检索结果-南通市图书馆

Assessment of trophic status in Changjiang (Yangtze) River estuary

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Oceanology and Limnology 2007年第3期25卷 261-269页

作者： WANG Baodong The first institute of oceanography State Oceanic Administration

The integrated methodology for the assessment of estuarine trophic status(ASSETS),which was extended and refined from the United states National Estuarine Eutrophication Assessment(NEEA),is a multi-parameter assessment system and has been widely used in eutrophication assessment in estuarine and coastal *** ASSETS was applied to evaluate the trophic status of the Changjiang(Yangtze)River estuary,one of the largest estuaries in the *** following main results were obtained:(i)The estuarine export potential is"moderate susceptibility"due to the"moderate"dilution potential and"moderate"flushing potential;(ii)The overall human influence(OHI)index classified the impact of nutrients in the system as"high"due to the high level of nutrient discharge by the river which channels anthropogenic impacts in the catchments to the estuarine system;(iii)The overall eutrophic condition(OEC)in the estuary was classified into the"high"category due to frequent occurrence of nuisance and toxic algal blooms in the mixing and seawater zones;(iv)Since the nutrient loadings(e.g.,DIN)in the river is expected to continue to increase in the near future following the population increase and rapid economic growth throughout the drainage basin,the nutrient-related symptoms in the estuary are likely to substantially worsen,which leads to the"worsen high"category for the definition of future outlook(DFO).The combinations of the three components(i.e.,OHI,OEC,and DFO)lead to an overall grade as"bad"for the trophic status in the Changjiang River estuary.

关键词： eutrophication model estuary Changjiang(Yangtze)River ASSETS index

Study on the current structure of the thermohaline front in the southeastern entrance of the Yellow Sea during winter

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2015年第12期34卷 29-36页

作者： OH Kyung-Hee LEE Seok LIE Heung-Jae JUNG Kyung Tae QIAO Fangli Korea institute of Ocean Science and Technology first institute of oceanography State Oceanic Administration

A thermohaline front is located at the southeastern entrance of the Yellow Sea in winter, and it is generated by the intrusion of warm saline water into the Yellow Sea caused by a strong northerly wind. Recently, a westward transversal current traveling away from the west coast of Korea toward the open sea area along the front was reported. The westward transversal current is dominant in the surface layer during the temperature inversion period. The formation and structure of this current are examined using a numerical vertical ocean-slice *** two different water masses meet, a front is formed and adjusted geostrophically. In this frontal zone, a horizontal pressure gradient flow by the vertically inclined isopycnal occurs under the thermal wind process in a baroclinic effect, and the cold fresh coastal water moves westward along the front in the upper layer. The barotropic effect across the front and the bottom friction effect strengthen the westward component of the velocity. The velocity of the bottom layer decreases remarkably in the increase of the bottom drag coefficient. This means that the bottom friction with the strong background tidal current causes a reduction in the current in the bottom layer.

关键词： Geostrophic adjustment Southeastern Yellow Sea Thermohaline front Thermal wind Westward transversal current

Features of the physical environment associated with green tide in the southwestern Yellow Sea during spring

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2015年第7期34卷 97-104页

作者： BAO Min GUAN Weibing WANG Zongling WANG Difeng CAO Zhenyi CHEN Qi state Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration institute of Physical oceanography Ocean College Zhejiang University first institute of oceanography State Oceanic Administration

Massive green tides caused by Ulva prolifera in the Yellow Sea have occurred every summer since 2007 and have caused huge economic losses for local governments. The Subei （North liangsu Province, China） Shoal, with its large-scale Porphyra aquaculture, has been regarded as the most important source of U. prolifera for green tides. To reveal the physical mechanisms of floating and drifting algae in this area, the characteristics of the current, the temperature, the salinity and suspended particulate matter （SPM） in the southwestern Yellow Sea, especially in the Subei Shoal, were studied. The topography of the radial sand ridges in the Subei Shoal constrains the features of the currents and causes net longitudinal and latitudinal movements. The longitudinal net movement is a dominant dynamic factor that can bring U. prolifera into offshore waters. The amount of gas that is produced by algae during photosynthesis determines whether U. prolifera can float well on the sea surface after it is disposed into the water from Porphyra aquacultural apparatus. The Subei Shoal is characterized by a high turbidity, which can result in significant light attenuation and affect the photosynthesis together with the buoyancy of a U. prolifera in the water. According to satellite remote sensing data from 2012, the three-month-averaged surface SPM （April, May and June） in the Subei Shoal was 140 mg/dm^3, and the north of the Subei Shoal （the north of 34.5°N）, it was 11 mg/dm^3. According to the monthly averaged surface SPM in April, the transparency in the Subei Shoal was only 0.1 m, but it often exceeded 2.0 m outside of the Subei Shoal. The results explain why the floating ability of U. prolifera increases significantly once the green algae drifted outside the Subei Shoal.

