连云港市位于中国江苏省北部,该地滨海湿地位于东亚-澳大利西亚迁飞路线(East Asia-Australasian F lyway,EAAF)的中心。连云港是候鸟在迁飞途中的重要停歇点之一,也是一个人口密集且正在快速发展的滨海城市。2003—2018年间,27%的连云...连云港市位于中国江苏省北部,该地滨海湿地位于东亚-澳大利西亚迁飞路线(East Asia-Australasian F lyway,EAAF)的中心。连云港是候鸟在迁飞途中的重要停歇点之一,也是一个人口密集且正在快速发展的滨海城市。2003—2018年间,27%的连云港潮间带被围垦,并逐步转化为工业园区和水产养殖塘。然而,这些区域目前仍有重要的保护价值。在2008—2018年的调查期间,连云港共记录到鹬类43种,其中有20种超过了1%的EAAF种群总数。此前的调查仅由一名当地调查员执行展开,这意味着调查结果在时间和空间的维度上都十分局限。为了对这片区域的水鸟,尤其是鹬类有更深入的了解,2019年5月9—13日,笔者团队在连云港市的临洪河口、青口河口和兴庄河口开展了水鸟同步调查,以期推动更有效的水鸟及其栖息地的保育工作。展开更多
In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite im...In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite （GOES）-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis （FNL） issued by the National Center for Environmental Prediction （NCEP） and Regional Atmospheric Modeling System （RANIS） results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm, moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005 reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation.展开更多
The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges...The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges of DMS, dissolved DMSP （DMSPd）, and particulate DMSP （DMSPp） in surface waters were 6.85 （1.60-12.36）, 7.25 （2.28-19.05） and 61.87 （6.28-224.01） nmol/L, respectively. There were strong correlations between DMSPp and chlorophyll a in the Bohai Sea and the North Yellow Sea, respectively, and concentrations of DMS and DMSP were high, with a relatively high proportion of dinoflagellates, in the region of the South Yellow Sea Cold Water Mass. Results show that phytoplankton biomass and species composition were important factors that controlled the distribution of DMS and DMSP. Complex environmental factors, including nutrients, transparency, and terrestrial runoff, might also influence the variability in DMS and DMSP. Biological production and consumption rates of DMS in the Bohai Sea were higher than those in the Yellow Sea. DMS production rates were closely correlated with DMSPd concentrations. DMS and DMSP exhibited obvious diel variations, with high concentrations occurring in the late afternoon （16：00-19：00） and low concentrations occurring during the night, implying that the intensity of solar radiation had a significant influence on these variations. Size distributions of chlorophyll a and DMSPp were also investigated and large nanoplankton （5-20 μm）, mainly diatoms, contributed significantly to chlorophyll a and DMSPp at most stations. The average sea-to-air flux of DMS in the study area was estimated to be 11.07 μmol/（m^2·d） during the summer.展开更多
The distribution of the suspended sediment concentration （SSC） in the Bohai Sea, Yellow Sea and East China Sea （BYECS） is studied based on the observed turbidity data and model simulation results. The observed tur...The distribution of the suspended sediment concentration （SSC） in the Bohai Sea, Yellow Sea and East China Sea （BYECS） is studied based on the observed turbidity data and model simulation results. The observed turbidity results show that （i） the highest SSC is found in the coastal areas while in the outer shelf sea areas turbid water is much more difficult to observe, （ii） the surface layer SSC is much lower than the bottom layer SSC and （iii） the winter SSC is higher than the summer SSC. The Regional Ocean Modeling System （ROMS） is used to simulate the SSC distribution in the BYECS. A comparison between the modeled SSC and the observed SSC in the BYECS shows that the modeled SSC can reproduce the principal features of tlte SSC distribution in the BYECS. The dynamic mechanisms of the sediment erosion and transport processes are studied based on the modeled results. The horizontal distribution of the SSC in the BYECS is mainly determined by the current-wave induced bottom stress and the fine-grain sediment distribution. The current-induced bottom stress is much higher than the wave-induced bottom stress, which means the tidal currents play a more significant role in the sediment resuspension than the wind waves. The vertical mixing strength is studied based on the mixed layer depth and the turbulent kinetic energy distribution in the BYECS. The strong winter time vertical mixing, which is mainly caused by the strong wind stress and surface cooling, leads to high surface layer SSC in winter. High surface layer SSC in summer is restricted in the coastal areas.展开更多
Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in...Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in which several IPs on the open boundary is assumed,values at these IPs can be optimized with an adjoint method,and those at other grid points are determined by linearly interpolating the values at IPs.The reasonability and feasibility of the model are tested by ideal twin experiments.In the practical experiment(PE) after assimilation,the cost function may reach 1% or less of its initial value.Mean absolute errors in amplitude and phase can be less than 5 cm and 5°,respectively,and the obtained co-chart can show the character of the M2 constituent in the BYS.The results of the PE indicate that using only two IPs on the open boundary can yield better simulated results.展开更多
Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have uniq...Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have unique geographical locations.Therefore,the characteristics of phytoplankton population distribution in the Bohai Sea and the Yellow Sea are of great significance to the study of marine ecology in China.In this work,the pigment data obtained from the Yellow Sea and Bohai Sea in August 2015 were analyzed by HPLC(High-Performance Liquid Chromatography).Then the pigment data were analyzed statistically by the CHEMTAX software,so that the phytoplankton community structure information was obtained.Results show that in summer 2015,from the perspective of sea area,the biomass of phytoplankton in the surface of Bohai Sea is higher than that in the Yellow Sea,while the phytoplankton biomass in the surface of North Yellow Sea is higher than that in the South.From the perspective of dominant species of phytoplankton,the surface waters of the Yellow Sea and Bohai Sea were dominated by diatoms,prymnesiophytes and chlorophytes,accounting for 55.76%,14.56%and 14.55%respectively.Among them,diatoms accounted for the absolute advantage.展开更多
An elliptical wind field model of typhoons is put forward based on the characteristics of the typhoon wind fields occurring in the Yellow Sea and Bohai Sea. By contrasting it with the circular typhoon wind field model...An elliptical wind field model of typhoons is put forward based on the characteristics of the typhoon wind fields occurring in the Yellow Sea and Bohai Sea. By contrasting it with the circular typhoon wind field model, it is found that the elliptical model can adequately represent the real wind field and trace the process of a typhoon storm surge. The numerically simulated results of storm surges by using the elliptical model are in good agreement with the observations and markedly better than those by using the circular model.展开更多
Two typical satellite sea surface temperature (SST) datasets, from the Multi-functional Transport Satellite (MTSAT) and Tropical Rainfall Measuring Mission Microwave Imager (TMI), were evaluated for the East China Sea...Two typical satellite sea surface temperature (SST) datasets, from the Multi-functional Transport Satellite (MTSAT) and Tropical Rainfall Measuring Mission Microwave Imager (TMI), were evaluated for the East China Sea, Yellow Sea, and Bohai Sea throughout 2008. Most monthly-mean availabilities of MTSAT are higher than those of TMI, whereas the seasonal variation of the latter is less than that of the former. The analysis on the one-year data shows that the annual mean availability of MTSAT (61%) is greater than that of TMI (56%). This is mainly because MTSAT is a geostationary satellite, which achieves longer observation than the sun-synchronous TMI. The daily availability of TMI (28%-75%) is more constant than that of MTSAT (9%-93%). The signal of infrared sensors on MTSAT is easily disturbed on cloudy days. In contrast, the TMI microwave sensor can obtain information through clouds. Based on in-situ SSTs, the SST accuracy of TMI is superior to that of MTSAT. In 2008, the root mean square (RMS) error of TMI and MTSAT were 0.77 K and 0.84 K, respectively. The annual mean biases were 0.14 K (TMI) and -0.31 K (MTSAT). To attain a high availability of SSTs, we propose a fusion method to merge both SSTs. The annual mean availability of fusion SSTs increases 17% compared to MTSAT. In addition, the availabilities of the fusion SSTs become more constant. The annual mean RMS and bias of fusion SSTs (0.78 K and -0.06 K, respectively) are better than those of MTSAT (0.84 K and -0.31 K).展开更多
Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors....Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors. In the present study, seasonal cycles of topography in the BS and YS and its relationship with atmospheric forcing and oceanic adjustment were examined and discussed using TOPEX/Poseidon and ERS-1/2 Sea Level Anomalies (SLA) data. Analyses revealed complicated seasonal cycles of topography composed mainly of2 REOF modes, the winter-summer mode (WIM) and spring-autumn mode (SAM). The WIM with action center in the BS displayed peak and southward pressure gradient in July, and valley and northward pressure gradient in January, which is obviously the direct response to monsoon with about 1-month response time. The SAM with action center in the western south YS displayed peak and northward pressure gradient in October and valley and southward pressure gradient in April. After the mature period of monsoon, the action center in the BS became weakened while that in the western south YS became strengthened because of regional convergence or divergence induced by seasonal variations of the Taiwan Warm Current and Yellow Sea Coastal Current. The direct response of topography to monsoon resulted in the WIM, while oceanic adjustment of topography played an important role in the forming of the SAM.展开更多
