任荣彩,吴国雄. 2003. 1998年夏季副热带高压的短期结构特征及形成机制[J]. 气象学报, 61(2):180-195, doi:10.11676/qxxb2003.017
1998年夏季副热带高压的短期结构特征及形成机制
ON THE SHORT-TERM STRUCTURE AND FORMATION OF THE SUBTROPICAL ANTICYCLONE IN THE SUMMER OF 1998
投稿时间:2002-08-12  修订日期:2002-10-20
DOI:10.11676/qxxb2003.017
中文关键词:  西太平洋副热带高压  短期结构  上升  下沉  动力学理论  强迫机制
英文关键词:SAWP  Short-term variation  Ascent  Descent forcing mechanism
基金项目:自然科学基金项目(40135020400230014022150340005006);中国科学院知识创新项目ZKCX2SW210
作者单位
任荣彩  
吴国雄  
摘要点击次数: 1945
全文下载次数: 1990
中文摘要:
      通过对1998年7月副热带高压短期结构及其演变的诊断,指出500hPa西太平洋副热带高压内并非均一的下沉运动,而是多处、多时存在上升运动,这是由西太平洋副热带高压的复杂的动力和热力性所决定。诊断还发现,在西太平洋副热带高压脊区下方的近地面层,多存在一个辐散下沉层,这是副热带高压内天气一般多晴空或少云的主要原因。利用动力学理论,研究副热带高压的复杂结构的成因,指出在500hPa副热带高压的西部,高低空风场的分布决定了该区域必然多上升运动;高空强负涡度平流的存在是副热带高压内出现下沉运动的主要强迫机制。
英文摘要:
      The diag nosis of the short-term structure of the subtropical anticyclone over the Western Pacific(SAWP) in the summer of 1998 shows that, other than uniform descent, ascent at 500hPa often exists with in the area of SAWP.These features are determined by the complicated dynamic and thermodynamic structures of the SAWP.Under the 500hPa SAWP ridge, along the ridge line in the planetary boundary layer, there always exist divergence and descent, which greatly accounts for the usual clearness in the SAWP area.This complicat ed structure was also studied by employing atmospheric dynamic theory.It was found that vertical wind shear over the west part of the SAWP that is forced by external forcing should be accompanied by ascent.On the other hand, the negative vorticity advection at higher levels is the major forcing for the appearance of descent over the west of the SAWP.
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