Hydrologists show environmental damage from fog reduction is observable from outer space

#Changements climatiques, #Afrique

Publié le 10 juin 2020

It’s now possible to use satellite data to measure the threat of climate change to ecological systems that depend on water from fog, according to a newly-published study.

The paper, in the AGU journal Geophysical Research Letters, presents the first clear evidence that the relationship between fog levels and vegetation status is measurable using remote sensing. The discovery opens up the potential to easily and rapidly assess fog’s impact on ecological health across large land masses — as compared to painstaking ground-level observation.

“It’s never been shown before that you can observe the effect of fog on vegetation from outer space,” said Lixin Wang, an associate professor in the School of Science at Indiana University-Purdue University Indianapolis (IUPUI), who is the senior author on the study. “The ability to use the satellite data for this purpose is a major technological advance.”

Two satellite images show vegetation change from fog in two areas of the Namib desert. The left image shows the areas during periods of lower fog; the right image shows the areas during periods of higher fog. Greener areas inside the squares indicate vegetation greening. Image courtesy of Lixin Wang, Indiana University.

The need to understand the relationship between fog and vegetation is urgent since environmental change is reducing fog levels across the globe. The shift most strongly affects regions that depend upon fog as a major source of water, including the redwood forests in California, the Atacama desert in Chile and the Namib desert in Namibia, with the latter two currently recognized as World Heritage sites under the United Nations due to their ecological rarity.

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