DC-8 Flying Lab Takes To Alaska Skies

NASA's DC-8 flying laboratory departed the NASA Dryden Aircraft Operations Facility in Palmdale, CA Tuesday for Fairbanks, AK to participate in one of the largest international atmospheric studies ever attempted.

The recent decline of sea ice is one indication the Arctic is undergoing significant environmental changes related to climate warming. NASA and its partners plan to investigate the atmosphere's role in this climate-sensitive region during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign.

The extensive field campaign will investigate the chemistry of the Arctic's lower atmosphere to help scientists identify how air pollution contributes to climate changes in the Arctic. Of particular interest is the formation of the springtime "arctic haze." The return of sunlight to the Arctic in the spring fuels chemical reactions of pollutants that have accumulated over the winter after traveling long distances from lower latitudes.

"It's important that we go to the Arctic to understand the atmospheric contribution to warming in a place that's rapidly changing," added Jim Crawford, manager of the Tropospheric Chemistry Program at NASA Headquarters in Washington. "We are in a position to provide the most complete characterization to date for a region that is seldom observed but critical to understanding climate change."

In addition to DC-8 airborne laboratory from NASA Dryden, two other NASA aircraft, a P-3 Orion from Wallops Flight Facility and a Beechcraft King Air 200 from Langley Research Center, will serve as airborne laboratories for the next three weeks, carrying instruments to measure solar radiation and air pollution gases and aerosols.

The DC-8 is equipped with a suite of 22 instruments designed to collect atmospheric data while flying in the Arctic regions during April and July. Researchers from around the world were selected to participate and bring complex sensing equipment, as well as expertise, to the campaign. Flight plans will be coordinated with orbiting satellites and other aircraft and modified en route as meteorological conditions develop to optimize scientific value.

"The DC-8 is unique in its ability to accommodate such a large science payload, capable of measuring more than 40 chemical constituents and aerosols, in a shirt-sleeve laboratory environment, while traversing air masses of continental scale," said Robert Curry, director of NASA Dryden's Science Mission Directorate. "Investigators will have direct access to their instruments in flight and can collaborate with each other and science teams on the ground as results are obtained."

ARCTAS is NASA's contribution to an international series of Arctic field experiments that is part of the International Polar Year. The National Oceanic and Atmospheric Administration and the Department of Energy also are sponsoring research flights from Fairbanks this month in collaboration with NASA.

"The Arctic is a poster child of global change and we don't understand the processes that are driving that rapid change," said Daniel Jacob, an ARCTAS project scientist at Harvard University, Cambridge, MA. "We need to understand it better and that's why we're going."

The wealth of data collected also will improve computer models used to study global atmospheric chemistry and climate. This ultimately will provide scientists with a better idea of how pollutants are transported to and around the Arctic and their impact on the environment and climate.

"We haven't looked at pollution transport in a comprehensive fashion," said Hanwant Singh, an ARCTAS project scientist at NASA Ames Research Center, Moffett Field, CA. "We can see Arctic haze coming in but we don't know its composition or how it got there. One goal of ARCTAS is to provide a comprehensive understanding of the aerosol composition, chemistry and climate effects in the Arctic region."

The new aircraft observations also will help researchers interpret data from NASA satellites orbiting over the Arctic, such as Aura, Terra, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, or CALIPSO. Interpreting satellite data can be difficult in the Arctic because of extensive cloud cover, bright reflective surfaces from snow and ice, and cold surface temperatures. The new airborne view of the Arctic atmosphere combined with satellite data will provide scientists with a better understanding of the atmospheric side of the climate question.

A second phase of the ARCTAS campaign takes place this summer from Cold Lake in Alberta, Canada, where flights will focus on measurements of emissions from forest fires. Researchers want to know how the impact of naturally occurring fires in the region compares to the pollution associated with human activity at lower latitudes. Understanding the relative influence of each is important to predictions of the Arctic's future climate.

FMI: www.nasa.gov/mission_pages/arctas, www.nasa.gov/centers/dryden