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Environment Sensitive Grain-Size Component (ESGSC) extracted from grain-size data of core ZJ2 from the mud area, northern shelf of the South China Sea, can be used to indicate the variations of East Asian Winter Monsoon (EAWM),with high (low) content/ mean-size of ESGSC denoting the strong (weak) EAWM. Combined with AMS ¹⁴C datings,core ZJ2 implies 8 strong EAWM periods over the last 3 ka, which corresponds well to climatic change records in Greenland ice core and nearby area. The result shows regional impact of the global climatic change.

Coastal soil salinization has become one of the most important land problems all over the world. It is very urgent now to ameliorate and take use of the saline-alkali soils effectively. In this paper,citric acid industrial wastewater after pretreatment was used to ameliorate a saline-alkali soil collected from a coastal oil factory in Dongying City,China. The effects and feasibility of saline-alkali soil amelioration with citric acid industrial wastewater were preliminary analyzed based on the variation of physicochemical properties of the soil before and after irrigation process. Results of the experiments showed that pH and electrical conductivity of soil solution decreased after citric acid industrial wastewater irrigation; saturated water ratio of the soil increased compared to tap water irrigation; organic matter content and the total nitrogen content increased significantly. All the changes indicated that the physicochemical properties and nutrition conditions of the saline-alkali soil were improved after the citric acid industrial wastewater irrigation. It can be concluded that citric acid industrial wastewater may be used as an effective enhancement agent of saline alkali soils, which achieves the goal of “waste treatment by waste”.

Based on the collected remote sensing and wave measurement data, this study investigated the interannual and seasonal evolution of the Boao tidal inlet, Hainan Province. The annual and seasonal longshore sediment transport was calculated based on CERC formula. The results show that on the time scale of inter-annually, the inlet throat is subject to a shrink due to the propagation of sand spits on its southern and northern sides. This decrease of inlet throat is interrupted by storm river discharge brought by typhoons during the wet season in the region. Based on the sand mass conservative law, the longshore sediment transport is inversely estimated. The magnitude of thus obtained sediment transport is similar to that based on CERC formula, although some discrepancy exists, which indicates the formula is adapted to Boao.

Using the empirical formula of TSUNOGAI et al, a preliminary study was made on the climatological distribution and seasonal variation of the sea surface pCO₂ and air-sea CO₂ flux in the East China Sea,and the influence of sea surface temperature, salinity, phosphate concentration and wind speed. The formula was based on environmental parameters ( sea surface temperature, salinity and phosphate concentration). The data used were from WOA09 ( monthly mean climatological sea surface temperature, salinity and phosphate concentration) ,Globalview ( atmospheric pCO₂ ) and NCEP ( monthly mean wind speed). The spatial distribution of the calculated pCO₂ maintains a gradually increasing trend from the northwest to the southeast while its magnitude varies significantly with seasons, lower in spring and winter, higher in summer and autumn. Space-time pattern of the CO₂ flux varies obviously, the continental shelf region as a whole is the convergence of CO₂ from atmosphere, while the Kuroshio region is the source. The convergence intensity gradually weakens from the northwest to the southeast and that of source strengthens from the north to the south. The East China Sea uptake CO₂ from atmosphere in spring and winter while release CO₂ to atmosphere in summer and autumn.
Analysis of seasonal change of the sea surface pCO₂ in the East China Sea shows that SST is its main controlling factor. They change in the same phase, reache the maximum in summer and minimum in winter. In the Kuroshio area, salinity and phosphate concentration remains stable all the year round, their seasonal variations could be neglected and the variation of pCO₂ is completely controlled by temperature. In the continental shelf area, the changes of salinity and phosphate concentration are contrary to that of temperature,but the magnitude is relatively low. The seasonal change of pCO₂ is still controlled by SST in most of the months except June,July and December,when the role of salinity and phosphate concentration tops that of SST.
For the East China Sea as a whole, the CO₂ flux changes with the wind speed from April to October, indicating that the wind speed is the leading role in the air-sea CO₂ exchange. During this period, the wind speed changes significantly due to monsoon conversion, which has great impacts on the CO₂ flux. From November to March, the CO₂ flux changes with sea surface pCO₂, when the wind speed remains high all along and pCO₂ varies significantly. In the continental shelf area, the surface pCO₂ remains lower than the atmosphere pressure all along,and the CO₂ flux is smaller than zero, its magnitude is closely related to the wing speed,and obviously high in winter except for a relatively high value in July associated with the strengthening of summer monsoon. The CO2 flux in the Kuroshio area is year-round positive and has a maximum in June-July and October-November respectively. The extreme value in June-July is closely related to summer monsoon enhancement,while that in October-November to the start of the winter monsoon and wind speed enhancement. It should be noted that though the wind speed is strong in winter, the CO₂ flux is not great because of comparatively low surface pCO₂. The variation of CO₂ flux in Kuroshio area is controlled by both wind speed and surface pCO₂.

