A New Global Lakes Database for a Remote Sensing Program Studying Climatically Sensitive Large Lakes

Abstract

World wide climate related programs have called for hydrological studies to be put into a more global perspective, and yet the global study of large climatically sensitive lakes has been neglected. A remote sensing program at the Mullard Space Science Laboratory (MSSL) aims to monitor short and medium-term lake volume changes and interpret them in terms of aridity variations, as a measure of regional climate change. The program thus requires the global identification of all potentially closed and climatically sensitive lakes. We review the availability of current global lake (particularly closed lake) information and note its limitations with respect to the requirements of the large lakes study. As a result of this the MSSL Global Lakes Database (MGLD) has been constructed containing locational and lake type information for over 1,400 inland water bodies including, as far as possible, all lakes and reservoirs (but not lagoons), with surface areas ≥ 100km2 (approximately). Of these, the database identifies 857 open lakes (those with outflows), 226 reservoirs, and 320 potentially closed lakes. Approximate areas of the lakes are also noted. The identification of the closed lakes (59% on the Asian continent) is a cornerstone of the remote sensing program which aims to derive lake levels and lake areas using satellite radar altimeters and satellite imaging radiometers respectively. The MGLD therefore also notes the spatial coverage of all large lakes by past and current radar altimeters including that on ERS-1, which overflies almost half of the lakes. With the addition of referenced closed-lake information the MGLD is thus a unique data set which has already been applied to several remote sensing projects.