NASA/Goddard长波辐射方案在GRAPES_Meso模式中的应用研究

本文将NASA（National Aeronautics and Space Administration）/Goddard长波辐射方案引入到GRAPES_ Meso（Global/Regional Assimilation and PrEdiction System_Meso）模式中，对2006年4月中国地区进行了一个月的模拟试验，并与相应的NCEP（National Centers for Environmental Prediction）再分析资料进行了对比分析。试验结果表明:在模拟区域内，使用GRAPES_Meso模式进行24 h、48 h预报得到的晴空大气顶向外长波辐射通量（the clear sky outgoing longwave radiation flux，OLRC）、地面接收到向下长波辐射通量（the clear sky downward longwave radiation flux at ground，GLWC）分布形势与NCEP再分析资料具有较好的对应关系；模式预报24 h、48 h OLRC和NCEP再分析资料月平均误差百分比控制在－10%～＋10%以内，GLWC月平均误差百分比比OLRC略大，但总体上两者误差都在合理和可接受范围之内。OLRC和GLWC 24 h、48 h的预报和NCEP再分析资料的逐日距平相关系数及标准误差的对比显示，模式24 h预报OLRC、GLWC的距平相关系数月平均值分别为0.96、0.98，标准误差月平均值分别为24.54 W m-2、27.23 W m-2；模式48 h预报OLRC、GLWC的距平相关系数月平均值分别为0.9521、0.9804，标准误差月平均值分别为22.43 W m-2、27.64 W m-2。总体上，模式24 h、48 h预报OLRC和GLWC的距平相关系数都在0.93以上，标准误差都在31 W m-2以内，且GLWC预报和NCEP再分析资料的相关性比OLRC略好，OLRC预报与NCEP再分析资料的的标准误差比GLWC略小。通过和RRTM长波辐射方案对比可知，两者的预报水平基本一致。本文研究结果表明，引入NASA/Goddard长波辐射方案后的GRAPES_Meso模式整体上能够较好地预报OLRC和GLWC，该辐射方案可以作为模式GRAPES_Meso的备选辐射方案之一。

Application Research of the NASA/Goddard Longwave Radiative Scheme in the GRAPES_Meso Model

The National Aeronautics and Space Administration (NASA)/Goddard long-wave radiative scheme is integrated into the Global/Regional Assimilation and Prediction System Mesoscale (GRAPES_Meso) model in this study. One month of simulation experiments conducted in China and its nearby areas are compared with the corresponding National Centers for Environmental Prediction (NCEP) reanalysis data recorded in April 2006. The results show that the distribution of the clear-sky outgoing longwave radiation flux (OLRC) at the top of atmosphere and downward long wave radiation flux at ground (GLWC) of 24-and 48-hour forecasts by using the GRAPES_Meso model are in good agreement with the NCEP reanalysis data. The monthly average percentage error of the OLRC of these forecasts is within －10% and 10%. Although the monthly average percentage error of the GLWC is slightly larger than that of the OLRC, both are within a reasonable and acceptable range. The comparison study of the daily averaged anomaly correlation coefficient and standard error of these fluxes of the both forecasts show that the monthly averaged anomaly correlation coefficients of the OLRC and the GLWC of the 24-hour forecast are 0.96 and 0.98, respectively, and that the monthly averaged standard errors are 24.54 W m-2 and 27.23 W m-2, respectively. Those of the OLRC and the GLWC of the 48-hour forecast are 0.95 and 0.98 and 22.43 W m-2 and 27.64 W m-2, respectively. Overall, the daily averaged anomaly correlation coefficient of the OLRC and the GLWC of both 24-hour and 48-hour forecasts are above 0.93, and the daily standard error is within 31 W m-2. Moreover, the correlation of the GLWC and the NCEP reanalysis data is stronger than that of the OLRC, whereas the standard error of the OLRC and the NCEP reanalysis data is smaller than that of the GLWC. A comparison of the longwave radiative schemes of the rapid radiative transfer (RRTM) and the NASA/Goddard models reveal that the forecasting of the two schemes is essentially identical. The results of OLRC and the GLWC show that NASA/Goddard longwave radiative scheme may be appropriate for application to the GRAPES_Meso model.