Seasonal Variations A Lake Chad, West Africa story
Water
Wetlands
While the overall trend in this time series is a shrinking lake, the northern portion has some water in the later images, but it varies widely. Water levels there remained below the 1900–2010 mean and far below what it was in the 1960s.
The region has a short rainy season, and changes in rainfall amounts can greatly affect the water supply. About 90% of the rain falls from June to September, but the lake doesn’t rise until November. This is the natural lag time of water flowing through the Chari River system.
In this series of Landsat images from 2017–2018, the water rises through February and then tapers off slowly for several months. So the rise in water levels actually occurs during the dry season.
Water displays as dark blue, and wetlands are green. The brighter speckles are sand dune islands. Landsat will continue to provide information about Lake Chad’s changes, its infrared imaging capability accurately delineating land, water, and wetland.
Location
Oct. 16, 2017, Landsat 8 (path/row 185/50) — northern Lake Chad
Dec. 19, 2017, Landsat 8 (path/row 185/50) — northern Lake Chad
Jan. 4, 2018, Landsat 8 (path/row 185/50) — northern Lake Chad
Feb. 5, 2018, Landsat 8 (path/row 185/50) — northern Lake Chad
Apr. 10, 2018, Landsat 8 (path/row 185/50) — northern Lake Chad
June 13, 2018, Landsat 8 (path/row 185/50) — northern Lake Chad
July 15, 2018, Landsat 8 (path/row 185/50) — northern Lake Chad
Lake Chad, West Africa Additional Imagery & Stories
Water Level Fluctuations
Lake Chad’s lakebed is flat and shallow, so small changes in water level greatly affect its surface water area. During an average rainy season, the wa...