Seminar: Satellites Document Accelerated Warming in the Arctic

Thursday, November 5th at 12 pm in ST 424

Dorothy K. Hall

Earth System Science Interdisciplinary Center (ESSIC)

University of Maryland

Abstract

Satellite data have been instrumental in documenting accelerated warming of the Arctic and high northern latitudes in recent decades. Rising temperatures, loss of summer sea ice, enhanced melting of the Greenland ice sheet and earlier spring snowmelt in the Northern Hemisphere have been measured. Feedbacks associated with shrinking sea ice and earlier snowmelt are implicated as the main causes of recent polar amplification. Using Advanced Very High Resolution Radiometer (AVHRR) satellite data, the extent of Northern Hemisphere spring snow cover has decreased up to 12% per decade (for the month of June) from 1967 – 2012. The Arctic sea ice September minimum extent reached new record lows in 2002, 2005, 2007, and 2012 according to studies done using passive-microwave instruments such as the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and its predecessors (1979 – 2012). Satellite gravimetry data show that mass loss of the Greenland ice sheet has accelerated in the last decade, and Moderate-resolution Imaging Radiometer (MODIS) satellite data show increasing surface temperature, especially in northwestern Greenland where accelerated ice discharge is also taking place. Other indications of high-latitude warming in the Northern Hemisphere include earlier melt of lake ice, shrinkage of mountain glaciers and warming of permafrost.