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Influences of Freshwater from Major Rivers on Global Ocean Circulation and Temperatures in the MIT Ocean General Circulation Model 被引量:3
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作者 Vikram M.MEHTA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第3期455-468,共14页
Responses of global ocean circulation and temperature to freshwater runoff from major rivers were studied by blocking regional runoff in the global ocean general circulation model (OGCM) developed at the Massachuset... Responses of global ocean circulation and temperature to freshwater runoff from major rivers were studied by blocking regional runoff in the global ocean general circulation model (OGCM) developed at the Massachusetts Institute of Technology. Runoff into the tropical Atlantic, the western North Pacific, and the Bay of Bengal and northern Arabian Sea were selectively blocked. The blocking of river runoff first resulted in a salinity increase near the river mouths (2 practical salinity units). The saltier and, therefore, denser water was then transported to higher latitudes in the North Atlantic, North Pacific, and southern Indian Ocean by the mean currents. The subsequent density contrasts between northern and southern hemispheric oceans resulted in changes in major ocean currents. These anomalous ocean currents lead to significant temperature changes (I^C -2~C) by the resulting anomalous heat transports. The current and temperature anomalies created by the blocked river runoff propagated from one ocean basin to others via coastal and equatorial Kelvin waves. This study suggests that river runoff may be playing an important role in oceanic salinity, temperature, and circulations; and that partially or fully blocking major rivers to divert freshwater for societal purposes might significantly change ocean salinity, circulations, temperature, and atmospheric climate. Further studies are necessary to assess the role of river runoff in the coupled atmosphere-ocean system. 展开更多
关键词 river runoff ocean general circulation freshwater flux
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Sediment Load of Asian Rivers flowing into the Oceans and their Regional Variation
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作者 刘曙光 郑永来 +1 位作者 诸葛正技 李从先 《Marine Science Bulletin》 CAS 2002年第1期61-70,共10页
Study of the major Asian rivers discharge to the ocean reveals variations of their water discharges and sediment loads, and local characteristics of river sediment concentrations. On the basis of this, the Asian river... Study of the major Asian rivers discharge to the ocean reveals variations of their water discharges and sediment loads, and local characteristics of river sediment concentrations. On the basis of this, the Asian rivers fall into three regions, including Eurasia Arctic, East Asia, Southeast and South Asia Regions. The Eurasia Arctic Region is characterized by the lowest sediment concentration and load, while the East Asia Region is of the highest sediment concentration and higher sediment load, and the South-East and South Asia Region yields higher sediment concentration and highest sediment load.The sediment loads of these regions are mainly controlled by climate, geomorphology and tectonic activity. The Eurasia Arctic rivers with large basin areas and water discharge, drain low relief which consists of tundra sediment, thus causing the lowest sediment load. The East Asia rivers with small basin areas and lowest water discharges, drain extensive loess plateau, and transport most erodible loess material, which results in highest sediment concentration. The SE and South Asia rivers originating from the Tibet Plateau have large basin areas and the largest water discharges because of the Summer Monsoon and high rainfall influence, causing the highest sediment load.In Asia, tectonic motion of the Tibet Plateau plays an important role. Those large rivers originating from the Tibet Plateau transport about 50% of the world river sediment load to ocean annually, forming large estuaries and deltas, and consequently exerting a great influence on sedimentation in the coastal zone and shelves. 展开更多
