evidence: It’s not just rising air and water temperatures influencing the decades-long decline of Arctic sea ice. Clouds, aerosols, even the bumps and dips on the ice itself can play a role. To explore how these factors interact and impact sea ice melting, NASA is flying two aircraft equipped with scientific instruments over the Arctic Ocean north of Greenland this summer. The first flights of the field campaign, called ARCSIX (Arctic Radiation Cloud Aerosol Surface Interaction Experiment), successfully began taking measurements on May 28. "The ARCSIX mission aims to measure the evolution of the sea ice pack over the course of an entire summer," said Patrick Taylor, deputy science lead with the campaign from NASA’s Langley Research Center in Hampton, Virginia. "There are many different factors that influence the sea ice. We’re measuring them to determine which were most important to melting ice this summer." On a completely clear day over smooth sea ice, most sunlight would reflect back into the atmosphere, which is one way that sea ice cools the planet. But when the ice has ridges or darker melt ponds — or is dotted with pollutants — it can change the equation, increasing the amount of ice melt. In the atmosphere, cloudy conditions and drifting aerosols also impact the rate of melt.