气象科学2017，Vol.37Issue(6)：709-717,9.DOI:10.3969/2017jms.0025
夏季印度洋海盆模与MC区域降水异常联系的进一步分析
A further look at the relationship between Indian Ocean Basin-wide Mode and the Maritime Continent precipitation anomalies during boreal summer
摘要
Abstract
By using the monthly mean Sea Surface temperature(SST) data from Hadley Centre and the NCEP/NCAR monthly reanalysis,and removing out the long term trend and simultaneous influences of two kinds of ENSO from the Indian Ocean Basin-wide Mode(IOBM) index IIOB,the modified IOBM index as ImIOB was defined and the variations of IOBM and its associated precipitation anomalies over the Maritime Continent(MC) were analyzed.Results demonstrate that,when IOBM in its warm phase,Indian O cean region undergoes an anomalous warm state in different seasons.The vertical motion of atmosphere over Indian Ocean changes large from a season to another.During boreal summer,the atmospheric updraft in most areas of Indian Ocean is possibly induced by the warmer sea temperature anomalies.It is found that the IOBM index ImIOB varies with periods of 3-5 years.When it is in its positive phase,SST in regions from the Indian Ocean to East China Sea is anomalously warmer.Precipitation in the western part of MC region is significantly more than the normal while it is less than the normal in the northeastern part of MC region.The anomalous convergence in the lower troposphere and anomalous divergence in the upper troposphere lead to both the strengthening upward motion and water vapor convergence there,inducing more than normal rainfall in the western part of MC.In the northeastern part of MC region,the anomalous divergence in the lower troposphere and anomalous convergence in the upper troposphere is observed,which do not facilitate occurrences of more precipitation there.In the lower troposphere,the divergent flows emanating from eastern part of MC and West Pacific induce a pair of anomalous anticyclones to merge in northern and southern tropics,which look almost symmetrical about the equator.The abnormal diabatic heating over equatorial Indian Ocean excites the eastward propagating Kelvin wave,strengthening easterly anomaly along equator.This strengthened easterly facilitates the intensification of Rossby waves in the north and south tropical regions outside the MC region.These results are helpful for our better understanding the formation of MC precipitation anomaly and tropical sea-land-atmosphere interactions.关键词
北半球夏季/印度洋海盆模/海洋性大陆/降水异常Key words
Boreal summer/Indian Ocean Basin-wide Mode/Maritime Continent/Precipitation anomaly分类
天文与地球科学引用本文复制引用
汪婉婷,管兆勇,许琪,王悦..夏季印度洋海盆模与MC区域降水异常联系的进一步分析[J].气象科学,2017,37(6):709-717,9.基金项目
国家自然科学基金资助项目(41330425 （）
40475028) （）
江苏省优势学科建设项目(PAPD) （PAPD）
