In the northern Bay of Bengal,the existence of intense temperature inversion during winter is a widely accepted phenomenon.However,occurrences of temperature inversion during other seasons and the spatial distribution...In the northern Bay of Bengal,the existence of intense temperature inversion during winter is a widely accepted phenomenon.However,occurrences of temperature inversion during other seasons and the spatial distribution within and adjacent to the Bay of Bengal are not well understood.In this study,a higher resolution spatiotemporal variation of temperature inversion and its mechanisms are examined with mixed layer heat and salt budget analysis utilizing long-term Argo(2004 to 2020)and RAMA(2007 to 2020)profiles data in the Bay of Bengal and eastern equatorial Indian Ocean(EEIO).Temperature inversion exists(17.5%of the total 39293 Argo and 51.6%of the 28894 RAMA profiles)throughout the year in the entire study area.It shows strong seasonal variation,with the highest occurrences in winter and the lowest in spring.Besides winter inversion in the northern Bay of Bengal,two other regions with frequent temperature inversion are identified in this study for the first time:the northeastern part of the Bay of Bengal and the eastern part of the EEIO during summer and autumn.Driving processes of temperature inversion for different subregions are revealed in the current study.Penetration of heat(mean~25 W/m;)below the haline-stratified shallow mixed layer leads to a relatively warmer subsurface layer along with the simultaneous cooling tendency in mixed layer,which controls more occurrence of temperature inversion in the northern Bay of Bengal throughout the year.Comparatively lower cooling tendency due to net surface heat loss and higher mixed layer salinity leaves the southern part of the bay less supportive to the formation of temperature inversion than the northern bay.In the EEIO,slightly cooling tendency in the mixed layer along with the subduction of warm-salty Arabian Sea water beneath the cold-fresher Bay of Bengal water,and downwelling of thermocline creates a favorable environment for forming temperature inversion mainly during summer and autumn.Deeper isothermal layer depth,and thicker barrier layer thickness intensify the temperature inversion both in the Bay of Bengal and EEIO.展开更多
2022年4月10—14日浙江沿海海面出现一次持续时间长、范围广、浓度大的海雾过程。利用卫星资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)发布的ERA-Interim(ECMWF Reanalysis-Interim)资料和...2022年4月10—14日浙江沿海海面出现一次持续时间长、范围广、浓度大的海雾过程。利用卫星资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)发布的ERA-Interim(ECMWF Reanalysis-Interim)资料和浙江沿海自动气象观测站资料,分析此次过程的特征和成因。结果表明,低层逆温层使得低层水汽不易扩散到高空,有利于大雾的生成和维持。成雾阶段,有明显的水汽辐合,同时气温高于海面温度且差值为0~2.0℃。海雾维持且浓度较大时,水汽辐合逐渐减弱;气海温差(2 m气温减海面温度)则在0℃左右。消散阶段,有明显的水汽辐散;气海温差大于2.0℃或小于0℃。展开更多
