It rains in Greenland

It rains in Greenland
It rains in Greenland
Anonim

On August 14, 2021, rain was observed at the highest point of the Greenland Ice Sheet for several hours, and the air temperature remained above freezing for about nine hours.

It was the third time in less than a decade and the last date in the year that temperatures above zero and sleet were observed at the National Science Foundation Summit station. Precipitation has not previously been reported at this location (72.58 ° N 38.46 ° W), which reaches a height of 3,216 meters (10,551 feet).

Earlier melting events in instrumental recording occurred in 1995, 2012, and 2019; prior to these events, ice cores have shown no melting since the event in the late 1800s. The reason for the melt, which occurred from 14 to 16 August 2021, was similar to the events that occurred in late July, when a strong center of low pressure over Baffin Island and high atmospheric pressure southeast of Greenland combined, pushing warm air and moisture quickly from the south. …

Large-scale surface melting and heavy rainfall along the southeast coast up to the Greenland Summit were observed on 14 and 15 August, while the area returned to a moderate level on 16 August.

The melting area peaked on August 14 at 872,000 square kilometers (337,000 sq mi), declining to 754,000 square kilometers on August 15 and 512,000 square kilometers (198,000 sq mi) on August 16. In 2012 and 2021 alone, more than one 800,000 square kilometers (309,000 square miles) melt occurred, and the August 14 event was the latest date on this magnitude in satellite records.

Temperatures exceeded freezing point at Summit Station around 07:00 UTC (5:00 am local time) on August 14, and it started to rain at the same time. For the next several hours, it rained and water droplets were visible on surfaces near the camp, as reported by observers at the station. At about 1400 UTC, thin flakes of ice crystals began to form on the surface of the snow as the rain froze into the snow.

The wind was 9.8 meters per second (22 miles per hour) from the southwest with a mixture of freezing and non-freezing rain. The temperature peaked at 48 degrees Celsius (33 degrees Fahrenheit) around 10:40 UTC and dropped below zero around 16:20 UTC. During the evening, the temperature dropped steadily. As the skies cleared late at night, the sudden cold snap caused temperatures to drop to -8.5 degrees Celsius (16.7 degrees Fahrenheit) early in the day on August 15. The temperature at the Summit did not reach a melting point either on 15 or 16 August.

The total surface melting area (gross melting area per day) for 2021 through August 16 is 21.3 million square kilometers (8.2 million square miles), the fourteenth largest to date and well above the 1981 average. 2010 - 18.6 million square kilometers (7.2 million square miles).

Freezing temperatures and precipitation were widespread in southern and western Greenland over a three-day period, with exceptional readings from several remote weather stations in the area. In total, 7 billion tons of precipitation fell on the ice sheet.

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