两种对流参数化方案对辐射能量收支的影响研究  

Influence of two convection schemes on the radiative energy budget

作　　者：李立娟[1] 王斌[1] 

机构地区：[1]中国科学院大气物理研究所大气科学与地球流体力学数值模拟国家重点实验室(LASG),北京100029

出　　处：《气象学报》2009年第6期1080-1088,共9页Acta Meteorologica Sinica

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-Q11-04);财政部/科技部公益性行业(气象)科研专项(GYHY200806007;GYHY200806006;GYHY200906020);中国科学院"十一五"信息化专项"超级计算环境建设与应用"(INFO-115-B01);中国科学院大气物理研究所LASG自由探索项目

摘　　要：利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室的格点大气环流模式(GAMIL)1.0版设计了两组数值模拟实验来研究两种不同的对流参数化方案对辐射能量收支的影响。这两种对流参数化方案分别是:Zhang and McFarlance/Hack方案(简称ZM)和Tiedtke/Nordeng方案(简称TN)。对应的数值模拟实验分别取名为EX_ZM和EX_TN。通过对实验结果的分析表明:在对流过程中,EX_ZM允许深对流和浅对流同时发生,因此两种对流同时在模式低层消耗了更多的水汽,释放了更多的潜热,引起了更大的增温;EX_TN每次只允许一种对流发生,也就避免了不同类型的对流在同一层同时消耗水汽的现象。因此对流过后,EX_ZM的环境空气相对湿度较小,而EX_TN周围空气的相对湿度较大,有利于低云云量的生成和大尺度的凝结,因此EX_TN模拟的低云云量偏多,低层的云水含量偏高,模式低层的云光学厚度偏大,这就使得EX_TN中更多的太阳短波辐射通量被云反射掉,严重低估了模式对短波波段的辐射通量的模拟。此外,不同的对流参数化方案通过改变云的长波发射率和降水,进而影响了模式对长波波段的辐射通量、感热和潜热通量的模拟。The Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics（LASG）,Institute of Atmospheric Physics（IAP）,version 1.0（GAMIL1.0） was used to investigate impacts of two different convective schemes on the energy budget.The two convective schemes are presented by Zhang and McFarlance/ Hack（ZM） and Tiedtke/Nordeng（TN）.Two simulations are performed：one with the ZM scheme（EX-ZM） and the other with the TN scheme（EX_ TN）.The results indicate that,during the convective process,the assumption that the deep and shallow convection clouds can happen at the same time in the ZM scheme is the main reason for more consumption of vapor and more release of heat in the low layers in EX_ ZM,while only one type of convection is allowed to take place in the TN scheme.Hence,the relative humidity of the atmosphere in EX_TN is larger than that in EX-ZM after the convection.The relative humidity of the atmosphere is very important for cloud formation and cloud microphysics processes：the larger the relative humidity is,the more cloud and more condensation there are.Therefore the moister atmosphere favors low cloud formation and large-scale condensation,and more low cloud fraction,cloud water mixing ratio and deeper cloud extinction optical depth are simulated,reflecting more solar radiation flux in EX_TN. This explains why the TN scheme underestimates the net shortwave radiation flux at the top of the atmosphere and at surface. In addition,convection influences longwave radiative,surface sensible and latent heat fluxes through changes in cloud emissivity and precipitation.

关 键 词：对流参数化方案 云量 云光学厚度 云短波辐射强迫 

分 类 号：P426[天文地球—大气科学及气象学]