Sea salt aerosol (SSA) exerts a major influence over a broad reach of geophysics. It is important to the physics and chemistry of the marine atmosphere and to marine geochemistry and biogeochemistry generally. It affects visibility, remote sensing, atmospheric chemistry, and air quality. Sea salt aerosol particles interact with other atmospheric gaseous and aerosol constituents by acting as sinks for condensable gases and suppressing new particle formation, thus influencing the size distribution of these other aerosols and more broadly influencing the geochemical cycles of substances with which they interact. As the key aerosol constituent over much of Earth's surface at present, and all the more so in pre-industrial times, SSA is central to description of Earth's aerosol burden.

Sea Salt Aerosol Production: Mechanisms, Methods, Measurements, and Models - A Critical Review

Application of fuzzy inference system in the prediction of wave parameters

In this study, we report on the ability of four one-dimensional lake models to simulate the water temperature profiles of Lake Geneva, the largest water body in Western Europe, over a 10-yr period from 1996 to 2005, using lake models driven by a common atmospheric forcing. These lake models have already demonstrated their capability of reproducing the temperature distribution in smaller lakes and include one eddy-diffusive lake model, the Hostetler model; a Lagrangian model, the one-dimensional Dynamic Reservoir Simulation Model "DYRESM" a к - e turbulence model, "SIMSTRAT"; and one based on the concept of self-similarity (assumed shape) of the temperature-depth curve, the Freshwater Lake model "FLake." Only DYRESM and SIMSTRAT reproduce the variability of the water temperature profiles and seasonal thermocline satisfactorily. In layers in which thermocline variability is greatest, the temperature root mean square error is ≪2°C and 3°C (at the time of highest stratification) for these models, respectively. It is possible to apply certain one-dimensional lake models that simulate the behavior of temperature to investigate the potential future warming of the water column in Lake Geneva. Importantly, the metalimnion boundary is successfully modeled, which represents an encouraging step toward demonstrating the feasibility of coupling biogeochemical modules, such as, for example, a phytoplanktonic model, to assess the possible biological responses within lakes to climate change.

/pdf/simulation-of-multiannual-thermal-profiles-in-deep-lake-2lbrojq9ya.pdf

Simulation of multiannual thermal profiles in deep Lake Geneva: a comparison of one-dimensional lake models.

Seagrasses of south–west Australia: A conceptual synthesis of the world's most diverse and extensive seagrass meadows

The dissolution of gypsum or plaster of Paris has been widely used as an inexpensive integral measure of ‘water motion’ in the field and in laboratory tanks for studies of physical‐biological interactions. Commonly, gypsumdissolution rates have been calibrated to steady flow speed or velocity in the laboratory and the calibrations have been applied to dissolution (i.e., mass-transfer) rates in the field or in tanks. We evaluated the gypsum-dissolution technique in a steady-flow, a fluctuating-flow, and a mixed-flow environment by comparing dissolution rate to direct flow measurements with an acoustic Doppler velocimeter. We found that dissolution rates were related to steady flow and to fluctuation intensity in the exclusively steady-flow and fluctuating-flow environments, respectively. The relationships were weak in the mixed-flow environment. Finally, dissolution and thus mass-transfer relationships were different in each flow environment, and the effects of steady flow and fluctuation intensity were not additive. Providing that it is rigorously checked and appropriately calibrated, the dissolution technique can be used to measure steady flow speed or fluctuation intensity in a steady-flow or fluctuating-flow environment, respectively. However, comparisons of dissolution rates between steady-flow, fluctuating-flow, and mixed-flow environments or within environments that change over time to determine water motion will be misleading. The gypsum-dissolution technique can be used as a good direct indicator of mass-transfer rates. However, mass-transfer rates are different in different flow environments. The gypsum-dissolution technique is not a universal integrator of ‘water motion.’ The dissolution of gypsum or gypsum-based plaster of Paris from ‘‘plaster balls’’ or ‘‘clod cards’’ was first introduced by Muus (1968) and Doty (1971) as an inexpensive technique to measure water flow in the absence of expensive field instrumentation for direct measurements of water velocity. Effects of temperature, salinity, and water volume on