The TEXh86 paleothermometer on the base of isoprenoid glycerol dialkyl glycerol tetraethers （iGDGTs） has been widely applied to various marine settings to reconstruct past sea surface temperatures （SSTs）. However,...The TEXh86 paleothermometer on the base of isoprenoid glycerol dialkyl glycerol tetraethers （iGDGTs） has been widely applied to various marine settings to reconstruct past sea surface temperatures （SSTs）. However, it remains uncertain how well this proxy reconstructs SSTs in marginal seas. In this study, we analyze the environmental factors governing distribution ofiGDGTs in surface sediments to assess the applicability of TEXH86 paleothermometer in the South China Sea （SCS）. Individual iGDGT concentrations increase gradually eastwards. Redundancy analysis based on the relative abundance of an individual iGDGT compound and environmental parameters suggests that water depth is the most influential factor to the distribution of iGDGTs, because thaumarchaeota communities are water-depth dependent. Interestingly, the SST difference （AT） between TEXH86 derived temperature and remote-sensing SST is less than 1°C in sediments with water depth 〉 200 m, indicating that TEXH86 was the robust proxy to trace the paleo-SST in the region if water depth is greater than 200 m.展开更多
根据2014—2017年南海北部200m等深线以浅海域渔业资源调查的短尾大眼鲷(Priacanthusmacracanthus)数据,结合遥感获得的海表温度(seasurfacetemperature,SST)数据,首次将渔场水深(D)与SST的乘积(SSTD)引入作为新的变量,采用灰色关联度...根据2014—2017年南海北部200m等深线以浅海域渔业资源调查的短尾大眼鲷(Priacanthusmacracanthus)数据,结合遥感获得的海表温度(seasurfacetemperature,SST)数据,首次将渔场水深(D)与SST的乘积(SSTD)引入作为新的变量,采用灰色关联度方法筛选与渔场关联度最高的变量,将关联度最高的变量与标准化后的单位捕捞努力量(catch per unit effect, CPUE)采用一元非线性回归建立模型,对模型理论CPUE与实际CPUE的时空变化进行分析。结果表明,南海北部短尾大眼鲷渔场随季节变化明显,各季节CPUE随SST呈先增大后减小的趋势;不同季节CPUE最高的海域水深不同,春季为160 m,夏季为140 m,秋季为60 m,冬季为140 m; CPUE与SST、D、SSTD进行灰色关联度分析发现,各季节CPUE与SSTD关联度最高且关联度均超过0.5;将SSTD作为变量, CPUE作为表征渔场好坏的指标值,建立环境因子与CPUE的关系模型,模型理论CPUE高值区有明显的季节变化,且实际CPUE高值区的分布与理论CPUE高值区分布一致,以上结果 P值均小于0.05,模型预测准确。展开更多
为明确不同粒型花生种子的吸胀特性及其大田的适宜播种深度,选用小、中小、大籽三类品种,先在室内进行25℃条件下0~10 h的清水浸种试验,测定种子吸水能力;然后在夏初正常气候条件下进行2、4、6、8 cm (SD2、SD4、SD6、SD8)4个播种深度试...为明确不同粒型花生种子的吸胀特性及其大田的适宜播种深度,选用小、中小、大籽三类品种,先在室内进行25℃条件下0~10 h的清水浸种试验,测定种子吸水能力;然后在夏初正常气候条件下进行2、4、6、8 cm (SD2、SD4、SD6、SD8)4个播种深度试验,研究其对播种出苗期田间小气候、种际土壤温湿度、出苗率及幼苗素质的影响。结果表明:(1)大籽品种吸水量最多,是中小籽、小籽的1.12~1.55倍,但吸水速度最慢,小籽吸水最快,这是大籽花生应适当深播而小籽花生可适当浅播的水分生理基础。(2)播深对种际生境有重大影响。外界气温及其有效积温与种际土温及其有效积温相差较大,但两个环境温度间高度正相关。播种出苗期15 d内三类品种各播深的平均种际土温比日均气温高1.93~2.20℃,有效积温高28.5~32.5℃。随着播深增加,各品种种际有效积温呈现出由少到多的二次抛物线趋势,即SD2、SD4有效积温少于SD6、SD8。各品种种际土壤含水量整体表现SD8、SD2>SD4>SD6,即播种最深、最浅处的土壤湿度大于播深中等的湿度。(3)播深对出苗率与幼苗素质有重要影响,中小籽、大籽品种出苗率对播深的响应比小籽更敏感。小籽和中小籽品种播深均以4 cm为宜,大籽品种播深以6 cm为宜,可使出苗快、出苗率高和幼苗素质好。展开更多
为探讨全球气候变化对东海鲐鱼(Scomber japonicus)栖息地时空分布的影响,减缓气候变化对鲐鱼渔场的不利影响,基于CMIP6气候模式输出的2.5 m (Temp_2.5 m)、25 m (Temp_25 m)和50 m (Temp_50 m)水温数据分析3种未来气候情境下(SSP126、S...为探讨全球气候变化对东海鲐鱼(Scomber japonicus)栖息地时空分布的影响,减缓气候变化对鲐鱼渔场的不利影响,基于CMIP6气候模式输出的2.5 m (Temp_2.5 m)、25 m (Temp_25 m)和50 m (Temp_50 m)水温数据分析3种未来气候情境下(SSP126、SSP370和SSP585)东海鲐鱼栖息地的时空变化。结果表明,SSP126情境下,2015—2100年渔场内所有水层温度整体变化幅度较小。SSP370和SSP585情境下,各水层温度均明显上升。3个水层温度在2015—2020、2055—2060和2095—2100年具有明显空间变化。2015—2100年东海鲐鱼渔场的栖息地指数(Habitat suitability index, HSI)和适宜栖息地面积比例在SSP126、SSP370和SSP585情境下整体呈下降趋势,而不适宜栖息地面积呈上升趋势。不同气候变化情境下,东海鲐鱼适宜栖息地在2015—2020、2055—2060和2095—2100年3个时间段内主要分布在122°E—126°E、28°N—30°N范围内,不适宜栖息地主要分布在渔场中部;此外,鲐鱼适宜栖息地重心具有向北移动的趋势。研究表明,在未来全球变暖的气候背景下东海海域不易形成适宜的鲐鱼栖息地。展开更多
基金The Marine Scholarship of ChinaChina Scholarship Council(CSC)for International Doctoral Students under contract No.2017SOA016552the National Natural Science Foundation of China under contract Nos U2106204 and 41676003。
