大气科学
大氣科學
대기과학
CHINESE JOURNAL OF ATMOSPHERIC SCIENCES
2010年
2期
275-289
,共15页
随机碰并模式%层状云降水%雷达反射率%PMS观测资料
隨機踫併模式%層狀雲降水%雷達反射率%PMS觀測資料
수궤팽병모식%층상운강수%뢰체반사솔%PMS관측자료
stochastic model%stratiform precipitation%radar reflectivity%PMS observation data
层状云由于在水平上较为均匀,可以用一维模式来模拟其云微物理过程.因此,本文使用一个包含详细微物理过程的一维层状云分档模式结合地面Doppler雷达、PMS观测资料,对2007年7月1日吉林省一次锋面抬升引起的层状云降水系统进行了模拟研究.计算结果详细地刻画了水滴、霰、雪花和冰晶粒子谱分布、含水量在垂直高度上的分布与变化,并定量分析了该例中冰晶层、混合层和暖层中凝华、凝结、碰并等微物理过程对粒子谱型的影响,以及冰晶层、混合层和暖层对地面降水的贡献率.结果表明,在该例中,冰晶层对混合层的播撒以直径D＜300 μm的小冰晶粒子为主.从混合层播撒D>100 μm的水滴粒子以及未完全融化的冰晶粒子对暖层中小云滴粒子的碰并收集作用较强,同时,一部分降水粒子在暖层内可通过随机碰并机制产生.三层云对降水的贡献分别为3.5%、38.5%和58%.三层云中若缺少混合层,地面降水仅为0.475 mm/h,谱宽920μm,且雨滴粒子数浓度较高;若无暖层,降水时间滞后,雨强增加缓慢,地面降水达0.807 mm/h,雨滴粒子谱宽达1500μm;无冰晶层时,降水强度与三层俱全时的模拟结果基本一致,降水及雨滴谱的改变非常微弱.
層狀雲由于在水平上較為均勻,可以用一維模式來模擬其雲微物理過程.因此,本文使用一箇包含詳細微物理過程的一維層狀雲分檔模式結閤地麵Doppler雷達、PMS觀測資料,對2007年7月1日吉林省一次鋒麵抬升引起的層狀雲降水繫統進行瞭模擬研究.計算結果詳細地刻畫瞭水滴、霰、雪花和冰晶粒子譜分佈、含水量在垂直高度上的分佈與變化,併定量分析瞭該例中冰晶層、混閤層和暖層中凝華、凝結、踫併等微物理過程對粒子譜型的影響,以及冰晶層、混閤層和暖層對地麵降水的貢獻率.結果錶明,在該例中,冰晶層對混閤層的播撒以直徑D＜300 μm的小冰晶粒子為主.從混閤層播撒D>100 μm的水滴粒子以及未完全融化的冰晶粒子對暖層中小雲滴粒子的踫併收集作用較彊,同時,一部分降水粒子在暖層內可通過隨機踫併機製產生.三層雲對降水的貢獻分彆為3.5%、38.5%和58%.三層雲中若缺少混閤層,地麵降水僅為0.475 mm/h,譜寬920μm,且雨滴粒子數濃度較高;若無暖層,降水時間滯後,雨彊增加緩慢,地麵降水達0.807 mm/h,雨滴粒子譜寬達1500μm;無冰晶層時,降水彊度與三層俱全時的模擬結果基本一緻,降水及雨滴譜的改變非常微弱.
층상운유우재수평상교위균균,가이용일유모식래모의기운미물리과정.인차,본문사용일개포함상세미물리과정적일유층상운분당모식결합지면Doppler뢰체、PMS관측자료,대2007년7월1일길림성일차봉면태승인기적층상운강수계통진행료모의연구.계산결과상세지각화료수적、산、설화화빙정입자보분포、함수량재수직고도상적분포여변화,병정량분석료해례중빙정층、혼합층화난층중응화、응결、팽병등미물리과정대입자보형적영향,이급빙정층、혼합층화난층대지면강수적공헌솔.결과표명,재해례중,빙정층대혼합층적파살이직경D＜300 μm적소빙정입자위주.종혼합층파살D>100 μm적수적입자이급미완전융화적빙정입자대난층중소운적입자적팽병수집작용교강,동시,일부분강수입자재난층내가통과수궤팽병궤제산생.삼층운대강수적공헌분별위3.5%、38.5%화58%.삼층운중약결소혼합층,지면강수부위0.475 mm/h,보관920μm,차우적입자수농도교고;약무난층,강수시간체후,우강증가완만,지면강수체0.807 mm/h,우적입자보관체1500μm;무빙정층시,강수강도여삼층구전시적모의결과기본일치,강수급우적보적개변비상미약.
The stratiform cloud can be simulated with a one-dimensional model,duo to its uniform horizontal distri-bution of physical characters.In this paper,a bin category model including detailed microphysical processes has been used to simulate a precipitation of the stratiform cloud on l June 2007 in Jilin Province,China.The simulation re-sults depict explicitly both the spectrums of water droplet,ice crystal,graupel,and snow and the vertical distribu-tion of the water content,The comparison between the simulation results and the data observed by Doppler radar and the Particle Measurement System(PMS)indicates that different microphysical processes contribute differently to the forming of particle spectrum within three layers,i.e. ice layer,mixed layer,and warm layer.The results show that the seeding particles from the ice layer to the mixed layer are ice crystals with diameter D>300μm.See-ded from the mixed layer to the Warm layer,both melting ice particles and water droplets with D>100 μm could col-lect abundant cloud droplets in the Warm layer,leading to an obvious increase of rain intensity in the warm layer.Meanwhile,some rain droplets can be produced by coalescing among small cloud particles in the warm layer. The contribution rates of the three layers to rain intensity are 3.5%、38.5%and 58%respectively.The rainfall intensity near the ground and the droplet spectrum width are considerably different when there is no mixed layer or warm lay-er,i.e.,0.475 mm/h and 920 μm for lack of the mixed layer,wheteas 0.807 mm/h and 1500 μm without the warm layer. With the absence of ice layer,there is no big difference in both rainfall intensity and water droplet spectrum,and the simulation result is close to that with presence of all the three layers.
