Dong Wu

NASA/GSFC: Climate and Radiation Laboratory

Rapid Arctic warming is the fundamental driving force of sea ice loss in recent years. Most of climate models tend to underestimate the rate of reduction of summertime sea ice extent in the Arctic. Observations show that Arctic surface warming occurs non-uniformly in geographical location and time of the season, and water vapor has been increasing steadily. However, as the Arctic warms, cloud responses and feedbacks remain unclear. Studying recent satellite cloud data over the Arctic Ocean, we find that low (0.5-2 km) cloud cover in October has been increasing significantly during 2000-2010 over the Beaufort and East Siberian Sea (BESS). This change is consistent with the expected response of boundary-layer cloud to evaporation increases in summer. Because of their net warming effect at the surface, the observed autumnal cloud increases supports the hypothesized positive feedback that involves interactions between boundary-layer cloud, water vapor, temperature and sea ice over the Arctic Ocean. The Arctic has warmed so fast in recent years that changes are observable by NASA’s EOS sensors in the short period of time. Yet, the underlying mechanisms and processes responsible for these rapid changes are still a matter of debate. Can a NASA’s Earth Venture mission be directed to shed more light on the diminishing ice problem?