Considering the interaction of different tidal waves, an adjoint numerical model is developed to simulate M2, S2, K1 and O1 tidal waves in the Bohai Sea, the Yellow Sea and the East China Sea （B-Y-E） simultaneously....Considering the interaction of different tidal waves, an adjoint numerical model is developed to simulate M2, S2, K1 and O1 tidal waves in the Bohai Sea, the Yellow Sea and the East China Sea （B-Y-E） simultaneously. Compared with previous researches, by using the adjoint assimilation technique to inverse open boundary conditions and bottom friction coefficients based on altimetric data from TOPEX/Poseidon （T/P） and tidal gauges data, the precision of the numerical simulation is significantly improved. Selecting 14 days of simulated results after the initial wanning run to conduct harmonic analysis, the results can show the characteristics of M2, S2, K1 and O1 tidal wave systems perfectly in B-Y-E. Compared with 9 current stations, the calculated harmonic constants of tidal currents for M2 and K1 are in good agreement with the observed ones.展开更多
In this paper, we characterize the North Yellow Sea （NYS） water masses in summer by analyzing temperature and salinity data surveyed in 2006. The Liaonan Coastal Water is characterized by low salinity westward and s...In this paper, we characterize the North Yellow Sea （NYS） water masses in summer by analyzing temperature and salinity data surveyed in 2006. The Liaonan Coastal Water is characterized by low salinity westward and southward flow paths. The westward path flows parallel to land, turns to the south, then to the southeast adjacent to the mouth of the Lushun River, where it mixes with other coastal water directly to the southwest. It becomes the main source of low salinity water in the deep water area west of 123°E. The high-salinity Lubei Coastal Water is the remnant of the winter Lubei Coastal Water, which is located mostly in a small area between Yantai and Weihai, and does not originate in the Bohai Sea Coastal Water. The two NYS zones demarcated at 123°E have distinctly different temperature and salinity characteristics. There are two high-salinity centers east of 123°E, whereas there is low-salinity water to the west whose temperature and salinity structures are complex, composed of the coastal water south of Chengshantou, the Liaonan Coastal Water and the Bohai Sea Water.展开更多
There are two different opinions on the formation history of Huanghe (Yellow) River. One postulates that Huanghe River might have come into existence before Tertiary. The other supposes that it joined up into a long r...There are two different opinions on the formation history of Huanghe (Yellow) River. One postulates that Huanghe River might have come into existence before Tertiary. The other supposes that it joined up into a long river only in the last stage of Late Pleistocene. The appearance of Huanghe River is believed to have close relation to the uplifting of Tibetan Plateau. It is not likely that it could have come into being before its high elevation riverhead was formed. Today Huanghe River occurred probably during the recession of the sea in glacial periods. In the last glacial age, the climate was very harsh in the area north of the modern estuary of Changjiang (Yangtse) River; some areas were permafrost and the others barren deserts. At that time, eolation was the major exogenic force on exposed shelf. Beginning from 12 Ka BP, the global climate warmed up, resulting in gradual disappearance of continental mountain glaciers retreated, and sea level rose. Consequently, Huanghe River was replenished with water to become modern river system. With continued rising of sea level, Huanghe River delta moved continuously eastward.展开更多
The oceanic front is a narrow zone in which water properties change abruptly within a short distance.The sea surface temperature(SST) front is an important type of oceanic front,which plays a significant role in many ...The oceanic front is a narrow zone in which water properties change abruptly within a short distance.The sea surface temperature(SST) front is an important type of oceanic front,which plays a significant role in many fields including fisheries,the military,and industry.Satellite-derived SST images have been used widely for front detection,although these data are susceptible to influence by many objective factors such as clouds,which can cause missing data and a reduction in front detection accuracy.However,front detection in a single SST image cannot fully reflect its temporal variability and therefore,the long-term mean frequency of occurrence of SST fronts and their gradients are often used to analyze the variations of fronts over time.In this paper,an SST front composite algorithm is proposed that exploits the frontal average gradient and frequency more effectively.Through experiments based on MODIS Terra and Aqua data,we verified that fronts could be distinguished better by using the proposed algorithm.Additionally through its use,we analyzed the monthly variations of fronts in the Bohai,Yellow,and East China Seas,based on Terra data from 2000 to 2013.展开更多
