Research On Automatic Parameterization Method And Application Of Atmospheric Radiation Absorptio

Atmospheric radiation absorption parameterization is an important part of various meteorological models,and can directly affect the accuracy of the calculation model results in the radiation absorption process.At present,the commonly used atmospheric radiation absorption parameterization scheme is the correlation k-distribution scheme（CKD）,and the key problem of the CKD scheme is how to deal with the gaseous overlapping absorption in the infrared band.In the past decades,several schemes have been proposed for handling gaseous overlapping bands,but most of these methods all require manual operation and the accuracy is limited by manual operation.In this thesis,two automatic methods are proposed for gas absorption calculation based on CKD,namely finding point method（FPM）and re-optimized method（ROM）,which avoid errors caused by manual operation and improve the accuracy and the speed of gaseous absorption calculation.The application of them in satellite radiation transmission simulation,Weather Research and Forecast Model（WRF）precipitation simulation and climate prediction are realized.The main works and conclusions are summarized as following:（1）The FPM and ROM are proposed based on the sequential quadratic programming.Compared with the line-by-line（LBL）results under standard profiles,the resulting accuracy of the two methods is higher than rapid radiative transfer model for general circulation models（RRTMG）.Under realistic profiles,the accuracy of FPM and ROM is slightly lower than that their accuracy under standard profiles but still higher than RRTMG.（2）The application of FPM and ROM in satellite brightness temperature simulation is realized,and high accuracy is obtained.Compared with LBL in the brightness temperature simulation under the standard profiles,the accuracy of FPM in 7.1μm channel is lower than that of Radiative Transfer for the Television Observation Satellite Operational Vertical Sounder（RTTOV）.For the real profiles,the accuracy of FPM in 7.1μm and 13.5μm channels is lower than that of RTTOV.The accuracy of ROM is better than RTTOV in all channels,but lower than FPM in a few results.In general,FPM and ROM can achieve very good accuracy in satellite infrared remote sensing.（3）The application of FPM in weather forecast model is realized.The accuracy performance of FPM,Rapid Radiative Transfer Model（RRTM）and RRTMG varies with individuals.The prediction accuracy of FPM is affected by the grid resolution,and the FPM accuracy increases with the grid resolution.The FPM forecast accuracy for heavy precipitation prediction is better than RRTM and RRTMG,but for light rain and no precipitation prediction is low,which leads to more false alarms.In addition,the prediction of cumulative precipitation at night by each parameterization scheme is generally better than that in daytime.（4）The application of FPM in climate model is realized.With the increase of CO₂ radiative forcing,both the temperature and precipitation in the future China will increase,and the winter precipitation area in China will shift northward.The extreme climate indices estimated by the climate model based on FPM and RRTMG are different.However,the differences are not affected by the magnitude of radiation forcing.For the extreme precipitation index,the difference between the two methods is mainly caused by the different positions of the extreme points of the climate index calculated by the two methods.For the extreme temperature index,there is a significant regional distribution of differences between the two methods,and the result of FPM is lower than RRTMG in most regions.