Based on the Sea WiFS derived chlorophyll-a (Chl-a) mass concentration and TRMM sea-surface temperature data from September 1997 to February 2007 from the South China Sea (SCS), seasonal variations of Chl-a and its relationship with sea surface temperature (SST) were studied. The results show that the Chl-a mass concentration of the SCS has remarkable seasonal variability. Generally the lowest phytoplankton biomass (<0. 12 mg·m^-3) occurs in spring or summer with low wind speed and high SST (>28 °C), while the highest Chl-a (>0. 16 mg·m^-3) occurs in winter with the strongest monsoon wind and low SST (<27 °C). The linear regression analysis shows that Chl-a mass concentration has obvious negative correlations with SST. Though the correlations level is different for the 4 typical sub regions of the south, central, and west SCS and the northwest of the Luzon Strait, the consistent negative correlations imply that the Chl-a mass concentration and phytoplankton biomass are controlled by vertical stratification reflected by the temperature variation. The SST is a key factor influencing the upper ocean stability and the strength of vertical exchanges, and thus controlling the variations of nutrients and phytoplankton.

The chemical composition of underground water samples in the coast area of Laizhou Bay was analyzed. The results show that: (1)the correlative coefficient among Na⁺、Cl^-and TDS of the underground water reached significant level in seawater intrusion area in eastern and southern coasts of the Laizhou Bay, while that in the underground fresh water was much less. The correlative coefficient among K⁺、Ca²⁺、Mg²⁺、SO^2-₄ and TDS of the underground water in seawater intrusion area reached a high level; (2)according to the characteristics of ionic ratio, the degree of ion exchange of the groundwater in the seawater intrusion area of southern Laizhou Bay is generally higher than that in the eastern coast, and its history of desalination is also longer than that in the eastern coast; (3) relative error between the calculated values of TDS by using the data of electrical conductivity and the the measured values was vary small in the coast area of Laizhou Bay, so the electrical conductivity was suggested as a substitute indicator for TDS.

Based on EGM2008 gravity field model, together with multi-satellite altimetric data,including T/P,new T/P,Jason-l,new Jason-l,Jason-2,Geosat/GM, Geosat/ ERM,Envisat RA-2,ERS-1/ERM and ERS-2/ERM data,the along-track vertical deflections was obtained with the primary difference of two successive geoidal heights. Then according to the least square principle, the meridional component and prime vertical component of the vertical deflections gridded in 2'X2' for China seas and their vicinity(0°~42°N,102°~138°E) were determined. When computing the vertical deflection of the grid point with along track vertical deflections, discrete measurement points in the 4' X 4' region around the grid point were used. The normal equation was easy to be ill-conditioned because the determinant of ATPA is close to zero. In this paper the solution of the observation equation was obtained with the method of computing minimum norm invers. The result was compared with the data of EGM2008 model, the corresponding RMS of the difference is 0. 91” at meridian component and 0. 27”at prime vertical component, and compared with the data of EIGEN_ CG01C model, the corresponding RMS of the difference is 1. 98”at meridian and 2.54" at prime vertical. The vertical deflection data computed in this paper and the data of EGM2008 model were respectively compared with EIGEN_ CG01C model,and the comparison results were roughly the same. It shows that the calculated resulst and EGM2008 model are matched in accuracy. We also analyzed the points with lager error compared with the EGM2008 model, and mapped the distribution of the points with differences greater than 10” at meridian and 5” at prime vertical respectively. It is found that almost all points having lager error were located in the coastal waters or near the islands, this is because the altimeter echo signals were disturbed in the coastal waters and near the islands.

The REE geochemical characteristics bear much information about the provenance and sedimentary environment of natural gas hydrate. The REE contents and patterns of the sedimentary samples from stations SHW2 and SHW7 in Shenhu Area of the northern South China Sea were analyzed by ICP-MS. The results show that the average REE contents of samples from SHW2 and SHW7 are close to average REE content in upper continental crust. Analysis on LREE and HREE shows that there are significant fractionations in sediments. The REE patterns of two stations are similar. These characteristics are close to REE pattern in the upper continental crust and post-Archean Australian shale (PAAS). It indicates that sediments of the hydrate area inherit characteristics of their provenance, which are mainly from terrigenous rocks. The profile charts of REE parameters of stations SHW2 and SHW7 show that there is much positive correlation amoung EREE,LREE and HREE,and there is negative correlation between δCe and δEu. It can be inferred that the sedimentary provenances of the two stations have similarity.

