A strong warm event happens during spring 1997 to spring 1999 in the South China Sea. Its intensity and duration show that it is the strongest event on the record over the past decades. It also corresponds with the se...A strong warm event happens during spring 1997 to spring 1999 in the South China Sea. Its intensity and duration show that it is the strongest event on the record over the past decades. It also corresponds with the severe flood over the valley of the Yangtze River and a couple of marine environmental events. This note addressed the evolution process by using several data sets, such as sea surface temperature, height and wind stress in addition to subsurface temperature. The onset of the warm event almost tele-connects with the El Nino event in the tropical Pacific Ocean. Summer monsoon is stronger and winter monsoon is weaker in 1997 so that there are persistent westerly anomalies in the South China Sea. During the development phase, the warm advection caused by southerly anomalies is the major factor while the adjustment of the thermocline is not obvious. Subsequently, the southerly anomalies decay and even northerly anomalies appear in the summer of 1998 resulting from the weaker than normal summer展开更多
In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plat...In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plateau, adjacent to the Sichuan basin, is characterized by very steep relief with high mountain ranges. The crust beneath this region slows the velocities in the middle and lower crust. We have adopted a relatively dense network to inverse the detailed structure of the crust and upper mantle along the eastern margin of the Tibetan plateau and Sichuan basin, using teleseismic data via receiver function analysis. The results are in-line with the hypothesis that viscous crustal material is flowing beneath the eastern margin of the Tibetan plateau and that this process drives overlying crustal material around the strong and rigid Sichuan basin. When the viscous material hits this obstruction, flows are divided into two or more branches with different directions. The upper part of the upwelling viscous flow produces the pressure to intrude the upper crust, thereby driving uplift of mountain ranges and high peaks. In contrast, the lower part of the downwelling viscous flow produces the pressure to intrude the lower crust and upper mantle to deepen the Moho discontinuity, causing observed crustal thickening.展开更多
During the boreal spring of 1966, a warm-core eddy is identified in the upper South China Sea (SCS) west of the Philippines through an analysis of the U.S. Navy′s Master Oceanographic Observation Data Set. This eddy ...During the boreal spring of 1966, a warm-core eddy is identified in the upper South China Sea (SCS) west of the Philippines through an analysis of the U.S. Navy′s Master Oceanographic Observation Data Set. This eddy occurred before the development of the northern summer monsoon and disappeared afterward. We propose that this eddy is a result of the radiative warming during spring and the downwelling due to the anticyclonic forcing at the surface. Our hypothesis suggests an air-sea feedback scenario that may explain the development and withdrawal of the summer monsoon over the SCS. The development phase of the warm-core eddy in this hypothesis is tested by using the Princeton Ocean model.展开更多
The impact of typhoon Kujira(2015)on the ocean environment around Yongxing Island in the South China Sea was observed using multiple-satellite sensors and on-site data.A subsurface buoy and Agro float were located to ...The impact of typhoon Kujira(2015)on the ocean environment around Yongxing Island in the South China Sea was observed using multiple-satellite sensors and on-site data.A subsurface buoy and Agro float were located to the left and lower right of the track of the typhoon.Satellite observations revealed sea surface cooling of up to 2.5℃,a maximum decrease in sea surface salinity of 2 in the main study area because of heavy rain,and increases in the chlorophyll concentration induced by the slow-moving typhoon with a maximum observed instantaneous wind speed of 35.1 m/s.The sea surface temperature to the right of the typhoon track changed more than that on the left owing to a right bias of the typhoon associated with coupling of the typhoon with wind stress on the sea surface.In the ocean interior,there was obvious downwelling at 24.7 m and upwelling at a depth of 35.7 m with the vertical entrainment and agitation of the typhoon,and the ef fects extended to different depths of up to more than 1000 m.When the typhoon passed through the main study area,the maximum flow velocity change at depths of 51 and 660 m was about 0.44 and 0.04 m/s,respectively.The typhoon af fected the flow field to a depth of 660 m as it formed and decayed in 11 h,moved at an average speed of 60 m/h,and af fected the sea surface over a range exceeding 700 km as it moved slowly and stayed at sea for 2 d.Vertical entrainment and agitation generated by the typhoon,as well as rainfall,cooled the sea surface.This inhibited the strengthening of the typhoon,but the energy transmitted to the ocean led to divergence-convergence flow from a shallow to deep layer.展开更多
