There is a vast upwelling area induced by the southeast monsoon in the waters off South Java,making the region an important fishing ground.Climate events can affect the variation of upwelling,but oceanographers have d...There is a vast upwelling area induced by the southeast monsoon in the waters off South Java,making the region an important fishing ground.Climate events can affect the variation of upwelling,but oceanographers have different understandings on the extent to which climate events control upwelling in this area,which leads to a lack of basis for studies on the evaluation and mechanisms of the variability of fishery resources in the region.The correlation between environmental parameters,including surface temperature(SST),chlorophyll-a(Chl-a)concentration,and climate event indices in South Java from 2003 to 2020 was analyzed.Results show that the Indian Ocean Dipole(IOD)has a greater influence on the interannual variability of upwelling intensity than ENSO.During the IOD,variations in equatorial latitudinal winds excite different types of Kelvin waves that anomalously deepen or shallow the thermocline,which is the main cause of anomalous variations in upwelling,independent of variations in the local wind field.A correlation between the interannual variability in upwelling and the annual catches was revealed,showing that climatic events indirectly affect fishery resources through upwelling effects.During positive IOD/El Niño periods,strong upwelling delivers more nutrients to the surface layer,which favors fish growth and reproduction,resulting in higher annual catches.A negative IOD/La Niña,on the other hand,leads to weaker upwelling and fewer nutrients into the surface waters.Fish tend to move in deeper waters,making traditional fishing methods less efficient and consequently lower annual catches.展开更多
This paper highlights the global warming of the lower atmosphere of West African tropical area using <em>in-situ</em> data. The study is based on the analysis of 500-m interval vertical profiles of radioso...This paper highlights the global warming of the lower atmosphere of West African tropical area using <em>in-situ</em> data. The study is based on the analysis of 500-m interval vertical profiles of radiosonde temperature above Niamey (13.47<span style="white-space:nowrap;">°</span>N;2.16<span style="white-space:nowrap;">°</span>E) a sub-Saharan meteorological station. The annual cycle of surface temperatures shows seasonally two peaks located in April/May and in October and two minimum in December/January and August respectively. In the mid-troposphere (between 5 km and 10 km height), time series of monthly mean temperatures from January 2001 to December 2018, shows an annual variability with a slight downward trend of -0.036<span style="white-space:nowrap;">°</span>C per decade. In the lower stratosphere (25 - 30 km altitude) a cooling of -0.64<span style="white-space:nowrap;">°</span>C/decade is observed. Temperatures time series also highlight the presence of two breaking points associated with the El Ni<span style="white-space:nowrap;">ñ</span>o-Southern Oscillation (ENSO) events. When performing a separation regarding Southern Oscillation Index (SOI) time series, model parameters of the linear regression indicate a tropospheric warming during the neutral and La Ni<span style="white-space:nowrap;">ñ</span>a phases and a stratospheric cooling. The analysis of the lower stratosphere zonal wind highlights different behaviours of the quasi-biennial oscillation (QBO) during the neutral and La Ni<span style="white-space:nowrap;">ñ</span>a phases.展开更多
Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,w...Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,which has a signifi cant correlation with winter El Niño Modoki index(R=0.62).During spring after an El Niño(La Niña)Modoki event,the Wyrtki Jet has a positive(negative)anomaly,forced by a westerly(easterly)wind anomaly.The result of a linear-continuously stratifi ed model shows that the fi rst two baroclinic modes explain most of the interannual variability of the spring Wyrtki Jet(~70%)and the third to fi fth modes together account for approximately 30%.Surface wind anomalies in the tropical Indian Ocean are related to the Walker circulation anomaly associated with El Niño/La Niña Modoki.The interannual variability of the spring Wyrtki Jet has an evident impact on sea surface salinity transport before the onset phase of the summer monsoon in the Indian Ocean.展开更多
为研究气候变化对渔业资源的影响,采用2008—2017年全球海洋Argo网格数据集(BOA_Argo)和同期商业渔船渔捞日志数据,分析了拉尼娜和厄尔尼诺年中西太平洋黄鳍金枪鱼围网主要作业渔场温跃层的时空变化特征,结合GAM(generalized additive m...为研究气候变化对渔业资源的影响,采用2008—2017年全球海洋Argo网格数据集(BOA_Argo)和同期商业渔船渔捞日志数据,分析了拉尼娜和厄尔尼诺年中西太平洋黄鳍金枪鱼围网主要作业渔场温跃层的时空变化特征,结合GAM(generalized additive model)对影响黄鳍金枪鱼渔场的变量进行分析。结果表明,拉尼娜年,单位捕捞努力量渔获量(catch per unit effort,CPUE)随温跃层上界温度的高值区向西收缩而西移,最西至145°E;厄尔尼诺年,东移至165°E以东。拉尼娜年较正常年份,赤道太平洋东、西侧温跃层的上界深度差拉大,80~130 m上界深度值偏西。温跃层强度整体上呈现西弱东强,温跃层厚度以15°N和15°S为轴线,分别存在一个较厚的带状分布结构,CPUE分布在厚度值120~200 m之间。温跃层上界温度为27.5~29.5℃、强度为0.08~0.13℃·m^(-1)时,CPUE分布密集,温跃层参数中上界温度对CPUE分布的影响最大。且厄尔尼诺年CPUE的东移和拉尼娜年CPUE的西移随渔场所在温跃层的最适参数值而移动。时间因子中年份对CPUE的影响是波动性的,拉尼娜年对CPUE的影响更密切。资源丰度较高海域在5°N—5°S,150°E—175°E。综上所述,异常气候导致的温跃层变化对于CPUE具有显著影响。展开更多
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB42010203,XDA19060401)the National Natural Science Foundation of China(Nos.42176090,41776011)。
文摘There is a vast upwelling area induced by the southeast monsoon in the waters off South Java,making the region an important fishing ground.Climate events can affect the variation of upwelling,but oceanographers have different understandings on the extent to which climate events control upwelling in this area,which leads to a lack of basis for studies on the evaluation and mechanisms of the variability of fishery resources in the region.The correlation between environmental parameters,including surface temperature(SST),chlorophyll-a(Chl-a)concentration,and climate event indices in South Java from 2003 to 2020 was analyzed.Results show that the Indian Ocean Dipole(IOD)has a greater influence on the interannual variability of upwelling intensity than ENSO.During the IOD,variations in equatorial latitudinal winds excite different types of Kelvin waves that anomalously deepen or shallow the thermocline,which is the main cause of anomalous variations in upwelling,independent of variations in the local wind field.A correlation between the interannual variability in upwelling and the annual catches was revealed,showing that climatic events indirectly affect fishery resources through upwelling effects.During positive IOD/El Niño periods,strong upwelling delivers more nutrients to the surface layer,which favors fish growth and reproduction,resulting in higher annual catches.A negative IOD/La Niña,on the other hand,leads to weaker upwelling and fewer nutrients into the surface waters.Fish tend to move in deeper waters,making traditional fishing methods less efficient and consequently lower annual catches.
