共查询到20条相似文献，搜索用时 125 毫秒
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根据营养盐在多介质海洋环境，包括海水、浮游植物、浮游动物、悬浮颗粒和沉积物中分布动力学模型建立了胶州湾溶解无机氮（DIN）和磷酸盐（PO4-P）自净容量、环境容量和剩余环境容量的计算方法。结果表明，胶州湾营养盐自净容量夏季最大，冬季最小，春秋居中，这主要是海洋中物理、化学和生物自净过程共同作用的结果。胶州湾DIN剩余环境容量和PO4-P剩余环境容量在20世纪70年代末至80年代中期变化较小，相对一级海水水质标准下的环境容量还具有约60％的容纳能力。但自80年代中后期至90年代中后期，营养盐剩余环境容量迅速减小，其中至1997年DIN剩余环境容量已超过1级海水水质标准下环境容量的70％，而自90年代末开始DIN剩余环境容量又有所增加，而PO4-P剩余环境容量减小速度趋缓。胶州湾营养盐环境容量计算不仅可以深入了解海洋各种自净过程对特定海域容纳营养盐能力的作用，而且更为重要的是可以为排海营养盐总量控制方案的制定提供直接、科学和实用的理论基础和技术支撑。 相似文献
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沙子口湾海水环境容量初步研究 总被引：1，自引：0，他引：1
为了保护沙子口湾的海域生态环境 ,防止湾内水体的污染 ,必须对湾内水体的环境容量进行估价 ,也就是通过湾内水体纳污能力的研究 ,制定相应的对策和总量控制方案 ,有效地控制湾内的水质状况。目前 ,对“环境容量”的定义不一 ,笔者认为“环境容量”是指某一环境单元所允许承纳污染物质的最大负荷量。它是一个变量并包括两个组成部分 ,即基本环境容量 (或称差值容量 )和变动环境容量 (或称同化容量 )。前者可以通过拟定的环境标准减去环境本底值求得 ,后者是指该环境单元的自净能力。所谓海湾水体的环境容量是指泄入湾内水体中污染物质的总量… 相似文献
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大连湾海水交换及自净能力的研究 总被引：3，自引：0，他引：3
控制污染物入海,是当前国内外防治海域污染的重要途径。但如何把污染物的入海量控制的最经济、最合理,即如何以最小的经济代价,去换取最大的环境效益,就必须知道海域的环境容量,而环境容量的核心问题又是环境的自净能力问题。所以研究环境容量,必须首 相似文献
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基于GIS的近海剩余环境容量计算模型 总被引：1，自引：0，他引：1
探讨一种基于GIS 克里格插值方法的剩余环境容量计算方法, 通过GIS 地统计分析插值模型将水质模拟问题转化为数学统计问题, 充分利用水质水体、沉积物监测数据, 采用克里格插值法对污染物浓度和水深在局部海域内进行插值, 将研究区域离散为一个个的均匀栅格单元, 比较每个单元污染物浓度与水质目标之间的差值, 从而估算得到研究海域的剩余环境容量。通过2009 年8 月锦州湾剩余环境容量的计算实例表明, 基于GIS 的剩余环境容量初步计算方法在资料缺乏地区是十分简便、有效的, 这为海域开发利用区环境管理与规划提供了参考。 相似文献
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在前人研究的基础上提出了基于非线性规划的排海通量最优化法(简称非线性规划法),以进行海域内非保守物质环境容量计算,并选取莱州湾这个水动力较强、面积较大的半封闭海域进行模拟、计算。为更好地保护生态环境,对于氮(N)、磷(P)等非保守物质(以无机氮(DIN)、无机磷(DIP)为例进行分析),选取其月最高浓度场数据,依次计算出莱州湾海域每个月的营养盐响应系数场,并进一步使用非线性规划法求解出营养盐的月环境容量。最终计算结果显示,21世纪初莱州湾的营养盐环境容量为:在保持莱州湾DIP排放现状不变的前提下,其DIN年环境容量为21 843t/a,剩余年环境容量为-8 264t/a,需要减少点源DIN的排放量;而在保持莱州湾DIN排放现状不变的前提下,其DIP年环境容量为1 794t/a,剩余年环境容量达1 485t/a,可继续容纳部分DIP的排放。 相似文献
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大连湾海域环境容量与环境标准的初步研究 总被引：1，自引：0，他引：1
本文是在“大连湾环境污染及综合防治的研究”中,对大连湾海域的环境容量进行的研究,并提出了相应的以总量控制为内容的大连湾区域性排海标准。 一、环境容量的基本概念及数学模式 环境容量是指在某一环境标准下,环境所能容许的最大污染负荷量,它随环境自净能力 相似文献
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日前，福建省海洋与渔业局组织专家，对由海洋三所和厦门大学牵头，福建省水产研究所、福州市海洋环境监测站等单位参加完成的“福建罗源湾环境容量调查研究”和“福建泉州湾环境容量调查研究”项目进行了评审验收。 相似文献
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为了探究冰层侧向融化过程,定量分析影响冰层侧向融化的主导因素,在低温实验室水槽内实施了浮冰融化实验。同步测量了冰底面和表面生消过程、浮冰侧向融化过程,同时记录了实验室气温、冰样内部不同深度处的冰温及开阔水域不同深度处的水温,利用相关分析方法研究了不同要素之间的关系及其对浮冰侧向融化速率的影响规律。结果表明,融冰前期冰样内部不同深度处的侧向融化缓慢且均匀,平均融化速率为0.05 mm/h;融冰中后期不同深度处的侧向融化速率显著增加且不再均匀,平均融化速率为0.15 mm/h。平均侧向融化速率与气温的相关系数较好（r=0.82）,优于其与平均水温（r=0.74）和水–冰温度差（r=0.48）的相关系数。建立侧向融化速率随温度（气温、水温）和深度变化的定量关系,可以准确描述浮冰侧向融化过程的非均匀性。同时验证了进行非均匀性侧向融化试验技术的可行性,为更加接近北极真实情况考虑风速和光源条件的海冰试验奠定了基础。 相似文献
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Xin He Changrong Liang Yang Yang Guiying Chen Xiaodong Shang Xiaozhou He Penger Tong 《海洋学报(英文版)》2022,41(10):14-21
We report field measurements of vertical profiles of the turbulent diffusivity and temperature at different stations in the South China Sea (SCS). Our study shows that the measured turbulent diffusivity follows a power-law distribution with a varying exponent in water layers. Similar multiple-layer scaling regimes were also observed from the temperature fluctuations. Combining turbulent diffusivity and temperature fluctuations, the vertical structure of temperature was revealed. Furthermore, we discussed the temperature profiles in each layer. A constant function of a dimensionless temperature profile was found in water layers that have identical turbulence conditions. Our results reveal the multiple-layer structure of temperature in the SCS. This study contributes to the understanding of the vertical structure of multiple layers in the SCS and provides clues for exploring the physical mechanism for maintaining the temperature structure. 相似文献