关键词： Ulva prolifera current temperature salinity suspended particulate matter

Zooplankton diel vertical migration and influence of upwelling on the biomass in the Chukchi Sea during summer

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2015年第5期34卷 68-74页

作者： WANG Huiwu CHEN Hongxia XUE Liang LIU Na LIU Yanliang College of Physical and Enviromental oceanography Ocean University of China first institute of oceanography State Oceanic Administration

The diel vertical migration （DVM） of zooplankton and the influence of upwelling on zooplankton biomass were examined using water column data of current velocity and mean volume backscattering strength （MVBS） collected by moored acoustic Doppler current profilers （ADCPs） deployed in the southeastern Chukchi Sea during the 5th Chinese National Arctic Research Expedition （CHINARE） in summer 2012, combined with the satellite observational data such as sea surface temperature （SST）, wind, and chlorophyll a （Chl a）. Hourly acoustic data were continuously collected for 49-d in the mooring site. Spectral analysis indicated that there were different migrating patterns of zooplankton, even though precisely classifying the zooplankton taxa was not available. The prevailing 24-h cycle corresponded to the normal DVM with zooplankton swimming upwards at sunrise and returning to deep waters at sunset. There was a clear DVM in the upper 17 m of the water column during the period with distinct day-night cycles, and no active DVM throughout the water column when the sun above the horizon （polar day）, suggesting that light intensity was the trigger for DVM. Also there was a second migrating pattern with 12-h cycle. The upwelling event occurring in the northwest of Alaskan coastal area had important influence on zooplankton biomass at the mooring site. During the upwelling, the SST close to the mooring site dropped significantly from maximal 6.35℃to minimal 1.31℃ within five days. Simultaneously, there was a rapid increase in the MVBS and Chl a level, suggesting the aggregation of zooplankton related to upwelling.

关键词： Chukchi Sea diel vertical migration zooplankton biomass upwelling

Water Vapor Transport and Cross-Equatorial Flow over the Asian-Australia Monsoon Region Simulated by CMIP5 Climate Models

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2013年第3期30卷 726-738页

作者：宋亚娟乔方利宋振亚姜春飞 College of Physical and Environmental oceanography Ocean University of China first institute of oceanography State Oceanic Administration

The summer mean water vapor transport （WVT） and cross-equatorial flow （CEF） over the Asian- Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models （AOGCMs） from the World Climate Research Programme＇s Coupled Model Intercomparison Project Phase 5 （CMIP5） were evaluated. Based on climatology of the twentieth-century simulations, most of models have a reason- ably realistic representation of summer monsoon WVT characterized by southeast water vapor conveyor belt over the South Indian Ocean and southwest belt from the Arabian Sea to the East Asian. The correlation coefficients between NCEP reanalysis and simulations of BCC-CSMI-1, BNU-ESM, CanESM2, FGOALS-s2, MIROC4h and MPI-ESM-LR are up to 0.8. The simulated CEF depicted by the meridional wind along the equator includes the Somali jet and eastern CEF in low atmosphere and the reverse circulation in upper atmosphere, which were generally consistent with NCEP reanalysis. Multi-model ensemble means （MME） can reproduce more reasonable climatological features in spatial distribution both of WVT and CEF. Ten models with more reasonable WVT simulations were selected for future projection studies, including BCC- CSMI-1, BNU-ESM, CanESM2, CCSM4, FGOALS-s2, FIO-ESM, GFDL-ESM2G, MRIOCS, MPI-ESM-LR and NorESM-1M. Analysis based on the future projection experiments in RCP （Representative Concentra- tion Pathway） 2.6, RCP4.5, RCP6 and RCP8.5 show that the global warming forced by different RCP scenarios will results in enhanced WVT over the Indian area and the west Pacific and weaken WVT in the low latitudes of tropical Indian Ocean.

关键词： CMIP5 AOGCMs water vapor transport cross-equatorial flow future projection

An efficient parallel algorithm for ocean circulation numerical model based on irregular rectangle decomposition scheme

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2016年第5期35卷 18-23页

作者： ZHUANG Zhanpeng YUAN Yeli ZHANG Jie HAN Lei YANG Jungang College of Physical and Environmental oceanography Ocean University of China The first institute of oceanography State Oceanic Administration

A parallel algorithm of circulation numerical model based on message passing interface（MPI） is developed using serialization and an irregular rectangle decomposition scheme. Neighboring point exchange strategy（NPES） is adopted to further enhance the computational efficiency. Two experiments are conducted on HP C7000 Blade System, the numerical results show that the parallel version with NPES（PVN） produces higher efficiency than the original parallel version（PV）. The PVN achieves parallel efficiency in excess of 0.9 in the second experiment when the number of processors increases to 100, while the efficiency of PV decreases to 0.39 rapidly. The PVN of ocean circulation model is used in a fine-resolution regional simulation, which produces better results. The capability of universal implementation of this algorithm makes it applicable in many other ocean models potentially.