关键词 ASIA river flowing into the ocean sediment load water discharge
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Dynamics of Primary Productivity and Oceanographic Parameters under Influence of the Amazon River Plume
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作者 Amanda Otsuka Fernando Feitosa +7 位作者 Moacyr Araújo Dóris Veleda Maria da Gloria Silva Cunha Nathalie Lefévre Felipe Gaspar Manuel Flores Montes Gislayne Borges Carlos Noriega 《Open Journal of Ecology》 2018年第11期590-606,共17页
The watershed of the Amazon River discharges about 120,000 m3·s-1?of freshwater into the adjacent platform and oceanic region. The aim of this work was to analyze the distribution of oceanographic parameters, chl... The watershed of the Amazon River discharges about 120,000 m3·s-1?of freshwater into the adjacent platform and oceanic region. The aim of this work was to analyze the distribution of oceanographic parameters, chlorophyll a and primary productivity under the influence of the Amazon River plume, during the period of greatest extension of the Amazon plume. Collections were carried out in September 14 in 16 stations including continental platform and oceanic region. It was possible to observe superficial currents along the coast in the northwest direction, but with less intensity and currents with greater speeds towards the east due to the North Brazil Current retroflexion at this time of the year, transporting the plume to the central Atlantic Ocean. The spatial influence of the plume was observed in the salinity, which ranged from 28 to 36.75, although the high precipitation in the region may also have contributed as a source of freshwater. However, the sampled region showed strong negative linear correlation of silicate, chlorophyll a and primary productivity with salinity. The primary productivity values ranged from 0.04 to 18.81 mg C m-3?day-1, whereas chlorophyll a concentrations ranged from 0.15 mg·m-3?to 1.83 mg·m-3, decreasing their values as they move away from the coast. The Amazon River plume can reach and influence the oceanographic and biological parameters in a large area of this oligotrophic region. However, the results also suggest that the export of material from the adjacent coastal region is another determinant of the region’s productivity. 展开更多
关键词 AMAZON river PLUME CONTINENTAL SHELF oceanIC Region Environmental Variables PHYTOPLANKTON Biomass Primary Productivity
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基于走航观测评估大气再分析中的南大洋大气河
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作者 项旭 韩博 +7 位作者 张功 刘长炜 梁凯昕 齐木荣 江可悦 林奕辰 钟锐 杨清华 《高原气象》 北大核心 2025年第1期83-94,共12页
大气河直接影响南极海-陆-冰-气相互作用,但对其开展的探空观测尚不多,造成数值模式和再分析数据的结论存在不确定性。本研究使用了中国第37次南极科考获得的走航探空数据,针对一次南大洋大气河事件评估了4种大气再分析数据——ERA5,CFS... 大气河直接影响南极海-陆-冰-气相互作用,但对其开展的探空观测尚不多,造成数值模式和再分析数据的结论存在不确定性。本研究使用了中国第37次南极科考获得的走航探空数据,针对一次南大洋大气河事件评估了4种大气再分析数据——ERA5,CFSv2,JRA-55和MERRA-2。评估结果表明:虽然所有大气再分析数据对南大洋水汽通量(IVT)的描述都与观测比较接近——包括在大气河期间,但这部分是因为再分析数据高估了大气整层(地表至300 hPa)湿度场的同时低估了大气整层风速。进一步分析发现,大气湿度和风速在垂直方向的协变项被多数再分析数据显著低估甚至给出了与观测相反的结果;而协变项的偏差对IVT影响与整层大气湿度和风速相当。ERA5在协变项的表现显著优于其他再分析数据。与此同时,ERA5也给出了大气河期间与观测最为一致的逆湿和低空急流结构。因此,仅就本次观测而言ERA5对南大洋大气河的描述能力是最佳的。 展开更多
关键词 南大洋 大气河 无线电探空 大气再分析