Abrupt changes in freshwater inputs from large rivers usually imply regime shifts in coastal water environments. The influence of a water regulation event on the age of the Yellow River water in the Bohai was modeled ...Abrupt changes in freshwater inputs from large rivers usually imply regime shifts in coastal water environments. The influence of a water regulation event on the age of the Yellow River water in the Bohai was modeled using constituent-oriented age and residence time theory to better understand the change in the environmental function of the hydrodynamic field owing to human activities. The water ages in Laizhou Bay, the central basin, and the Bohai strait are sensitive to water regulation. The surface ages in those areas can decrease by about 300 days, particularly in July, and the age stratification is also strengthened. A water regulation event can result in declines in the water age in early July ahead of declines in the water age under climatological conditions(without the regulation event) by about 1 and 5 months in the central basin and Laizhou Bay, respectively. The change in the coastal circulation due to the water regulation event is the primary reason for the change in the Yellow River water age. The high Yellow River flow rate can enhance the density flow and, therefore, reduce the age of the Yellow River water. The subsequent impact of a single water regulation event can last about 1.0 to 4.0 years in different subregions.展开更多
文摘连云港市位于中国江苏省北部,该地滨海湿地位于东亚-澳大利西亚迁飞路线(East Asia-Australasian F lyway,EAAF)的中心。连云港是候鸟在迁飞途中的重要停歇点之一,也是一个人口密集且正在快速发展的滨海城市。2003—2018年间,27%的连云港潮间带被围垦,并逐步转化为工业园区和水产养殖塘。然而,这些区域目前仍有重要的保护价值。在2008—2018年的调查期间,连云港共记录到鹬类43种,其中有20种超过了1%的EAAF种群总数。此前的调查仅由一名当地调查员执行展开,这意味着调查结果在时间和空间的维度上都十分局限。为了对这片区域的水鸟,尤其是鹬类有更深入的了解,2019年5月9—13日,笔者团队在连云港市的临洪河口、青口河口和兴庄河口开展了水鸟同步调查,以期推动更有效的水鸟及其栖息地的保育工作。
基金supported by the National Natural Science Foundation of China under the grant number 40675060the Chinese Ministry of Science and Technology under the 863 Project grant number 2006AA09Z151+2 种基金supported by the State Oceanic Administration under the grant 908-02-03-10the Chinese Meteorological Administration under the grant CMATG 2006M32supported by the National Science Foundation under grant number OISE-0229657.
文摘In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite （GOES）-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis （FNL） issued by the National Center for Environmental Prediction （NCEP） and Regional Atmospheric Modeling System （RANIS） results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm, moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005 reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation.
基金Supported by the National Natural Science Foundation of China(Nos.41320104008,41030858,41306069)the National Natural Science Foundation for Creative Research Groups(No.41221004)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110132120010)the Cheung Kong Scholars Program of Chinathe Taishan Scholar Program of Shandong Provincethe Fundamental Research Funds for the Central Universities
文摘The distributions of dimethylsulfide （DMS） and its precursor dimethylsulfoniopropionate （DMSP） in surface water of the Yellow Sea and the Bohai Sea were studied during June 2011. The mean concentrations and ranges of DMS, dissolved DMSP （DMSPd）, and particulate DMSP （DMSPp） in surface waters were 6.85 （1.60-12.36）, 7.25 （2.28-19.05） and 61.87 （6.28-224.01） nmol/L, respectively. There were strong correlations between DMSPp and chlorophyll a in the Bohai Sea and the North Yellow Sea, respectively, and concentrations of DMS and DMSP were high, with a relatively high proportion of dinoflagellates, in the region of the South Yellow Sea Cold Water Mass. Results show that phytoplankton biomass and species composition were important factors that controlled the distribution of DMS and DMSP. Complex environmental factors, including nutrients, transparency, and terrestrial runoff, might also influence the variability in DMS and DMSP. Biological production and consumption rates of DMS in the Bohai Sea were higher than those in the Yellow Sea. DMS production rates were closely correlated with DMSPd concentrations. DMS and DMSP exhibited obvious diel variations, with high concentrations occurring in the late afternoon （16：00-19：00） and low concentrations occurring during the night, implying that the intensity of solar radiation had a significant influence on these variations. Size distributions of chlorophyll a and DMSPp were also investigated and large nanoplankton （5-20 μm）, mainly diatoms, contributed significantly to chlorophyll a and DMSPp at most stations. The average sea-to-air flux of DMS in the study area was estimated to be 11.07 μmol/（m^2·d） during the summer.
