1 March 2017

WMO verifies highest temperatures for Antarctic Region

Posted by llipuma

Workers setting up and calibrating a weather station on Antarctica. A committee of experts has just announced new records for the highest temperatures recorded in the Antarctic Region.
Credit: WMO.

By Clare Nullis

A World Meteorological Organization (WMO) committee of experts has announced new records for the highest temperatures recorded in the Antarctic Region as part of continuing efforts to expand a database of extreme weather and climate conditions throughout the world.

Knowledge and verification of such extremes is important in the study of weather patterns, naturally occurring climate variability and human-induced climate change at global and regional scales, according to WMO.

“The Antarctic and the Arctic are poorly covered in terms of weather observations and forecasts, even though both play an important role in driving climate and ocean patterns and in sea level rise,” said Michael Sparrow, a polar expert with the WMO co-sponsored World Climate Research Program. “Verification of maximum and minimum temperatures help us to build up a picture of the weather and climate in one of Earth’s final frontiers.”

The committee announced today that the highest temperature for the “Antarctica Region,” defined by the WMO and United Nations as all land and ice south of 60°S, was 19.8 degrees Celsius (67.6 degrees Fahrenheit), observed on January 30, 1982 at Signy Research Station on Signy Island.

The highest temperature for the “Antarctic continent,” defined as the main continental landmass and adjoining islands, was 17.5 degrees C (63.5 degrees Fahrenheit), recorded on March 24, 2015 at the Esperanza Research Base located near the northern tip of the Antarctic Peninsula.

The highest temperature for the Antarctic Plateau, at or above 2,500 meters (8,200 feet), was minus 7.0 degrees Celsius (19.4 degrees Fahrenheit), observed on December 28, 1980 at an Automatic Weather Station (AWS) site located inland of the Adélie Coast.

A map of Antarctica showing the three research stations that observed the highest recorded Antarctic temperatures.
Credit: WMO.

The lowest temperature yet recorded by ground measurements for the Antarctic Region, and for the whole world, was minus 89.2 degrees Celsius (minus 128.6 degrees Fahrenheit) at Vostok Station on July 21, 1983.

Spanning 14 million square kilometers (5.4 million square miles) – roughly twice the size of Australia – the Antarctic is cold, windy and dry. The average annual temperature ranges from about minus 10 degrees Celsius (14 degrees Fahrenheit) on the Antarctic coast to minus 60 degrees Celsius (minus 76 degrees Fahrenheit) at the highest parts of the interior. Its immense ice sheet is up to 4.8 kilometers (3 miles) thick and contains 90 percent of Earth’s fresh water, enough to raise sea level by around 60 meters (200 feet), were it all to melt. The Antarctic Peninsula (the northwest tip near to South America) is among the fastest warming regions of the planet, having warmed almost 3 degrees Celsius (5.4 degrees Fahrenheit) over the last 50 years. Some 87 percent of glaciers along the west coast of the Antarctic Peninsula have retreated in the last 50 years with most of these showing accelerated retreat in the last 12 years.

A composite image of three Antarctic research stations: Signy Research Station in 1969 (A), Esperanza Station in 2016 (B), and AWS D-80 in 1993 (C).
Credit: WMO.

WMO’s Commission for Climatology maintains an Archive of Weather and Climate Extremes. This includes the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, longest lightning flash and highest significant wave height.

It is possible, indeed likely, that greater extremes than reported here can and have occurred in the Antarctic Region, according to WMO. As with all WMO evaluations, the extremes are identified based on only those events with available high-quality ground-based data.

Verifying these three Antarctic extremes helps increase understanding of the Antarctic’s normal temperature ranges, specifically at the coast and on the plateau. The committee noted that the records at all three stations occurred during an influx of warm air.

The WMO investigations also serve to improve the quality of observations through the careful analysis of observation practices and proper equipment selection.

In an effort to increase weather forecasting and environmental prediction capability in the Antarctic and Arctic, WMO is one of the organizers of the Year of Polar Prediction from mid-2017 to mid-2019 – a concerted effort to increase and improve research, observing and modeling capabilities in the poles.

“This investigation highlights the need to continually monitor all of the Antarctic Region is ensure that we have the best possible data for climate change analysis at both the regional and global scales,” said Randall Cerveny, chief Rapporteur of Climate and Weather Extremes for WMO.

— Clare Nullis is a media officer at the World Meteorological Organization. This post originally appeared as a press release on the WMO website. Full details of the assessment are published in a feature article on Eos.org.