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Macrobenthic assemblage characteristics under stressed waters and ecological health assessment using AMBI and M-AMBI:a case study at the Xin'an River Estuary,Yantai,China 被引量:5
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作者 ZHOU Zhengquan LI Xiaojing +6 位作者 CHEN Linlin LI Baoquan LIU Tiantian AI Binghua YANG Lufei LIU Bo CHEN Qiao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2018年第5期77-86,共10页
To understand the ecological status and macrobenthic assemblages of the Xin'an River Estuary and its adjacent waters, a survey was conducted for environmental variables and macrobenthic assemblage structure in Septem... To understand the ecological status and macrobenthic assemblages of the Xin'an River Estuary and its adjacent waters, a survey was conducted for environmental variables and macrobenthic assemblage structure in September 2012(Yantai, China). Several methods are adopted in the data analysis process: dominance index,diversity indices, cluster analysis, non-metric multi-dimentional scaling ordination, AMBI and M-AMBI. The dissolved inorganic nitrogen and soluble reactive phosphorus of six out of eight sampling stations were in a good condition with low concentration. The average value of DO((2.89±0.60) mg/L) and p H(4.28±0.43) indicated that the research area faced with the risk of ocean acidification and underlying hypoxia. A total of 62 species were identified, of which the dominant species group was polychaetes. The average abundance and biomass was577.50 ind./m^2 and 6.01 g/m^2, respectively. Compared with historical data, the macrobenthic assemblage structure at waters around the Xin'an River Estuary was in a relatively stable status from 2009 to 2012.Contaminant indicator species Capitella capitata appeared at Sta. Y1, indicating the animals here suffered from hypoxia and acidification. AMBI and M-AMBI results showed that most sampling stations were slightly disturbed,which were coincided with the abiotic measurement on evaluating the health conditions. Macrobenthic communities suffered pressures from ocean acidification and hypoxia at the research waters, particularly those at Stas Y1, Y2 and Y5, which displays negative results in benthic health evaluation. 展开更多
关键词 macrobenthos Xin'an river Estuary ocean acidification hypoxia AMBI M-AMBI
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Modeling of suspended sediment by coupled wave-current model in the Zhujiang(Pearl) River Estuary 被引量:4
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作者 Guangping Liu Shuqun Cai 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第7期22-35,共14页
A three-dimensional wave-current-sediment coupled numerical model is developed to understand the sediment transport dynamics in the Zhujiang(Pearl)River Estuary(ZRE),China.The model results are in good agreement with ... A three-dimensional wave-current-sediment coupled numerical model is developed to understand the sediment transport dynamics in the Zhujiang(Pearl)River Estuary(ZRE),China.The model results are in good agreement with observed data,and statistics show good model skill scores.Numerical studies are conducted to assess the scenarios of suspended sediment in the ZRE under the effects of different forcing(river discharges,waves,and winds).The model results indicate that the estuarine gravitational circulation plays an important role in the development of estuarine turbidity maximum in the ZRE,particularly during neap tides.The increased river discharge can result in a seaward sediment transport.The suspended sediment concentration(SSC)in the bottom increases with both wave bottom orbital velocity and wave height.Because of the