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Asymmetric Distribution of Convection in Tropical Cyclones over the Western North Pacific Ocean

Advances in Atmospheric Sciences 2016年第11期33卷 1306-1321页

作者： Lu YANG Jianfang FEI Xiaogang HUANG Xiaoping CHENG Xiangrong YANG Juli DING Wenli SHI institute of Meteorology and oceanography PLA University of Science and Technology

Forecasts of the intensity and quantitative precipitation of tropical cyclones（TCs） are generally inaccurate, because the strength and structure of a TC show a complicated spatiotemporal pattern and are affected by various factors. Among these, asymmetric convection plays an important role. This study investigates the asymmetric distribution of convection in TCs over the western North Pacific during the period 2005–2012, based on data obtained from the Feng Yun 2（FY2）geostationary satellite. The asymmetric distributions of the incidence, intensity and morphology of convections are analyzed.Results show that the PDFs of the convection occurrence curve to the azimuth are sinusoidal. The rear-left quadrant relative to TC motion shows the highest occurrence rate of convection, while the front-right quadrant has the lowest. In terms of intensity, weak convections are favored in the front-left of a TC at large distances, whereas strong convections are more likely to appear to the rear-right of a TC within a 300 km range. More than 70% of all MCSs examined here are elongated systems, and meso-β enlongated convective systems（MβECSs） are the most dominant type observed in the outer region of a TC. Smaller MCSs tend to be more concentrated near the center of a TC. While semi-circular MCSs [MβCCSs, MCCs（mesoscale convective complexes）] show a high incidence rate to the rear of a TC, elongated MCSs [MβECSs, PECSs（persistent elongated convective systems）] are more likely to appear in the rear-right quadrant of a TC within a range of 400 km.

关键词： convection Tropical convective asymmetric tropical mesoscale elongated typhoon likely storm

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Projections of changes in marine environment in coastal China seas over the 21^st century based on CMIP5 models

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Journal of Oceanology and Limnology 2020年第6期38卷 1676-1691页

作者： TAN Hongjian CAI Rongshuo HUO Yunlong GUO Haixia Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361005China

The increases of atmospheric carbon dioxide and other greenhouse gases have caused fundamental changes to the physical and biogeochemical properties of the oceans,and it will continue to occur in the foreseeable future.Based on the outputs of nine Earth System Models from the fifth phase of the Coupled Model Intercomparison Project(CMIP5),in this study,we provided a synoptic assessment of future changes in the sea surface temperature(SST),salinity,dissolved oxygen(DO),seawater pH,and marine net primary productivity(NPP)in the coastal China seas over the 21st century.The results show that the mid-high latitude areas of the coastal China seas(East China Seas(ECS),including the Bohai Sea,Yellow Sea,and East China Sea)will be simultaneously exposed to enhanced warming,deoxygenation,acidification,and decreasing NPP as a consequence of increasing greenhouse gas emissions.The magnitudes of the changes will increase as the greenhouse gas concentrations increase.Under the high emission scenario(Representative Concentration Pathway 8.5),the ECS will experience an SST increase of 3.24±1.23℃,a DO concentration decrease of 10.90±3.92μmol/L(decrease of 6.3%),a pH decline of 0.36±0.02,and a NPP reduction of-17.7±6.2 mg/(m2·d)(decrease of 12.9%)relative to the current levels(1980-2005)by the end of this century.The co-occurrence of these changes and their cascade effects are expected to induce considerable biological and ecological responses,thereby making the ECS among the most vulnerable ocean areas to future climate change.Despite high uncertainties,our results have important implications for regional marine assessments.

关键词： Coupled Model Intercomparison Project(CMIP5) sea surface temperature(SST) dissolved oxygen(DO) seawater pH net primary productivity

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Ventilation of the Sulu Sea retrieved from historical data

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Acta Oceanologica Sinica 2014年第9期33卷 1-11页

作者： LI Li GAN Zijun Third Institute of Oceanography State Oceanic Administration State Key Laboratory of Tropical oceanography South China Sea Institute of Oceanoglogy

