Bathymetry of Alaskan arctic lakes: a key to resource inventory with remote-sensing methods

Abstract

Water depth is a major factor in predicting resources associated with tens-of-thousands of uninventoried Alaskan arctic lakes. Lakes were studied for physical, chemical, and biological resources related to water depth in 3 specific areas along a north/south transect extending from Pt. Barrow on the Arctic Ocean to the foothills of the Brooks Range. Side-Looking Airborne Radar (SLAR) imagery was acquired over the same study transect to investigate its application for determining lake depth. Ice thicknesses, necessary for the interpretation of depth contours from SLAR imagery, were measured along with other parameters in the study lakes throughout the winter 1978-79. This ice-thickness data and sequential SLAR images are used to illustrate a method of contouring water depths in arctic lakes. This is based on changes in intensity of SLAR signal return which define the zone at which ice cover contacts the bottom. This intensity is a function of physical and dielectric properties of the snow, ice, water, bottom substrates, and ice inclusions within these lakes. A computer program was developed to manipulate Landsat satellite digital data and compile a master file of lakes and their computer-calculated surface features (i.e. area, perimeter, crenulation, and centroid). The master file uniquely identifies each computer catalogued lake by latitude and longitude and stores the calculated features in a data base that can be retrieved for a specified geographic ABSTRACT area. Each lake record also provides storage space for resource data collected outside the computer generated data. The application of these remote-sensing tools and the knowledge of aquatic resources associated with bathymetry add to our ability for regional inventory, classification, and management of arctic lake resources.