1) Coastal Ocean Processes (CoOP)Human activity profoundly afects the coastal ocean, and coastal waters, in turn, infuence the lives of the vast and increasing populations that live near them.A better understanding of this environment is imperative for reasons that range from navigation and defense needs to fisheries and weather forecasting.Toward this end, an interdisciplinar group of coastal ocean scientists has joined together to launch CoOP (Coastal Ocean Processes).We defie the coastal ocean as extending from the sur zone to the edge of the continental rise, an area generally ranging from 100 to 1000 kilometers wide and including large inland water bodies that exhibit similar processes.The coastal ocean provides a buffer between the land and the deep ocean.It is dynamcally distinct and often isolated from the rest of the ocean.It harbors a number of unique physical and meteorological processes that promote high biological productivity (Figure 1), active sedimentary processes, dynamic chemical transformations and intense air-sea interaction.Coastal ocean science has traditionally been undertaken by small groups of investigators from one or two disciplines.This approach has succeeded in studies of processes specific to a single discipline, such as tides, but has not built understanding of the complex processes that cut across traditional scientific divisions, such as toxic blooms or sediment dynamics.Although there wil always be a crucial role for small groups of investigators, we believe the time is right for large-scale, fully interdisciplinar approaches to the study of the coastal ocean.CoOP therefore encompasses biological, chemical and geological oceanographers as well as marine meteorologists and physical oceanographers.This group's goal (Ta.ble 1) is:to obtain a new level of quantitative understanding of the processes that dominate the transports, transformations and fates of biologically, chemically and geologically important matter on the continental margins.Understanding cross-margin transport is central to achieving this goal.It links processes at work near the coast to those operating over the shelf and farther offshore.the specific interdisciplinary objectives and approach.The CoOP steering committee wil then work with the scientist to refine the resulting plan to assure that it is well-defied, scientifically satisfying and appropriately interdisciplinary.FUrther, the steering committee wil interact with funding agencies to help coordinate and prioritize the scientific efforts. 2) Societal Implications of Coastal Ocean SciencePractical issues make a better understanding of the coastal ocean imperative.They include (Table 3):Anthropogenic Inputs: Humanty provides various chemical, biological and sedimentary inputs to the coastal ocean by such diverse means as sewage dumping, acid rain, agricultural land drainage and industrial wastes.At present, we know relatively little about the fates of these inputs and their net effect on the coastal ecosystem.Interdisciplinary studies of coastal ocean processes can greatly enhance this understanding and lead to reliable information for planning future activities.Mineral Exploitation: The United States relies on numerous offshore mineral sources, especially petroleum.Offshore drillng requires information for risk assessment, structural design, and reaction to spils.Society demands ever higher standards for this information, taxing our ability to predict spil trajectories and biological impacts.Improved knowledge of physical, chemical and geological ocean processes wil increase our abilty to assess these risks and to react wisely to emergencies.Navigation: Major world commerce routes cross the coastal ocean, and it is increasingly used for recreational boating.In both cases, safe, effective use of the ocean, as well as search and rescue operations, require a knowledge of sea state, over-the-water weather and currents.In addition, large vessels often require dredged channels, leading to problems in the disposal of spoils and the choice of channel routes to minimize silting.Improved knowledge of coastal meteorology, physical oceanography and sediment processes would help to improve safety and effciency.Recreation: In many localities, shore-based leisure use of the coastal ocean is an important source of revenue.Activities such as wildlife observation, sport fishing, v bathing ,and general sightseeing contribute to the attraction, yet all are sensitive to environmental quality.Understanding of the coastal ocean system can help to preserve and restore recreational resources.Defense Needs: With decreasing cold-war tensions, but increasing potential for third world conflicts, the United States Navy is increasingly concerned with operating in coastal waters.Issues such as submarine detection (acoustic and otherwise), amphibious operations, mine warfare, biofouling and atmospheric interference with weapon system operation have gained new emphasis.Better knowledge of coastal meteorology, physical oceanography, sedimentary processes and biological oceanography would help the Navy with these defense requirements.Fisheries: The coastal ocean provides a disproportionately large part of the world's fish catch.Effective fishery management requires understanding variations in fish stocks (both natural and anthropogenic) and maintaining a sustainable harvest.This is an extraordinarly diffcult problem, requiring better understanding of physical, chemical and biological variability in the coastal ocean in order to improve the predictive capabilities of fisheries managers.Coastal Meteorology: Humanity is affected by coastal meteorology through extreme storms, air pollution and localized patterns of fog, clouds and precipitation.Better prediction of these atmospheric conditions requires greater attention to air-sea interactions in the coastal ocean, a central focus of the CoOP effort.The Global Carbon Cycle: Although this is essentially a scientific issue, public concern over potential climate change has made it a policy issue as well.Because so much of the world ocean's primary productivity is concentrated in the coastal ocean, we should consider its role in removing carbon from the atmosphere.At present, we do not know with certainty whether the coastal ocean is even a net source or sink of carbon from the atmosphere.Better understanding of air-sea fluxes, biological production and carbon removal from coastal waters can help to reduce our uncertainties about the fate of carbon in the coastal zone.Coastal Hazards:' Flooding and erosion of coastal lands pose major problems.Siich events normally occur during severe storms (such as hurricanes), and a better understanding of coastal meteorology, surface-wave physics and sediment transport wil necessarily lead to to a better abilty to mitigate and predict such impacts.vi These considerations point to the need for a coordinated, interdisciplinary, basicscience effort in the coastal ocean.Most of the societal issues mentioned above would not be well-served by single-discipline approaches to the underlying science.Although the proposed CoOP program does not directly tackle the societal problems, it wil address the underlying scientific problems that must be understood and communicated to allow applied' scientists, engineers and managers to make informed practical decisions.We contend that a large part of our society's diffculty in dealing with coastal ocean problems stems from an insuffcient understanding of baSic processes.CoOP wil contribute significantly to the needed understanding, and wil thereby help to address societal issues concerning the coastal oceans.