Based on historical observations, ventilation of the Sulu Sea （SS） is investigated and, its interbasin exchange is also partly discussed. The results suggest that near the surface the water renewal process not only occurs through the Mindoro Strait （MS） and the Sibutu Passage, but also depends on the inflows through the Surigao Strait and the Bohol Sea from the Pacific and through the Balabac Strait from the South China Sea （SCS）. Both inflows are likely persistent year round and their transports might not be negligible. Below the surface, the core layer of the Subtropical LowerWater （SLW） lies at about 200 m, which enters the SS through the Mindoro Strait not hampered by topography. Moreover, there is no indication of SLW inflow through the Sibutu Passage even though the channel is deep enough to allow its passage. The most significant ventilation process of the SS takes place in depths from 20a m to about 1200 m where intermediate convection driven by quasi-steady inflows through the Mindoro and Panay straits （MS-PS） dominates. Since the invaded water is drawn from the upper part of the North Pacific Intermediate Water （NPIW） of the SCS, it is normally not dense enough to sink to the bottom. Hence, the convective process generally can only reach some intermediate depths resulting in a layer of weak salinity minimum （about 34.45）. Below that layer, there is the Sulu Sea Deep Water （SSDW） homogeneously distributed from 1200 m down to the sea floor, of which the salinity is only a bit higher （about 34.46） above the minimum. Observational evidence shows that hydrographic conditions near the entrance of the MS in the SCS vary significantly from season to season, which make it possi- ble to provide the MS-PS overflowwith denser water of higher salinity sporadically. It is hence proposed that the SSDW is derived from intermittent deed convection resulted from DroDertv changes of the MS-PS inflow.

关键词： Sulu Sea ventilation overflow interbasin exchange

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Comparison of Wind Sat and buoy-measured ocean products from 2004 to 2013

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Acta Oceanologica Sinica 2016年第1期35卷 67-78页

作者： ZHANG Lei SHI Hanqing DU Huadong ZHU Enze ZHANG Zhihua FANG Xun institute of Meteorology and oceanography PLA University of Science and Technology

To evaluate the ocean surface wind vector and the sea surface temperature obtained from WindSat, we compare these quantities over the time period from January 2004 to December 2013 with moored buoy measurements. The mean bias between the WindSat wind speed and the buoy wind speed is low for the low frequency wind speed product （WSPD_LF）, ranging from -0.07 to 0.08 m/s in different selected areas. The overall RMS error is 0.98 m/s for WSPD_LF, ranging from 0.82 to 1.16 m/s in different selected regions. The wind speed retrieval result in the tropical Ocean is better than that of the coastal and offshore waters of the United States. In addition, the wind speed retrieval accuracy ofWSPD LF is better than that of the medium frequency wind speed product. The crosstalk analysis indicates that the WindSat wind speed retrieval contains some cross influences from the other geophysical parameters, such as sea surface temperature, water vapor and cloud liquid water. The mean bias between the WindSat wind direction and the buoy wind direction ranges from -0.46° to 1.19° in different selected regions. The overall RMS error is 19.59° when the wind speed is greater than 6 m/s. Measurements of the tropical ocean region have a better accuracy than those of the US west and east coasts. Very good agreement is obtained between sea surface temperatures of WindSat and buoy measurements in the tropical Pacific Ocean; the overall RMS error is only 0.36℃, and the retrieval accuracy of the low latitudes is better than that of the middle and high latitudes.

关键词： WindSat polarimetric microwave radiometer wind vector sea surface temperature validation

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Green synthesis of iron oxide(Fe_3O_4)nanoparticles using two selected brown seaweeds:Characterization and application for lead bioremediation

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Acta Oceanologica Sinica 2016年第8期35卷 89-98页

作者： EL-KASSAS Hala Y. ALY-ELDEEN Mohamed A. GHARIB Samiha M. National Institute of Oceanography and Fisheries Alexandria 21556Egypt

The exploitation of different plant materials for the biosynthesis of nanoparticles is considered a green technology because it does not involve any harmful chemicals. In this study, iron oxide nanoparticles（Fe3O4-NPs） were synthesized using a completely green biosynthetic method by reduction of ferric chloride solution using brown seaweed water extracts. The two seaweeds Padina pavonica（Linnaeus） Thivy and Sargassum acinarium（Linnaeus） Setchell 1933 were used in this study. The algae extract was used as a reductant of Fe Cl3 resulting in the phytosynthesis of Fe3O4-NPs. The phytogenic Fe3O4-NPs were characterized by surface plasmon band observed close to 402 nm and 415 nm; the obtained Fe3O4-NPs are in the particle sizes ranged from 10 to 19.5 nm and 21.6 to 27.4 nm for P. pavonica and S. acinarium, respectively. The strong signals of iron were reported in their corresponding EDX spectra. FTIR analyses revealed that sulphated polysaccharides are the main biomolecules in the algae extracts that do dual function of reducing the Fe Cl3 and stabilizing the phytogenic Fe3O4-NPs. The biosynthesized Fe3O4-NPs were entrapped in calcium alginates beads and used in Pb adsorption experiments. The biosynthesized Fe3O4-NPs alginate beads via P. pavonica（Linnaeus） Thivy had high capacity for bioremoval of Pb（91%） while that of S. acinarium（Linnaeus） Setchell 1933 had a capacity of（78%） after 75 min.The values of the process parameters for the maximum Pb removal efficiency by Fe3O4-NPs alginate beads synthesized via P. pavonica（Linnaeus） Thivy were also estimated.

