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1.
During the Second Chinese National Arctic Expedition (CHINARE) from July to September 2003, depth profiles of dissolved and particulate 234Th in upper water columns were collected at two stations of BR03 and BR24 in the Bering Sea. 234Th was sampled by using a traditional Fe(OH)3 co-precipitation technique, which is a reliable approach to 234Th measurement. We observed 234Th excess at station BR03 below the euphotic zone, which was possibly due to the intensive remineralization of particulate matter. Particulate organic carbon (POC) export fluxes were estimated from a one-dimensional irreversible steady state model of 234Th fluxes together with measurements of the POC/234Th ratio on the suspended particles. The POC export fluxes from the euphotic zone were 11.66 and 11.69 mmol C m-2 d-1 at BR03 and BR24 stations,respectively. The ratios of POC fluxes to primary production at the two stations were about 0.5 and 0.59, respectively, probably due to the presence of large phytoplankton (in particular diatoms). 相似文献
2.
A WRF-Chem model including a comprehensive gas-phase nitrogen chemistry module was used to simulate a severe dust event appearing in the eastern China on 19-25 March, 2002. The modeling result well reproduced PM10 concentrations in various distances from the dust sources and the transport pathway of the dust strom. The results showed that both the concentrations and the dry deposition fluxes of PM10 increased over the China seas during the dust event following the passage of a cold front system. The maximum fluxes of PM10 in the Yellow Sea and the East China Sea during the dust event were 5.5 and 8.4 times of those before the event, respectively. However, the temporal variations of the dry deposition fluxes of particulate inorganic nitrogen differed over the Yellow Sea from those over the East China Sea. Nitrate and ammonium in the whole northern China rapidly decreased because of the intrusion of dust-loaded air on 19 March. The dust plume arrived in the Yellow Sea on 20 March, decreasing the particulate inorganic nitrogen in mass concentration accordingly. The minimum dry deposition fluxes of nitrate and ammonium in the Yellow Sea were about 3/5 and 1/6 of those before the dust arrival, respectively. In contrast, when the dust plume crossed over the Yangtze Delta area, it became abundant in nitrate and ammonium and increased the concentrations and dry deposition fluxes of particulate inorganic nitrogen over the East China Sea, where the maximum dry deposition fluxes of nitrate and ammonium increased approximately by 4.1 and 2.6 times of those prior to the dust arrival. 相似文献
3.
Size-fractionated 210Po and 210Pb, in the size fractions >0.4 μm, >2 μm and >10 μm, were examined to determine the seasonal variability of particulate fluxes
in Xiamen Bay. Good correlations between 210Po and particulate organic carbon (POC) or non-Particulate Organic Matter (nPOM) suggested that 210Po can be used to trace the export fluxes of POC and nPOM. Both steady-state (SS) model and nSS model were used to evaluate
fluxes of size-fractionated 210Po, results showed that nSS model was better than the SS model in coastal areas. Based on the nSS model, size-fractionated
POC fluxes decreased with increasing particle size. For the particle size studied, maximum POC fluxes occurred in autumn,
followed by spring, winter, and summer. Fluxes of nPOM were an order of magnitude higher than the corresponding size-fractionated
POC fluxes. Differences between size-fractionated nPOM fluxes indicated that hydrodynamic conditions were the main factor
regulating transportation of particulate out of the inner Bay. In winter most particulates, including >10 μm particles, were
transported under the strongest hydrodynamic conditions. In contrast, only a fraction of the <2 μm particulates were transported
from the inner Bay in spring. This study suggested that 210Po is a powerful tracer of seasonal particulate export in coastal seas. 相似文献
4.
Distribution of suspended matter in seawater in the Southern Yellow Sea is investigated in five regions: 1) the Northern Jiangsu
bank, the highest TSM (total suspended matter) content region; 2) the high TSM content region off the Changjiang River mouth;
3) the high TSM content region off the Chengshan Cape; 4) the low TSM region off Haizhou Bay; 5) the central part of the Southern
Yellow Sea, a low TSM content region. The vertical distribution of TSM is mainly characterized by a spring layer of suspended
matter, written as “suspended-cline” whose genesis is related to storms in winter. In this paper, non-combustible components
and grain sizes in suspended matter, relationship between suspended matter and bottom sediments, and salinity in seawater
are described. Investigation result shows that, in this area, suspended matter comes mainly from resuspended bottom sediment
and secondarily from present discharge loads from rivers and biogenic materials. Discharged sediments from the Huanghe River
move around the Chengshan Cape and affect the northwestern region of this area. Sediments from the Changjiang River affect
only the southern part and have little or no direct influence on the central deep region. Wave is the main factor affecting
distribution of suspended matter. Water depth controls the critical depth acted on by waves. The cold water mass in the central
region limits horizontal and vertical dispersions of terrigenous materials. Suspended matter here has the transitional properties
of the epicontinental sea. Its concentration and composition are different from those of a semi-closed sea (such as the Bohai
Sea) and those of the East China Sea outer continental shelf or those near oceanic areas. 相似文献
5.
