Author(s): Lennart Jonsson
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Keywords: No Keywords
Abstract: This paper describes the use of NOAA-AVHRR thermal data and different kinds of image processing techniques on a PC-based system as a means of obtaining unique information on large-scale flow patterns or flow processes in large water bodies such as large lakes or coastal seas. Three examples are discussed. The first example concerns the discharge pattern of Oresund water into the southern Kattegatt where differences in surface water temperature are used as a tracer for obtaining qualitative information on the transport of the Oresund water. The satellite derived data indicates a northbound, distinct coastal stream at times, the appearance of which is briefly discussed in relation to existing oxygen deficiency problems in the bottom layer of southern Kattegatt. The second example deals with a study of dynamics of the thermal bar-4 ~0C isotherm-in lake Ladoga during the heating-up period in spring/early summer. One environmental effect of the thermal bar is assumed to be that the horizontal water exchange is inhibited between nearshore and offshore waters. The satellite-derived evolution of this isotherm is in fairly good agreement with the results of a simple model. The third example will discuss a method using sequential satellite data and statistical techniques for tracking the movement of surface water temperature patterns as a measure of the large-scale surface velocity vectors in the southern Baltic. Some initial results will also be shown.
Year: 1993