关键词： seaweeds iron oxide silver nanoparticles

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Distribution and ecological risk assessment of some heavy metals in coastal surface sediments along the Red Sea,Egypt

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International Journal of Sediment Research 2016年第2期31卷 164-172页

作者： Ahmed El Nemr Ghada F.El-Said Azza Khaled Safaa Ragab Environmental Division National Institute of Oceanography and Fisheries

The ecological risk assessment for Al,Zn,Cu,Ni,V,Pb,Cd,and Hg in surface sediment collected from the Egyptian Red Sea coast was evaluated using the Geo-accumulation Index(I).Sediment Enrichment Factor(SEF) and Potential Ecological Risk Index(PERI) methods.The predominant heavy metal,aluminum,showed high concentrations along both of Aqaba Gulf(4378.8 ± 2554.1 μg/g) and southern part of the Red Sea(2972.8 + 1527.5 μg/g).while it recorded the lowest concentration in Suez Gulf(829.7 ± 398.2 μg/g).The determined heavy metal concentrations had the order of Al > Zn >-Ni > V > Pb > Cu > Cd > Hg.The statistical analyses showed some correlations among the heavy metals contents.Several international sediment quality guidelines were used to estimate the quality of the collected sediments.Interestingly,the recorded average heavy metals concentrations were lower than those of the permissible contents for sediment quality guidelines.The Geo-accumulation index calculations(I) proved that the investigated region could be classified as an unpolluted area.Sediment Enrichment Factor(K) study showed high values in Suez Gulf region.The single pollution index analysis of heavy metals in the sediments(C~i) indicated that Al,Zn,V,and Pb were of natural origin,while Ni,Cd and Hg were seriously affected by human activities.Interestingly,amongst,all the determined heavy metals,Cd and Hg gave moderate ecological risk indicators.

关键词： Heavy metals Coastal surface sediments Ecological risk assessment Suez and Aqaba Gulfs Red Sea

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Nutrient and eutrophication characteristics of the Dongshan Bay, South China

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Chinese Journal of Oceanology and Limnology 2014年第4期32卷 886-898页

作者：陈宝红暨卫东周开文贺青傅婷婷 Third Institute of Oceanography State Oceanic Administration

We recorded NO 3-N, NO 2-N, NH 4-N, PO 4-P, SiO 3-Si, salinity, and temperature data at 10 stations in the Dongshan Bay in May, June, July, August, October, and November 2008, analyzing nutrient and eutrophication characteristics. The mean concentration of dissolved inorganic nitrogen(DIN) was 0.30–0.40 mg/dm 3; generally, NO 3-N was the main form in most areas. The mean concentrations of PO 4-P and SiO 3-Si were 0.040–0.060 mg/dm 3 and 1.00–1.50 mg/dm 3, respectively. We proved that the majority of the SiO 3-Si in the Dongshan Bay came from the Zhangjiang River, with some coming from the Bachimen Strait. DIN originated from both the Zhangjiang River and the Bachimen Strait. Most PO 4-P originated from the Bachimen Strait, and some came from the Zhangjiang River. We found that P was an overall limiting factor to the phytoplankton community in most of the Dongshan Bay, and that Si and N were in surplus. However, near the Bachimen Strait Si became a limiting factor, especially for diatoms, while P and N were in comparative surplus. We used a potential eutrophication assessment method to analyze eutrophication, and showed that the most serious eutrophication occurred near the Zhangjiang River estuary and near the Bachimen Strait. In 2008, DIN levels were four times higher than that in 1988; PO 4-P levels were threefold higher, while SiO 3-Si was approximately double. Dissolved nutrients increased between 1988 and 2008. DIN increased at the greatest rate comparing to PO 4-P and SiO 3-Si, thus the N/P and N/Si mol ratios increased. Further studies on the effects of high DIN concentrations on the phytoplankton communities and marine ecosystems of the Dongshan Bay are needed.

关键词：水体富营养化东山湾特征浮游植物群落 NO3-N 中国平均浓度海洋生态系统

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The distribution of chlorophyll a and its influencing factors in different regions of the Bering Sea

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Acta Oceanologica Sinica 2014年第6期33卷 112-119页

作者： KANG Jianhua CHEN Xingqun ZHANG Ming Third Institute of Oceanography State Oceanic Administration