To evaluate the particle dynamics and estimate the POC (particulate organic carbon) export flux from the euphotic zone in
the western Arctic Ocean, 234Th-238U disequilibrium was applied during the second Chinese National Arctic Research Expedition (July 15–September 26, 2003). The
POC export fluxes are estimated from the measured profiles of the 234Th/238U activity ratios and the POC/PTh ratios. The average residence times of the particulate and dissolved 234Th in the euphotic zone are 33 d and 121 d, and their average export fluxes are 480 dpm/m2d and 760 dpm/m2d, respectively. The scavenging and removal processes of particle reactive elements are active in the upper layer of the Chukchi
Sea. The average residence time of 234Th increases from shelf to basin, while the export fluxes of 234Th decrease. The estimated POC export fluxes from the euphotic zone vary from 2.1 to 20.3 mmol/m2d, indicating that the western Arctic Ocean is an important carbon sink in summer due to efficient biological pump. 相似文献
6.
Numerical Study of Water and Suspended Matter Exchange Between the Yellow Sea and the East China Sea 总被引：3，自引：1，他引：2
INTRODUCTIONTheYellowSeaandtheEastChinaSea (ECS)aremarginalseasofthenorthwestPacificandhaveexpansivecontinentalshelves .TheuniqueandstrikingfeaturesoftheYellowSeaandtheECSarethattheyhavestrongtidalcurrent;aresubjecttostrongmonsooninfluence ;andreceiveinflowfromthebiggestriverinChina ,theChangjiangRiver ;andthatthefamouswesternboundarycurrent,theKuroshio ,passesthroughtheECS ,withitsbranchesintrudingupwardintothecontinentalshelfareas.Generallyspeaking ,thewaterexchangecapacityofthe… 相似文献
7.
A dynamic box model was applied to study the characteristics of biogeochemical cycling of PO_4-P,NO_3-N,AOU,POC and PON in the southern Taiwan Strait region based on field data of the"Minnan Taiwan Bank Fishing Ground Upwelling Ecosystem Study" during the period of Dec.1987-Nov.1988.According to the unique hydrological and topographical features of the region,six boxesand three layers were considered in the model.The variation rates and fluxes of elements induced by hor-izontal current,upwelling,by diffusion,sinking of particles and biogeochemical processes were estimatedrespectively.Results further confirmed that upwellings had important effects in this region.Thenearshore upwelling areas had net input fluxes of nutrients brought by upwelling water,also had high de-pletion rates of nutrients and production rates of particulate organic matter and dissolved oxygen.Theabnormal net production of nutrients in the middle layer(10-30m) indicated the important role of bacte-ria in this high production region.Th 相似文献
8.
234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea. 相似文献
9.
Concentrations of dissolved and particulate organic carbon (DOC and POC) were documented in 1996–1997 at 4 different trophic
state stations in Donghu Lake, a typical shallow eutrophic lake along the Changjiang River's middle reaches. The mean concentrations
of DOC were 15.11±3.26, 15.19±4.24, 14.27±3.43, and 13.31±3.30 mg/L in Station I, II, III, and IV, respectively. The DOC concentrations
of the studied area were very similar to that in other lakes along the Changjiang River's middle reaches. The POC mean of
the whole lake was 5.01 mg/L due to the large amount of organic detritus of both allochthonous and autochthonous origin. Significant
linear relationship was found between POC and chlorophyll a at all 4 stations, which presumably reflect that phytoplankton,
its exudates and its metabolic products were the main contributors to the POC pool in the water column. The slope of such
linear relationship at Station IV was significantly steeper than that at Station I, II and III. In addition, the DOC/POC ratios
(mean value: 4.40) indicated that the organic detritus was the most important component of the particulate organic matter;
in other works, next to organic detritus, phytoplankton dominated the particulate organic matter in Donghu Lake.
Project 39770146, 39430101 supported by NSFC and the State Key Laboratory of Freshwater Ecology and Biotechnology, affiliated
to the Institute of Hydrobiology, Chinese Academy of Sciences. 相似文献
10.