关键词： irregular rectangle decomposition scheme message passing interface(MPI) neighboring point exchange strategy data communication

Evaluation on data assimilation of a global high resolution wave-tide-circulation coupled model using the tropical Pacific TAO buoy observations

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2018年第3期37卷 8-20页

作者： SHI Junqiang YIN Xunqiang SHU Qi XIAO Bin QIAO Fangli College of oceanic and Atmospheric Sciences Ocean University of China The first institute of oceanography State Oceanic Administration Laboratory for Regional oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Key Laboratory of state oceanic administration for Marine Sciences and Numerical Modeling The First Institute of OceanographyState Oceanic Administration

In order to evaluate the assimilation results from a global high resolution ocean model, the buoy observations from tropical atmosphere ocean（TAO） during August 2014 to July 2015 are employed. The horizontal resolution of wave-tide-circulation coupled ocean model developed by The first institute of oceanography（FIOCOM model） is 0.1°×0.1°, and ensemble adjustment Kalman filter is used to assimilate the sea surface temperature（SST）, sea level anomaly（SLA） and Argo temperature/salinity profiles. The simulation results with and without data assimilation are examined. first, the overall statistic errors of model results are analyzed. The scatter diagrams of model simulations versus observations and corresponding error probability density distribution show that the errors of all the observed variables, including the temperature, isotherm depth of 20°C（D20）, salinity and two horizontal component of velocity are reduced to some extent with a maximum improvement of 54% after assimilation. Second, time-averaged variables are used to investigate the horizontal and vertical structures of the model results. Owing to the data assimilation, the biases of the time-averaged distribution are reduced more than70% for the temperature and D20 especially in the eastern Pacific. The obvious improvement of D20 which represents the upper mixed layer depth indicates that the structure of the temperature after the data assimilation becomes more close to the reality and the vertical structure of the upper ocean becomes more reasonable. At last,the physical processes of time series are compared with observations. The time evolution processes of all variables after the data assimilation are more consistent with the observations. The temperature bias and RMSE of D20 are reduced by 76% and 56% respectively with the data assimilation. More events during this period are also reproduced after the data assimilation. Under the condition of strong 2014/2016 El Ni？o, the Equatorial Undercurrent（EUC） from

关键词： tropical Pacific tropical atmosphere ocean data assimilation evaluation

An evaluation of sea surface height assimilation using along-track and gridded products based on the Regional Ocean Modeling System(ROMS) and the four-dimensional variational data assimilation

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2018年第9期37卷 50-58页

作者： ZHOU Chaojie DING Xiaohua ZHANG Jie YANG Jungang MA Qiang Department of Mathematics Harbin Institute of Technology at Weihai The first institute of oceanography State Oceanic Administration

Remote sensing products are significant in the data assimilation of an ocean model. Considering the resolution and space coverage of different remote sensing data, two types of sea surface height（SSH） product are employed in the assimilation, including the gridded products from AVISO and the original along-track observations used in the generation. To explore their impact on the assimilation results, an experiment focus on the South China Sea（SCS） is conducted based on the Regional Ocean Modeling System（ROMS） and the four-dimensional variational data assimilation（4 DVAR） technology. The comparison with EN4 data set and Argo profile indicates that, the along-track SSH assimilation result presents to be more accurate than the gridded SSH assimilation, because some noises may have been introduced in the merging process. Moreover, the mesoscale eddy detection capability of the assimilation results is analyzed by a vector geometry–based algorithm. It is verified that, the assimilation of the gridded SSH shows superiority in describing the eddy＇s characteristics, since the complete structure of the ocean surface has been reconstructed by the original data merging.

关键词： ROMS 4DVAR sea surface height assimilation along-track gridded product

STUDY ON THE ANALYTICAL MODEL OF DECAY OF MESOSCALE EDDY ON THE CONTINENTAL SHELF

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1989年第9期32卷 1135-1143页

作者：郑全安袁业立 first institute of oceanography State Oceanic Administration Qingdao

Observations indicate that the motion of an oceanic mesoscale eddy entering the conti-nental shelf will quickly decay. This shows that the surface area of the eddy continuouslyexpands, and the rotational angular velocity gradually decays with time. Starting from avorticity equation for a vertically stratified, horizontally uniform fluid the above process isdynamically analyzed in this paper. Under the condition to consider the Ekman pump effectof the upper and lower boundary layers and side friction, the analytical models for thesurface area expansion and angular velocity decay of the eddy are deduced.

关键词： mesoscale eddy decay model vorticity equation satellite data