Declining spring snow cover extent over high latitude Northern Hemisphere lands

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Thursday, 6 February 2014: 4:00 PM
Room C102 (The Georgia World Congress Center )
David A. Robinson, Rutgers University and NJ State Climatologist, Piscataway, NJ; and T. W. Estilow

It is well known that annual snow cover extent (SCE) over Northern Hemisphere (NH) lands has averaged lower since the late 1980s than earlier in the satellite era that began in the late 1960s. This is most evident from late winter through spring, and in the past decade has been exceedingly pronounced at high latitudes in May and June. Monthly SCE is calculated at the Rutgers Global Snow Lab from daily SCE maps produced by meteorologists at the National Ice Center, who rely primarily on visible satellite imagery to construct the maps. The most recent four Mays have had four of the five lowest NH SCEs on record, with Eurasian (Eur) SCE at a record low in 2013. North American (NA) SCE achieved a record minimum in May 2010, but of late has not been as consistently low as over Eurasia. The May 2013 NH ranking of third least extensive was especially noteworthy given that April SCE was the most extensive since 1996. The past six Junes have seen record minimum SCEs over NH and Eur, with five of these six the lowest over NA. The recent decline in early snow melt over high latitude lands appears to be at an equivalent if not greater pace than the loss of summer Arctic sea ice extent (SIE). This presentation will delve into the snow decline in more detail and speculate as to the reasons for this behavior as well as potential relationships between SCE and SIE.