RUI: Quantifying and Predicting the Impact of the Madden-Julian Oscillation on the State of the Arctic
Many authors have documented variability in the state of the Arctic on a range of time scales, including the intraseasonal. 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 ice and snow extent. The character of Arctic sea ice and snow cover extent is the result of a complex interrelationship between meteorological and oceaongraphical factors. These parameters have been found to vary on a number of time and spatial scales, including the intraseasonal, and Arctic sea ice and snow extent have been found to be strongly related to both thermodynamic and dynamic forcing on that time scale. Furthermore, several recent studies have found that the leading mode of tropical atmospheric variability on the intraseasonal scale, the MJO, modifies these mid- and highlatitude thermodynamic and dynamic forcing mechanisms. However, the MJO’s impact on sea ice and snow cover remains largely unstudied. Therefore, by mapping the dependence of Arctic sea ice and snow cover extent on phase of the MJO, explaining the observed variability via known relationships to atmospheric state variables, and transitioning the results to a statistical prediction model, this research effort fills important gaps in knowledge and prediction of the Arctic system. Intellectual merit The PIs have previously investigated the character of Northern Hemisphere snow cover extent and intraseasonal variability of other components of the atmosphere, including precipitation, tropospheric pressure and circulation patterns, fronts, and tropical cyclones. Preliminary results for the Arctic show statistically significant modulation of summer sea ice, both volume and extent, by phase of the MJO. The scientific objectives of this research are motivated by these findings, and the methods of this grant extend analysis techniques from prior studies to explore a new topic: impact of the MJO on the state of the Arctic system. The broader impacts of this activity center in three areas. First, the project will integrate undergraduate oceanography majors as participants in all components of the effort: data analysis, explanation of observed patterns, and presentation of results. Through weekly group and individual meetings, these students will learn both the techniques of cutting-edge science inquiry and the meteorology governing intraseasonal variability of the Arctic. Participation by students from underrepresented groups will be particularly solicited. Second, project results will be disseminated broadly to the scientific community. The PIs and students will publish results in peer-reviewed journals and give presentations at scientific conferences. At the end of each academic year, students will present their theses to peers and faculty, highlighting both methodology and results. Composite maps, a description of the methodology, and results from the statistical prediction model will be hosted on a project web site. Third, the research represents the first steps in a long-term goal of the PIs to understand and predict the Arctic on the intraseasonal time scale. The results of this study will be used to build one of the first prediction schemes for Arctic sea ice and snow cover extent on an intraseasonal time scale.