The equatorial response to subtropical Pacific forcing was studied in a coupled climate model.The forcings in the western,central and eastern subtropical Pacific all caused a significant response in the equatorial the...The equatorial response to subtropical Pacific forcing was studied in a coupled climate model.The forcings in the western,central and eastern subtropical Pacific all caused a significant response in the equatorial thermocline,with comparable magnitudes.This work highlights the key role of air-sea coupling in the subtropical impact on the equatorial thermocline,instead of only the role of the ＂oceanic tunnel＂.The suggested mechanism is that the cyclonic （anticyclonic） circulation in the atmosphere caused by the subtropical surface warming （cooling） can generate an anomalous upwelling （downwelling） in the interior region.At the same time,an anomalous downwelling （upwelling） occurs at the equatorward flank of the forcing,which produces anomalous thermocline warming （cooling）,propagating equatorward and resulting in warming （cooling） in the equatorial thermocline.This is an indirect process that is much faster than the ＂oceanic tunnel＂ mechanism in the subtropical impact on the equator.展开更多
Climate warming, variation of East Asian atmospheric system have affected the Chinese offshore environment through the air-sea interaction, the coastal waters of South China Sea had been influenced, leading a correspo...Climate warming, variation of East Asian atmospheric system have affected the Chinese offshore environment through the air-sea interaction, the coastal waters of South China Sea had been influenced, leading a corresponding impact on the coral reef growth. This paper reports on coral coverage and dominant coral species changes in Xu wen National Coral Reef Nature Reserve, examines their relationship with meteorological factors anomalies recorded by satellite. The study reveals that: compared to the period from 1979 to 2003, the temperature of surface coastal water dropped significantly in South China Sea in 2004-2008, the divergence of low layer of atmosphere over it strengthened, produced a zonal westerly anomaly field, which had an opposite direction to the local northeastern trade wind. The increasing of suspended matter in water, the decreasing of down welling in northwestern South China Sea, made the water quality deteriorating, water transparency decreased significantly, coral reef survival environment worsened, which would cause adverse effects on coral reef building capacity in the Reserve. Continued monitoring efforts are necessary to further assess the relationship between coral building capacity and in situ meteorological factors anomalies and improve the use of the dataset in future regional degradation predictions.展开更多
Based on observational evidence and the known physical characteristics of surface gravity waves, an argument is made that downwelling is not a significant feature over the life history of these waves under the usual c...Based on observational evidence and the known physical characteristics of surface gravity waves, an argument is made that downwelling is not a significant feature over the life history of these waves under the usual conditions existing in the open oceans. Since it has recently been predicted that upwelling due to surface gravity waves should occur within a storm at sea, when the waves are growing in amplitude, the contrast is explained. As a result the importance of the upwelling concept due to waves in stimulating biological productivity is further emphasized, and the possibility for reducing global warming is worth repeating.展开更多
The diffuse attenuation coefficient for downwelling irradiance(Kd(λ)) is an important parameter for ocean studies.Based on the optical profile data measured during three cruises in the northern South China Sea in aut...The diffuse attenuation coefficient for downwelling irradiance(Kd(λ)) is an important parameter for ocean studies.Based on the optical profile data measured during three cruises in the northern South China Sea in autumn from 2003 to 2005,variations in the Kd(λ) spectra were analyzed.The variability of Kd(λ) shows much distinct features in both magnitude and spectra pattern,it is much higher in coastal waters than that of open oceanic waters;and the blue-to-green(443/555) ratio of Kd(λ) tends to increase with chlorophyll a concentration([Chl-a]) from open ocean to coastal waters.These characteristics can be explained most by the increase of aw+p(443)/aw+p(555) with [Chl-a].In short waveband,the relation between Kd(λ)-Kw(λ) and [Chl-a] can be well described by a power law function,indicating the large contribution of phytoplankton to the variations in Kd(λ).As for the spectral model of the diffuse attenuation coefficient,there are good linear relationships between Kd(490) and Kd(λ) in other wavelengths with own slope and intercept of a linear functions in the spectral range 412-555 nm.Kd(490) is well correlated with the spectral ratio of remote sensing reflectance;and should enough measurement data are given,this empirical algorithm would be used in the Kd(λ) retrieval from ocean color satellite data.The variation in Kd(λ) provides much useful information for us to study the bio-optical property in the northern South China Sea.展开更多
