Mesoscale Moist Adjoint Sensitivity Study of a Mei-yu Heavy Rainfall Event  

作　　者：储可宽 谈哲敏 

机构地区：[1]Key Lab of Mesoscale Severe Weather/MOE,and School of Atmospheric Sciences,Nanjing University

出　　处：《Advances in Atmospheric Sciences》2010年第6期1415-1424,共10页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China under Grant Nos.40805019,40828005,and 40325014;the National Special Funding Project for Meteorology(GYHY200706033,GYHY200706020);the Key Project for National Science and Technology Program in Eleventh Five Year Plan (2006BAC02B03);the Specialized Research Fund for the Doctoral Program of Higher Education(20080284019);the Key project of Ministry of Education of China (02109)

摘　　要：The mesoscale moist adjoint sensitivities related to the initiation of mesoscale convective systems （MCSs） are evaluated for a mei-yu heavy rainfall event. The sensitivities were calculated on a realistic background gained from a four-dimensional variational data assimilation of precipitation experiment to make the sensitivity computation possible and reasonable within a strong moist convective event at the mesoscale. The results show that the computed sensitivities at the mesoscale were capable of capturing the factors affecting MCS initiation. The sensitivities to the initial temperature and moisture are enhanced greatly by diabatic processes, especially at lower levels, and these sensitivities are much larger than those stemming from the horizontal winds, which implies that initiation of MCSs is more sensitive to low-level temperature and moisture perturbations rather than the horizontal winds. Moreover, concentration of sensitivities at low levels reflects the characteristics of the mei-yu front. The results provide some hints about how to improve quantitative precipitation forecasts of mei-yu heavy rainfall, such as by conducting mesoscale targetted observations via the adjoint-based method to reduce the low-level errors in the initial temperature and moisture.The mesoscale moist adjoint sensitivities related to the initiation of mesoscale convective systems （MCSs） are evaluated for a mei-yu heavy rainfall event. The sensitivities were calculated on a realistic background gained from a four-dimensional variational data assimilation of precipitation experiment to make the sensitivity computation possible and reasonable within a strong moist convective event at the mesoscale. The results show that the computed sensitivities at the mesoscale were capable of capturing the factors affecting MCS initiation. The sensitivities to the initial temperature and moisture are enhanced greatly by diabatic processes, especially at lower levels, and these sensitivities are much larger than those stemming from the horizontal winds, which implies that initiation of MCSs is more sensitive to low-level temperature and moisture perturbations rather than the horizontal winds. Moreover, concentration of sensitivities at low levels reflects the characteristics of the mei-yu front. The results provide some hints about how to improve quantitative precipitation forecasts of mei-yu heavy rainfall, such as by conducting mesoscale targetted observations via the adjoint-based method to reduce the low-level errors in the initial temperature and moisture.

关 键 词：adjoint sensitivity analysis mei-yu heavy rainfall MESOSCALE 

分 类 号：P457.6[天文地球—大气科学及气象学]