自然科学基金项目(40375032,40675043)
中国气象局兰州干旱气象研究所干旱气象科学研究基金项目(IAM200609)
中国气象局成都高原气象研究所高原气象开放基金项目(LPM2007002)共同资助
关键词
西北地区东部
夏季极端降水
非均匀性
the East Part of Northwest China
summer extreme precipitation
inhomogeneity
