Water level, areal extent and volume change of Lake Tanganyika, Lake Turkana, Lake Tonle Sap and Lake Constance: Multi-year time series from satellite altimetry and remote sensing

摘要

This dataset contains time series of the water level, the areal extent and the volume change of the four large lakes Tanganyika, Turkana, Tonle Sap and Constance. For each lake, the time series cover a time-span of many years at a variable temporal resolution between several days and approximately one month: Lake Tanganyika: October 1992 - February 2015 Lake Turkana: October 1992 - September 2017 Lake Tonle Sap: June 2002 - September 2017 Lake Constance: July 2002 - May 2016 The data are based on satellite observations. Lake levels have been estimated from multi-mission satellite altimetry within DGFI-TUM's Database for Hydrological Time Series of Inland Waters (DAHITI; Schwatke et al., 2015). The areal extent of the water bodies has been derived from optical remote sensing data (Landsat 7/8 images with land/water classification). The relation between water level, areal extent and water volume change has been analyzed for these four lakes in the frame of the related DFG-project WLDYN (Assessing the spatiotemporal dynamics of water volumes in large wetlands and lakes by combining remote sensing with macro-scale hydrological modelling; grant No. SE 1916/4-1). Except for Lake Constance, where the change in areal extent was not mensurable in Landsat images, a linear relationship between water level and areal extent was found for the lakes in this data set. Based on this linear relationship, the areal extent of the lakes Tanganyika, Turkana and Tonle Saphas been interpolated to unobserved epochs. Changed in water volume were subsequently computed from combining water level and areal extent via the so-called truncated pyramid approach.