Times of India , Thursday, April 03, 2008

Correspondent : Staff Reporter

WASHINGTON: NASA is starting a field campaign to investigate the chemistry of the Arctic's lower atmosphere this week to discern how air pollution contributes to climate changes in the Arctic. The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) aircraft mission is the most extensive field campaign ever to investigate the atmosphere's role in the climate-sensitive Arctic region. "It's important that we go to the Arctic to understand the atmospheric contribution to warming in a place that's rapidly changing. 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," said Jim Crawford, manager of the Tropospheric Chemistry Program at NASA Headquarters in Washington. During the campaign, which begins in Fairbanks, Alaska, NASA's aircraft will serve as airborne laboratories for the next three weeks. The aircraft will be equipped with instruments to measure air pollution gases and aerosols and solar radiation. Experts say that 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 travelling long distances from lower latitudes. "The Arctic is a poster child of global change and we don't understand the processes that are driving that rapid change. We need to understand it better and that's why we're going," said Daniel Jacob, an ARCTAS project scientist at Harvard University, Cambridge, Mass. The researchers hope that the data collected during the project will help improve computer models used to study global atmospheric chemistry and climate, and, eventually, 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. 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," said Hanwant Singh, an ARCTAS project scientist at NASA Ames Research Center, Moffett Field, California. The new aircraft observations will also help researchers interpret data from NASA satellites orbiting over the Arctic, and thus provide scientists with a better understanding of the atmospheric side of the climate question. "We're interested in data that will help models better characterise the current state of the atmosphere, to set a benchmark for them so we can gain confidence in their ability to predict future warming in the Arctic," Crawford said. 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.

SOURCE : Times of India, Thursday, 03 April 2008