NASA Study Improves Forecasts of Summer Arctic Sea Ice
March 3, 2017
The Arctic has been losing sea ice over the past several decades as Earth warms. However, each year, as the sea ice starts to melt in the spring following its maximum wintertime extent, scientists still struggle to estimate exactly how much ice they expect will disappear through the melt season. Now, a new NASA forecasting model based on satellite measurements is allowing researchers to make better estimates.
Sea ice plays an important role in maintaining Earths temperature, so predicting how the ice extent might change helps us understand the warming climate. Scientists have developed a new model to predict the sea ice minimum extent Credits: NASA's Goddard Space Flight Center/Kathryn Mersmann This video is public domain and can be downloaded from the Scientific Visualization Studio. http://svs.gsfc.nasa.gov/12519
Forecasts of how much Arctic sea ice will shrink from spring into fall is valuable information for such communities as shipping companies and native people that depend on sea ice for hunting. Many animal and plant species are impacted directly by changes in the coverage of sea ice across the Arctic. Uncertain weather conditions through spring and summer make the forecasting of Arctic sea ice for a given year extremely challenging.
Small remnants of thicker ice that has survived the summer float among newly formed, thinner ice in this image taken in the Beaufort Sea on Sept. 30, 2016, past the end of the melt season in the Arctic. Credits: Alek Petty/NASA's Goddard Space Flight Center
With data from satellites, which have been measuring sea ice in the Arctic since 1979, scientists can easily calculate the downward trend in Arctic sea ice. To make forecasts of how the Arctic sea ice cover might behave in the upcoming year, researchers have several options. The simplest approach is to assume a continuation of the long-term trend into the current year. The problem with this approach is that it will miss outliers -- years when the sea ice cover will be a lot higher or lower than expected. Another option is to analyze the physical characteristics of the sea ice cover as the melt season develops, to try to more precisely estimate if the amount of sea ice come September will be more or less than expected from the long-term trend.
A Canadian Coast Guard icebreaker travels through the Beaufort Sea ice pack in September 2016. Credits: Alek Petty/NASA's Goddard Space Flight Center
“What we have shown is that we can use information collected in the spring and onwards to determine if we should see more or less ice come the end of summer than expected from the long-term decline,” said Alek Petty, lead author of the new paper, which was published on February 27 in the journal Earth’s Future, and a sea ice researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The study used satellite measurements of sea ice coverage and melt onset. Petty’s team found that the forecasts based on melt onset -- the time at which sea ice starts to melt and open water appears in the Arctic Ocean -- were most reliable in early spring, while sea ice coverage-based predictions were more reliable from June onwards. The forecasts focus specifically on regions that historically corresponded with how much sea ice remains come the September minimum extent. The predictions become more accurate with each passing month, as the model integrates more near-real-time information about sea ice melt and the distribution of open water areas across the Arctic Ocean and surrounding seas
To test whether their model produced reliable forecasts, Petty’s team went back in time and made predictions for each year of the satellite record, using historical data of the Arctic sea ice conditions. They then evaluated the results against both the actual minimum extent for that year and what the long-term trend would have predicted.
“We found that our forecast model does much better than the linear trend at capturing what actually happened to the sea ice in any specific year,” Petty said. “Our model is very good at catching the highs and the lows. The absolute values? Not exactly, but it tends to do very well at seeing when the sea ice extent is going to go up and when it’s going to go down compared to what we might be expecting for that year.”
Petty’s research also showed that models can produce reliable forecasts of sea ice not only for the whole Arctic, but for concrete regions; specifically, the Beaufort and Chukchi seas north of Alaska.
“The state of sea ice has a large impact on the Alaskan hunting communities,” Petty said. “If they know ahead of time what the sea ice cover is going to be like that year, they might be able to infer the availability of the species they hunt.”
Future research will explore synthesizing different sea ice measurements into the same model to improve the reliability of the forecasts, Petty said.
