Associations between the Madden-Julian Oscillation and Arctic sea ice concentration

The Arctic is an integrated component of the earth-ocean-atmosphere system and therefore responds to a variety of both internal and external forcing mechanisms. The Arctic has experienced significant changes in the past decades, particularly in the reduction of both sea ice extent and thickness and in the increase of surface air temperatures over land. While external, cryospheric forcings that have produced these changes have been studied extensively, much less is known about variability in the state of the Arctic on shorter time scales, including the intraseasonal. Several recent studies have noted the dependence of Arctic surface temperature and tropospheric circulation on tropical deep convection associated with the leading mode of tropical intraseasonal atmospheric variability, the Madden-Julian Oscillation (MJO). However, the MJO's impact on sea ice remains largely unstudied.

This study seeks to fills important gaps in knowledge and prediction of the Arctic system, by mapping the dependence of Arctic sea ice on phase of the MJO, attempting to explain the observed variability via known relationships to atmospheric state variables. Preliminary results for the Arctic show statistically significant modulation of summer sea ice, both extent and volume, by phase of the MJO. On a monthly time-scale, tendencies in sea ice concentration, atmospheric surface pressure, and mid-tropospheric height observations by phase of MJO demonstrate organized patterns in variability. These patterns and tendencies will be presented and expanded upon.