Section Coordinator: James E. Overland
National Oceanographic and Atmospheric Administration,
Pacific Marine Environmental Laboratory, Seattle, WA, USA
November 21, 2013
The Atmosphere section includes reports on Air Temperature, Cloud Cover and Surface Radiation, Ozone, UV Radiation and Black carbon (soot). Surface Radiation and Black Carbon are new topics that appear for the first time in the Arctic Report Card.
The Arctic atmosphere showed considerable spatial and seasonal variability during the period from fall 2012 through summer 2013. For January-August 2013, air temperatures in the Arctic relaxed from the high extremes seen during the last five years, but remained warmer than all but one year since the beginning of the 20th century.
Fall 2012 was anomalously warm over the Arctic Ocean and adjacent lands after the record sea ice loss in summer 2012. Spring 2013 temperatures were cooler than normal in North America and Greenland, and warmer than average in Eurasia, leading to record early snow loss in Eurasia. Except for Alaska, air temperatures in summer were anomalously low across most of the Arctic, consistent with more sea ice and less melting at the surface of the Greenland ice sheet than occurred in the extraordinary summer of 2012. Increased summer cloud cover and its effect on surface radiation had an overall cooling effect, and may have contributed to the larger sea ice extent in 2013.
At several locations in the high Arctic, UV levels were below the long-term average for prolonged periods between February and May of 2013. This was primarily due to high ozone levels, which were higher than the average of the last decade because of a very early stratospheric sudden warming event in January 2013. Black carbon (a short-lived climate forcer that affects the radiation balance in the Arctic by absorbing solar radiation when suspended in the atmosphere) has declined by 55% and 45% since the early 1990s at Alert (Nunavut, Canada) and Barrow (Alaska, USA), respectively, which have the longest records of atmospheric black carbon concentrations in the Arctic. These declines are related to decreasing emissions due to the economic collapse in the former Soviet Union during the early 1990s.