The effects of using different types of glass fiber filters (GF/F, GF/C) and of sample treatments evaluated. Studies on the variation of suspended matter (SM) and particulate organic carbon (POC) showed that: 1) the transversal and day to night variations are important and must be taken into account in order to get a corrcet river flux; 2) no regular seasonal variations of SM and POC observed, as they are controlled essentially by the climatological, hydrologic, physiochernical, biological, and geological conditions of the drainage area. 相似文献
11.
Variations of the suspended matter and the particulate organic carbon in the entry of the Gironde Estuary,France 总被引：1，自引：0，他引：1
The effects of using different types of glass fiber filters (GF/F, GF/C) and of sample treatments were evaluated. Studies
on the variation of suspended matter (SM) and particulate organic carbon (POC) showed that: 1) the transversal and day to
night variations are important and must be taken into account in order to get a correct river flux; 2) no regular seasonal
variations of SM and POC were observed, as they are controlled essentially by the climatological, hydrologic, physiochemical,
biological, and geological conditions of the drainage area.
Contribution No 2246 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
12.
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 the 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. 相似文献
13.
The concentration of suspended load can be determined by its linear relationship to turbidity. Our results present the basic
distribution of suspended load in North Yellow Sea. In summer, the suspended load concentration is high along the coast and
low in the center of the sea. There are four regions of high concentration in the surface layer: Penglai and Chengshantou
along the north of the Shandong Peninsula, and the coastal areas of Lüshun and Changshan Islands. There is a 2 mg/L contour
at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. And there is
a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the
west. The distribution features in the 10 m and bottom layer are similar to the surface layer, however, the suspended load
concentration declines in the 10 m layer while it increases in the bottom layer. And in the bottom layer there is a low suspended
load concentration water mass at the region south of 38°N and east of 123°E extending to the southeast. In general, the lowest
suspended load concentration in a vertical profile is at a depth of 10 to 20 m, the highest suspended load concentration is
in the bottom near Chengshantou area.
In winter, the distribution of suspended load is similar to summer, but the average concentrations are three times higher.
There are two tongue-shaped high suspended load concentration belt, one occurring from surface to seafloor, extends to the
north near Chengshantou and the other invades north to south along the east margin of Dalian Bay. They separate the low suspended
load concentration water masses in the center of North Yellow Sea into east and west parts. Vertical distribution is quite
uniform in the whole North Yellow Sea because of the cooling effect and strong northeast winds. The distribution of suspended
load has a very close relationship to the current circulation and wind-induced waves in the North Yellow Sea. Because of this,
we have been able to show for the first time that the distribution of suspended load can be used to identify water masses. 相似文献
14.
Investigation of dissolved organic carbon (DOC) and particulate organic carbon (POC) at 12 stations in Yantal Sishili Bay in May, August, and November of 1997 and March and May of 1998 showed that DOC concentrations varied from 1.14 mg/L to 5.35 mg/L; that the average values at all staticrLs ineach entise varied from 1.52 mg/L to 2.12 mg/L; that POC concentrafions varied from 0.049 mg/L to 1.411mg/L; and averaged 0.159 mg/L to 0.631 mg/L in each cruise. Horizontal distribution of DOC was influ-enced by factors such as continental input, organism activity, temperature, aquieulture environment, etc. The higher POC concentration occurred along the coast. The vertical distribution of DOC and POC changed obviously in spring and summer, but not obviously in autumn and winter. DOC concentration was highest in summer and POC in spring; both were lowest in winter. The seasonal change of DOC was con-sistent with primary productivity seasonal variation, and that of POC was consistent with ehlorophyll-a sea-sanal variation. The seasonal change trend of the C/N ratio of dissolved organic matter was obvious, but the C/N ratio of particulate organic matter had no such trend. 相似文献
15.
