Measuring surface currents in lakes with high spatial resolution thermal infrared imagery

Abstract

High spatial resolution thermal infrared satellite images acquired 38 minutes apart from Landsat ETM+ and ASTER were used to measure the surface currents and circulation in Lake Tahoe, California-Nevada, USA. Mean currents of 5-10 cm/s were measured, with maximum currents approaching 35 cm/s. The eastward transport of an upwelling surface jet was clearly apparent, with 15-30 cm/s currents. Three gyres were evident in the vector fields. The satellite image-derived surface currents and circulation patterns are consistent with surface drifter measurements acquired during a different period. These results modify the findings of an earlier study using 1.1 km AVHRR imagery, which concluded there were two counter-rotating gyres in the opposite sense to the two dominant large gyres measured in this study. The high spatial resolution and small time separation allow the surface currents and general circulation in lakes and coastal environments to be accurately quantified using the maximum cross-correlation method. Copyright 2005 by the American Geophysical Union.