The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west.A positive temperature skewness appears in the equatorial eastern Pacific,while th...The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west.A positive temperature skewness appears in the equatorial eastern Pacific,while the temperature skewness in the western and central Pacific is primarily negative.There is also an asymmetry of the temperature skewness above and below the climatological mean thermocline in the central and western Pacific.A positive skewness appears below the thermocline,but the skewness is negative above the thermocline.The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure.Because of positive(negative) second derivative of temperature with respect to depth below(above) the thermocline,an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline.In the far eastern equatorial Pacific,the thermocline is close to the base of the mixed layer,the shape of the upper-ocean vertical temperature profile cannot be kept.Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin.Over the central and eastern Pacific,the anomalies of the subsurface waters tend to entrain into the surface mixed layer(by climatological mean upwelling) and then affect the SST.Hence,the positive(negative) subsurface skewness in the far eastern(central) Pacific may favor positive(negative) SST skewness,which is consistent with the observational fact that more La Nia(El Nio) occur in the central(eastern) Pacific.The present result implies a possible new paradigm for El Nio and La Nia amplitude asymmetry in the eastern Pacific.展开更多
A dataset of drifting buoys from the Marine Environmental Data Service of Canada was analyzed to map surface circulation of the Pacific. More information of the surface circulation than that acquired before was report...A dataset of drifting buoys from the Marine Environmental Data Service of Canada was analyzed to map surface circulation of the Pacific. More information of the surface circulation than that acquired before was reported in this paper, showing clear and strong western boundary currents, equato- rial currents, and subtropical gyres in the North and South Pacific regions in velocity field, with a more systematic structure in the North Pacific.展开更多
基金Supported by the National Basic Research Program of China (973 Program)(No 2007CB816005)the National Natural Science Foundation of China (No 40706003)+1 种基金International S&T Cooperation Project of the Ministry of Science and Technology of China (No2009DFA21430)the COPES in China (GYHY200706005)
文摘The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west.A positive temperature skewness appears in the equatorial eastern Pacific,while the temperature skewness in the western and central Pacific is primarily negative.There is also an asymmetry of the temperature skewness above and below the climatological mean thermocline in the central and western Pacific.A positive skewness appears below the thermocline,but the skewness is negative above the thermocline.The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure.Because of positive(negative) second derivative of temperature with respect to depth below(above) the thermocline,an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline.In the far eastern equatorial Pacific,the thermocline is close to the base of the mixed layer,the shape of the upper-ocean vertical temperature profile cannot be kept.Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin.Over the central and eastern Pacific,the anomalies of the subsurface waters tend to entrain into the surface mixed layer(by climatological mean upwelling) and then affect the SST.Hence,the positive(negative) subsurface skewness in the far eastern(central) Pacific may favor positive(negative) SST skewness,which is consistent with the observational fact that more La Nia(El Nio) occur in the central(eastern) Pacific.The present result implies a possible new paradigm for El Nio and La Nia amplitude asymmetry in the eastern Pacific.
基金Supported by the NSFC (Key Program, No. 90411013)
文摘A dataset of drifting buoys from the Marine Environmental Data Service of Canada was analyzed to map surface circulation of the Pacific. More information of the surface circulation than that acquired before was reported in this paper, showing clear and strong western boundary currents, equato- rial currents, and subtropical gyres in the North and South Pacific regions in velocity field, with a more systematic structure in the North Pacific.