Future temperature distributions of the marginal Chinese seas are studied by dynamic downscaling of global CCSM3 IPCC_AR4 scenario runs.Different forcing fields from 2080-2099 Special Report on Emissions Scenarios(SRES) B1,A1,and A2 to 1980-1999 20C3M are averaged and superimposed on CORE2 and SODA2.2.4 data to force high-resolution regional future simulations using the Regional Ocean Modeling System(ROMS).Volume transport increments in downscaling simulation support the CCSM3 result that with a weakening subtropical gyre circulation,the Kuroshio Current in the East China Sea(ECS) is possibly strengthened under the global warming scheme.This mostly relates to local wind change,whereby the summer monsoon is strengthened and winter monsoon weakened.Future temperature fluxes and their seasonal variations are larger than in the CCSM3 result.Downscaling 100 years’ temperature increments are comparable to the CCSM3,with a minimum in B1 scenario of 1.2-2.0°C and a maximum in A2 scenario of 2.5-4.5°C.More detailed temperature distributions are shown in the downscaling simulation.Larger increments are in the Bohai Sea and middle Yellow Sea,and smaller increments near the southeast coast of China,west coast of Korea,and southern ECS.There is a reduction of advective heat north of Taiwan Island and west of Tsushima in summer,and along the southern part of the Yellow Sea warm current in winter.There is enhancement of advective heat in the northern Yellow Sea in winter,related to the delicate temperature increment distribution.At 50 meter depth,the Yellow Sea cold water mass is destroyed.Our simulations suggest that in the formation season of the cold water mass,regional temperature is higher in the future and the water remains at the bottom until next summer.In summer,the mixed layer is deeper,making it much easier for the strengthened surface heat flux to penetrate to the bottom of this water. 相似文献
16.
用交叉点数据计算中国近海海平面变化 总被引：2，自引：0，他引：2
讨论了由测高卫星升、降弧段海面高在交叉点上的约束监测海平面变化的方法；用TOPEX／POSIDON测高数据计算了中国黄海、东海、南海海域的海平面变化，其中黄海、东海海域受两个月周期分量的振荡信号影响，而南海海域以年周期变化为主要表现特征；分析了3个海区海平面变化的相关性，扣除两个月的周期分量振荡信号后，其海平面变化的相关性达到90％以上；分析了海水面积随纬度带的变化对不同纬度分布的海区海平面变化量的影响。 相似文献
17.
The Chinese east coastal areas and marginal seas are foggy regions.The development of effective forecasting methodsrests upon a comprehensive knowledge of the fog phenomena.This study provides new observations associated with the sea fogsover the northwestern Yellow Sea by means of L-band radar soundings with a high vertical resolution of 30 m.The monthly tem-perature lapse rate,the Richardson Numbers,and the humidity show obvious seasonal variations in the lower level of the planetaryboundary layer (PBL) that are related to the onset,peak and end of the Yellow Sea fog season.The typical pattern of stratification forthe sea fog season in the northwestern Yellow Sea is that a stable layer of about 400 m thick caps a 150 m conditionally unstable layer.Besides,the differences between fogs and stratus clouds in terms of humidity,turbulence and temperature are analyzed,which is ofsignificance for sea fog forecast and detection by satellites.The thickness of the sea fogs varies in different stages of the fog season,and is associated with the temperature inversion.The numerical simulation proves that the seasonal variations obtained by the radarwell represent the situations over the Yellow Sea. 相似文献
18.
Journal of Oceanology and Limnology - The Yellow Sea (YS) and East China Sea (ECS) are important marginal seas of the western Pacific. Understanding the dynamics of methane (CH4) in the YS and ECS... 相似文献
19.
��־�� 《中国海洋湖沼学报》2012,30(5):791-795
Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ) of the Changjiang(Yangtze) estuary during 2005.Results show that there was a range of 18.7%±27.9% to 73.9%±22.5% per annum of total suspended particulate matter(SPM),with an average of 49.2%.Nearly half of the particulate matter in the TMZ originates from sediment resuspension.This indicates that sediment resuspension is one of the major mechanisms involved in formation of the TMZ.Compared with traditional method for calculating these ratios in the estuary,this new method evaluates the dynamic variation of SPM content carried by river runoff from the river mouth to the ocean.The new method produced more reliable results than the traditional one and could produce a better estimation of resuspension flux for particulate matter in estuaries. 相似文献
20.
A one-year field study was conducted to determine the conversion ratio of phytoplankton biomass carbon (Phyto-C) to chlorophyll-a (Chl-a) in Jiaozhou Bay, China. We measured suspended particulate organic carbon (POC) and phytoplankton Chl-a samples collected in surface water monthly from March 2005 to February 2006. The temporal and spatial variations of Chl-a and POC concentrations were observed in the bay. Based on the field measurements, a linear regression model II was used to
generate the conversion ratio of Phyto-C to Chl-a. In most cases, a good linear correlation was found between the observed POC and Chl-a concentrations, and the calculated conversion ratios ranged from 26 to 250 with a mean value of 56 μg μg−1. The conversion ratio in the fall was higher than that in the winter and spring months, and had the lowest values in the
summer. The ratios also exhibited spatial variations, generally with low values in the near shore regions and relatively high
values in offshore waters. Our study suggests that temperature was likely to be the main factor influencing the observed seasonal
variations of conversion ratios while nutrient supply and light penetration played important roles in controlling the spatial
variations. 相似文献