The Kuroshio frontal instable processes （KFIP） in the East China Sea （ECS） not only have a great impact on the hydrologic characteristics,the pollutants drift,the distribution of seafloor sediment and the ships na...The Kuroshio frontal instable processes （KFIP） in the East China Sea （ECS） not only have a great impact on the hydrologic characteristics,the pollutants drift,the distribution of seafloor sediment and the ships navigation of the ECS,but also are closely related to the climate changes of the coastal areas of the ECS.However the frequency and area of occurrence of the KFIP have not been studied fully and detailedly.Because of its high spatial and temporal resolution,MODIS data is a kind of very good data source for surveying and researching the KFIP in the ECS.The aim of this study is to detect the KFIP in the ECS by using MODIS data,and to study the frequency and region of occurrence of the KFIP in the ECS.The selection has coverage of level 2 data of MODIS SST and Kd490 ranging from July 1,2002 to June 30,2009 of the ECS when there was no cloud impact or little.By using of the data,the minimum standard of the Kuroshio temperature fronts and the diffuse attenuation coefficient （Kd490） fronts of the ECS are given.Based on these standards and the curvature distinguish methods,the standard of curvature distinguish for the KFIP in the ECS are put forward.By making use of this standard,we study a total of 2073 satellite-derived images,and discover that as long as there is no cloud impact from January to May and October to December,the KFIP in the ECS are surely found in MODIS satellite images.From June to September,the frequency of occurrence can also reach to 82.9% at least.Moreover,it is obtained that there are three source regions of these instability processes,namely,（26°N,121.5°E） nearby,（27°N,125°E） nearby and （30°N,128°E） nearby.The differences of the characteristics of these instability processes which are generated in different regions are analyzed in the present study.展开更多
大气^(210)Po、^(210)Bi和^(210)Pb的沉降通量是海洋中核素示踪颗粒物动力学过程(颗粒有机碳输出、颗粒物输运)的基础参数,为揭示我国近海地区^(210)Po、^(210)Bi和^(210)Pb活度浓度的时空变化规律并估算其沉降入海通量,本文于2016年9...大气^(210)Po、^(210)Bi和^(210)Pb的沉降通量是海洋中核素示踪颗粒物动力学过程(颗粒有机碳输出、颗粒物输运)的基础参数,为揭示我国近海地区^(210)Po、^(210)Bi和^(210)Pb活度浓度的时空变化规律并估算其沉降入海通量,本文于2016年9月至翌年2月和2021年9-11月分别对上海及厦门地区近地表大气气溶胶中^(210)Po、^(210)Pb和^(210)Bi的活度浓度进行了连续观测;基于^(210)Po-^(210)Pb活度比(^(210)Po/^(210)Pb)和^(210)Bi-^(210)Pb活度比(^(210)Bi/^(210)Pb)两种示踪法计算了气溶胶颗粒物的滞留时间,并利用一维简单气溶胶沉降速率模型估算了3种核素以大气沉降方式输入东海的通量。结果显示,2016年上海秋、冬两季^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.11~1.27 m Bq/m^(3)、0.45~1.83 m Bq/m^(3)和1.12~6.10 m Bq/m^(3);2021年秋季厦门^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.05~0.85 m Bq/m^(3)、0.83~2.52 m Bq/m^(3)和0.17~1.32 m Bq/m^(3),上海近地表气溶胶中3种核素的活度浓度秋季平均值比厦门地区高。利用^(210)Po/^(210)Pb和^(210)Bi/^(210)Pb计算得到上海和厦门近地面大气的气溶胶滞留时间存在显著差异,基于^(210)Po/^(210)Pb计算上海气溶胶滞留时间均值为(94±54)d,基于^(210)Bi/^(210)Pb计算上海气溶胶滞留时间均值为(6.4±4.8)d,造成这种差异的原因很可能是两种示踪法本身具有的系统性差异。本文基于一维简易气溶胶沉降速率模型估算了上海地区的^(210)Pb、^(210)Bi和^(210)Po的大气沉降入东海的通量,其在秋季期间的变化范围分别为0.1~26.35 Bq/(m^(2)·d)、0.04~7.91 Bq/(m^(2)·d)和0.01~5.49 Bq/(m^(2)·d)。基于模型估算的^(210)Po、^(210)Bi和^(210)Pb沉降通量与研究区域的实际观测值接近一致,表明利用一维简易气溶胶沉降速率模型间接估算法在替代观测站直测核素的沉降入海通量方面具有一定可行性。展开更多
