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(LASG/IAP)新版大气环流模式SAMIL(Spectral Atmosphere Model of IAP LASG),分析比较了Manabe和Tiedtke两种对流方案对降水和潜热加热空间结构的模拟性能....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(LASG/IAP)新版大气环流模式SAMIL(Spectral Atmosphere Model of IAP LASG),分析比较了Manabe和Tiedtke两种对流方案对降水和潜热加热空间结构的模拟性能.结果表明,Tiedtke方案模拟的对流降水偏强,层状降水偏弱,致使层状降水占总降水比例低于观测.与此相比,Manabe方案较为合理地再现了沿赤道的层状降水中心,但其模拟的孟加拉湾降水中心向东向北伸展,在高原下游有虚假强降水出现.通过比较两种对流方案模拟的潜热加热空间结构,结果表明Tiedtke方案的模拟结果远较Manabe方案合理,表现为与观测一致的位于对流层中层的对流加热峰值,以及0℃层之上的层状加热与其下的冷却.而Manabe方案模拟的对流加热峰值所在高度较观测偏低,大致位于700 hPa.另外对于层状加热,Manabe方案模拟不出0℃层以下的冷却,而表现为整层加热.温度、比湿等要素的Taylor图表明:Tiedtke方案的模拟结果与ERA40,NCEP再分析资料的相关系数更高,尤其是对流层高层200 hPa温度的模拟.文中同时提出Tiedtke方案下层状降水模拟失真的可能原因是层状降水方案忽略了积云对流过程中卷出水凝物的影响,该猜想通过敏感性试验得到证实.展开更多
Using the latest version of SAMIL (Spectral Atmosphere Model of IAP LASG) developed by LASG/IAP,we evaluate the model performance by analyzing rainfall,latent heating structure and other basic fields with two differen...Using the latest version of SAMIL (Spectral Atmosphere Model of IAP LASG) developed by LASG/IAP,we evaluate the model performance by analyzing rainfall,latent heating structure and other basic fields with two different convective parameterization schemes:Manabe Scheme and Tiedtke Scheme.Results show that convective precipitation is excessively overestimated while stratiform precipitation is underestimated by Tiedtke scheme,thus causing less stratiform rainfall proportion compared with TRMM observation.In contrast,for Manabe scheme stratiform rainfall belt is well simulated,although precipitation center near Bay of Bengal (BOB) spreads eastward and northward associated with unrealistic strong rainfall downstream of the Tibet Plateau.The simulated latent heating structure indicates that Tiedtke scheme has an advantage over Manabe scheme,as the maximum convective latent heating near middle of troposphere is well reproduced.Moreover,the stratiform latent heating structure is also well simulated by Tiedtke scheme with warming above freezing level and cooling beneath freezing level.As for Manabe scheme,the simulated maximum convective latent heating lies near 700 hPa,lower than the observation.Additionally,the warming due to stratiform latent heating extends to the whole vertical levels,which is unreasonable compared with observation.Taylor diagram further indicates that Tiedtke scheme is superior to Manabe scheme as higher correlation between model output and observation data is achieved when Tiedtke scheme is employed,especially for the temperature near 200 hPa.Finally,a possible explanation is addressed for the unrealistic stratiform rainfall by Tiedtke scheme,which is due to the neglect of detrained cloud water and cloud ice during convective process.The speculation is verified through an established sensitivity experiment.展开更多
文摘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(LASG/IAP)新版大气环流模式SAMIL(Spectral Atmosphere Model of IAP LASG),分析比较了Manabe和Tiedtke两种对流方案对降水和潜热加热空间结构的模拟性能.结果表明,Tiedtke方案模拟的对流降水偏强,层状降水偏弱,致使层状降水占总降水比例低于观测.与此相比,Manabe方案较为合理地再现了沿赤道的层状降水中心,但其模拟的孟加拉湾降水中心向东向北伸展,在高原下游有虚假强降水出现.通过比较两种对流方案模拟的潜热加热空间结构,结果表明Tiedtke方案的模拟结果远较Manabe方案合理,表现为与观测一致的位于对流层中层的对流加热峰值,以及0℃层之上的层状加热与其下的冷却.而Manabe方案模拟的对流加热峰值所在高度较观测偏低,大致位于700 hPa.另外对于层状加热,Manabe方案模拟不出0℃层以下的冷却,而表现为整层加热.温度、比湿等要素的Taylor图表明:Tiedtke方案的模拟结果与ERA40,NCEP再分析资料的相关系数更高,尤其是对流层高层200 hPa温度的模拟.文中同时提出Tiedtke方案下层状降水模拟失真的可能原因是层状降水方案忽略了积云对流过程中卷出水凝物的影响,该猜想通过敏感性试验得到证实.
基金supported by Special Fund Project of the Ministry of Science and Technology (Grant No. GYHY200806006)Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-Q11-01)National Natural Science Foundation of China (Grant Nos. 40925015,40875034 and 40821092)
文摘Using the latest version of SAMIL (Spectral Atmosphere Model of IAP LASG) developed by LASG/IAP,we evaluate the model performance by analyzing rainfall,latent heating structure and other basic fields with two different convective parameterization schemes:Manabe Scheme and Tiedtke Scheme.Results show that convective precipitation is excessively overestimated while stratiform precipitation is underestimated by Tiedtke scheme,thus causing less stratiform rainfall proportion compared with TRMM observation.In contrast,for Manabe scheme stratiform rainfall belt is well simulated,although precipitation center near Bay of Bengal (BOB) spreads eastward and northward associated with unrealistic strong rainfall downstream of the Tibet Plateau.The simulated latent heating structure indicates that Tiedtke scheme has an advantage over Manabe scheme,as the maximum convective latent heating near middle of troposphere is well reproduced.Moreover,the stratiform latent heating structure is also well simulated by Tiedtke scheme with warming above freezing level and cooling beneath freezing level.As for Manabe scheme,the simulated maximum convective latent heating lies near 700 hPa,lower than the observation.Additionally,the warming due to stratiform latent heating extends to the whole vertical levels,which is unreasonable compared with observation.Taylor diagram further indicates that Tiedtke scheme is superior to Manabe scheme as higher correlation between model output and observation data is achieved when Tiedtke scheme is employed,especially for the temperature near 200 hPa.Finally,a possible explanation is addressed for the unrealistic stratiform rainfall by Tiedtke scheme,which is due to the neglect of detrained cloud water and cloud ice during convective process.The speculation is verified through an established sensitivity experiment.
