Water Occurrence Change Intensity (1984-2019)

The Water Occurrence Change Intensity layer shows where surface water occurrence increased, decreased or remained invariant between 1984 and 2019. Both the direction of change (i.e. increase, decrease or no change) and its intensity are documented.

Increases in water occurrence are shown in green and decreases are shown in red. Black areas are those areas where there is no significant change in the water occurrence during the 1984-2019 period. The intensity of the color represents the degree of change (as a percentage). For example, bright red areas show greater loss of water than light red areas. Some areas appear grey in the maps, these are locations where there is insufficient data to compute meaningful change statistics.

The occurrence change accommodates for variations in data acquisition over time (i.e. temporal deepness and frequency density of the satellite observations) in order to provide a consistent occurrence change measurement.

For more detail see: Jean-Francois Pekel, Andrew Cottam, Noel Gorelick, Alan S. Belward, High-resolution mapping of global surface water and its long-term changes. Nature 540, 418-422 (2016) [https://www.nature.com/articles/nature20584].