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S.J. Harrison 《Estuarine, Coastal and Shelf Science》1985,20(4):477-490
Temperature observations made from a lightweight tower assembly in Chichester Harbour, West Sussex, demonstrate that marked changes in temperature at intertidal mud surfaces occur on a flow tide. The magnitude and direction of these changes are dependent on the external atmospheric and marine conditions, and on the timing of tidal inundation. Calculated heat exchange values for the 3h prior to high water fall into four distinct timing zones. There is a relationship between thermal stress, measured as rate of change of temperature with time, and time of high water. Mud surfaces are net receivers of heat energy from inundating water layers. 相似文献
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Every year, the during springtime heating conditions, the seasonal thermal frontal zone appears in Lake Ladoga. It features high horizontal water temperature gradients. The coastal waters, stably stratified in density, interact with the waters of the open lake that are unstably stratified because of the free convection developing in the temperature range between 0°C and the maximum density of the water at 4°C. In Lake Ladoga, the advance of the vernal frontal zone lasts about 7?C8 weeks from mid-May to the beginning of July. Both the water temperature and air temperature distributions over the water??s surface show that large spatial temperature ranges exist in the vernal front reaching more than 11°C. We investigated the spatial horizontal gradients of the water??s surface and the air temperature using a spatial grid with a resolution of 5 km. The surface water temperature and the air temperature gradients were compared with each other as well as with the temperatures in the region of varying depths. During the spring peak of the frontal activity in Lake Ladoga, most of the fronts feature mean temperatures greater than 4°C. This indicates that the thermal bar marks the offshore edge of the most extensive frontal zone. 相似文献
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From 1980 to 1995, in August, the bottom layer of Osaka Bay was occupied by cold, nutrient-rich water compared with that observed
during both previous and subsequent decades. To investigate the mechanisms for the intrusion of bottom-layer cold water into
Osaka Bay, the intrusion into Osaka Bay via the Kii Channel is simulated using a finite-volume coastal ocean model with unstructured
triangular cell grids. The initial conditions, boundary conditions, and surface temperature given to the model are obtained
from daily reanalysis data provided by the Japan Coastal Ocean Predictability Experiment. The model shows that cold water
uplifted on the eastern side of the Kii Peninsula is propagated westward at 1.0 m/s as a coastal boundary current; it reaches
the Kii Channel mouth when the Kuroshio axis is located around 74 km south of Cape Shionomisaki. However, the modeled cold
water mass at the Kii Channel mouth does not intrude further to the north of the Kii Channel; therefore, another mechanism
is required to explain the cold-water intrusion into the bottom layer of Osaka Bay. A plausible explanation is the estuarine
circulation established by the freshwater supply at the bay head. When the river runoff is included in the model without forced
vertical mixing, the temperature in Osaka Bay decreases 6.6 days later than the temperature decreases at the Kii Channel mouth.