shallow water depth,the effect of waves on sediment in the west shoal is greater than that in the east channel.The southwesterly wind-induced wave affects the SSC more than those resulting from the northeasterly wind,while the northeasterly wind-driven circulation has a slightly greater influence on the SSC than that of the southwesterly wind.However,a steady southwesterly wind condition favors the increase of the SSC in the Lingding Bay more so than a steady northeasterly wind condition.If the other forcings are same,the averaged SSC under a steady southwesterly wind condition is about 1.1 times that resulting from a steady northeasterly wind. 展开更多
关键词 SEDIMENT transport TURBIDITY Regional ocean Modeling System(ROMS) Zhujiang river ESTUARY
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Analysis of the characteristics of offshore currents in the Changjiang(Yangtze River) estuarine waters based on buoy observations 被引量:2
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作者 LI Peng SHI Benwei +3 位作者 WANG Yaping QIN Weihua LI Yangang CHEN Jian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第4期13-20,共8页
A buoy of 10 m in diameter was used to record the current speed and direction in a vertical profile in the offshore area of the Changjiang(Yangtze River) Estuary(with an average water depth of 46.0 m) for one year... A buoy of 10 m in diameter was used to record the current speed and direction in a vertical profile in the offshore area of the Changjiang(Yangtze River) Estuary(with an average water depth of 46.0 m) for one year.The results include:(1) the currents rotate clockwise and the current direction is consistent in a vertical profile without clear seasonal variations.(2) The horizontal current speeds are generally high,with a maximum of 128.5 cm/s occurring in summer and 105.5 cm/s appearing in winter commonly close to the surface.The average current speeds in the vertical profile fall in the same range(the differences are less than 8.0 cm/s),with the maximum of47.0 cm/s occurring in summer and 40.8 cm/s in winter.The average current speed during spring tides is twice that during neap tides(26.5 cm/s).(3) Significant differences of speeds are observed in the vertical profile.The maximum current speed occurs at either surface(spring and winter) or sub-surface(summer and autumn),with the minimum current speed appearing at the bottom.The maximum average current speed of all layers is 57.9cm/s,which occurs in the 18-m layer during summer.(4) The average speed of the residual currents ranges from7.5 cm/s to 11.3 cm/s,with the strongest occurring in spring and weakest in winter.The residual currents of all layers are eastward during spring and winter,whereas northeastward or northward during summer and autumn.(5) The currents in the offshore of Changjiang Estuary are impacted collectively by diluted Changjiang River discharge,the Taiwan Warm Current,monsoon and tides. 展开更多
关键词 ocean currents buoy observation seasonal variations Changjiang(Yangtze river Estuary
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A numerical study of summertime expansion pattern of Changjiang (Yangtze) River diluted water 被引量:6
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作者 SHAN Feng QIAO Fangli XIA Changshui 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2009年第3期11-16,共6页
