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Trends in snow ablation over North America
Author(s) -
Dyer Jamie L.,
Mote Thomas L.
Publication year - 2007
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.1426
Subject(s) - ablation , snow , environmental science , climatology , snow cover , atmospheric sciences , flux (metallurgy) , ablation zone , meteorology , geography , geology , medicine , materials science , cardiology , metallurgy
A substantial decrease in snow cover extent (SCE) and snow depth over North America has been observed over the 1960–2000 period. One explanation for the changes in North American snow cover is a change in the frequency and/or intensity of snow ablation. This study uses a gridded dataset of United States and Canadian surface observations from 1960 to 2000 to examine patterns of snow ablation over North America. An ablation event is defined as an interdiurnal snow depth change exceeding a critical value. Results show a significant positive trend in the frequency of ablation events during March ( p < 0.05) and a significant negative trend in May ( p < 0.05), indicating an earlier onset of ablation. This pattern is consistent for ablation of varying intensity. Surface energy budget components and air mass frequencies are examined in relation to the observed trends in snow ablation. Changes in March ablation frequency were shown to be dominated by increases in the sensible heat flux. A higher frequency of dry moderate instead of moist polar air masses during high ablation years may explain the increase in sensible heat flux and ablation over the study period. Copyright © 2006 Royal Meteorological Society