Study on sea dikes breaching flood of the reclamation was carried out by means of numerical simulation in this thesis. The numerical model was based on the finite volume algorithm, which applied the HLI approximate Riemann solver to compute the numerical flux. A computational case study was presented of the flooding in a reclamation project of Zhejiang,where the flooded area and depth varying with time were obtained. The boundary condition of sea dikes breaching flow was taken by a constant water level, which is 20-year high tide level combined with the same frequency maximum wave height under the most unfavorable conditions. The model simulated the flooding in different locations of sea dikes failure successfully and the result shows that the submerged area and submerged depth rises quickly at the beginning of sea dikes breaching, and then the advance speed of flood tends to slow down,the average depth is followed by three stages of development: a slight decline, a dramatic rise and a small increase. The average depth for the south dike breaching flood is higher than that under the east dike-break case by 0.3~0.5 m at the same moment, so is the catastrophe and risk. The movement of flood caused by double breaching locations was further analysed. The flood spends only 60 minutes to overwhelm the reclamation, and the submerged depth rises to l.7 m after 4 hours. In the southeast, the convergence area between two sea dikes breaching flow, heavy personnel casualty will be caused, but the people in the rest area will have 15 minutes to escape the flood. In addition,the impact of roughness range from plus 15 per cent to minus 15 per cent on the flood was discussed. It is concluded that the differences between the maximum and minimum of average depth and submerged area reached 20 and 14 percent, respectively. This research will be of great practical significance to reduce the loss of sea dikes breaching accident as well as raise the management standard in the construction period and running period, which aims to provide the base of safety design and risk assessment of reclamation project.

An integrated model system that combines POM,a viscous sediment model and a water quality ecological model was applied to Changjiang River Estuary and its adjacent areas. The computational domain covered an area of 29°00'~33° 30' N, 120°00'~ 125°10' E with a mesh grid which has a finest horizontal resolution of 998 m and average of 2 789 m. In vertical, the grid was divided into 11 sigma layers. The model system was initialized and driven by averaged hydrometeorological conditions of the dry season from November to April. The runoff of the Changjiang Riveris given by the perennial average from December to April,with an average discharge of 15 200 m³/s and that for the Qiantang River was set as 925 m³/s. At the open boundary, eight tidal components were calculated, that is Q₁,O,P₁, K₁,N₂,M₂,S₂ and K₂ and the amplitudes and phase lags were interpolated from the results of OTPS. The sediment mass concentration from the upper stream of the Changjiang and Qiantang Riversis 0. 547 kg/m³ and 0. 2 kg/m³,respectively. The biochemical elements for the upper streams of the two rivers were DIN 100 imol/L,DIP 0.7 imol/L, detrital organic matter of N 1. 0 imol/L,detrital organic matter of P 0. 08 imol/L, phytoplankton N 1. 2 imol/L, zooplankton N 0. 4 imol/L, and dissolved oxygen 8. 62 mg/L. On the off-sea open boundary, all the scalar fields use the approach given by Thatcher-Harleman boundary conditions at the hypothesis that the scalar field values outside the domain all remain the initial set values, and the time lag is set as 2 h.
According to the observed data in March 2003,high DIN concentration occurred near the Changjiang Estuary and Hangzhou bay and the value near the surface is 65 imol/L while that of the bottom layer is a little bit higher with the highest value of 80 imol/L near the bottom. For the modeling result, the highest DIN concentration zone matches with the observation data only the value is greater than 50 imol/L at the surface. According to the observed data in March 2003,the highest surface DIP concentration is approximately 0. 8 imol/L and that at the bottom approaches 1 imol/L. In the modeling results, the high concentration zones of DIP are not only in the Changjiang River Estuary and Hangzhou bay,but also in other areas off the Zhejiang Province and DIP concentration near the surface is 0. 75 imol/L, a little bit lower than that near the bottom, which matches well with the observed data. Chlorophyll a is usually used to represent the phytoplankton. The observed data of chlorophyll a in March 2003 indicates that there's little difference between the mass concentration near surface and bottom while the highest chlorophyll a mass concentration zone is located to the north of Changjiang River Estuary and comparatively high mass concentration zone at the open sea near the Zhoushan Islands. According to the observed data in November 2002,the zone of highest chlorophyll a mass concentration near surface is located near 30°~31°N,123°E and the zone of highest chlorophyll a mass concentration near the surface is distinctly different from that near the bottom. The modeling result of chlorophyll a doesn't match with the observed data, which may be caused by the transparency of the seawater. Because chlorophyll a was measured with fluorescence method, it's affected badly by the suspended sediment. Comparisons above show that the modeling results match well with the distributions of temperature, salinity, suspended sediment, inorganic nitrogen and inorganic phosphorus both horizontally and vertically, which indicates that the model system has simulated the key processes of hydrodynamics, siltation and water quality ecology in the computational domain.
Finally,three numerical experiments were run to check the modeling response to the change of initial conditions, which led to some helpful conclusions. For example, the high concentration zone of chlorophyll a is in the Changjiang River Estuary with a much higher value if the impact of suspended sediment on the light intensity is not considered. This indicates the great suppression on the growth of phytoplankton by sediment. If only the imput of DIN and detrital organic matter of nitrogen from the two rivers into the area was decreased by 50%,the modeling results of phytoplankton distribution in the surface layer is almost the same as that from standard operation test. But if only the imput of DIP and detrital organic matter of phosphorus from the two rivers into the area was decreased by 50% while keep the DIN value in the standard operation test unchanged, the resulted peak chlorophyll a mass concentration changed little. These three numerical experiments indicate that during dry season, the nutrients of inorganic nitrogen and phosphorous in the Changjiang River Estuary and its adjacent area are surplus especially the former. Even half of the input of the terrigenous inorganic nutrients is still surplus. The factor that controls the growth of phytoplankton is not nutrients but the high mass concentration silt that has great impacts on the light intensity and thus on the growth of phytoplankton.