For more information, visit:
www.nasa.gov/content/water-and-ice
Maria-Jose Viñas
NASA's Earth Science News Team Last Updated: March 3, 2017 Editor: Karl Hille
Aurora Australis to examine ‘super-cooled’ clouds as research season begins
"Antarctic sea ice used to be the darling of climate doubters. Not anymore."
Aurora Australis will examine 'super-cooled' clouds as research season begins. Photo: ABC
Rebecca Hewitt and Emile Gramenz
Researchers will turn their eyes to the low-level clouds that form over Antarctica this summer, with the help of state-of-the-art equipment provided by the US Department of Energy.
The equipment, worth $14 million, will allow atmospheric scientists to better understand the “super-cooled” clouds that form over the Southern Ocean.
Along with 105 expeditioners the equipment — weighing seven tonnes — is being taken to Davis Station on the icebreaker Aurora Australia’s first voyage of the season.
“Clouds are one of the biggest uncertainties in the Earth’s climate system and the area where there’s most uncertainty is the Southern Ocean,” atmospheric scientist Simon Alexander said.
“We have satellites to look down on the clouds from space but it’s very difficult for the satellite to see low-level cloud.
Two of the four helicoptors on the Aurora Australis. Photo: ABC
“In the Southern Ocean most of the cloud is low-level, so we need to look up at them from the surface.”
To that end, a US research plane will join the project in January and February, flying through the clouds to take measurements from above.
“At the same time we’ll be taking measurements from the ship and from Macquarie Island, so we’ll get a complete understanding of these clouds,” Dr Alexander said.
The data will help improve climate modelling and ultimately weather forecasting in southern Australia.
The ship’s deck was reinforced and the equipment bolted on to withstand the ferocious conditions often found in the Southern Ocean.
About 500 expeditioners will travel to Antarctica this summer, with a handful staying on over winter.
Australian Antarctic Division’s Acting Director Charlton Clark said this year there were 92 projects planned, including ice core sampling 300 kilometres south of Davis Station, and another looking at the breeding and feeding patterns of Adelie penguins.
The Aurora Australis will make four trips south this summer, resupplying Casey and Mawson stations and retrieving summer expeditioners.
The French ship L’Astrolabe is taking expeditioners to Macquarie Island.
“That’s typical of the cooperation between a number of countries in Antarctica,” Mr Clark said.
Australia and French ships dock in Hobart
L’Astrolabe is crewed by the French Navy and is briefly docked in Hobart before it sets sail on a resupply mission to France’s main Antarctic station – Dumont d’Urville in Adelie Land.
Commander Céline Tuccelli said it was the first time in 70 years the French Navy would have a vessel sailing in the Antarctic.
“The particular mission here is to work for the French Polar Institute, and be part of the logistic chain to deliver the French station in Antarctica,” she said.
L’Astrolabe captain Celine Tuccelli and head of logistics Patrice Bretel. Photo: ABC
“It’s very much exciting, it’s a challenge, and we are all trained to do our best.”
Head of Logistics at the French Polar Instittute, Patrice Bretel is coordinating the French Antarctic efforts.
“There are many different parts with different ways of transferring equipment, transferring people, organising all the different steps with the L’Astrolabe through Hobart,” he said.
“We have a lot of work before the season to organise and to prepare the time schedule … but for us the main challenge is to refuel the station, because of the sea ice conditions of the last years, we couldn’t provide all the fuel we wanted.
“Our main challenge this year is to refuel especially the station Concordia.”
Penguin jumps into Australian Antarctic Division boat
"Antarctic sea ice used to be the darling of climate doubters. Not anymore"
Viral Wave Published on Jan 17, 2018
When a penguin drops in to check on your work. Footage released on Wednesday by the Australian Antarctic Division shows a penguin quickly dropping in on communications specialist Matthew McKay, who was travelling through sea ice at the time.
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