The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by Qui...The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island's east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.展开更多
An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was ...An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was recoded in FORTRAN-90 style, and some new data types were defined to improve the efficiency of system design and execution. This system is arranged for parallel computing by using UNIX shell scripts: it is easier with single models running separately with the required information exchanged through input/output files. Tests are carried out to check the performance of the system: one for checking the ensemble spread and another for the performance of assimilation of the Argo data in 2005. The first experiment shows that the assimilation system performs well. The comparison with the Satellite derived sea surface temperature (SST) shows that modeled SST errors are reduced after assimilation; at the same time, the spatial correlation between the simulated SST anomalies and the satellite data is improved because of Argo assimilation. Furthermore, the temporal evolution/trend of SST becomes much better than those results without data assimilation. The comparison against GTSPP profiles shows that the improvement is not only in the upper layers of ocean, but also in the deeper layers. All these results suggest that this system is potentially capable of reconstructing oceanic data sets that are of high quality and are temporally and spatially continuous.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 Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX2-YW-Q11-02, KZCX2-EW-208)the One Hundred Talent Program of Chinese Academy of Sciences+1 种基金the National Natural Science Foundation of China (No. 41076009)the Youth Frontier Science Project of the South China Sea Institute of Oceanology(No. SQ200914)
文摘The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island's east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.
基金Supported by the Project of National Basic Research Program of China (No. 2007CB816002)Special Fund for Fundamental Scientific Research (No. 2008G08)
文摘An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was recoded in FORTRAN-90 style, and some new data types were defined to improve the efficiency of system design and execution. This system is arranged for parallel computing by using UNIX shell scripts: it is easier with single models running separately with the required information exchanged through input/output files. Tests are carried out to check the performance of the system: one for checking the ensemble spread and another for the performance of assimilation of the Argo data in 2005. The first experiment shows that the assimilation system performs well. The comparison with the Satellite derived sea surface temperature (SST) shows that modeled SST errors are reduced after assimilation; at the same time, the spatial correlation between the simulated SST anomalies and the satellite data is improved because of Argo assimilation. Furthermore, the temporal evolution/trend of SST becomes much better than those results without data assimilation. The comparison against GTSPP profiles shows that the improvement is not only in the upper layers of ocean, but also in the deeper layers. All these results suggest that this system is potentially capable of reconstructing oceanic data sets that are of high quality and are temporally and spatially continuous.
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.
