摘要
根据湿位涡(MPV)定义的南海季风爆发时间序列,选出了南海季风爆发的早晚年和强弱年,利用EOF分析了早晚年地表温度和海表温度时空变化的差异,并分别对南海夏季风爆发早晚年和正常年进行了数值模拟。结果发现,在18—28候地表温度在40°N以北东部地区较高,西部地区较低,我国东部沿海地区和印度半岛的地表温度增温较快,以及台湾附近海域的海表温度较低,都会使南海夏季风提前爆发。通过对强弱季风年潜热通量和感热通量的合成分析发现,冬季感热和潜热在强弱年的主要差异在海洋上和近海地区,合成距平呈现沿海岸线的东北-西南向的带状分布,强年沿岸为正距平,弱年为负距平。春季的差异往往与冬季的分布相反。冬、春季下垫面热力异常引发的海陆热力差异的变化对南海季风爆发早晚和强弱有重要的影响。
The earlier and later onset years and stronger and weaker years of the South China Sea summer monsoon（SCSSM） are picked out with the SCSSM Index defined by moist potential vorticity（MPV）.By means of EOF,the surface temperature differences of spatial and temporal variations between earlier and later onset years of the SCSSM are analyzed.Three types of years with early,normal,and late EASM onset are selected and the EASM regimes are numerically simulated.It is revealed that when the land surface temperature is higher in the eastern part from 40 °N to north and lower in the western part,and it rises faster in eastern coastal regions and Indian Peninsula during 18—28 pentads,while sea surface temperature in Taiwan Strait is lower,the early onset of the EASM can be expected.The composite analysis of the anomaly fields of the surface sensible heat flux（SHF） and the surface latent heat flux（LHF） in these strong and weak years is conducted.The anomaly fields of the SHF and the LHF in the previous winters occur over and close to the ocean and show the banded distribution going through northeast to southwest along the coastline.There are the positive anomaly fields in these strong and the negative anomaly fields in these weak years.The anomaly fields in spring is usually opposite in winter.The previous analysis validates that the change of the land-sea thermal contrast caused by the underlying surface thermal anomalies have important effect on the onset and intensity of the SCSSM.
出处
《热带气象学报》
CSCD
北大核心
2011年第2期209-218,共10页
Journal of Tropical Meteorology
基金
科技部公益性行业专项(GYHY200906016)
国家自然科学基金青年项目(41005047)
南京信息工程大学科研基金共同资助
关键词
气候学
数值试验
南海夏季风
早晚年和强弱年
表面温度和表面通量
climatology
numerical simulations
South China Sea summer monsoon
earlier and later onset years and stronger and weaker years
surface temperature and surface flux