基金supported by the China Scholarship Council and the National Basic Research Program of China(973 Program 2010CB428904 and 2005CB422300)
文摘The distribution of the suspended sediment concentration （SSC） in the Bohai Sea, Yellow Sea and East China Sea （BYECS） is studied based on the observed turbidity data and model simulation results. The observed turbidity results show that （i） the highest SSC is found in the coastal areas while in the outer shelf sea areas turbid water is much more difficult to observe, （ii） the surface layer SSC is much lower than the bottom layer SSC and （iii） the winter SSC is higher than the summer SSC. The Regional Ocean Modeling System （ROMS） is used to simulate the SSC distribution in the BYECS. A comparison between the modeled SSC and the observed SSC in the BYECS shows that the modeled SSC can reproduce the principal features of tlte SSC distribution in the BYECS. The dynamic mechanisms of the sediment erosion and transport processes are studied based on the modeled results. The horizontal distribution of the SSC in the BYECS is mainly determined by the current-wave induced bottom stress and the fine-grain sediment distribution. The current-induced bottom stress is much higher than the wave-induced bottom stress, which means the tidal currents play a more significant role in the sediment resuspension than the wind waves. The vertical mixing strength is studied based on the mixed layer depth and the turbulent kinetic energy distribution in the BYECS. The strong winter time vertical mixing, which is mainly caused by the strong wind stress and surface cooling, leads to high surface layer SSC in winter. High surface layer SSC in summer is restricted in the coastal areas.
基金Supported by the State Ministry of Science and Technology of China (Nos.2007AA09Z118,2008AA09A402)the National Natural Science Foundation of China(No.41076006)the Ministry of Education's 111 Project(No.B07036)
文摘Two-dimensional tidal open boundary conditions of the M2 constituent in the Bohai and Yellow Seas(BYS) have been estimated by assimilating T/P altimeter data.During inversion,independent point(IP) strategy was used,in which several IPs on the open boundary is assumed,values at these IPs can be optimized with an adjoint method,and those at other grid points are determined by linearly interpolating the values at IPs.The reasonability and feasibility of the model are tested by ideal twin experiments.In the practical experiment(PE) after assimilation,the cost function may reach 1% or less of its initial value.Mean absolute errors in amplitude and phase can be less than 5 cm and 5°,respectively,and the obtained co-chart can show the character of the M2 constituent in the BYS.The results of the PE indicate that using only two IPs on the open boundary can yield better simulated results.
基金supported by Liao Ning Revitalization Talents Program No. XLYC1807161Dalian High-level Talents Innovation Support Plan No. 2017RQ063+4 种基金Dalian Ocean University “Zhanlan scholar”ProgramThe National Natural Science Foundation of China under contract Nos. 41206013 and 41430963the Public Science and Technology Research Funds Projects of Ocean under contract No. 201205018the National Science and Technology Support Program under contract No. 2014BAB12B02Projects of Institute of Marine Industry Technology of Liaoning Universities
文摘Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have unique geographical locations.Therefore,the characteristics of phytoplankton population distribution in the Bohai Sea and the Yellow Sea are of great significance to the study of marine ecology in China.In this work,the pigment data obtained from the Yellow Sea and Bohai Sea in August 2015 were analyzed by HPLC(High-Performance Liquid Chromatography).Then the pigment data were analyzed statistically by the CHEMTAX software,so that the phytoplankton community structure information was obtained.Results show that in summer 2015,from the perspective of sea area,the biomass of phytoplankton in the surface of Bohai Sea is higher than that in the Yellow Sea,while the phytoplankton biomass in the surface of North Yellow Sea is higher than that in the South.From the perspective of dominant species of phytoplankton,the surface waters of the Yellow Sea and Bohai Sea were dominated by diatoms,prymnesiophytes and chlorophytes,accounting for 55.76%,14.56%and 14.55%respectively.Among them,diatoms accounted for the absolute advantage.