Observations show that during summer especially in August, the northward expansion of the Changjiang(Yangtze) River diluted water (CRDW) is blocked in the vicinity of the Changjiang Estuary. To explain this phenom... Observations show that during summer especially in August, the northward expansion of the Changjiang(Yangtze) River diluted water (CRDW) is blocked in the vicinity of the Changjiang Estuary. To explain this phenomenon, Princeton ocean model (POM) is applied to simulate the summertime expansion pattern of CRDW. Numerical experiments show that to the north of the Changjiang Estuary, a tide-induced temperature front of a cold water centered at (34°N, I22.5°E) plays the key role in determining the expansion pattern of CRDW. This front splits the CRDW into two parts: the main part expands northeastward, and the other small part expands northwestward off the coast of Jiangsu Province, China. 展开更多
关键词 Changjiang river diluted water Princeton ocean model expansion dynamics
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Spectral classification of water masses under the influence of the Amazon River plume 被引量:2
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作者 Gustavo Souto Fontes Molleri Milton Kampel Evlyn Mrcia Leo de Moraes Novo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2010年第3期1-8,共8页
The large amount of dissolved and particulate material discharged by the Amazon River into the Equatorial Atlantic Ocean cause distinct spectral response of its waters as compared to the nearby ocean waters. This pape... The large amount of dissolved and particulate material discharged by the Amazon River into the Equatorial Atlantic Ocean cause distinct spectral response of its waters as compared to the nearby ocean waters. This paper shows the application of K-means clustering algorithm for classifying water masses in the region under the Amazon River plume influence according to their spectral behavior. Salinity and temperature data from 67 oceanographic stations were related to Sea-viewing Wide Field-of-view Sensor (SeaWiFS) remote sensing reflectances values and the following bio-optical products: (i) chlorophyll-a concentration, (ii) water attenuation coefficient and (iii) absorption coefficient for dissolved and detrital material. Four different water masses were identified such as: (1) oceanic water, (2) intermediate oceanic water, (3) intermediate river plume water and (4) Amazon River plume water. The spectral behavior of these water masses allowed concluding that the main active optical component of the waters in the region is the colored dissolved organic matter originated mostly from the Amazon River. 展开更多
关键词 ocean color remote sensing amazon river plume spectral behavior cluster analysis
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Areas of the global major river plumes
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作者 KANG Yan PAN Delu +4 位作者 BAI Yan HE Xianqiang CHEN Xiaoyan CHEN Chen-Tung Arthur WANG Difeng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第1期79-88,共10页
River plumes are the regions where the most intense river-sea-land interaction occurs, and they are char- acterized by complex material transport and biogeochemical processes. However, due to their highly dy- namic na... River plumes are the regions where the most intense river-sea-land interaction occurs, and they are char- acterized by complex material transport and biogeochemical processes. However, due to their highly dy- namic nature, global river plume areas have not yet been determined for use in synthetic studies of global oceanography. Based on global climatological monthly averaged salinity data from the NOAA World Ocean Atlas 2009 (WOA09), and monthly averaged salinity contour maps of the East and South China Seas from the Chinese Marine Atlas, we extract the monthly plume areas of major global rivers using a geographic information system (GIS) technique. Only areas with salinities that are three salinity units lower than the average salinity in each ocean are counted. This