Science & Technology

Incredible Rare Peek at Patagonia in Winter

June 26, 2020

In southern South America, clouds typically rule the skies. However in June 2020, simply the suitable climate patterns have been in place to offer a uncommon, clear view of Patagonia in winter.

On June 26, when the Reasonable Decision Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite tv for pc acquired these photographs, skies have been clear over practically all of Patagonia, which spans greater than 1 million sq. kilometers of the continent’s southern finish. Snow cowl is seen from the western slopes of the Andes Mountains in Chile to the coastal lowlands in Argentina.

Based on René Darío Garreaud, a professor at the College of Chile, it’s uncommon to see such a widespread cloud-free space over Patagonia. “The final time that I noticed a very clear picture was in ,” he mentioned. At the moment, in the course of the Southern Hemisphere’s summer season, the nice and cozy seasonal temperatures meant snow and ice have been largely restricted to the backbone of the Andes and the Patagonian icefields.

The area is usually cloudy in satellite tv for pc imagery because of the year-round passage of storms. The southern tip of the continent dips right into a belt of prevailing westerly winds, alongside which high- and low-pressure techniques continually drift eastward. The terrain additionally enhances the area’s cloudiness: when winds encounter the Andes, moist air blowing in from the Pacific Ocean is compelled upward, the place it cools and condenses into clouds.

In June, the standard climate sample got here to a halt. A system of excessive stress settled in over the Drake Passage—the waterway simply south of the continent—and introduced clear skies to the broader area. The climate system stayed put for practically per week. The phenomenon is called a “blocking excessive,” aptly named as a result of it blocks the standard motion of air plenty. On this case, westerly winds have been compelled to take a detour.

On account of the blocking excessive, unusually chilly temperatures stretched from Patagonia all the best way to Paraguay and Bolivia. Cloud-free skies imply that warmth close to the land floor can extra simply escape to area, ensuing in cooler temperatures. As well as, the diverted westerly winds introduced chilly air from Antarctica and funneled it proper into southern Patagonia.

June 26, 2020

These chilly temperatures saved the Patagonian plateau in Argentina blanketed below snow that fell throughout a serious storm on June 23-24. Components of the southern Andes obtain plentiful precipitation annually, measuring greater than 500 centimeters (200 inches). It’s much less frequent, nonetheless, to see snowfall to this point east on an arid a part of the continent that receives lower than 30 centimeters (12 inches) of precipitation annually.

The bout of frigid air, nonetheless, was not sufficient to freeze the deep lakes east of the icefield (detailed picture). “Even in winter, floor air temperatures are usually above 0 levels C.,” Garreaud mentioned. “So the chilly occasion was intense, however not lengthy sufficient to freeze these lakes.” Left unfrozen, the lakes’ turquoise colour—a results of “glacial flour*”—contrasts much more with the encompassing white snow.

* Glacial flour is a superb powder of silt- and clay-sized particles {that a} glacier creates as its rock-laden ice scrapes over bedrock; normally flushed out in meltwater streams and causes water to look powdery grey; lakes and oceans that fill with glacier flour might develop a banded look; additionally referred to as rock flour. 

NASA Earth Observatory photographs by Lauren Dauphin, utilizing MODIS knowledge from NASA EOSDIS/LANCE and GIBS/Worldview.

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