WASHINGTON, Dec. 6, 2012 /PRNewswire-USNewswire/ -- NASA is inviting media to look behind-the-scenes at several active Earth science missions that will take to the air next month to study climate change and air pollution. These airborne missions are all based at NASA's Dryden Flight Research Center in Southern California. (Logo: http://photos.prnewswire.com/prnh/20081007/38461LOGO) On Jan. 25, journalists will have the opportunity to meet with mission scientists to find out how they are using airborne instruments in conjunction with satellite observations to advance our understanding of complex Earth systems. Tours of mission operations and NASA research aircraft will be provided at the Dryden Aircraft Operations Facility in Palmdale, Calif., and at Dryden's main campus on Edwards Air Force Base. The three major Earth Science missions highlighted during the day-long media opportunity will be probing air pollution across central California and key climate change unknowns high over the tropical Pacific Ocean. Two of NASA's high-altitude aircraft, the unmanned Global Hawk and the ER-2, are among the planes that will fly during these missions. The multi-year DISCOVER-AQ campaign will fly NASA's P3B and B200 King Air planes over California's San Joaquin Valley to measure air pollution this winter. The mission seeks to improve the monitoring of pollution from satellites so that scientists can produce better air-quality forecasts and more accurately identify pollution sources. The Airborne Tropical Tropopause Experiment campaign focuses on the region of the upper atmosphere where pollutants and other gases enter the stratosphere and potentially influence our climate. A key focus of the mission is water vapor, which can significantly impact Earth's energy budget, ozone layer and climate. The Polarimeter Definition Experiment campaign will fly several of a new breed of instruments that scientists plan to fly in space one day to improve our measurements of aerosols and clouds. Aerosols, tiny particles produced across the world from many different sources, influence Earth's climate and can affect human health.