Intraseasonal variability of Northern Hemisphere snow by the Madden Julian Oscillation

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Sunday, 4 January 2015
Joshua S. Werling, United States Naval Academy, Annapolis, MD; and G. R. Henderson and B. S. Barrett

The variability of high-latitude snow and snow cover extent has been extensively studied. However, connections between shorter-term, intraseasonal variability of the climate system and high latitude snow cover extent are less well understood. The Madden Julian Oscillation (MJO) is the primary mode of intraseasonal variability in the tropics, and it is known to have important teleconnections outside the tropics, including the modulation of high-latitude atmospheric circulation. This study examines variability of high-latitude Northern Hemisphere snow cover extent and explores possible connections to the MJO. To accomplish this objective, variability in snow cover extent was examined by phase of the Real-time Multivariate MJO (RMM) index. Snow cover extent data were obtained from the National Snow and Ice Data Center's MEaSUREs Northern Hemisphere Terrestrial Snow Cover Extent Daily 25km EASE-Grid 2.0 product from 1 January 1999 to 31 December 2012. These data were used to create daily snow cover extent change, which was then tested for intraseasonal variability. Preliminary results focused on MJO phases 3-4 and 7-8, as prior studies indicated uncharacteristic surface air temperatures anomalies were associated with those phases. Additionally, data from previous literature also indicated that the Arctic Oscillation is more positive during phases 1 through 3, resulting in a preference for positive polarity, and more negative during phases 6 through 8. Given the continued increase in predictive skill of the MJO, work such as this that establishes statistical relationships between the MJO and smaller-scale, less predictable phenomena (such as high-latitude snow cover) may lead to increased predictability of the smaller-scale phenomena.