Mapping changing shorelines in the Malombe and Chiuta lakes of Malawi—environmental effects of recent climatic variations

This study examines patterns of climate variability by mapping shoreline changes between 1973 and 2008 for two shallow lakes in Malawi, East Africa. Multi-temporal LANDSAT data covering eight different years within the period of investigation were utilised for lake-area mapping, using image classification techniques. The approach was verified using simple comparisons with local rainfall data and satellite altimetry data. Results indicated that the lake areas varied between the different years investigated and that, although the lakes were affected by the same climate-forcing mechanisms, the individual basin characteristics had a critical effect on their responses. The most likely drivers for the climate-related shoreline variations are the El Niño/Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), causing synchronous changes to the water levels in both lakes, albeit showing differences in climate signal amplification.

► Evidence of near-decadal climate variability driven by variations in ENSO/IOD events.
► Variable responses to similar climatic forcing factors due to basin morphology.
► Choice of climate proxies needs to take account basin characteristics.