Furthermore, the shoreward current speed in the bottom layer of the modeled estuarine circulation is 15 cm/s, which provides
the mechanism required for the cold water mass to pass the Kii Channel. 相似文献
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为促进海洋渔业经济的健康可持续发展，文章以连云港高公岛附近的紫菜养殖区为研究区域，利用海洋环境综合监测浮标实时监测水环境和气象数据，采用定性和定量相结合的方法，分析紫菜养殖区海域的水温、电导率、水压、溶解氧浓度、pH值、盐度、叶绿素浓度和浊度等水环境因子的统计和变化特征及其相关性，在此基础上分析气象条件对水环境因子的影响。研究结果表明：研究区域的水温和盐度适宜紫菜养殖，浊度属于强变异性；水温和电导率整体呈逐渐升高的趋势，溶解氧浓度和pH值呈逐渐降低的趋势，其他水环境因子呈波动状态；水压的变化与气压具有一致性，水体未受到溶解氧和酸碱污染；水温与电导率之间存在较强的正相关性，水温与溶解氧浓度和pH值之间存在较强的负相关性，pH值与叶绿素浓度和盐度之间存在较强的正相关性；气象条件对水环境因子存在一定的影响，海上大风导致水体浊度陡增。 相似文献
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L. J. Paul 《新西兰海洋与淡水研究杂志》2013,47(3):535-558
The changing pattern of water temperature in the Hauraki Gulf at approximately two‐monthly intervals during one and one‐half seasonal cycles in 1965–66 was determined from sea surface temperatures and bathythermograph profiles. Surface and bottom temperatures ranged from 22.0°c and 20.5°c respectively in March to 12.5°c and 13.0°c in July‐September. Seasonal temperature ranges and short‐term variations were greatest in the shallow south‐west Gulf. In winter the Gulf water was coolest close to shore. It was typically isothermal in depth but a temperature inversion of approximately l°c frequently formed, probably because of the combination of strong winds and an increased outflow of cool, low salinity water from harbours and bays. A similar inversion in Colville Channel may have been caused by more complex tidal and/or ocean current conditions. In spring and summer the Gulf became thermally stratified, with warmest temperatures in the shallow areas. Thermoclines were generally irregular in position and size, and probably represented solar heating and minor current boundaries rather than a distinct separation of major water masses. In late summer and autumn bottom temperatures increased and almost equalled the maximum surface temperature. During autumn surface water temperatures close to land decreased rapidly to return the Gulf to its winter isothermal condition. Local factors (wind, rainfall, tides, depth of water, and proximity to land) probably influence sea temperatures in the Gulf. Seawards of a line from Cape Rodney to Cape Colville oceanic conditions prevail; water temperatures are more constant and increase to seaward in both winter and summer. Oceanic and Gulf waters meet and mix in the Rodney‐Colville area, and Gulf water is transported east through Colville Channel. The extent of oceanic water penetration into the Gulf at depth is unknown. 相似文献
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Velda Lauringson Evely Mlton Jonne Kotta Külli Kangur Helen Orav-Kotta Ilmar Kotta 《Estuarine, Coastal and Shelf Science》2007,75(4):459-467
Invasive suspension feeders have been particularly successful in shallow eutrophic estuarine and freshwater ecosystems. The impact of an invasive species is strong under favourable conditions. However, suboptimal feeding conditions may significantly reduce the impact to ambient environment. The invasive bivalve Dreissena polymorpha (Pallas) is able to colonize both fresh and brackish waterbodies. In an in situ experiment the seasonal variability in the biodeposition of D. polymorpha from fresh and brackish water populations was quantified at different temperature, salinity and chlorophyll a (Chl a) regimes. Salinity fluctuations in brackish water areas, temperature and water Chl a content were all important factors in the model of mussels' feeding. The results indicated that D. polymorpha fed significantly more in fresh than in brackish water. Mussels acclimated more easily to acute transfer from brackish to freshwater than vice versa. The biodeposition of zebra mussels increased with temperature and water Chl a content but these effects were less straightforward than that of salinity. The results suggest that the impact of D. polymorpha on recipient ecosystem is more pronounced in fresh than in brackish water environments. 相似文献
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A one-dimensional numerical model with a level-2.5 turbulent closure scheme to provide vertical mixing coefficients has been
used to investigate the process by which the dichothermal water is formed in the Bering Sea, the density of which is about
26.6 sigma-theta. The water column to be simulated is assumed to move along a predetermined path. That is, the present model
is of the Lagrangian-type. Surface boundary conditions are given using the climatologies of heat, freshwater and momentum
fluxes. In order to obtain a plausible moving speed of the water column along the path, pre-liminary experiments were done
using the surface fluxes in the central part of the Bering Sea for the initial temperature and salinity profiles at the entrance
of the Sea. As a result, it was found that the temperature minimum layer, i.e., the dichothermal water with temperature similar
to the climatology at the exit of the Bering Sea, was formed after about two years of integration. Based on the result, the
movement speed of the water column along the path was set as 4.5 cm/s in the standard run. It was found that this model could
plausibly reproduce the subsurface temperature minimum layer. That is, the dichothermal water was formed in the winter mixed
layer process in the Bering Sea. The existence of the subsurface halocline (pycnocline) prohibited the deeper penetration
of the winter mixed layer, and therefore water with a temperature colder than that under the mixed layer was formed in the
mixed layer due to wintertime surface cooling. In the warming season this water remains as the subsurface temperature minimum
layer between the upper seasonal thermocline and the lower halocline.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献