基金This work was supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX2-205)the Ministry of Science and Technology (Grant Nos. G1999043806 and 2001DIA50041) National Natural Science Foundation of China (Grant N
文摘A strong warm event happens during spring 1997 to spring 1999 in the South China Sea. Its intensity and duration show that it is the strongest event on the record over the past decades. It also corresponds with the severe flood over the valley of the Yangtze River and a couple of marine environmental events. This note addressed the evolution process by using several data sets, such as sea surface temperature, height and wind stress in addition to subsurface temperature. The onset of the warm event almost tele-connects with the El Nino event in the tropical Pacific Ocean. Summer monsoon is stronger and winter monsoon is weaker in 1997 so that there are persistent westerly anomalies in the South China Sea. During the development phase, the warm advection caused by southerly anomalies is the major factor while the adjustment of the thermocline is not obvious. Subsequently, the southerly anomalies decay and even northerly anomalies appear in the summer of 1998 resulting from the weaker than normal summer
基金supported by National Natural Science Foundation of China under grant Nos. 40839909,41074062, and 40674040
文摘In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plateau, adjacent to the Sichuan basin, is characterized by very steep relief with high mountain ranges. The crust beneath this region slows the velocities in the middle and lower crust. We have adopted a relatively dense network to inverse the detailed structure of the crust and upper mantle along the eastern margin of the Tibetan plateau and Sichuan basin, using teleseismic data via receiver function analysis. The results are in-line with the hypothesis that viscous crustal material is flowing beneath the eastern margin of the Tibetan plateau and that this process drives overlying crustal material around the strong and rigid Sichuan basin. When the viscous material hits this obstruction, flows are divided into two or more branches with different directions. The upper part of the upwelling viscous flow produces the pressure to intrude the upper crust, thereby driving uplift of mountain ranges and high peaks. In contrast, the lower part of the downwelling viscous flow produces the pressure to intrude the lower crust and upper mantle to deepen the Moho discontinuity, causing observed crustal thickening.
文摘During the boreal spring of 1966, a warm-core eddy is identified in the upper South China Sea (SCS) west of the Philippines through an analysis of the U.S. Navy′s Master Oceanographic Observation Data Set. This eddy occurred before the development of the northern summer monsoon and disappeared afterward. We propose that this eddy is a result of the radiative warming during spring and the downwelling due to the anticyclonic forcing at the surface. Our hypothesis suggests an air-sea feedback scenario that may explain the development and withdrawal of the summer monsoon over the SCS. The development phase of the warm-core eddy in this hypothesis is tested by using the Princeton Ocean model.
基金Supported by the National Natural Science Foundation of China(Nos.41576032,41176160)the International Cooperation,CAS,ChineseForeign Cooperation in Key Projects(No.133337KYSB20160002)the National Key R&D Program of China(No.2017YFC1405600)
文摘The impact of typhoon Kujira(2015)on the ocean environment around Yongxing Island in the South China Sea was observed using multiple-satellite sensors and on-site data.A subsurface buoy and Agro float were located to the left and lower right of the track of the typhoon.Satellite observations revealed sea surface cooling of up to 2.5℃,a maximum decrease in sea surface salinity of 2 in the main study area because of heavy rain,and increases in the chlorophyll concentration induced by the slow-moving typhoon with a maximum observed instantaneous wind speed of 35.1 m/s.The sea surface temperature to the right of the typhoon track changed more than that on the left owing to a right bias of the typhoon associated with coupling of the typhoon with wind stress on the sea surface.In the ocean interior,there was obvious downwelling at 24.7 m and upwelling at a depth of 35.7 m with the vertical entrainment and agitation of the typhoon,and the ef fects extended to different depths of up to more than 1000 m.When the typhoon passed through the main study area,the maximum flow velocity change at depths of 51 and 660 m was about 0.44 and 0.04 m/s,respectively.The typhoon af fected the flow field to a depth of 660 m as it formed and decayed in 11 h,moved at an average speed of 60 m/h,and af fected the sea surface over a range exceeding 700 km as it moved slowly and stayed at sea for 2 d.Vertical entrainment and agitation generated by the typhoon,as well as rainfall,cooled the sea surface.This inhibited the strengthening of the typhoon,but the energy transmitted to the ocean led to divergence-convergence flow from a shallow to deep layer.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos. 40976007, 41176002, and 41376007)the National Basic Research Program of China (Grant No. 2012CB955201)+2 种基金the Special Fund for Meteorological Scientific Research in the Public Interest of the China Meteorological Administration (Grant No. GYHY201006022)the Specialized Research Fund for the Doctoral Program of Higher Education of China (2010)the Special Fund for Environmental Protection Scientific Research in the Public Interest of the Ministry of Environmental Protection of the People’s Republic of China (Grant No. 201309056)