Abstract : Areas critical to naval operations are the prediction and application of atmospheric refractivity gradients. This report describes the use of the evaporation duct over the ocean and a plan for obtaining information about the evaporation duct by space-borne sensors. There has been little research on the theory and modeling of lower atmospheric refractivity, particularly evaporation ducts over a nonhomogeneous ocean over the past five decades. Much is known about surface layer similarity theory and propagation model techniques, but little attention has been placed on the spatial variabilities in the turbulent propagation medium (such as the atmospheric surface layer) in regions of strategic Navy interest. These regions include the coastal shelf, Gulf Stream, marginal ice zone, and those places where sharp sea surface temperature fronts exist. For tomorrow's Navy, using remote sensing techniques to infer evaporative and tropospheric ducts are a requirement. Although research efforts on ducts must couple the tropospheric and surface layer components, this report summarizes the state of the art for the evaporative duct and assess the potential of new and future results on improving next generation naval warfare capabilities. Keywords: Sea surface temperature fronts; Evaporation ducting; Radar propagation; Marine atmospheres; Atmospheric refraction; Radar holes.
Estimates of any given flux (momentum, heat, or moisture) that use the full set of diabatic profile relations applicable to the marine atmospheric surface layer require an accurate representation of flux coefficients, diabatic parameters, roughness lengths, and mean values for all meteorological quantities. Calculation of the momentum flux, for example, requires that the stratification function include both temperature and humidity effects and that the solution to the equation set be based on full set iteration. We find that over warm water, particularly during cases of low humidity, the momentum flux and stratification estimates are very sensitive to the reported relative humidity. Similarly, we find that the ERS 1 radar cross section, when treated as a function of the wind stress (or momentum flux), varies significantly with relative humidity, particularly when surface temperatures are warm. This study suggests that any calibration/validation campaign using remote‐sensing observations, in particular the ERS 1 scatterometer, should utilize high‐quality ground truth relative humidity measurements in addition to the traditional suite of high‐quality wind and temperature gradient measurements.
Using aircraft radar instruments designed for sea surface wave measurements, we have obtained fetch‐limited directional wind wave spectra under steady off‐shore wind conditions. The results from these observations in different areas at different times show that, up to a fetch of 150 km, the dominant waves propagate at an angle to the wind. The angle is near to that suggested by the Phillips resonance wind wave generation condition, but with one important difference: The waves are not always symmetric to the left and right of the wind. Most of the cases show the eventual dominance of one side lobe. The asymmetry of the wave direction relative to the wind suggests that the surface wind stress vector may not always be parallel to the mean wind direction.
Atmospheric mercury depletion episodes (AMDEs) were studied at Station Nord, Northeast Greenland, 81°36' N, 16°40' W, during the Arctic Spring. Gaseous elemental mercury (GEM) and ozone were measured starting from 1998 and 1999, respectively, until August 2002. GEM was measured with a TEKRAN 2735A automatic mercury analyzer based on preconcentration of mercury on a gold trap followed by detection using fluorescence spectroscopy. Ozone was measured by UV absorption. A scatter plot of GEM and ozone concentrations confirmed that also at Station Nord GEM and ozone are linearly correlated during AMDEs. The relationship between ozone and GEM is further investigated in this paper using basic reaction kinetics (i.e., Cl, ClO, Br, and BrO have been suggested as reactants for GEM). The analyses in this paper show that GEM in the Arctic troposphere most probably reacts with Br. On the basis of the experimental results of this paper and results from the literature, a simple parametrization for AMDE was included into the Danish Eulerian Hemispheric Model (DEHM). In the model, GEM is converted linearly to reactive gaseous mercury (RGM) over sea ice with temperature below −4 °C with a lifetime of 3 or 10 h. The new AMDE parametrization was used together with the general parametrization of mercury chemistry [Petersen, G.; Munthe, J.; Pleijel, K.; Bloxam, R.; Vinod Kumar, A. Atmos. Environ. 1998, 32, 829−843]. The obtained model results were compared with measurements of GEM at Station Nord. There was good agreement between the start and general features periods with AMDEs, although the model could not reproduce the fast concentration changes, and the correlation between modeled and measured values decreased from 2000 to 2001 and further in 2002. The modeled RGM concentrations over the Arctic in 2000 were found to agree well with the temporal and geographical variability of the boundary column of monthly average BrO observed by the GOME satellite. Scenario calculations were performed with and without AMDEs. For the area north of the Polar Circle, the mercury deposition increases from 89 tons/year for calculations without an AMDE to 208 tons/year with the AMDE. The 208 tons/year represent an upper limit for the mercury load to the Arctic.
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