文摘In the northern Bay of Bengal,the existence of intense temperature inversion during winter is a widely accepted phenomenon.However,occurrences of temperature inversion during other seasons and the spatial distribution within and adjacent to the Bay of Bengal are not well understood.In this study,a higher resolution spatiotemporal variation of temperature inversion and its mechanisms are examined with mixed layer heat and salt budget analysis utilizing long-term Argo(2004 to 2020)and RAMA(2007 to 2020)profiles data in the Bay of Bengal and eastern equatorial Indian Ocean(EEIO).Temperature inversion exists(17.5%of the total 39293 Argo and 51.6%of the 28894 RAMA profiles)throughout the year in the entire study area.It shows strong seasonal variation,with the highest occurrences in winter and the lowest in spring.Besides winter inversion in the northern Bay of Bengal,two other regions with frequent temperature inversion are identified in this study for the first time:the northeastern part of the Bay of Bengal and the eastern part of the EEIO during summer and autumn.Driving processes of temperature inversion for different subregions are revealed in the current study.Penetration of heat(mean~25 W/m;)below the haline-stratified shallow mixed layer leads to a relatively warmer subsurface layer along with the simultaneous cooling tendency in mixed layer,which controls more occurrence of temperature inversion in the northern Bay of Bengal throughout the year.Comparatively lower cooling tendency due to net surface heat loss and higher mixed layer salinity leaves the southern part of the bay less supportive to the formation of temperature inversion than the northern bay.In the EEIO,slightly cooling tendency in the mixed layer along with the subduction of warm-salty Arabian Sea water beneath the cold-fresher Bay of Bengal water,and downwelling of thermocline creates a favorable environment for forming temperature inversion mainly during summer and autumn.Deeper isothermal layer depth,and thicker barrier layer thickness intensify the temperature inversion both in the Bay of Bengal and EEIO.
文摘2022年4月10—14日浙江沿海海面出现一次持续时间长、范围广、浓度大的海雾过程。利用卫星资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)发布的ERA-Interim(ECMWF Reanalysis-Interim)资料和浙江沿海自动气象观测站资料,分析此次过程的特征和成因。结果表明,低层逆温层使得低层水汽不易扩散到高空,有利于大雾的生成和维持。成雾阶段,有明显的水汽辐合,同时气温高于海面温度且差值为0~2.0℃。海雾维持且浓度较大时,水汽辐合逐渐减弱;气海温差(2 m气温减海面温度)则在0℃左右。消散阶段,有明显的水汽辐散;气海温差大于2.0℃或小于0℃。
基金We thank each member of the organic geochemistry group in the State Key Laboratory of Biogeology and Environmental Geology for technical support. We also thank Y. Qin, x. Chen and L. Gong from China University of Geosciences for help with data processing. We also thank Changbing Yang and Angelo R. Yang from The University of Texas in Austin for the language polishing. The research was funded by the National Natural Science Foundation of China （Grant No. 41376090）, the ＂Strategic Priority Research Program＂ of the Chinese Academy of Sciences （XDA 11020102）, The Project of China Geological Survey （DD20160138）, and Marine Safeguard Project （GZH201200503）.
