Rains over Atacama desert
26 March 2015 13:30 UTC
On Thursday 26th March 2015, an unusual rain event brought almost an inch of precipitation to the Atacama, Antofagasta and Coquimbo regions.
04 May 2023
26 March 2015
By Hans Peter and Jose Prieto (EUMETSAT)
The rising air at the equator, generating the intertropical convergence zone, is replaced by low-level air from higher latitudes north and south of the equator. To complete the convection loop, in the regions around 25 degrees north and 25 degrees south of the equator, this cool and dry air descends back to the surface in areas called subtropical highs (in pressure charts). These are the desert belts, including the Sahara and the Atacama Desert on the west coast of South America.
On Thursday 26th March 2015, an unusual rain event brought almost an inch of precipitation to the Atacama, Antofagasta and Coquimbo regions. At least 10 fatalities resulted from the intense run-off on a ground of a very dry and impervious nature. The rain was in itself at a moderate rate for most parts of the world, but not for these desert areas.
Download animation, GOES-13, IR 10.7, 26 March 02:45 UTC - 27 March 23:45 UTC
Image Comparison
Figure 1: Comparison of the Natural Colour RGB channel and Infrared 10.8 on 26 March, 13:30 UTC
The imagery, in particular the Metop-A IR10.8 channel in the infrared at 13:30 UTC, indicates shallow precipitation in Antofagasta, and more developed with higher cloud towards Atacama. The latter cloud stayed for longer around that time over the same area, which resulted in persistent rain fed from the north west with humid air from the tropics. The GOES loop shows for a few hours that the convective activity was stationary over the Atacama region, and organised as a convergence line.