基金supported by the Nationa1 High Technology Research and Development Program of China(863 Program)(Grant No.2002AA639370)the Natural Science Foundation of Shandong Province(Grant No.Q99E02)the Special Fund of Excellent Ph.D Dissertation(200021).
文摘An elliptical wind field model of typhoons is put forward based on the characteristics of the typhoon wind fields occurring in the Yellow Sea and Bohai Sea. By contrasting it with the circular typhoon wind field model, it is found that the elliptical model can adequately represent the real wind field and trace the process of a typhoon storm surge. The numerically simulated results of storm surges by using the elliptical model are in good agreement with the observations and markedly better than those by using the circular model.
基金Supported by the Open Fund of the Key Laboratory of Ocean Circulationand Waves,Chinese Academy of Sciences(No.KLOCAW1010)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX1-YW-12-04)the National High Technology Research and Development Program of China(863Program)(Nos.2007AA092202,2008AA121701)
文摘Two typical satellite sea surface temperature (SST) datasets, from the Multi-functional Transport Satellite (MTSAT) and Tropical Rainfall Measuring Mission Microwave Imager (TMI), were evaluated for the East China Sea, Yellow Sea, and Bohai Sea throughout 2008. Most monthly-mean availabilities of MTSAT are higher than those of TMI, whereas the seasonal variation of the latter is less than that of the former. The analysis on the one-year data shows that the annual mean availability of MTSAT (61%) is greater than that of TMI (56%). This is mainly because MTSAT is a geostationary satellite, which achieves longer observation than the sun-synchronous TMI. The daily availability of TMI (28%-75%) is more constant than that of MTSAT (9%-93%). The signal of infrared sensors on MTSAT is easily disturbed on cloudy days. In contrast, the TMI microwave sensor can obtain information through clouds. Based on in-situ SSTs, the SST accuracy of TMI is superior to that of MTSAT. In 2008, the root mean square (RMS) error of TMI and MTSAT were 0.77 K and 0.84 K, respectively. The annual mean biases were 0.14 K (TMI) and -0.31 K (MTSAT). To attain a high availability of SSTs, we propose a fusion method to merge both SSTs. The annual mean availability of fusion SSTs increases 17% compared to MTSAT. In addition, the availabilities of the fusion SSTs become more constant. The annual mean RMS and bias of fusion SSTs (0.78 K and -0.06 K, respectively) are better than those of MTSAT (0.84 K and -0.31 K).
文摘Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors. In the present study, seasonal cycles of topography in the BS and YS and its relationship with atmospheric forcing and oceanic adjustment were examined and discussed using TOPEX/Poseidon and ERS-1/2 Sea Level Anomalies (SLA) data. Analyses revealed complicated seasonal cycles of topography composed mainly of2 REOF modes, the winter-summer mode (WIM) and spring-autumn mode (SAM). The WIM with action center in the BS displayed peak and southward pressure gradient in July, and valley and northward pressure gradient in January, which is obviously the direct response to monsoon with about 1-month response time. The SAM with action center in the western south YS displayed peak and northward pressure gradient in October and valley and southward pressure gradient in April. After the mature period of monsoon, the action center in the BS became weakened while that in the western south YS became strengthened because of regional convergence or divergence induced by seasonal variations of the Taiwan Warm Current and Yellow Sea Coastal Current. The direct response of topography to monsoon resulted in the WIM, while oceanic adjustment of topography played an important role in the forming of the SAM.
文摘Considering the interaction of different tidal waves, an adjoint numerical model is developed to simulate M2, S2, K1 and O1 tidal waves in the Bohai Sea, the Yellow Sea and the East China Sea （B-Y-E） simultaneously. Compared with previous researches, by using the adjoint assimilation technique to inverse open boundary conditions and bottom friction coefficients based on altimetric data from TOPEX/Poseidon （T/P） and tidal gauges data, the precision of the numerical simulation is significantly improved. Selecting 14 days of simulated results after the initial wanning run to conduct harmonic analysis, the results can show the characteristics of M2, S2, K1 and O1 tidal wave systems perfectly in B-Y-E. Compared with 9 current stations, the calculated harmonic constants of tidal currents for M2 and K1 are in good agreement with the observed ones.
