An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climat...An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data.展开更多
A regional ocean atmosphere coupled model (ROAM) is developed through coupler OASIS3,and is composed of regional climate model RegCM3 and CREM (Climate version of Regional Eta Model) as its atmospheric component and o...A regional ocean atmosphere coupled model (ROAM) is developed through coupler OASIS3,and is composed of regional climate model RegCM3 and CREM (Climate version of Regional Eta Model) as its atmospheric component and of a revised Princeton ocean model (POM2000) as its oceanic component.The performance of the ROAM over the western North Pacific summer monsoon region is assessed by the case simulation of warm season in 1998.Impacts of different atmospheric model components on the performance of ROAM are investigated.Compared with stand-alone simulation,CREM (RegCM3) produces more (or less) rainfall over ocean area with inclusion of the air-sea coupling.Different biases of rainfall are caused by the different biases of SST derived from the coupled simulation.Warm (or cold) SST bias simulated by CREM_CPL (RegCM3_CPL) increases (or decreases) the evaporation at sea surface,then increases (or decreases) the rainfall over ocean.The analyses suggest that the biases of vertical profile of temperature and specific humidity in stand-alone simulations may be responsible for the SST biases in regional coupled simulations.Compared with reanalysis data,the warmer (or colder) and moister (or dryer) lower troposphere simulated in CREM (RegCM3) produces less (or more) sea surface latent heat flux.Meanwhile,the more unstable (or stable) lower troposphere produces less (or more) cloudiness at low-level,which increases (or decreases) the solar radiation reaching on the sea surface.CREM (RegCM3) forced by observed SST overestimates (or underestimates) the sea surface net heat flux,implying a potential warm (or cold) heat source.After coupling with POM2000,the warm (or cold) heat source would further increase (or decrease) the SST.The biases of vertical profile of temperature and specific humidity may be ascribed to the different representation of cumulus convection in atmospheric models.展开更多
基金supported by the Chinese Academy of Sciences (Grant No. KZCX2-YW-202)the 973 Pro-gram (Grant No. 2006CB403606),the 863 Program (Grant No.2009AA12Z138)the National Natural Science Foundation of China (Grant Nos. 40606008,40437017,and 40221503)
文摘An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data.
基金supported by the Ocean Projects of Public Science and Technology Research Funds (Grant No. 201105019-3)
文摘A regional ocean atmosphere coupled model (ROAM) is developed through coupler OASIS3,and is composed of regional climate model RegCM3 and CREM (Climate version of Regional Eta Model) as its atmospheric component and of a revised Princeton ocean model (POM2000) as its oceanic component.The performance of the ROAM over the western North Pacific summer monsoon region is assessed by the case simulation of warm season in 1998.Impacts of different atmospheric model components on the performance of ROAM are investigated.Compared with stand-alone simulation,CREM (RegCM3) produces more (or less) rainfall over ocean area with inclusion of the air-sea coupling.Different biases of rainfall are caused by the different biases of SST derived from the coupled simulation.Warm (or cold) SST bias simulated by CREM_CPL (RegCM3_CPL) increases (or decreases) the evaporation at sea surface,then increases (or decreases) the rainfall over ocean.The analyses suggest that the biases of vertical profile of temperature and specific humidity in stand-alone simulations may be responsible for the SST biases in regional coupled simulations.Compared with reanalysis data,the warmer (or colder) and moister (or dryer) lower troposphere simulated in CREM (RegCM3) produces less (or more) sea surface latent heat flux.Meanwhile,the more unstable (or stable) lower troposphere produces less (or more) cloudiness at low-level,which increases (or decreases) the solar radiation reaching on the sea surface.CREM (RegCM3) forced by observed SST overestimates (or underestimates) the sea surface net heat flux,implying a potential warm (or cold) heat source.After coupling with POM2000,the warm (or cold) heat source would further increase (or decrease) the SST.The biases of vertical profile of temperature and specific humidity may be ascribed to the different representation of cumulus convection in atmospheric models.
