Interannual variability of thermal front west of Luzon Island during the winter of 1993-2013 is examined with the method of singular value decomposition （SVD） and a suite of satellite measurements in this paper. It ...Interannual variability of thermal front west of Luzon Island during the winter of 1993-2013 is examined with the method of singular value decomposition （SVD） and a suite of satellite measurements in this paper. It is found that both the area and intensity of the thermal front west of Luzon Island show apparent interannual variability. Further study based on SVD shows that the interannual variability of the thermal front is highly associated with E1 Nifio and Southern Oscillation （ENSO）, and the correlation coefficient between Nifio3.4 index and the first Principal Component （PC1） of thermal front can reach -0.65. The mechanism can be described as follows. In E1 Nifio （La Nifia） years, the East Asian winter monsoon （EAWM） is weakened （enhanced）, inducing weaker （stronger） local wind stress curl （WSC） west of Luzon Island, and resulting in weakened （enhanced） Luzon cold eddy, which finally leads to the weakening （enhancement） of the thermal front.展开更多
Using satellite remote sensing data and hydrological observation data,this study investigated the cold water in the lee of the Batanes Islands in the Luzon Strait.The formation of cold water in climate is mainly due t...Using satellite remote sensing data and hydrological observation data,this study investigated the cold water in the lee of the Batanes Islands in the Luzon Strait.The formation of cold water in climate is mainly due to the geostrophic heat advection on the east and west sides of the Batanes Islands:the Kuroshio separates into two branches on the east and west sides of the Batanes Islands.These two branches cause two warm tongues by transferring heat from low latitudes to mid-latitudes,and then the two warm tongues lead to the formation of the relatively cold water in the lee of the Batanes Islands.Further study shows that the cold water range has obvious seasonal and inter-annual variations.Except for August,the seasonal variation of the cold water range is caused by the interaction of geostrophic heat advection and net surface heat flux,whereas the low temperature in August in the lee of the Batanes Islands is caused by the island wake effect.The inter-annual of the cold water range is related to the difference in the meridional velocity between the east and west sides of the Batanes Islands,and the correlation coefficient can reach−0.68 at the 95%confidence level.展开更多
In this paper, we use the optimum interpolation sea surface temperature (OISST) provided by the National Center for Environmental Prediction (NCEP) to replace the temperature in the top three layers in the ISHII data,...In this paper, we use the optimum interpolation sea surface temperature (OISST) provided by the National Center for Environmental Prediction (NCEP) to replace the temperature in the top three layers in the ISHII data, and make use of the modified ISHII temperature data to calculate the thermosteric sea level (called modified steric sea level (SSL) hereafter). We subtract the modified SSL and the steric sea level (called ordinary SSL hereafter) derived from the ISHII temperature and salinity from the steric sea level (SSL) provided by the Gravity Recovery and Climate Experiment (GRACE), respectively, and find that the rms error of the difference of the former is obviously smaller than that of the latter. Therefore we reach the conclusion that under the assumption that the GRACE SSL is accurate, the modified SSL can reflect the true steric sea level more accurately. Making use of the modified SSL, we can find that the modified SSL in sea areas of different spatial scales shows an obvious rising trend in the upper 0-700 m layer for the period 1982-2006. The global mean SSL rises with a rate of 0.6 mm year-1 .The modified SSLs in sea areas of different spatial scales all show obvious oscillations with period of one year. There are oscillations with periods of 4-8 years in global oceans and with periods of 2-7 years in the Pacific. The Empirical Orthogonal Function method is applied to the sea areas of different spatial scales and we find that the first modes all have obvious 1-year period oscillations, the first mode of the global ocean has 4-8 year period oscillations, and that of the Pacific has 2-6 year period oscillations. The spatial distribution of the linear rising trend of the global modified SSL in the upper 0-700 m layer is inhomogeneous with intense regional characteristics. The modified SSL linear trend indicates a zonal dipole in the tropical Pacific, rising in the west and descending in the east. In the North Atlantic, the modified SSL indicates a meridional dipole, rising in the latitude band of 20°N-40°N and 45°N-65.5°N and descending obviously in the latitude band of 40°N-45°N.展开更多
The Atlantic inflow in the Fram Strait（78°50′N） has synoptic scale variability based on an array of moorings over the period of 1998–2010. The synoptic scale variability of Atlantic inflow, whose significant ...The Atlantic inflow in the Fram Strait（78°50′N） has synoptic scale variability based on an array of moorings over the period of 1998–2010. The synoptic scale variability of Atlantic inflow, whose significant cycle is 3–16 d, occurs mainly in winter and spring（from January to April） and is related with polar lows in the Barents Sea. On the synoptic scale, the enhancement（weakening） of Atlantic inflow in the Fram Strait is accompanied by less（more）polar lows in the Barents Sea. Wind stress curl induced by polar lows in the Barents Sea causes Ekman-transport,leads to decrease of sea surface height in the Barents Sea, due to geostrophic adjustment, further induces a cyclonic circulation anomaly around the Barents Sea, and causes the weakening of the Atlantic inflow in the Fram Strait. Our results highlight the importance of polar lows in forcing the Atlantic inflow in the Fram Strait and can help us to further understand the effect of Atlantic warm water on the change of the Arctic Ocean.展开更多
基金The Distinguished Young Scholars of National Natural Science Foundation of China under contract Nos 41125019 and 41306024the National Basic Research Program(973 Program) of China under contract No.2013CB430301+1 种基金the Basic Scientific Research Fund of Second Institute of Oceanography,State Oceanic Administration under contract No.JT1301the National Natural Science Foundation under contract No.41476002
文摘Interannual variability of thermal front west of Luzon Island during the winter of 1993-2013 is examined with the method of singular value decomposition （SVD） and a suite of satellite measurements in this paper. It is found that both the area and intensity of the thermal front west of Luzon Island show apparent interannual variability. Further study based on SVD shows that the interannual variability of the thermal front is highly associated with E1 Nifio and Southern Oscillation （ENSO）, and the correlation coefficient between Nifio3.4 index and the first Principal Component （PC1） of thermal front can reach -0.65. The mechanism can be described as follows. In E1 Nifio （La Nifia） years, the East Asian winter monsoon （EAWM） is weakened （enhanced）, inducing weaker （stronger） local wind stress curl （WSC） west of Luzon Island, and resulting in weakened （enhanced） Luzon cold eddy, which finally leads to the weakening （enhancement） of the thermal front.
