Cryospheric and Polar Processes Seminar: Alex Crawford

Alex Crawford - Graduate student, Geography, NSIDC/CIRES

A New Look at the Summer Arctic Frontal Zone

A notable characteristic of the summertime Arctic is the existence of a narrow band of strong horizontal temperature gradients spanning the coastlines of Siberia, Alaska, and western Canada that extends through a considerable depth of the troposphere.  This summer Arctic Frontal Zone (AFZ) is best expressed in July.  It is manifested aloft as a separate Arctic jet feature at about 300 hPa. It is clearly associated with differential atmospheric heating, as evidenced by the sharp difference in surface energy balance terms between the Arctic Ocean and land. Interannual variations in monthly strength of the summer AFZ are spatially heterogeneous and primarily dependent on local variability in cloud cover, surface wind direction, snow cover extent, and sea ice concentration. Throughout the period 1979 to 2012, monthly June AFZ strength increased throughout most of Eurasia, which is likely related to amplification of Arctic atmospheric warming over land by snow cover loss.