The distribution of chlorophyll a （Chl a） and its relationships with physical and chemical parameters in different regions of the Bering Sea were discussed in July 2010. The results showed the seawater column Chl a concentrations were 13.41-553.89 mg/m2 and the average value was 118.15 mg/m2 in the study areas. The horizontal distribution of Chl a varied remarkably from basin to shelf in the Bering Sea. The regional order of Chl a concentrations from low to high was basin, slope, outer shelf, inner shelf, and middle shelf. The verti- cal distribution of Chl a was grouped mainly from single-peak type in basin, slope, outer shelf, and middle shelf, where the deep Chl a maxima （DCM） layer was observed at 25-50 m, 30-35 m, 36-44 m, and 37-47 m, respectively. The vertical distribution of Chl a mainly had three basic patterns： standard single-peak type, surface maximum type, and bottom maximum type in the inner shelf. The analysis also showed that the transportation of ocean currents may control the distribution of Chl a, and the effects were not simple in the basin of the Bering Sea. There was a positive correlation between Chl a and temperature, but no significant correlation between Chl a and nutrients. The Bering Sea slope was an area deeply influenced by slope current. Silicate was the factor that controlled the distribution of Chl a within parts of the water in the slope. Light intensity was an important environmental factor in controlling seawater column Chl a in the shelf, where Chl a was limited by nitrate rather than phosphate within the upper water. Meanwhile, there was a positive relationship between Chl a and salinity. Algal blooms broke out at Sta. B6 of the southwestern St. Lawrence Island and Stas F6 and F11 in the middle of the Bering Strait.

关键词： chlorophyll a distribution characteristics environmental influence factor algal bloom Bering Sea

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Retrieval of Eddy Thermal Conductivity in the Weakly Nonlinear Prandtl Model for Katabatic Flows

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Journal of Meteorological Research 2017年第5期31卷 965-975页

作者： Bing YAN Sixun HUANG Jing FENG institute of Meteorology and oceanography National University of Defense Technology State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Because the nonlinearity of actual physical processes can be expressed more precisely by the introduction of a non- linear term, the weakly nonlinear Prandtl model is one of the most effective ways to describe the pure katabatic flow （no backgrotmd flow）. Features of the weak nonlinearity are reflected by two factors： the small parameter c and the gradually varying eddy thermal conductivity. This paper first shows how to apply the Wentzel-Kramers-Brillouin （WKB） method for the approximate solution of the weakly nonlinear Prandtl model, and then describes the retrieval of gradually varying eddy thermal conductivity from observed wind speed and perturbed potential temperature. Gradually varying eddy thermal conductivity is generally derived from an empirical parameterization scheme. We utilize wind speed and potential temperature measurements, along with the variational assimilation technique, to de- rive this parameter. The objective function is constructed by the square of the differences between the observation and model value. The new method is validated by numerical experiments with simulated measurements, revealing that the order of the root mean squre error is 10-2 and thus confirming the method＇s robustness. In addition, this me- thod is caoable of anti-interference, as it effectivelv reduces the influence of observation error.

关键词： weakly nonlinear Prandtl model parameter retrieval variational method Wentzel-Kramers-Brillouin（WKB） method

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Regional disparities of phytoplankton in relation to different water masses in the Northwest Pacific Ocean during the spring and summer of 2017

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Acta Oceanologica Sinica 2020年第6期39卷 107-118页

作者： Gengming Lin Yanghang Chen Jiang Huang Yanguo Wang Youyin Ye Qingliang Yang Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361005China

The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain,effects on climate change,fish resources as well as the entire ecosystem.However,there are few large-scale surveys covering several currents with different hydrographic characteristics.This study aimed to explore the relationships between the spatio-temporal variation in phytoplankton community structure and different water masses.A total of 630 water samples and 90 net samples of phytoplankton were collected at 45 stations in the Northwest Pacific Ocean(21.0°–42.0°N,118.0°–156.0°E)during spring and summer 2017.A total of 281 phytoplankton taxa(>5μm)belonging to 61 genera were identified in the study area.The distribution pattern of the phytoplankton community differed significantly both spatially and temporally.The average abundances of phytoplankton in spring and summer were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.Whether in spring or summer,the maximum abundance always appeared in the northern transition region affected by the Oyashio Current,where nutrients were abundant and diatoms dominated the phytoplankton community;whereas the phytoplankton abundance was very low in the oligotrophic Kuroshio region,and the proportion of dinoflagellates in total abundance increased significantly.The horizontal distribution of phytoplankton abundance increased from low to high latitudes,which was consistent with the trend of nutrient distributions,but contrary to that of water temperature and salinity.In the northern area affected by the Oyashio Current,the phytoplankton abundance was mainly concentrated in the upper 30 m of water column,while the maximum abundance often occurred at depths of 50–75 m in the south-central area affected by the Kuroshio Current.Pearson correlation and redundancy analysis(RDA)showed that phytoplankton abundance was significant negatively correlated with temperatur

关键词： phytoplankton regional disparity species composition spatial distribution Northwest Pacific Ocean

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