Using atmospheric observational data from 1998 to 2013,station rainfall data,TRMM（Tropical Rainfall Measuring Mission） data,as well as annual statistics for the plateau vortex and shear line,the joint activity featu...Using atmospheric observational data from 1998 to 2013,station rainfall data,TRMM（Tropical Rainfall Measuring Mission） data,as well as annual statistics for the plateau vortex and shear line,the joint activity features of sustained departure plateau vortexes（SDPVs） and southwest vortexes（SWVs） are analyzed.Some new and useful observational facts and understanding are obtained about the joint activities of the two types of vortex.The results show that：（1） The joint active period of the two vortexes is from May to August,and mostly in June and July.（2） The SDPVs of the partnership mainly originate near Zaduo,while the SWVs come from Jiulong.（3） Most of the two vortexes move in almost the same direction,moving eastward together with the low trough.The SDPVs mainly act in the area to the north of the Yangtze River,while the SWVs are situated across the Yangtze River valley.（4） The joint activity of the two vortexes often produces sustained regional heavy rainfall to the south of the Yellow River,influencing wide areas of China,and even as far as the Korean Peninsula,Japan and Vietnam.（5） Most of the two vortexes are baroclinic or cold vortexes,and they both become strengthened in terms of their joint activity.（6） When the two vortexes move over the sea,their central pressure descends and their rainfall increases,especially for SWVs.（7） The two vortexes might spin over the same area simultaneously when there are tropical cyclones in the eastern and southern seas of China,or move southward together if a tropical cyclone appears near Hainan Island.展开更多
Based on the long-term marine ship observation data, records of meteorological stations and High-Reflective Cloud(HRC) data by satellite remote sensing , this paper has studied the circulation patterns and variability...Based on the long-term marine ship observation data, records of meteorological stations and High-Reflective Cloud(HRC) data by satellite remote sensing , this paper has studied the circulation patterns and variability in elements during onset and the established periods of the South China Sea(SCS) southwest(SW) monsoon. The averaged date of the onset SW monsoon in the SCS occurs in the middle of May climatologically. The corresponding date for the northern part is little earlier (May 12) and those for the southern parts are little later (May 20). The interannual range of the onset dates is about one month. Following the onset of the SW monsoon, the cloud amount and the precipitation increase while the convection activities enhance over the SCS. But there is a strong spatial heterogeneity within the domain. After onset of the SW monsoon the strong convective area moves northwards, while the SCS rain band moves to the center and north. Sea surface temperature(SST) increases rapidly before the onset and the leading time is about one month. The increment of SST supplies heat and vapor for the onset. From April to May the surface heat fluxes display obvious changes, e.g., latent heat exchange and evaporation enhancement. It is one of the reasons why the SW monsoon bursts firstly in the SCS.展开更多
基金supported by project funds from the National Natural Science Foundation of China(Grant Nos.91332715 and 41275052)the National Key Foundation Development Study Developing(973)Programme(Grant No.2012CB417202)
文摘Using atmospheric observational data from 1998 to 2013,station rainfall data,TRMM（Tropical Rainfall Measuring Mission） data,as well as annual statistics for the plateau vortex and shear line,the joint activity features of sustained departure plateau vortexes（SDPVs） and southwest vortexes（SWVs） are analyzed.Some new and useful observational facts and understanding are obtained about the joint activities of the two types of vortex.The results show that：（1） The joint active period of the two vortexes is from May to August,and mostly in June and July.（2） The SDPVs of the partnership mainly originate near Zaduo,while the SWVs come from Jiulong.（3） Most of the two vortexes move in almost the same direction,moving eastward together with the low trough.The SDPVs mainly act in the area to the north of the Yangtze River,while the SWVs are situated across the Yangtze River valley.（4） The joint activity of the two vortexes often produces sustained regional heavy rainfall to the south of the Yellow River,influencing wide areas of China,and even as far as the Korean Peninsula,Japan and Vietnam.（5） Most of the two vortexes are baroclinic or cold vortexes,and they both become strengthened in terms of their joint activity.（6） When the two vortexes move over the sea,their central pressure descends and their rainfall increases,especially for SWVs.（7） The two vortexes might spin over the same area simultaneously when there are tropical cyclones in the eastern and southern seas of China,or move southward together if a tropical cyclone appears near Hainan Island.
文摘Based on the long-term marine ship observation data, records of meteorological stations and High-Reflective Cloud(HRC) data by satellite remote sensing , this paper has studied the circulation patterns and variability in elements during onset and the established periods of the South China Sea(SCS) southwest(SW) monsoon. The averaged date of the onset SW monsoon in the SCS occurs in the middle of May climatologically. The corresponding date for the northern part is little earlier (May 12) and those for the southern parts are little later (May 20). The interannual range of the onset dates is about one month. Following the onset of the SW monsoon, the cloud amount and the precipitation increase while the convection activities enhance over the SCS. But there is a strong spatial heterogeneity within the domain. After onset of the SW monsoon the strong convective area moves northwards, while the SCS rain band moves to the center and north. Sea surface temperature(SST) increases rapidly before the onset and the leading time is about one month. The increment of SST supplies heat and vapor for the onset. From April to May the surface heat fluxes display obvious changes, e.g., latent heat exchange and evaporation enhancement. It is one of the reasons why the SW monsoon bursts firstly in the SCS.
