Enduring the elements to enhance space weather forecasts

  • Published
  • By Michael P. Kleiman
  • AFRL Space Vehicles Directorate
HANSCOM AIR FORCE BASE, Mass. --  Instruments installed in Greenland provide prediction data on cosmos-generated disturbances impacting warfighter communication, navigation, and surveillance systems

Two weeks of determined digging through 3 feet of snow, a layer of ice, slush and water in the tundra of Greenland, a self-governed territory of Denmark and the globe's biggest non-continent island, by four members of the Air Force Research Laboratory's Space Vehicles Directorate, with assistance from Danish personnel, will ultimately improve the prediction of ionospheric-created disturbances, which disrupt military radar and global positioning systems, as well as satellite and high frequency communications.

Following three and a half years of negotiations with the Danish government, the group of researchers serving with the organization's Battlespace Environment Division, Hanscom Air Force Base, Mass., received approval last year from the European country to install equipment measuring the different properties of the ionosphere, part of the atmosphere impacted by the sun's radiation, at Station Nord, a military outpost located in the far northeast portion of the giant isle.

"Installing the equipment was a challenge due to the harsh environment where there was snow on top of ice on top of frozen ground. Our team spent a lot of time wading in slush," said Todd Pedersen, research physicist, AFRL's Space Vehicles Directorate. "We needed to dig 4 to 5 feet down in the hardened ground to anchor the equipment. We were determined to take care of business."

In the polar region, located above the Arctic Circle, instabilities in the ionosphere, heightened during the winter months, create structuring of sunlight-produced plasma, which causes significant effects on radio wave transmissions. Similar in form to cumulus clouds, but not visible to the naked eye, these disruptions drift away from the direction of the sun across the polar cap. For the past 20 plus years, the Air Force has conducted ionospheric research at Danish Meteorological Institute sites in western Greenland, and also since the mid-1990s at a civilian facility at Svalbard, a group of several islands belonging to the Kingdom of Norway, situated between the Scandinavian nation and the North Pole.

Both stations have provided real-time data to the Air Force Weather Agency, Offutt Air Force Base, Neb., but the bulk of the information has been returned months later to the Hanscom Air Force Base team. In addition, forecast capabilities at the two locations have experienced a gap in coverage as the ionospheric turbulence moves at 500 meters per second across the polar cap, becoming fully developed by the time it reaches Thule Air Base, the U.S. installation in northwest Greenland. To bridge the lapse, placing instrumentation at Station Nord served as the optimum option.

"With the new instruments, we can observe the forces creating the disturbances, as well as how they evolve and we can also observe their impacts on systems such as GPS and radar," Dr. Pedersen said. "We hope to be able to take the data to forecast the creation of ionospheric disturbances."

In July, after experiencing three days of travel through Germany, Denmark, Iceland and Thule Air Base to their intended destination, the four-person Air Force contingent, consisting of two junior officers and two civilians, arrived at Station Nord aboard a Danish Air Force C-130 aircraft. During the next 14 days, the AFRL scientists installed five instruments including an approximately 82 feet by 200 feet ionosonde transmit antenna, capable of determining ionospheric density profiles; an all-sky imager for viewing aurora and ionospheric plasma clouds; and three other systems employed to identify ionospheric scintillation through fluctuations in the strength of radio signals transmitted by various satellites such as GPS.

Researchers expect the exterior sensors to produce data for one year at a time, and believe the equipment's output can be extended another 48 months with annual maintenance. Meanwhile, the Station Nord site crew, comprised of five Danish military personnel, manages the instrument suite, which compiles short summaries, comprised primarily of text with occasional imagery, of ionospheric disruptions every 15 minutes.

"Data from Station Nord will allow us to solve the scientific challenges, and to forecast space weather impacts on a variety of civilian/military systems," Dr. Pedersen said. "The remote geographical location creates an unbroken chain of measurements across the polar cap that allows ionospheric disturbances to be tracked from start to finish in this region."