热带西北太平洋与东南印度洋对流活动年际变化联系的年代际改变
投稿时间:2018-08-29  修订日期:2018-11-01  点此下载全文
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作者单位E-mail
张奔奔 南京信息工程大学大气科学学院 zbb_zhangbb@126.com 
管兆勇 南京信息工程大学 guanzy@nuist.edu.cn 
张萌萌 南京信息工程大学  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目);公益性行业(气象)科研专项(GYHY201406024)以及江苏省优势学科建设项目(PAPD)
中文摘要:利用美国NOAA卫星观测OLR(Outing Longwave Radiation)资料以及NCEP/NCAR、CMAP月平均资料,利用合成分析等方法,研究了热带西北太平洋(10?20癗,125?140癊)与热带东南印度洋(5?15癝,90?105癊)对流活动异常的联系。结果表明:热带西北太平洋与东南印度洋对流活动异常的联系有显著的年代际变化。在1980年代至1990年代这个时间段存在显著的正相关,而在1990年到21世纪初这个时间段则有显著的负相关,其后时段又转变为正相关。合成分析表明,热带西北太平洋与东南印度洋对流活动正相关时,两地区均存在反气旋性环流,低层辐散,高层辐合,对流活动弱,不利于降水的产生,有降水负异常;当热带西北太平洋与东南印度洋对流活动负相关时,两地区环流异常存在明显差别,热带东南印度洋有正的海温异常,高层辐散,低层辐合,有上升运动,对流活动强,有降水正异常,而热带西北太平洋则相反。在热带西北太平洋和热带东南印度洋之间的斜向垂直环流圈将这两个地区联系起来,并决定了这两个地区对流活动负相关关系的形成。
中文关键词:热带西北太平洋,热带东南印度洋,对流活动,年际变化,年代际变化
 
Interdecadal change in relations of convective activities over regions between tropical Northwest Pacific and the Southeast tropical India Ocean
Abstract:Using the OLR(Outgoing Longwave Radiation) date from NOAA and the NECP/NCAR reanalysis along with CMAP precipitation data, we have investigated the interdecadal change in relations of convective activity between the tropical Northwest Pacific(10°-20°N,125°-140°E) and the Southeast India ocean(5°-15°S,90°-105°E). The results demonstrate that there are significant interdecadal variations in convective activity between the tropical Northwest Pacific and the south-eastern Indian Ocean, with a significant positive correlation period from 1980s through to 1990s, and a significant negative correlation period from the 1990s through to the beginning of the twenty-first century, and another positive correlation period after 2004. When the convective activities in the tropical Northwest Pacific and the Southeast Indian Ocean are positively correlated, there are two anti-cyclonic circulations over these two regions, respectively, which lead to weak convective activity and negative precipitation anomalies in these two places. When the convective activities in the tropical Northwest Pacific and the southeastern Indian Ocean are negatively correlated, the distinctly different circulation anomalies are observed in these two regions. Accordingly, during the negative correlation period, the positive sea temperature anomalies are found in the tropical Southeast Indian Ocean where the upper level divergence and lower level convergence facilitate the anomalous strong convections and more than normal precipitation. This scenario is opposite in the tropical Northwest Pacific. The slanted vertical circulation between the tropical Northwest Pacific and the tropical Southeast Indian Ocean connects these two regions, which induces the negative correlation between convection activities over the two regions.
keywords:Tropical Northwest Pacific, Tropical Southeast India Ocean, Convective activities, Interannual variation, Interdecadal variation
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