文摘The TEXh86 paleothermometer on the base of isoprenoid glycerol dialkyl glycerol tetraethers （iGDGTs） has been widely applied to various marine settings to reconstruct past sea surface temperatures （SSTs）. However, it remains uncertain how well this proxy reconstructs SSTs in marginal seas. In this study, we analyze the environmental factors governing distribution ofiGDGTs in surface sediments to assess the applicability of TEXH86 paleothermometer in the South China Sea （SCS）. Individual iGDGT concentrations increase gradually eastwards. Redundancy analysis based on the relative abundance of an individual iGDGT compound and environmental parameters suggests that water depth is the most influential factor to the distribution of iGDGTs, because thaumarchaeota communities are water-depth dependent. Interestingly, the SST difference （AT） between TEXH86 derived temperature and remote-sensing SST is less than 1°C in sediments with water depth 〉 200 m, indicating that TEXH86 was the robust proxy to trace the paleo-SST in the region if water depth is greater than 200 m.
文摘根据2014—2017年南海北部200m等深线以浅海域渔业资源调查的短尾大眼鲷(Priacanthusmacracanthus)数据,结合遥感获得的海表温度(seasurfacetemperature,SST)数据,首次将渔场水深(D)与SST的乘积(SSTD)引入作为新的变量,采用灰色关联度方法筛选与渔场关联度最高的变量,将关联度最高的变量与标准化后的单位捕捞努力量(catch per unit effect, CPUE)采用一元非线性回归建立模型,对模型理论CPUE与实际CPUE的时空变化进行分析。结果表明,南海北部短尾大眼鲷渔场随季节变化明显,各季节CPUE随SST呈先增大后减小的趋势;不同季节CPUE最高的海域水深不同,春季为160 m,夏季为140 m,秋季为60 m,冬季为140 m; CPUE与SST、D、SSTD进行灰色关联度分析发现,各季节CPUE与SSTD关联度最高且关联度均超过0.5;将SSTD作为变量, CPUE作为表征渔场好坏的指标值,建立环境因子与CPUE的关系模型,模型理论CPUE高值区有明显的季节变化,且实际CPUE高值区的分布与理论CPUE高值区分布一致,以上结果 P值均小于0.05,模型预测准确。
文摘为探讨全球气候变化对东海鲐鱼(Scomber japonicus)栖息地时空分布的影响,减缓气候变化对鲐鱼渔场的不利影响,基于CMIP6气候模式输出的2.5 m (Temp_2.5 m)、25 m (Temp_25 m)和50 m (Temp_50 m)水温数据分析3种未来气候情境下(SSP126、SSP370和SSP585)东海鲐鱼栖息地的时空变化。结果表明,SSP126情境下,2015—2100年渔场内所有水层温度整体变化幅度较小。SSP370和SSP585情境下,各水层温度均明显上升。3个水层温度在2015—2020、2055—2060和2095—2100年具有明显空间变化。2015—2100年东海鲐鱼渔场的栖息地指数(Habitat suitability index, HSI)和适宜栖息地面积比例在SSP126、SSP370和SSP585情境下整体呈下降趋势,而不适宜栖息地面积呈上升趋势。不同气候变化情境下,东海鲐鱼适宜栖息地在2015—2020、2055—2060和2095—2100年3个时间段内主要分布在122°E—126°E、28°N—30°N范围内,不适宜栖息地主要分布在渔场中部;此外,鲐鱼适宜栖息地重心具有向北移动的趋势。研究表明,在未来全球变暖的气候背景下东海海域不易形成适宜的鲐鱼栖息地。
