摘要
使用一个高分辨率的公用大气环流模式(CAM5.1)研究我国东部地区人为气溶胶对东亚夏季风爆发和推进过程的影响。结果表明,CAM5.1模式能很好地模拟出南海夏季风爆发前后大尺度环流的季节性转变。南海夏季风在中国东部地区人为气溶胶的影响下提前2候爆发,并且可能是影响1993年后南海夏季风提前爆发的重要原因。人为气溶胶使得低纬度地区的东西风分界线在5月中旬明显向东扩展,南海地区出现显著的西/西南风差值气流,同时赤道纬向西风提前向北增强。人为气溶胶中硫酸盐和黑碳气溶胶含量的季节变化通过改变大气的热力结构,影响我国东部地区大气低层环流场,减弱夏季风前期北上的西南风暖湿气流,而相反地增强了其盛期在华北地区的偏南风分量,造成东亚夏季风北边缘从5月上旬—6月初缓慢北移至长江中下游地区,而后在7月中旬加速向北推进,且到达的最北位置要偏北1个纬度。
The effect of anthropogenic aerosols over the eastern China on East Asian summer monsoon （EASM） onset and its northward advancement is investigated using a high resolution Community Atmosphere Model Version 5.1 （CAM5.1）.Results show that the seasonal transition characteristics of large-scale atmospheric circulation during the onset of South China Sea summer monsoon （SCSSM） are well reproduced in CAM5.1 model.An earlier SCSSM onset is detected due to the anthropogenic aerosols,implying that the anthropogenic aerosols probably play an important role in the observed earlier SCSSM onset around 1993.The aerosols-induced earlier SCSSM onset is further manifested by an eastward shift of the boundary between easterly and westerly winds over the low latitudes in mid-May,together with enhanced westerly/southwesterly winds over the South China Sea and northward expanded equatorial zonal wind.The seasonal variations of sulfate and black carbon can lead to the changes in low-level circulation over the eastern China by changing the thermal structure,thus weakening the southwest winds in the early period of EASM,and conversely strengthening the southerly winds over the North China in the prime period.Therefore,the northern edge of EASM slowly moves to the middle and lower reaches of Yangtze River during May to early June and then advances northward quickly until mid-July.As a result,the anthropogenic aerosols act to push the north edge of EASM farther.
出处
《热带气象学报》
CSCD
北大核心
2014年第5期952-962,共11页
Journal of Tropical Meteorology
基金
国家重点基础研究发展计划项目(2010CB428505)
国家自然科学基金项目(41275094)
江苏高校优势学科建设工程资助项目(PAPD)
江苏省高校"青蓝工程"
江苏省研究生培养创新工程(KYLX_0831)共同资助
