To determine the relative contributions of local atmospheric forcing and advective transport to the evolution of Long Island Sound density stratification and thus to the evolution of Long Island Sound hypoxia events. |
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| The schematic above illustrates the processes involved in determining the temperature of the ocean surface. At the air-sea interface, these mainly include heat transfer due to solar radiation, infrared radiation, evaporation and conduction. Contributing processes in the ocean include advection of warm/cool water due to currents and vertcal mixing between warmer (i.e. lighter) water in the upper portion of the water column and cooler (i.e. heavy) water in the lower portion of the water column. The numbers for the atmospheric processes above are in Watts per meter squared and are based on globally averaged values. For any given region (such as the Long Island Sound), time of day, season, and current weather condition, the contribution from each of the above processes will vary. During the summer months, surface heating processes in the Long Island Sound generally outweigh the cooling processes. This results in the development of vertical stratification, whereby warm (light) water develops and rests over cooler (heavy) water. Since strong wind events, which typically drive vertical mixing in the ocean and thus surface cooling, are rare in the summer, oxygen in the surface layers of the ocean is unable to mix downward and reach the bottom layers of the water column. This condition can result in the development of hypoxia (i.e. low oxygen). At present there is still significant uncertainty regarding the relative roles that the above atmospheric and ocean processes play in determining the development, evolution and breakdown of stratification in the Long Island Sound. Measurements obtained by this project will enable a more comphrensive examination of this question. |
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