文摘This paper highlights the global warming of the lower atmosphere of West African tropical area using <em>in-situ</em> data. The study is based on the analysis of 500-m interval vertical profiles of radiosonde temperature above Niamey (13.47<span style="white-space:nowrap;">°</span>N;2.16<span style="white-space:nowrap;">°</span>E) a sub-Saharan meteorological station. The annual cycle of surface temperatures shows seasonally two peaks located in April/May and in October and two minimum in December/January and August respectively. In the mid-troposphere (between 5 km and 10 km height), time series of monthly mean temperatures from January 2001 to December 2018, shows an annual variability with a slight downward trend of -0.036<span style="white-space:nowrap;">°</span>C per decade. In the lower stratosphere (25 - 30 km altitude) a cooling of -0.64<span style="white-space:nowrap;">°</span>C/decade is observed. Temperatures time series also highlight the presence of two breaking points associated with the El Ni<span style="white-space:nowrap;">ñ</span>o-Southern Oscillation (ENSO) events. When performing a separation regarding Southern Oscillation Index (SOI) time series, model parameters of the linear regression indicate a tropospheric warming during the neutral and La Ni<span style="white-space:nowrap;">ñ</span>a phases and a stratospheric cooling. The analysis of the lower stratosphere zonal wind highlights different behaviours of the quasi-biennial oscillation (QBO) during the neutral and La Ni<span style="white-space:nowrap;">ñ</span>a phases.
基金Supported by the National Key R&D Program of China(No.2018YFA0605702)the National Natural Science Foundation of China(Nos.41876002,41776002)the Fundamental Research Funds for the Central Universities(Nos.2017B04714,2017B04114)。
文摘Features of the interannual variability of the spring Wyrtki Jet in the tropical Indian Ocean are revealed using observation data and model output.The results show that the jet has signifi cant interannual variation,which has a signifi cant correlation with winter El Niño Modoki index(R=0.62).During spring after an El Niño(La Niña)Modoki event,the Wyrtki Jet has a positive(negative)anomaly,forced by a westerly(easterly)wind anomaly.The result of a linear-continuously stratifi ed model shows that the fi rst two baroclinic modes explain most of the interannual variability of the spring Wyrtki Jet(~70%)and the third to fi fth modes together account for approximately 30%.Surface wind anomalies in the tropical Indian Ocean are related to the Walker circulation anomaly associated with El Niño/La Niña Modoki.The interannual variability of the spring Wyrtki Jet has an evident impact on sea surface salinity transport before the onset phase of the summer monsoon in the Indian Ocean.
文摘为研究气候变化对渔业资源的影响,采用2008—2017年全球海洋Argo网格数据集(BOA_Argo)和同期商业渔船渔捞日志数据,分析了拉尼娜和厄尔尼诺年中西太平洋黄鳍金枪鱼围网主要作业渔场温跃层的时空变化特征,结合GAM(generalized additive model)对影响黄鳍金枪鱼渔场的变量进行分析。结果表明,拉尼娜年,单位捕捞努力量渔获量(catch per unit effort,CPUE)随温跃层上界温度的高值区向西收缩而西移,最西至145°E;厄尔尼诺年,东移至165°E以东。拉尼娜年较正常年份,赤道太平洋东、西侧温跃层的上界深度差拉大,80~130 m上界深度值偏西。温跃层强度整体上呈现西弱东强,温跃层厚度以15°N和15°S为轴线,分别存在一个较厚的带状分布结构,CPUE分布在厚度值120~200 m之间。温跃层上界温度为27.5~29.5℃、强度为0.08~0.13℃·m^(-1)时,CPUE分布密集,温跃层参数中上界温度对CPUE分布的影响最大。且厄尔尼诺年CPUE的东移和拉尼娜年CPUE的西移随渔场所在温跃层的最适参数值而移动。时间因子中年份对CPUE的影响是波动性的,拉尼娜年对CPUE的影响更密切。资源丰度较高海域在5°N—5°S,150°E—175°E。综上所述,异常气候导致的温跃层变化对于CPUE具有显著影响。
