Associations between the Madden-Julian Oscillation and pan-Arctic terrestrial snow

Unlike the recent and precipitous downward trend in Arctic sea ice, changes in Northern Hemisphere snow cover extent over the same period have been more complex. In particular, trends in pan-Arctic terrestrial snow extent are not well understood. While external, cryospheric forcings associated with the rapidly changing Arctic climate have been studied extensively, much less is known about variability in the state of the Arctic on shorter, intraseasonal time scales. Recent studies have noted the dependence of Arctic surface temperature and circulation on deep convection associated with the leading mode of tropical intraseasonal atmospheric variability, the Madden-Julian Oscillation (MJO). However, very few studies have connected this relationship to the key Arctic parameters of snow extent and sea ice.

Expanding on recent findings linking MJO to North American snowstorms and snowpack accumulation in the midlatitudes, this study investigates pan-Arctic snow variability by mapping the dependence of snow extent by phase of MJO. The seasonality of this MJO-snow extent relationship will be explored in particular, in light of recently documented early and extensive spring snow melt at lower latitudes. Preliminary results for the Arctic show statistically significant modulation of pan-Arctic snow extent, by phase of the MJO. These preliminary results will be presented and expanded upon.