Solar Radiation Influences Arctic Sea Ice Extent
22.04.2008 - Other
A team of scientists from the National Centre for Atmospheric Research (NCAR) and Colorado State University (CSU) have determined that Arctic summer sunshine has been producing more pronounced melting than in the past.
According to their research, last year's unusually sunny weather contributed to the Arctic's record sea ice low. However, previous similar weather conditions have had no comparable impacts on the sea ice. This suggests that summer sunshine in the Arctic is causing more melting than in the past, largely because there is less ice to reflect the sun back into space.
It is well know that, as ice shrinks, the incoming sunshine is attracted by the dark ocean waters, thereby raising the water's temperature. Lead author of this study, Jennifer Kay from the NCRA, says that "the sunshine reaching the Arctic is increasingly influential, as there is less ice to reflect it back into space. Dry, sunny conditions in a single summer can now act as a potent force to melt sea ice."
Having gathered observations using a new group of NASA satellites called the "A-train", Tristan L'Ecuyer from CSU, co-author of the study, explains that "satellite radar and lidar measurements allow us to observe Arctic clouds in a new way". A 16% less cloud coverage was observed in 2007 in comparison to 2006 over the Western Arctic. This caused the sea-surface temperature to increase by 2.4 degrees Celsius and the sea ice to reach its record low.
Having said this, solar radiation is not the only contributing factor to sea ice loss. Other factors also influence sea ice loss, although their precise contribution is not yet known:
- changes in wind patterns, especially strong winds blowing over regions of sea ice retreat;
- shifts in ocean circulation patterns (possibly).