Based on the Krig gridding method, 4D space-time terrain models of Lingdingyang estuary were constructed for two years of 1990 and 2008 respectively. And then, the Lingyingyang estuary can be divided into 5 regions of Humen region, Qi’ao island region, Lingdingyang shallow shoal region, Lingding waterway region and marginal region of Tonggu waterway, the shoreline migration and scour-and-fill space-time alternation in all these five regions since 1975 were quantitatively analyzed, combining with ²¹⁰Pb dating method. It had found that the land area of whole region had increased 216. 0 km² ,the water area had decreased 84.6 km², and the tidal-flat area had decreased 131. 4 km²,the holding capacity of water area had reduced 19 783.7X10⁴ m³,the mean annual silting quantity had reached 477. 4 X 10⁴ m³,and the whole estuary was silting and atrophying constantly. The annual silting quantities of the 5 regions were-236.6X10⁴,135.3X10⁴, 663.7X10⁴,-452.7X10⁴ and 367.7X 10⁴ m³ respectively, while the mean silting velocity Were-4.46,0.93,1.27,-5.49 and 2.93 cm/a respectively. The total depths in Humen region and Lingding waterway region had increased while those in other regions had decreased. The silting extent in marginal region of Tonggu waterway was significant. The main reason of the increasing water depth in Humen region is natural degradation and manual sand digging while the deepening in Lingding waterway region is the result of artificial desilting. Tonggu waterway is a new digged artificial channel. Influenced by manual dredging mud, water depths at both sides of each channels decreased apparently. But the changes of water depths in other regions were the results of natural evolution of delta. With the fast development of economics at two sides of Lingdingyang estuary, the manual activity had been the main factor for the evolution of seafloor relief and landform in this region.

According to the high resolution pollen record in the Core SA09-040 which was taken in the low latitude of the South China Sea,four pollen zones have been divided in ascending order. Based on the pollen composition change, the vegetation evolution and climate change since 22. 25 Ka B P were reconstructed. The research result shows that the pollen mainly came from the Borneo and nearby islands. In Pollen zone 1(22. 25~16.6 Ka B P),the low mountain rainforest were luxuriant, the climate was warm to hot. Judged from the dating result, the age was the late stage of the Last glacial period. Pollen zone 2(16. 6~10. 82 Ka B P,the Last deglaciation) shows that the vegetation were mainly tropical low mountain rainforest and lowland rainforest. There were many conifer pines. The temperature was lower than that of now. Pollen zone 3(the early stage of Holocene, 10. 82~6. 43 Ka B P)shows that the vegetation were mainly tropical low mountain rainforest and lowland rainforest. The conifer pines were fewer than that in Pollen zone 2,the temperature was higher than before, the sea-level rose. Pollen zone 4(the middle or late Holocene, 6. 43Ka B P to now) shows that the middle stage of Holocene was hot and wet, and at the late stage of the Holocene, the vegetation in Borneo was similar to the environment of now. The climate was hot and wet.