The analysis of observed salinity data over 35 years (1961—1996) at four stations around the Bohai Sea, i.e. Huludao, Qinhuangdao, Tanggu and Beihuangcheng, reveals that the salinity of the 4 observation stations has...The analysis of observed salinity data over 35 years (1961—1996) at four stations around the Bohai Sea, i.e. Huludao, Qinhuangdao, Tanggu and Beihuangcheng, reveals that the salinity of the 4 observation stations has increased 1.1, 1.6, 1.9 and 0.4, respectively. The data also show that over the past 35 years, there have been at least 5 large salin-ity variation processes. The salinity data from two cruises of the Bohai Sea in August 1958 and 2000, show that the salin-ity pattern of the Bohai Sea has changed markedly. Low sa-linity in the sea surface layer around the old Yellow River mouth in August 1958 had been replaced by high salinity in August 2000 and the maximum variation of salinity is over 10.0. In addition, the values and distribution of salinity were almost the same from surface to bottom there in August 2000, but there existed significantly different salinity levels be-tween the surface layer and the deep layer in August 1958. When a comparison is made between the salinity levels of the above-mentioned two years, it is found that the salinity in August 2000 is on average 2.0 higher than that of August 1958 in the main part of the Bohai Sea. The change of tem-perature and salinity field in the Bohai Sea leads to the change of the circulation. The numerical simulation shows that in comparison with the circulation structure of the Bohai Sea in August 1958, the circulation in August 2000 changes markedly. The significant changes of circulation appeared in Bohai Bay, Laizhou Bay and in the middle of the Bohai Sea. The clockwise current loop outside of the Bohai Bay and counterclockwise current loop outside of the Laizhou Bay in August 1958 disappeared in August 2000, and the counterclockwise current loop of the Bohai Bay mi-grated obviously outward. The flow direction in the Laizhou Bay turned 180° around. Corresponding to the variation of the Bohai Sea circulation, the amount of water exchange between the Bohai Sea and the Yellow Sea has also changed. The water exchange rate through the Bohai Strait de展开更多
The E1 Nifio-Southern Oscillation （ENSO） is emphasized the roles of wind stress and heat flux environmental forcing to the ocean; its effect and modulated by many factors; most previous studies have in the tropical ...The E1 Nifio-Southern Oscillation （ENSO） is emphasized the roles of wind stress and heat flux environmental forcing to the ocean; its effect and modulated by many factors; most previous studies have in the tropical Pacific. Freshwater flux （FWF） is another the related ocean salinity variability in the ENSO region have been of increased interest recently. Currently, accurate quantifications of the FWF roles in the climate remain challenging; the related observations and coupled ocean-atmosphere modeling involve large elements of uncertainty. In this study, we utilized satellite-based data to represent FWF-induced feedback in the tropical Pacific climate system; we then incorporated these data into a hybrid coupled ocean-atmosphere model （HCM） to quantify its effects on ENSO. A new mechanism was revealed by which interannual FWF forcing modulates ENSO in a significant way. As a direct forcing, FWF exerts a significant influence on the ocean through sea surface salinity （SSS） and buoyancy flux （QB） in the western-central tropical Pacific. The SSS perturbations directly induced by ENSO-related interannual FWF variability affect the stability and mixing in the upper ocean. At the same time, the ENSO-induced FWF has a compensating effect on heat flux, acting to reduce interannual Qs variability during ENSO cycles. These FWF-induced processes in the ocean tend to modulate the vertical mixing and entrainment in the upper ocean, enhancing cooling during La Nifia and enhancing warming during E1 Nifio, respectively. The interannual FWF forcing-induced positive feedback acts to enhance ENSO amplitude and lengthen its time scales in the tropical Pacific coupled climate system.展开更多
文摘The analysis of observed salinity data over 35 years (1961—1996) at four stations around the Bohai Sea, i.e. Huludao, Qinhuangdao, Tanggu and Beihuangcheng, reveals that the salinity of the 4 observation stations has increased 1.1, 1.6, 1.9 and 0.4, respectively. The data also show that over the past 35 years, there have been at least 5 large salin-ity variation processes. The salinity data from two cruises of the Bohai Sea in August 1958 and 2000, show that the salin-ity pattern of the Bohai Sea has changed markedly. Low sa-linity in the sea surface layer around the old Yellow River mouth in August 1958 had been replaced by high salinity in August 2000 and the maximum variation of salinity is over 10.0. In addition, the values and distribution of salinity were almost the same from surface to bottom there in August 2000, but there existed significantly different salinity levels be-tween the surface layer and the deep layer in August 1958. When a comparison is made between the salinity levels of the above-mentioned two years, it is found that the salinity in August 2000 is on average 2.0 higher than that of August 1958 in the main part of the Bohai Sea. The change of tem-perature and salinity field in the Bohai Sea leads to the change of the circulation. The numerical simulation shows that in comparison with the circulation structure of the Bohai Sea in August 1958, the circulation in August 2000 changes markedly. The significant changes of circulation appeared in Bohai Bay, Laizhou Bay and in the middle of the Bohai Sea. The clockwise current loop outside of the Bohai Bay and counterclockwise current loop outside of the Laizhou Bay in August 1958 disappeared in August 2000, and the counterclockwise current loop of the Bohai Bay mi-grated obviously outward. The flow direction in the Laizhou Bay turned 180° around. Corresponding to the variation of the Bohai Sea circulation, the amount of water exchange between the Bohai Sea and the Yellow Sea has also changed. The water exchange rate through the Bohai Strait de
基金supported in part by NSF Grant(ATM-0727668and AGS-1061998)NOAA Grant(NA08OAR4310885)+3 种基金NASA Grants(NNX08AI74G,NNX08AI76G,and NNX09AF41G)F.Zheng is supported by the National Basic Research Program of China(GrantNos.2012CB417404and2012CB955202)the Natural Science Foundation of China(Grant No.41075064)Pei is additionally supported by China Scholarship Coun-cil(CSC) with the Ocean University of China,Qingdao,China
文摘The E1 Nifio-Southern Oscillation （ENSO） is emphasized the roles of wind stress and heat flux environmental forcing to the ocean; its effect and modulated by many factors; most previous studies have in the tropical Pacific. Freshwater flux （FWF） is another the related ocean salinity variability in the ENSO region have been of increased interest recently. Currently, accurate quantifications of the FWF roles in the climate remain challenging; the related observations and coupled ocean-atmosphere modeling involve large elements of uncertainty. In this study, we utilized satellite-based data to represent FWF-induced feedback in the tropical Pacific climate system; we then incorporated these data into a hybrid coupled ocean-atmosphere model （HCM） to quantify its effects on ENSO. A new mechanism was revealed by which interannual FWF forcing modulates ENSO in a significant way. As a direct forcing, FWF exerts a significant influence on the ocean through sea surface salinity （SSS） and buoyancy flux （QB） in the western-central tropical Pacific. The SSS perturbations directly induced by ENSO-related interannual FWF variability affect the stability and mixing in the upper ocean. At the same time, the ENSO-induced FWF has a compensating effect on heat flux, acting to reduce interannual Qs variability during ENSO cycles. These FWF-induced processes in the ocean tend to modulate the vertical mixing and entrainment in the upper ocean, enhancing cooling during La Nifia and enhancing warming during E1 Nifio, respectively. The interannual FWF forcing-induced positive feedback acts to enhance ENSO amplitude and lengthen its time scales in the tropical Pacific coupled climate system.