conservative estimate shows that the minimum and max- imum monthly values of the total plume area of the world's 19 largest rivers are 1.72× 106 kin2 in May and 5.38× 106 klTl2 inAugust. The annual mean area of these river plumes (3.72× 106 knl2) takes up approximately 14.2% of the total continental shelves area worldwide (26.15 × 106 km2). This paper also presents river plume areas for different oceans and latitude zones, and analyzes seasonal variations of the plume areas and their relationships with river discharge. These statistics describing the major global river plume areas can now provide the basic data for the various flux calculations in the marginal seas, and therefore will be of useful for many oceanographic studies. 展开更多
关键词 river plume World ocean Atlas geography information system Changjiang river marginal sea
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Numerical Study of Flow Near River Outlet in Namtso Lake
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作者 德吉玉珍 Jarle Berntsen 《Journal of Southwest Jiaotong University(English Edition)》 2008年第4期404-413,共10页
A river plume dynamics analysis was made in Namtso Lake by using a sigma coordinate non-hydrostatic numerical ocean model, the Bergen Ocean Model. Simulations were carried out by hydrostatic and non-hydrostatic models... A river plume dynamics analysis was made in Namtso Lake by using a sigma coordinate non-hydrostatic numerical ocean model, the Bergen Ocean Model. Simulations were carried out by hydrostatic and non-hydrostatic models with horizontal resolution of 5.00 m, 2.50 m and 1, 25 m, respectively. The simulation results for the homogeneous lake are robust to the grid size, and the non-hydrostatic pressure effect is not important in this ease. For the stratified case, the results are sensitive to both the grid size and non-hydrostatic pressure corrections. 展开更多
关键词 Non-hydrostatics river plume Numerical ocean model Σ-COORDINATE STRATIFIED
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The Relationship of Land-Ocean Thermal Anomaly Difference with Mei-yu and South China Sea Summer Monsoon 被引量:3
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作者 王志福 钱永甫 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第1期169-179,共11页
Based on the NCEP/NCAR reanalysis data for the period of 1948-2004 and the monthly rainfall data at 160 stations in China from 1951 to 2004, the relationships among the land-ocean temperature anomaly difference in the... Based on the NCEP/NCAR reanalysis data for the period of 1948-2004 and the monthly rainfall data at 160 stations in China from 1951 to 2004, the relationships among the land-ocean temperature anomaly difference in the mid-lower troposphere in spring (April-May), the mei-yu rainfall in the Yangtze River- Huaihe River basin, and the activities of the South China Sea summer monsoon (SCSSM) are analyzed by using correlation and composite analyses. Results show that a significant positive correlation exists between mei-yu rainfall and air temperature in the middle latitudes above the western Pacific, while a significant negative correlation is located to the southwest of the Baikal Lake. When the land-ocean thermal anomaly difference is stronger in spring, the western Pacific subtropical high (WPSH) will be weaker and retreat eastward in summer (June-July), and the SCSSM will be stronger and advance further north, resulting in deficient moisture along the mei-yu front and below-normal precipitation in the mid and lower reaches of the Yangtze River, and vice versa for the weaker difference case. The effects and relative importance of the land and ocean anomalous heating on monsoon variability is also compared. It is found that the land and ocean thermal anomalies are both closely related to the summer circulation and mei-yu rainfall and SCSSM intensity, whereas the land heating anomaly is more important than ocean heating in changing the land-ocean thermal contrast and hence the summer monsoon intensity. 展开更多
