Author(s): S. Frankenstein; G. Frankenstein
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Keywords: No Keywords
Abstract: Being able to forecast ice conditions in the Arctic Ocean and its surrounding basins is important when operating in the area during all but the summer months. Of special interest is the progression of new ice growth in the shallow shelf seas, since this is where most of the activity takes place. This progression has a large effect on the local climate and environment, creating conditions unique to arctic habitats. Satellites are a tool with which we can study ice conditions. During the fall, when new ice growth is at a maximum, it is necessary to make observations at wavelengths at which atmospheric water vapor is transparent. This is due to the presence of high cloud concentrations during these months. The SMMR, SSMI and the upcoming SAR, which will download data in real time, are passive response satellites that operate in the gigahertz frequency range. The most widely used frequencies to study sea ice are 37 and 18 GHz. At these frequencies, it is possible to distinguish open water from first-year and multi-year ice. To break these signals down into frazil/new ice and other categories, it is necessary to combine the satellite observations with heat flux calculations. To do this, weather data for the area of interest are needed. These are available globally on a nearly real-time basis. The only other information needed to approximate the heat flux is the water or ice surface temperature. If no such data exist, a reasonable estimate of the water temperature can be obtained from published monthly sea-surface charts, and surface ice temperatures determined from equations developed from studies on the relationships between air/water temperatures and the concurrent ice thickness. Combining the satellite data and the resulting heat flux calculations into a model, we thus can follow the growth of first-year ice into the open water in a given area. At present, this can only be done for historical data. With the advent of the SAR satellite, these estimates can be done in real time, thus providing an important tool for analyzing offshore operations in the arctic shelf seas.
Year: 1990