Growing economic activity in the Arctic, such as fishing, mineral exploration and shipping, is emphasizing the need for accurate predictions of how much of the Arctic will be covered by sea ice. Every June, an international research group known as the Study of Environmental Arctic Change (SEARCH) publishes a summary of the expected September Arctic sea ice minimum known as the Sea Ice Outlook. The initial reports and monthly updates aim to give the scientific community and public the best available information on sea ice.
A Digital Mapping System (DMS) mosaic of Arctic sea ice. The dark areas are leads, or open areas of water. Identifying leads is one of the necessary steps in preparing IceBridge’s quick look sea ice thickness data product. Credit: NASA / DMS team
Researchers rely on models that use estimated ice thickness data and simulated atmospheric conditions to forecast how sea ice will change during the summer. For the first time, near real-time ice thickness data obtained by NASA's Operation IceBridge has been used to correct a forecast model's initial measurements, which could lead to improved seasonal predictions.
In a paper published last month in the journal Geophysical Research Letters, Ron Lindsay, IceBridge science team member and Arctic climatologist with the Polar Science Center at the University of Washington in Seattle, outlined efforts to use IceBridge data to improve the accuracy of seasonal sea ice forecasts. Lindsay and colleagues used a new quick look sea ice data product that IceBridge scientists released before the end of the Arctic campaign earlier this year. The quick look data, intended for use in time-sensitive applications like seasonal forecasts, supplements the final sea ice data product typically released roughly six months after the campaign. By using new data processing techniques, IceBridge scientists were able to publish the quick look measurements in a matter of weeks. "The idea was to make the data available for anyone to use for the Sea Ice Outlook," said sea ice scientist Nathan Kurtz of NASA's Goddard Space Flight Center in Greenbelt, Md.
The work outlined in Lindsay's paper marks the first use of IceBridge quick look data in an ensemble sea ice forecast (computer) model. "An ensemble forecast is where you run a single forecast model many different times," said Lindsay. In this case, they ran the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) model seven times using conditions from previous summers. PIOMAS uses sea ice extent, the area of sea containing sea ice, and atmospheric data to simulate ice and ocean conditions.
IceBridge data and thickness measurements made by the Seasonal Ice Zone Observing Network (SIZONet), a multidisciplinary project aimed at observing Arctic sea ice, served as a way to correct initial sea ice conditions. These initial measurements come from running the forecast model with historical atmospheric conditions. Lindsay and colleagues used IceBridge and SIZONet data to adjust these measurements and then used the PIOMAS model to create a forecast of September's mean sea ice extent. To make sure what effect the corrected measurements had, they also ran the model as normal, something known as a control run.
Before this forecasting work could begin though, the researchers had to gather and process data, something that takes the hard work of many people. During March and April of 2012, IceBridge gathered sea ice thickness data using four different airborne science instruments.
First, researchers measure the surface freeboard, or the amount of ice and snow above the sea level height, using a laser altimeter known as the Airborne Topographic Mapper (ATM). Next, they use snow thickness data derived from airborne snow radar and subtract that to get an accurate ice freeboard measurement. This figure is then combined with known average density measurements to calculate total ice thickness, of which freeboard is typically only 10 percent. One other instrument, the KT-19 temperature sensor, was used to detect leads, or openings, in sea ice, which are used to determine the sea level height.
SIZONet scientists used a different method, measurements from a helicopter-borne electromagnetic sensor that detects differences in how well sea ice and ocean water conduct electricity, giving a distance between the sensor and ocean water below.
Collecting measurements is only the beginning of the work. Measurements from the ATM laser have to be combined with information from the aircraft's GPS and inertial navigation systems and the readings have to be filtered to remove things like false returns from low clouds and fog. Preparing instrument data for release is a labor-intensive and time-consuming process that normally takes six months. With the quick look product, it was done in a matter of weeks.
Producing quality data so quickly is challenging, but the process proved a good test of the instrument team's talents. "We gained some valuable insights into our capabilities," said ATM senior scientist John Sonntag. "This new confidence in the quick data may open new avenues for us in the future."
The September mean ice extent for the corrected model were slightly closer to the actual result than the control forecast run, but both were fairly far off from the actual record minimum. This may have been due to unusual weather over the summer, including a large Arctic storm in August, or to deficiencies in the model simulation of the new very thin ice conditions of the Arctic. Lindsay said winds have a bigger impact on the thinner ice of recent years than on thick ice. It may be possible to redo this experiment, using this summer's atmospheric conditions in the forecasts. "This would tell us the impact of the observations for the weather we actually experienced," said Lindsay.
As a step in a new direction, the study and quick look data collection could improve sea ice forecasts in the future. Providing near real-time sea ice data may also help in other areas, such as evaluating model performance.
With plans to produce another quick look product in the coming 2013 Arctic campaign, Kurtz is hopeful that IceBridge data will be useful to sea ice forecasters and other researchers. "The question is how will people use it," Kurtz said.For more information about the SEARCH Sea Ice Outlook, visit:
George Hale | EurekAlert!
Further reports about: > Arctic Ocean > Arctic campaign > Arctic sea ice > Goddard Space Flight Center > IceBridge > Outlook > PIOMAS > Sea Ice Outlook > atmospheric condition > crystalline > forecast model > forecasting > ice extent > ice thickness > navigation system > ocean water > sea ice > sea level > sea snails
A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington
Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Ecology, The Environment and Conservation
24.05.2018 | Medical Engineering
24.05.2018 | Physics and Astronomy