基金Supported by China’s National 908 Program (Nos. 908-01-ST02,908-02-02-02 908-02-02-03)+2 种基金National Natural Science Foundation of China (No. 40976001)National Basic Research Priorities Program (No. 2005CB422308)National High Technology Research and Development Program (863 Program,No. 2007AA092104)
文摘In this paper, we characterize the North Yellow Sea （NYS） water masses in summer by analyzing temperature and salinity data surveyed in 2006. The Liaonan Coastal Water is characterized by low salinity westward and southward flow paths. The westward path flows parallel to land, turns to the south, then to the southeast adjacent to the mouth of the Lushun River, where it mixes with other coastal water directly to the southwest. It becomes the main source of low salinity water in the deep water area west of 123°E. The high-salinity Lubei Coastal Water is the remnant of the winter Lubei Coastal Water, which is located mostly in a small area between Yantai and Weihai, and does not originate in the Bohai Sea Coastal Water. The two NYS zones demarcated at 123°E have distinctly different temperature and salinity characteristics. There are two high-salinity centers east of 123°E, whereas there is low-salinity water to the west whose temperature and salinity structures are complex, composed of the coastal water south of Chengshantou, the Liaonan Coastal Water and the Bohai Sea Water.
基金Project 40076014 supported by NSFC &"Study on ocean geology environment and ocean torrent" supported by Natural Science Fund of Qingdao.
文摘There are two different opinions on the formation history of Huanghe (Yellow) River. One postulates that Huanghe River might have come into existence before Tertiary. The other supposes that it joined up into a long river only in the last stage of Late Pleistocene. The appearance of Huanghe River is believed to have close relation to the uplifting of Tibetan Plateau. It is not likely that it could have come into being before its high elevation riverhead was formed. Today Huanghe River occurred probably during the recession of the sea in glacial periods. In the last glacial age, the climate was very harsh in the area north of the modern estuary of Changjiang (Yangtse) River; some areas were permafrost and the others barren deserts. At that time, eolation was the major exogenic force on exposed shelf. Beginning from 12 Ka BP, the global climate warmed up, resulting in gradual disappearance of continental mountain glaciers retreated, and sea level rose. Consequently, Huanghe River was replenished with water to become modern river system. With continued rising of sea level, Huanghe River delta moved continuously eastward.
基金Supported by the National Natural Science Foundation of China(No.41271409)
文摘The oceanic front is a narrow zone in which water properties change abruptly within a short distance.The sea surface temperature(SST) front is an important type of oceanic front,which plays a significant role in many fields including fisheries,the military,and industry.Satellite-derived SST images have been used widely for front detection,although these data are susceptible to influence by many objective factors such as clouds,which can cause missing data and a reduction in front detection accuracy.However,front detection in a single SST image cannot fully reflect its temporal variability and therefore,the long-term mean frequency of occurrence of SST fronts and their gradients are often used to analyze the variations of fronts over time.In this paper,an SST front composite algorithm is proposed that exploits the frontal average gradient and frequency more effectively.Through experiments based on MODIS Terra and Aqua data,we verified that fronts could be distinguished better by using the proposed algorithm.Additionally through its use,we analyzed the monthly variations of fronts in the Bohai,Yellow,and East China Seas,based on Terra data from 2000 to 2013.
基金the National Natural Science Foundation of China (Nos. 41176007 and 40706007)
文摘Abrupt changes in freshwater inputs from large rivers usually imply regime shifts in coastal water environments. The influence of a water regulation event on the age of the Yellow River water in the Bohai was modeled using constituent-oriented age and residence time theory to better understand the change in the environmental function of the hydrodynamic field owing to human activities. The water ages in Laizhou Bay, the central basin, and the Bohai strait are sensitive to water regulation. The surface ages in those areas can decrease by about 300 days, particularly in July, and the age stratification is also strengthened. A water regulation event can result in declines in the water age in early July ahead of declines in the water age under climatological conditions(without the regulation event) by about 1 and 5 months in the central basin and Laizhou Bay, respectively. The change in the coastal circulation due to the water regulation event is the primary reason for the change in the Yellow River water age. The high Yellow River flow rate can enhance the density flow and, therefore, reduce the age of the Yellow River water. The subsequent impact of a single water regulation event can last about 1.0 to 4.0 years in different subregions.
