Jul 15, 2009

Greenland Ice Sheet Surface Air Temperature Variability: 1840–2007

Jason E. Box, Lei Yang, David H. Bromwich and Le-Sheng Bai
American Meteorological Society
  • Combines meteorological station records and regional climate model output to develop a continuous 168-yr (1840–2007) spatial reconstruction of monthly, seasonal, and annual mean Greenland ice sheet near-surface air temperatures
  • Uses independent observations to assess and compensate for systematic errors in the model output
  • Investigates spatial and temporal temperature variability on seasonal and annual time scales
  • Finds that volcanic cooling episodes are concentrated in winter and along the western ice sheet slope, and interdecadal warming trends coincide with an absence of major volcanic eruptions
  • Finds that the year 2003 was the only year of 1840–2007 with a warm anomaly that exceeds three standard deviations from the 1951–80 base period
  • Finds the annual whole ice sheet 1919–32 warming trend is 33% greater in magnitude than the 1994–2007 warming
  • However, the data also shows the recent warming was stronger along western Greenland in autumn and southern Greenland in winter
  • Finds spring trends marked the 1920s warming onset, while autumn leads the 1994–2007 warming
  • Finds in contrast to the 1920s warming, the 1994–2007 warming has not surpassed the Northern Hemisphere anomaly—states an additional 1.0°–1.5°C of annual mean warming would be needed for Greenland to be in phase with the Northern Hemispheric pattern
  • Results suggest that the ice sheet melt rates and mass deficit will continue to grow in the early twenty-first century as Greenland’s climate catches up with the Northern Hemisphere warming trend and the Arctic climate warms according to global climate model predictions