Previous studies have demonstrated that the low-frequency sea surface temperature(SST) variability in the Yellow Sea and East China Sea(YECS) is linked to large-scale climate variability, but explanations on the mecha...Previous studies have demonstrated that the low-frequency sea surface temperature(SST) variability in the Yellow Sea and East China Sea(YECS) is linked to large-scale climate variability, but explanations on the mechanisms vary. This study examines the low-frequency variability and trends of some atmospheric and oceanic variables to discuss their different effects on the YECS warming. The increasing temperature trend is also observed at a hydrographic section transecting the Kuroshio.The increasing rate of ocean temperature decreases with depth, which might result in an increase in vertical stratification and a decrease in vertical mixing, and thus plays a positive role on the YECS warming. The surface net heat flux(downward positive)displays a decreasing trend, which is possibly a result of the YECS warming, and, in turn, inhibits it. Wind speeds show different trends in different datasets, such that its role in the YECS warming is uncertain. The trends in wind stress divergence and curl have large uncertainties, so their effects on SST warming are still unclear. The Kuroshio heat transport calculated in this study,displays no significantly increasing trend, so is an unlikely explanation for the SST warming. Limited by sparse ocean observations,sophisticated assimilative climate models are still needed to unravel the mechanisms behind the YECS warming.展开更多
基金the special funds for marine commonweal research under contract No.200705027variability of the subtropical gyre in North Pacific and its impacts on dynamic environment of China marginal seas under contract No.2007CB411800defense industrial technology development program and the special funds for basic scientific research project of the First Institute of Oceanography,SOA under contract No.2010G12
文摘The Kuroshio frontal instable processes （KFIP） in the East China Sea （ECS） not only have a great impact on the hydrologic characteristics,the pollutants drift,the distribution of seafloor sediment and the ships navigation of the ECS,but also are closely related to the climate changes of the coastal areas of the ECS.However the frequency and area of occurrence of the KFIP have not been studied fully and detailedly.Because of its high spatial and temporal resolution,MODIS data is a kind of very good data source for surveying and researching the KFIP in the ECS.The aim of this study is to detect the KFIP in the ECS by using MODIS data,and to study the frequency and region of occurrence of the KFIP in the ECS.The selection has coverage of level 2 data of MODIS SST and Kd490 ranging from July 1,2002 to June 30,2009 of the ECS when there was no cloud impact or little.By using of the data,the minimum standard of the Kuroshio temperature fronts and the diffuse attenuation coefficient （Kd490） fronts of the ECS are given.Based on these standards and the curvature distinguish methods,the standard of curvature distinguish for the KFIP in the ECS are put forward.By making use of this standard,we study a total of 2073 satellite-derived images,and discover that as long as there is no cloud impact from January to May and October to December,the KFIP in the ECS are surely found in MODIS satellite images.From June to September,the frequency of occurrence can also reach to 82.9% at least.Moreover,it is obtained that there are three source regions of these instability processes,namely,（26°N,121.5°E） nearby,（27°N,125°E） nearby and （30°N,128°E） nearby.The differences of the characteristics of these instability processes which are generated in different regions are analyzed in the present study.
