姚慧茹,李栋梁. 2017. 1981-2012年西北东部夏季降水不同强度雨日变化及其环流特征的对比分析[J]. 气象学报, ():-, doi:10.11676/qxxb2017.032
1981-2012年西北东部夏季降水不同强度雨日变化及其环流特征的对比分析
Contrast analysis on the atmospheric circulation related to summer precipitation days of different intensity in the eastern Northwest China during 1981-2012
投稿时间:2016-09-28  最后修改时间:2017-01-28
DOI:10.11676/qxxb2017.032
中文关键词:  西北东部,降水日数,降水强度,环流特征
英文关键词:Eastern Northwest China, precipitation days, precipitation intensity, character of atmosphere circulation
基金项目:公益性行业(气象)科研专项(GYHY201506001-1,GYHY201306027,GYHY201006038 )、国家自然科学基金项目(91337109)、2014年江苏省普通高校研究生科研创新计划项目(KYLX_0830)、江苏高校优势学科建设工程资助项目(PAPD);其它;高校基金
作者单位E-mail
姚慧茹 南京信息工程大学大气科学学院/气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室 huiru_yao@126.com 
李栋梁 南京信息工程大学大气科学学院/气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室 lidl@nuist.edu.cn 
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中文摘要:
      本文利用1981-2012年西北东部地区198个台站的逐日气象观测数据和Era-Interim再分析资料,分析了近32a西北东部地区夏季不同强度降水的雨日和雨量的变化特征,并对比了产生不同强度降水的大气环流系统的异同。结果表明,西北东部夏季降水以小雨和中雨为主,二者占夏季雨日的90%以上、占夏季雨量的70%左右。小雨日数占总雨日的比率在空间上自东南向西北递增;中雨、大雨、暴雨和(特)大暴雨日数的比率自东南向西北递减。夏季小雨、中雨日数和降水量均呈减少的趋势,21世纪初的减少速率慢于80~90年代;暴雨则呈略微增多的趋势。通过对1981年和2003年的个例分析发现,乌拉尔山阻塞高压、蒙古气旋和西北太平洋副热带高压增强西伸时,有利于北方干冷气流和南方暖湿气流在西北东部交汇,降水较多;反之则降水较少。在冷、暖空气均增强的背景下,若冷、暖气团的交界线偏南,西北东部主要受北方冷气团控制,南边界的水汽输送较微弱,易发生小雨;若冷、暖气团的交界线偏北,西北东部主要受到南方暖湿空气的影响,南边界的水汽输送和辐合较强,多出现强降水,降水强度取决于水汽的强度和上升运动的高度。
英文摘要:
      Using a daily dataset constituting of 198 stations in the eastern part of Northwest China and Era-Interim reanalysis data during 1981-2012, the tendency of days and amount of summer precipitation in different types are investigated. Moreover, the similarities and differences of atmosphere circulation with different types of precipitation are compared. Major results show that light rain and moderate rain are the major types of precipitation in summer, which account for more than 90% of summer rainy days and about 70% of amount. Spatially, proportion of light rain days increases from southeast to northwest, while proportion of moderate rain days, heavy rain days and torrential rain days decrease from southeast to northwest. Days of light rain and moderate rain have experienced significant decline during the study period, as well as the amount of precipitation. Large decline is found in 1980s and 1990s, while precipitation days and amount have slowly decline in recent several years. On the other hand, days and amount of torrential rain have a slightly growing trend. Through analyzing cases of 1981 and 2003, it is found that when Ura blocking high and Mongolian cyclone are strengthened and there is west extension of the subtropical high, which may give rise to enhancement of cold air flow from north and warm air flow from south, the cold air and the warm one may well converge in the east part of northwestern China and precipitation will increase, otherwise it will decrease. It is also indicated that under the condition of both cold air and warm air are enhanced, light rain is mainly controlled by north cold current, in such a situation the boundary line between cold and warm air mass is laid to the south and the water vapor transport in the south boundary is relatively weak. while moderate rain, heavy rain and torrential rain are mainly influenced by warm and humid air from south which lead to the boundary line laid to the north, meanwhile the water vapor transport and its convergence in the south boundary is strengthened, under these circumstances rainfall intensity depends on the input capacity of moisture and the rising height of ascending motion.
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