TIME-SERIES REMOTE-SENSING OF A CLIMATICALLY SENSITIVE LAKE

The importance of remote sensing of lake area and level changes for climate research, particularly for closed lakes in semiarid regions, is noted, and the initial need for simultaneous measurement of level and area is discussed. The European Space Agency's ERS-1 satellite is uniquely suited to the latter task, carrying a radar altimeter and the Along-Track Scanning Radiometer (ATSR), the latter providing regular global repeat coverage ad 1 km resolution for the first time. The accuracy of two area measurement algorithms are assessed using simulated coarse resolution (approximate to 1 km) data for a semiarid closed lake, and one of them is shown to be capable of retrieving an area of 133 km(2) to 1%. Results are presented using data from the Advanced Very High Resolution Radiometer (AVHRR) instrument (similar to ATSR), showing the measured area of a small (approximate to 140 km(2)) climatically sensitive lake over a 5-year period, that display significant interannual variability that can be correlated with climate. In addition, it is shown that the sensitivity of a closed lake to changes in catchment basin precipitation is increased if its inflow is derived from the outflow of an open lake.