Annual rainfall
Sumatran orangutans live in lowland tropical rainforests, with precipitation normally between 1,680 mm and 4,070 mm annually. Western regions receive much more rain than those in the east, as prevailing winds from the Indonesian ocean are forced upwards, cooling rapidly and condensing water vapour, which then falls as precipitation.
Year: 2011
From collection: Orangutans and the Economics of Sustainable Forest Management in Sumatra
Cartographer: Riccardo Pravettoni, UNEP/GRID-Arendal