文摘大气^(210)Po、^(210)Bi和^(210)Pb的沉降通量是海洋中核素示踪颗粒物动力学过程(颗粒有机碳输出、颗粒物输运)的基础参数,为揭示我国近海地区^(210)Po、^(210)Bi和^(210)Pb活度浓度的时空变化规律并估算其沉降入海通量,本文于2016年9月至翌年2月和2021年9-11月分别对上海及厦门地区近地表大气气溶胶中^(210)Po、^(210)Pb和^(210)Bi的活度浓度进行了连续观测;基于^(210)Po-^(210)Pb活度比(^(210)Po/^(210)Pb)和^(210)Bi-^(210)Pb活度比(^(210)Bi/^(210)Pb)两种示踪法计算了气溶胶颗粒物的滞留时间,并利用一维简单气溶胶沉降速率模型估算了3种核素以大气沉降方式输入东海的通量。结果显示,2016年上海秋、冬两季^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.11~1.27 m Bq/m^(3)、0.45~1.83 m Bq/m^(3)和1.12~6.10 m Bq/m^(3);2021年秋季厦门^(210)Po、^(210)Bi、^(210)Pb 3种核素活度浓度的变化范围分别为0.05~0.85 m Bq/m^(3)、0.83~2.52 m Bq/m^(3)和0.17~1.32 m Bq/m^(3),上海近地表气溶胶中3种核素的活度浓度秋季平均值比厦门地区高。利用^(210)Po/^(210)Pb和^(210)Bi/^(210)Pb计算得到上海和厦门近地面大气的气溶胶滞留时间存在显著差异,基于^(210)Po/^(210)Pb计算上海气溶胶滞留时间均值为(94±54)d,基于^(210)Bi/^(210)Pb计算上海气溶胶滞留时间均值为(6.4±4.8)d,造成这种差异的原因很可能是两种示踪法本身具有的系统性差异。本文基于一维简易气溶胶沉降速率模型估算了上海地区的^(210)Pb、^(210)Bi和^(210)Po的大气沉降入东海的通量,其在秋季期间的变化范围分别为0.1~26.35 Bq/(m^(2)·d)、0.04~7.91 Bq/(m^(2)·d)和0.01~5.49 Bq/(m^(2)·d)。基于模型估算的^(210)Po、^(210)Bi和^(210)Pb沉降通量与研究区域的实际观测值接近一致,表明利用一维简易气溶胶沉降速率模型间接估算法在替代观测站直测核素的沉降入海通量方面具有一定可行性。
基金supported by the the National Natural Science Foundation of China (Grant Nos. 41690120, 41690121, 41621064, 91528304 & 41476021)the National Program on Global Change and Air-Sea Interaction (Grant No. GASI-IPOVAI-04)+1 种基金the National Basic Research Program (Grant No. 2013CB430302)the Scientific Research Fund of the Second Institute of Oceanography (Grant No. JG1501)
文摘Previous studies have demonstrated that the low-frequency sea surface temperature(SST) variability in the Yellow Sea and East China Sea(YECS) is linked to large-scale climate variability, but explanations on the mechanisms vary. This study examines the low-frequency variability and trends of some atmospheric and oceanic variables to discuss their different effects on the YECS warming. The increasing temperature trend is also observed at a hydrographic section transecting the Kuroshio.The increasing rate of ocean temperature decreases with depth, which might result in an increase in vertical stratification and a decrease in vertical mixing, and thus plays a positive role on the YECS warming. The surface net heat flux(downward positive)displays a decreasing trend, which is possibly a result of the YECS warming, and, in turn, inhibits it. Wind speeds show different trends in different datasets, such that its role in the YECS warming is uncertain. The trends in wind stress divergence and curl have large uncertainties, so their effects on SST warming are still unclear. The Kuroshio heat transport calculated in this study,displays no significantly increasing trend, so is an unlikely explanation for the SST warming. Limited by sparse ocean observations,sophisticated assimilative climate models are still needed to unravel the mechanisms behind the YECS warming.