文摘The equatorial response to subtropical Pacific forcing was studied in a coupled climate model.The forcings in the western,central and eastern subtropical Pacific all caused a significant response in the equatorial thermocline,with comparable magnitudes.This work highlights the key role of air-sea coupling in the subtropical impact on the equatorial thermocline,instead of only the role of the ＂oceanic tunnel＂.The suggested mechanism is that the cyclonic （anticyclonic） circulation in the atmosphere caused by the subtropical surface warming （cooling） can generate an anomalous upwelling （downwelling） in the interior region.At the same time,an anomalous downwelling （upwelling） occurs at the equatorward flank of the forcing,which produces anomalous thermocline warming （cooling）,propagating equatorward and resulting in warming （cooling） in the equatorial thermocline.This is an indirect process that is much faster than the ＂oceanic tunnel＂ mechanism in the subtropical impact on the equator.
文摘Climate warming, variation of East Asian atmospheric system have affected the Chinese offshore environment through the air-sea interaction, the coastal waters of South China Sea had been influenced, leading a corresponding impact on the coral reef growth. This paper reports on coral coverage and dominant coral species changes in Xu wen National Coral Reef Nature Reserve, examines their relationship with meteorological factors anomalies recorded by satellite. The study reveals that: compared to the period from 1979 to 2003, the temperature of surface coastal water dropped significantly in South China Sea in 2004-2008, the divergence of low layer of atmosphere over it strengthened, produced a zonal westerly anomaly field, which had an opposite direction to the local northeastern trade wind. The increasing of suspended matter in water, the decreasing of down welling in northwestern South China Sea, made the water quality deteriorating, water transparency decreased significantly, coral reef survival environment worsened, which would cause adverse effects on coral reef building capacity in the Reserve. Continued monitoring efforts are necessary to further assess the relationship between coral building capacity and in situ meteorological factors anomalies and improve the use of the dataset in future regional degradation predictions.
文摘Based on observational evidence and the known physical characteristics of surface gravity waves, an argument is made that downwelling is not a significant feature over the life history of these waves under the usual conditions existing in the open oceans. Since it has recently been predicted that upwelling due to surface gravity waves should occur within a storm at sea, when the waves are growing in amplitude, the contrast is explained. As a result the importance of the upwelling concept due to waves in stimulating biological productivity is further emphasized, and the possibility for reducing global warming is worth repeating.
基金Supported by the Chinese Academy of Sciences (No. KZCX2-YW-215)the National Natural Science Foundation of China (No. 40476019)the Project of Knowledge Innovation of South China Sea Institute of Oceanology (No. LYQY200701)
文摘The diffuse attenuation coefficient for downwelling irradiance(Kd(λ)) is an important parameter for ocean studies.Based on the optical profile data measured during three cruises in the northern South China Sea in autumn from 2003 to 2005,variations in the Kd(λ) spectra were analyzed.The variability of Kd(λ) shows much distinct features in both magnitude and spectra pattern,it is much higher in coastal waters than that of open oceanic waters;and the blue-to-green(443/555) ratio of Kd(λ) tends to increase with chlorophyll a concentration([Chl-a]) from open ocean to coastal waters.These characteristics can be explained most by the increase of aw+p(443)/aw+p(555) with [Chl-a].In short waveband,the relation between Kd(λ)-Kw(λ) and [Chl-a] can be well described by a power law function,indicating the large contribution of phytoplankton to the variations in Kd(λ).As for the spectral model of the diffuse attenuation coefficient,there are good linear relationships between Kd(490) and Kd(λ) in other wavelengths with own slope and intercept of a linear functions in the spectral range 412-555 nm.Kd(490) is well correlated with the spectral ratio of remote sensing reflectance;and should enough measurement data are given,this empirical algorithm would be used in the Kd(λ) retrieval from ocean color satellite data.The variation in Kd(λ) provides much useful information for us to study the bio-optical property in the northern South China Sea.