基金This research was supported by the National Natural Science Foundation of China(No.41806019)the Natural Science Foundation of Zhejiang Province(No.LY18D060004)+3 种基金the National Programme on Global Change and Air-Sea Interaction(No.GASI-IPOVAI-04)the National Natural Science Foundation of China(Nos.41976028,41806219,and 41706193)the Project of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography(No.SOEDZZ1805)the National Key R&D Program of China(No.2019YFD0901305),and in part by the Startup Foundation for Introducing Talent of NUIST.
文摘Using satellite remote sensing data and hydrological observation data,this study investigated the cold water in the lee of the Batanes Islands in the Luzon Strait.The formation of cold water in climate is mainly due to the geostrophic heat advection on the east and west sides of the Batanes Islands:the Kuroshio separates into two branches on the east and west sides of the Batanes Islands.These two branches cause two warm tongues by transferring heat from low latitudes to mid-latitudes,and then the two warm tongues lead to the formation of the relatively cold water in the lee of the Batanes Islands.Further study shows that the cold water range has obvious seasonal and inter-annual variations.Except for August,the seasonal variation of the cold water range is caused by the interaction of geostrophic heat advection and net surface heat flux,whereas the low temperature in August in the lee of the Batanes Islands is caused by the island wake effect.The inter-annual of the cold water range is related to the difference in the meridional velocity between the east and west sides of the Batanes Islands,and the correlation coefficient can reach−0.68 at the 95%confidence level.
基金supported by the National Natural Science Foundation of China (Grants 40806072, 40906002 and 41176009)Public Science and Technology Research Funds Projects of Ocean (201005019)
文摘In this paper, we use the optimum interpolation sea surface temperature (OISST) provided by the National Center for Environmental Prediction (NCEP) to replace the temperature in the top three layers in the ISHII data, and make use of the modified ISHII temperature data to calculate the thermosteric sea level (called modified steric sea level (SSL) hereafter). We subtract the modified SSL and the steric sea level (called ordinary SSL hereafter) derived from the ISHII temperature and salinity from the steric sea level (SSL) provided by the Gravity Recovery and Climate Experiment (GRACE), respectively, and find that the rms error of the difference of the former is obviously smaller than that of the latter. Therefore we reach the conclusion that under the assumption that the GRACE SSL is accurate, the modified SSL can reflect the true steric sea level more accurately. Making use of the modified SSL, we can find that the modified SSL in sea areas of different spatial scales shows an obvious rising trend in the upper 0-700 m layer for the period 1982-2006. The global mean SSL rises with a rate of 0.6 mm year-1 .The modified SSLs in sea areas of different spatial scales all show obvious oscillations with period of one year. There are oscillations with periods of 4-8 years in global oceans and with periods of 2-7 years in the Pacific. The Empirical Orthogonal Function method is applied to the sea areas of different spatial scales and we find that the first modes all have obvious 1-year period oscillations, the first mode of the global ocean has 4-8 year period oscillations, and that of the Pacific has 2-6 year period oscillations. The spatial distribution of the linear rising trend of the global modified SSL in the upper 0-700 m layer is inhomogeneous with intense regional characteristics. The modified SSL linear trend indicates a zonal dipole in the tropical Pacific, rising in the west and descending in the east. In the North Atlantic, the modified SSL indicates a meridional dipole, rising in the latitude band of 20°N-40°N and 45°N-65.5°N and descending obviously in the latitude band of 40°N-45°N.
基金The Global Change Research Program of China under contract No.2015CB953900the General Program of National Natural Science Foundation of China under contract No.41276197+2 种基金the Natural Science Foundation of Zhejiang Province under contract Nos LY18D060004 and LQ18D060001the Foundation of Zhejiang Education Department under contract No.1260KZ0417982the Talent Start Foundation of Zhejiang Gongshang University under contract Nos 1260XJ2317015 and1260XJ2117015
文摘The Atlantic inflow in the Fram Strait（78°50′N） has synoptic scale variability based on an array of moorings over the period of 1998–2010. The synoptic scale variability of Atlantic inflow, whose significant cycle is 3–16 d, occurs mainly in winter and spring（from January to April） and is related with polar lows in the Barents Sea. On the synoptic scale, the enhancement（weakening） of Atlantic inflow in the Fram Strait is accompanied by less（more）polar lows in the Barents Sea. Wind stress curl induced by polar lows in the Barents Sea causes Ekman-transport,leads to decrease of sea surface height in the Barents Sea, due to geostrophic adjustment, further induces a cyclonic circulation anomaly around the Barents Sea, and causes the weakening of the Atlantic inflow in the Fram Strait. Our results highlight the importance of polar lows in forcing the Atlantic inflow in the Fram Strait and can help us to further understand the effect of Atlantic warm water on the change of the Arctic Ocean.