/pdf/gypsum-dissolution-is-not-a-universal-integrator-of-water-af5qa92otv.pdf

Gypsum dissolution is not a universal integrator of ‘water motion’

Three recently measured wind and wave data sets in the northern part of Chesapeake Bay (CB) are presented. Two of the three data sets were collected in late 1995. The third one was collected in July of 1998. The analyzed wind and wave data show that waves were dominated by locally generated, fetch limited young wind seas. Significant wave heights were highly correlated to the local driving wind speeds and the response time of the waves to the winds was about 1 h. We also tested two very different numerical wave models, Simulation of WAves Nearshore (SWAN) and Great Lakes Environmental Research Laboratory (GLERL), to hind-cast the wave conditions against the data sets. Time series model–data comparisons made using SWAN and GLERL showed that both models behaved well in response to a suddenly changing wind. In general, both SWAN and GLERL over-predicted significant wave height; SWAN over-predicted more than GLERL did. SWAN had a larger scatter index and a smaller correlation coefficient for wave height than GLERL had. In addition, both models slightly under-predicted the peak period with a fairly large scatter and low correlation coefficient. SWAN predicted mean wave direction better than GLERL did. Directional wave spectral comparisons between SWAN predictions and the data support these statistical comparisons. The GLERL model was much more computationally efficient for wind wave forecasts in CB. SWAN and GLERL predicted different wave height field distributions for the same winds in deeper water areas of the Bay where data were not available, however. These differences are as yet unresolved.

Wave measurement and modeling in Chesapeake Bay

Air‐sea fluxes of momentum and heat were measured simultaneously with surface wind waves and nearsurface currents in mid Chesapeake Bay during summer 1998 under low wind conditions. The data were collected using a Gill sonic anemometer and a Sontek Acoustic Doppler Velocimeter with a pressure sensor mounted on a temporary fixed tower in 8.8 m of water. The analyzed data show that the neutral drag coefficients depend upon both wind speed and wave age. They are better correlated to wave age than to wind speed. Data scatter is significantly larger in low winds than in high winds. Under light winds, the neutral drag coefficients increase with decreasing wind speed and have values much higher than those for relatively higher wind speeds. At higher wind speeds, neutral drag coefficients increase with increasing wind speed. Regardless of wind speed, neutral drag coefficients always decrease with increasing wave age. Neutral drag coefficients are lower than the results of similar field studies when fit to wind speed alone, but they statistically agree with other studies if they are fit to wave age. The momentum transfer mechanism is investigated using a parametric wave model with a seastate-dependent form drag and a reference system moving with the waves. The relationship between modeled drag coefficient and modeled wave age agrees well with the relationship derived from the data.

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0485%282002%29032%3C3058%3ADCWFLW%3E2.0.CO%3B2

Drag Coefficients with Fetch-Limited Wind Waves*

Surface Wind Wave Modeling in Chesapeake Bay

: Surface wind waves play an important role in the air-sea transfer of momentum, mass and heat. Several field experiments reported that wave age, C/u. (Cp is the wave phase velocity at spectral peak), is an important parameter for determining air-sea drag coefficient, Cd, or surface roughness length, Zg (Donelan 1990; Geemaert et al. 1987; Smith et al. 1992; Lin 2000; Lin et al. 2002). Other theoretical or modeling studies (Janssen 1989,1991) also suggested that wave age is a controlling factor for determining Zg. Wave breaking generates air bubbles and significantly enhances gas transfer over water surface (Loewen 2002). Most recently, Deane and Stokes (2002) found that the size distribution of the entrained bubbles is critical to the way that air and sea interacts.

Weiqi Lin

Papers

Wave measurement and modeling in Chesapeake Bay

Drag Coefficients with Fetch-Limited Wind Waves*

Surface Wind Wave Modeling in Chesapeake Bay

Coupling GLERL with RAMS to Study Surface Wind Wave Effects on Air-Sea Fluxes in Chesapeake Bay