关键词 land-ocean thermal anomaly difference South China Sea summer monsoon Yangtze river-Huaihe river mei-yu rainfall correlation analysis composite analysis
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基于高、低潮位的西江感潮河段潮汐特征分析
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作者 武家兴 彭棋 +5 位作者 张卓 陈欣颖 陈鹏 温亚娟 王浩丞 张璐 《海洋学研究》 CSCD 北大核心 2024年第2期91-103,共13页
通过对高、低潮位数据插值和NS_TIDE模型应用,分析西江感潮河段(马口—大横琴)的潮汐特征。对比三种插值方法发现,相对于三次样条插值法和线性插值法,Hermite插值法对逐时潮位的模拟效果最佳。潮位验证结果显示NS_TIDE模型总体误差较低... 通过对高、低潮位数据插值和NS_TIDE模型应用,分析西江感潮河段(马口—大横琴)的潮汐特征。对比三种插值方法发现,相对于三次样条插值法和线性插值法,Hermite插值法对逐时潮位的模拟效果最佳。潮位验证结果显示NS_TIDE模型总体误差较低,异常值主要是源自台风和洪水的影响。西江感潮河段平均水位和分潮振幅存在洪、枯季差异,上游受径流的影响大于潮汐,下游则相反;径流量和潮差增大,促进上游河段平均水位增高,对分潮振幅和迟角的影响在不同河段表现不同,主要与其所处空间位置和分潮自身频率有关。 展开更多
关键词 高、低潮插值 调和分析 河流径流 海洋潮汐
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2022年夏季热带印度洋-太平洋海温异常对长江中下游高温异常的影响
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作者 金大超 管兆勇 +1 位作者 王子佳 闫尊 《大气科学学报》 CSCD 北大核心 2024年第5期713-720,共8页
利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江... 利用NCEP/NCAR再分析资料、ERSST v5海表温度资料和大气环流模式,分析了2022年夏季热带印度洋-太平洋海温异常对长江中下游地区高温事件的影响机理及相对贡献。研究表明,此次高温异常事件受La Ni a事件和负位相IOD事件的共同影响,长江中下游地区的温度异常为1.52℃、为近40年来最高,温度正异常的极大值位于河南和湖北两省交界处的西侧。热带印度洋和太平洋海温异常引起了长江中下游约0.39℃的增温,对长江中下游地区此次高温异常的贡献为25.66%。La Ni a事件和负位相IOD事件可通过增强西太平洋副热带高压,进而有利于维持长江中下游地区的异常下沉运动,为高温事件的发生提供了有利条件。 展开更多
关键词 2022年夏季 长江中下游地区 高温异常 热带印度洋-太平洋 海温异常
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冬、夏季长江口海域二甲基硫化物的时空分布及对海水酸化和铁添加的响应
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作者 孙茂祥 于娟 杨桂朋 《中国海洋大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第6期108-120,共13页
本文于2022年2和7月测定了长江口及其邻近海域表层海水及重要断面海水中的二甲基硫(Dimethylsulfide, DMS)、二甲基巯基丙酸内盐(Dimethylsulfoniopropionate, DMSP)浓度;基于DMS生产速率、消耗速率和溶解态DMSP(DMSPd)降解速率,综合评... 本文于2022年2和7月测定了长江口及其邻近海域表层海水及重要断面海水中的二甲基硫(Dimethylsulfide, DMS)、二甲基巯基丙酸内盐(Dimethylsulfoniopropionate, DMSP)浓度;基于DMS生产速率、消耗速率和溶解态DMSP(DMSPd)降解速率,综合评价了DMS的迁移转化速率,并通过船基培养实验探究了二甲基硫化物对海水酸化和Fe添加的响应。结果表明:冬季长江口海域DMS、DMSPd、颗粒态DMSP(DMSPp)平均浓度分别为(1.55±0.96)、(3.55±2.38)和(4.42±3.11) nmol·L^(-1);夏季分别为(8.45±5.76)、(18.90±6.86)和(22.41±15.99) nmol·L^(-1)。冬、夏两季长江口二甲基硫化物高浓度主要出现在远岸,垂直方向上呈现出表层到底层逐渐降低的变化特征。冬季和夏季的DMS海气通量分别为2.23和22.96μmol·m^(-2)·d^(-1)。夏季DMSPd的转化率和DMS生物产率高于冬季,使得夏季DMS浓度较高。微生物消耗是长江口海域DMS的主要去除途径。船基培养实验表明,在pH=7.7、7.9条件下,海水酸化抑制了DMS和DMSP的产生,而Fe的添加促进了它们的释放。因此,未来海水酸化和Fe的输入会对长江口DMS的生物地球化学循环产生重要影响。 展开更多
关键词 二甲基硫 二甲基巯基丙酸内盐 时空分布 生产消费 海气通量 海水酸化 长江口
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冬季海洋锋面对大气河影响的理想数值试验研究
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作者 韩子清 杨小绘 +2 位作者 贾英来 谢晓敏 吕东方 《中国海洋大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第9期12-20,共9页
本文利用天气研究和预报(Weather research and forecasting,WRF)模式设置了两组具有不同海洋锋面强度的“渠道模型”理想数值试验,忽略地形作用,探讨了冬季海洋锋面对大气河(Atmospheric river,AR)的影响。结果表明,在不同强度的海洋... 本文利用天气研究和预报(Weather research and forecasting,WRF)模式设置了两组具有不同海洋锋面强度的“渠道模型”理想数值试验,忽略地形作用,探讨了冬季海洋锋面对大气河(Atmospheric river,AR)的影响。结果表明,在不同强度的海洋锋面试验中,大气低层风速、湍流热通量等物理量的响应与海温的变化同位相,且大气低层各变量对海洋锋面南侧海温变化的响应较北侧更大,呈现出南北不对称性。海洋锋强度的增强促进了向高空的涡动热量和水汽输送,导致高空风速加强和风暴轴北移。海洋锋面的增强还为经过其上空的气旋提供了更多的动量和水汽,加强了气旋南侧的水汽输送带,从而促进了大气河发生频数的增加和大气河强度的增强。 展开更多
关键词 海洋锋面 大气河 渠道模型 风暴轴 大气锋面
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基于机器学习的长江口表层水体溶解有机碳遥感反演研究
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作者 陈灏 何贤强 +1 位作者 李润 曹芳 《华东师范大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第4期123-136,共14页
