doi:  10.3878/j.issn.1006-9895.1812.18204
热带气旋“苏迪罗”(2015)海上活动时段降水物理过程模拟诊断研究——海表温度敏感性试验

Diagnostic and Numerical Study on Surface Rainfall Processes of Tropical Cyclone Soudelor (2015) over Sea——Sensitivity Experiment on the Roles of Sea Surface Temperature
摘要点击 345  全文点击 66  投稿时间:2018-07-26  修订日期:2018-11-23
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基金:  国家重点基础研究发展计划,国家自然科学基金
中文关键词:  降水物理过程  热带气旋 海表温度  三维降水诊断方程
英文关键词:  Rainfall  process, Tropical  cyclone, Sea  surface temperature, Three-dimensional WRF-based precipitation equation
           
作者中文名作者英文名单位
王晓慧WANG Xiaohui中国科学院大气物理研究所,中国科学院大学,宁波市海曙区气象局
崔晓鹏CUI Xiaopeng中国科学院大气物理研究所
郝世峰Hao Shifeng
姜嘉俊Jiang Jiajun
引用:王晓慧,崔晓鹏,郝世峰,姜嘉俊.2019.热带气旋“苏迪罗”(2015)海上活动时段降水物理过程模拟诊断研究——海表温度敏感性试验[J].大气科学
Citation:WANG Xiaohui,CUI Xiaopeng,Hao Shifeng,Jiang Jiajun.2019.Diagnostic and Numerical Study on Surface Rainfall Processes of Tropical Cyclone Soudelor (2015) over Sea——Sensitivity Experiment on the Roles of Sea Surface Temperature[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      利用WRF模式,在前期工作(王晓慧等,2018)模拟试验(CTL试验)基础上,设计敏感性试验(SNC试验),借助三维降水诊断方程,分析揭示了海表温度(SST)变化对热带气旋(TC)“苏迪罗”(2015)海上活动时段降水物理过程的可能影响。由于TC活动引起的海水上翻等过程影响,CTL试验(SST随时间变化)和SNC试验(SST固定为初始值)的SST存在明显差异(CTL试验平均SST低于SNC试验)。对比分析表明:两试验模拟的海上时段TC路径差异不大,但SNC试验模拟的TC强度较CTL试验偏强;TC环流区域内,两试验垂直速度差值在对流层基本为正(SNC试验上升运动更强),随着SST差值不断增大,垂直运动差值也不断加大;SNC试验的降水强度(PS)大于CTL试验,但PS差值随SST差值增大并非线性变化,体现了PS变化的复杂性;SNC试验的QWVA(垂直积分的三维水汽通量辐合/辐散率)均基本大于CTL试验(后期差别更大),SST的不同可通过影响垂直运动,造成QWVA的差异,进而影响PS;分析时段内,两试验TC环流区域大气均持续变干(正值QWVL),且存在较明显海面蒸发(正值QWVE),其中,两试验之间的QWVL差异不明显,但SNC试验的QWVE总体上强于CTL试验(尤其是分析时段中后期);两试验间云相关过程变率差异的时间变化复杂,最大差异量级与QWVE相当;SST对水凝物发展和深对流活动有一定影响,伴随SST差异的逐渐增大,水凝物含量差异也逐渐增大,液相水凝物中,雨滴差异较大,而与液相水凝物相比,冰相水凝物差异更为突出,尤其是较大的冰相粒子(雪和霰);SNC试验中,零度层下更多的霰粒子和雨滴,在更强上升运动配合下,有助于云滴和雨滴碰并(Pacw>)及霰粒子融化(Pgmlt)微物理过程的加强,进而造成更强降水。TC环流区域时间和空间平均的物理量对比分析揭示,两试验降水物理过程定性上基本相似,但定量上存在明显不同,SNC试验的PS与CTL试验相比,增幅达8.8%,这种差异主要源于降水宏、微观物理过程的差异,其中,不同SST环境下QWVE的差异最为显著。
Abstract:
      To investigate the possible impact of sea surface temperature(SST) variations on surface rainfall processes of tropical cyclone Soudelor over sea, sensitivity simulation was conducted using WRF model and the 3D WRF-based precipitation equation based on the previous study(Wang et al.,2018).Because of cold water upwelling processes induced by TC, SST in CTL experiment (SST changed with time) had much difference with that of SNC experiment (SST remained constant). The results show that the difference of track over sea was small in the two experiments,but the simulated intensity in SNC experiment was stronger than that in CTL experiment.Inside the TC circulation,the difference of the vertical velocity between the two tests was basically positive in the troposphere(SNC test had stronger updrafts),as the difference of SST increases, the vertical motion difference also rises. PS in SNC test was increased in comparison with CTL test, but the difference of PS among the two experiments increased non-linearly with the SST difference, which reflected the complicacy of PS variation. QWVA of the SNC experiment was basically larger than that of the CTL test (especially in later period),the SST difference can affect the vertical motion and cause QWVA difference, which in turn affected PS.During the research period of the two experiments,the atmosphere inside the TC circulation continuously got drier (positive QWVL), and evaporation from sea surface(positive QWVE) was obvious,.there was little difference of QWVL between the two tests,however, QWVE of the SNC test was generally stronger than the CTL test (especially at the middle and later stages). The temporal variation of the change rate of hydrometeor-related processes among the two tests was complex, but the magnitude of the maximum difference was comparable to that of QWVE.SST had impacts on growth of the cloud hydrometeor contents and deep convection,the variation of hydrometeor contents increased gradually with the rising SST difference between the two experiments,the content of raindrops of liquid-phase hydrometeors was in great difference,with a more obvious difference in ice-phase hydrometeors, particularly the large ice particles (snow and graupel).In the SNC experiment,much more graupel particles and raindrops below the melting layer and concomitant stronger updrafts,contribute to the occurrence and enhancement of Pracw and Pgmlt, finally enhance precipitation. By making a comparative analysis of regional and temporal averaged macroscopic and microphysical processes related to rainfall within the TC circulation between the CTL and SNC experiments,the result showed that rainfall processes among the two tests were qualitatively similar, but had a significantly quantitative difference. Compared with the CTL test, PS of the SNC test increased 8.8%, mainly resulting from the difference in macroscopic and microscopic physical processes of precipitation among the two tests. The variation of QWVE was obvious with different SST.
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