溶解有机碳(dissolved organic carbon,DOC)是海洋中最大的活跃有机碳库.精确刻画大河河口及其近海水体表层DOC浓度的时空分布,有助于更好地理解河流输送的有机碳在河口近海经历的生物地化过程及在该区域的归宿.本研究采用机器学习方法... 溶解有机碳(dissolved organic carbon,DOC)是海洋中最大的活跃有机碳库.精确刻画大河河口及其近海水体表层DOC浓度的时空分布,有助于更好地理解河流输送的有机碳在河口近海经历的生物地化过程及在该区域的归宿.本研究采用机器学习方法,通过反演水体溶解态有机碳库中的有色溶解有机物(colored dissolved organic matter,CDOM)的吸收光谱信息,并基于其与水体DOC浓度的相关关系,发展了基于地球静止轨道水色成像仪(geostationary ocean color imager,GOCI)的DOC遥感反演模型.结果表明,Nu支持向量回归(nu-supporting vector regression,NuSVR)方法可准确反演CDOM光谱吸收特性(如验证集CDOM在300 nm处的吸收系数aCDOM(300)和275~295 nm处的光谱斜率S275–295的平均绝对误差(mean absolute percent differences,MAPD)分别为32%和8.6%).分别基于该区域表层水体CDOM光谱吸收特性与DOC浓度之间表现的3种不同的相关关系进行DOC算法构建,结果表明,基于aCDOM(300)与DOC浓度之间的线性相关,并考虑这一相关关系的季节性差异所构建的DOC反演算法可较为准确地反演水体DOC浓度,DOC反演现场数据验证集和卫星验证集的MAPD分别为11%和14%.将构建的DOC算法模型应用到GOCI卫星图像上,结果显示,受长江径流影响,季节尺度上,长江口夏季水体表层DOC浓度显著高于冬季;而受潮汐、风场等因素的影响,小时尺度上河口近岸海域DOC分布呈现逐时高动态变化.本研究利用卫星遥感反演河口近海水体DOC浓度,为进一步在不同时间尺度上研究该区域水体DOC动态变化及驱动因素提供了有效手段. 展开更多
关键词 地球静止轨道水色成像仪 有色溶解有机物 机器学习 长江口 溶解有机碳
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基于SWOT的中缅印度洋通道瑞丽与孟定清水河对比研究
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作者 李如英 牛福长 +1 位作者 胡志丁 赵正贤 《热带地理》 CSCD 北大核心 2024年第7期1171-1183,共13页
瑞丽出境的中缅“人字形”经济走廊(简称“人字形”走廊)与孟定清水河出境的中缅印度洋新通道(简称“新通道”)建设与发展上的极大反差引起学界广泛关注。鉴于此,搭建SWOT的国际通道分析理论与框架,对“人字形”走廊与新通道的差异部分... 瑞丽出境的中缅“人字形”经济走廊(简称“人字形”走廊)与孟定清水河出境的中缅印度洋新通道(简称“新通道”)建设与发展上的极大反差引起学界广泛关注。鉴于此,搭建SWOT的国际通道分析理论与框架,对“人字形”走廊与新通道的差异部分(即瑞丽—腊戌与孟定清水河—腊戌)进行SWOT要素阐述和关键影响因素的对比分析,以揭示二者的比较优势与不同时期侧重选择的地理逻辑。研究表明:1)不同时空序列下中缅印度洋通道建设的关键影响因素存在显著差别。历史域上的关键影响因素有明显的“地理决定论意味”,以地形、高程、河流、地质等为代表的自然地理环境与特征深刻影响着早期的中缅通道建设;现实域层面的关键影响因素多为“人类主观能动性的发挥程度和科技进步是否促生通道建设“时空压缩”,即主观能动性和科技进步等能否缩短通道的建设里程和关键路段建设工期、是否能提升与城市群关联度和完善运输网络体系等;未来域的关键影响因素则是关注通道的“成长”、国家话语支持和战略定位以及服务国家的长效机制等方面,最直接的便是国家对通道的定位、赋能及话语政策支持等。2)瑞丽与孟定清水河作为中缅印度洋通道的中方出境口岸,其选址在不同时期侧重不同地理考量,受到各自S、W、O、T主导要素的裹挟影响与约束。瑞丽(“人字形”走廊)为抗争战略调整型,孟定清水河(新通道)为抗争战略进取型。3)总体上孟定清水河至腊戌一线(新通道)相较瑞丽至腊戌一线(“人字形”走廊)的优势和潜力较为明显,阻碍和困难相对较小,佐证了“优势在孟”的新通道方案。“人字形”走廊与新通道具有明显的互补性特征,传递出双“Y”轴通道设想的科学性与可行性。 展开更多
关键词 中缅“人字形”经济走廊 中缅印度洋新通道 SWOT分析 地理过程 孟定清水河 瑞丽
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污染物入海通量非点源贡献率的分析方法 被引量:10
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作者 袁宇 朱京海 +1 位作者 侯永顺 胡筱敏 《环境科学研究》 EI CAS CSCD 北大核心 2008年第5期169-172,共4页
针对采用控制断面实测通量进行点源与非点源分割的常规方法,容易夸大非点源贡献率的情况,提出简易分割技术,在概念上明确改进的方法,从实用的角度提出以月径流量与月通量相关系数确定丰水期通量增量的非点源比例系数,建立简单的估算公式... 针对采用控制断面实测通量进行点源与非点源分割的常规方法,容易夸大非点源贡献率的情况,提出简易分割技术,在概念上明确改进的方法,从实用的角度提出以月径流量与月通量相关系数确定丰水期通量增量的非点源比例系数,建立简单的估算公式,以辽东湾主要入海河流之一的大凌河为例,利用2003年实测数据对大凌河进入辽东湾的高锰酸盐指数、总氮、总磷、石油类、氨氮等入海通量进行计算分析,得到对不同污染物不同分割比例的较为合理的结果.该方法对于闸控调节导致的入海径流反季节变化的情况不一定适用,但可以采用类似的思路进行研究. 展开更多
关键词 海洋 河流 非点源 入海通量 污染
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2016—2020年中国地表水中总氮浓度时空变化特征分析 被引量:13
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作者 嵇晓燕 王姗姗 +1 位作者 杨凯 任蓓 《生态环境学报》 CSCD 北大核心 2022年第6期1184-1192,共9页
地表水中总氮是影响水生态环境状况的重要因素,总氮浓度升高会导致水体富营养化、赤潮等现象,危害水生生物甚至人体健康。为分析近年来全国地表水中总氮浓度时空变化特征,为水污染防治中总氮污染治理的决策和部署提供依据和支撑,基于国... 地表水中总氮是影响水生态环境状况的重要因素,总氮浓度升高会导致水体富营养化、赤潮等现象,危害水生生物甚至人体健康。为分析近年来全国地表水中总氮浓度时空变化特征,为水污染防治中总氮污染治理的决策和部署提供依据和支撑,基于国家地表水环境质量监测网总氮监测结果,以《地表水环境质量标准》和《地表水环境质量评价办法(试行)》为评价依据,结合皮尔逊相关系数法,系统分析了中国2016—2020年(“十三五”时期)地表水中总氮浓度的时间变化趋势和空间分布特征。2016—2020年,全国地表水、河流与湖库总氮质量浓度范围分别在2.54—3.00、2.72—3.23和1.19—1.31 mg·L^(−1),河流总氮浓度远高于湖库。从时间变化来看,全国地表水总氮浓度年际变化呈现先升后降的趋势,总氮浓度月际变化具有季节性特征,春季与冬季较高,夏季与秋季相对较低。从流域分布来看,各流域总氮浓度由高到低为海河>黄河>辽河>淮河>珠江>浙闽片>长江>松花江>西北>西南;湖区总氮浓度由高到低为云贵>东部平原>蒙新>东北>青藏高原;海河、辽河、黄河和淮河流域总氮质量浓度较高,均在3.00 mg·L^(−1)以上;珠江、浙闽片、长江和松花江流域总氮年均值在2.00 mg·L^(−1)附近波动;西北诸河和西南诸河总氮质量浓度较低,分别为1.39 mg·L^(−1)和1.23 mg·L^(−1)。此外,入湖河流与对应湖库总氮浓度相关性较强;入湖河流与入海河流总氮年均值分别达到或超过4.00 mg·L^(−1)与2.00 mg·L^(−1),均远高于汇入的湖体与海区,对湖体和海区的水质产生重要影响,因此入湖河流和入海河流的控氮措施对于防控或缓解湖体和海区的氮素负荷及富营养化具有重要意义。 展开更多
关键词 总氮 富营养化 流域 入湖河流 入海河流 湖库
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