Madeline Clark Frank- Oct 16

Name:     Madeline Clark Frank

Title:    Atmospheric Conditions Preceding Very Rapid Sea Ice Loss Events

Location: TBD

Date:     2019/10/16

Time:     3:00 PM

Series:   Weather and Climate Systems

Abstract: As Arctic sea ice continues to decline and resources in that region become more accessible, there is a growing need to understand the dynamics of Arctic sea ice. In all seasons there are times when sea ice extent undergoes dramatic, negative changes over synoptic time scales. We refer to these events as very rapid sea ice loss events (VRILEs). Prior work on individual ice loss events of this nature show that the event was often preceded by an Arctic cyclone. Our aim is to understand the atmospheric and sea ice conditions that allow VRILEs to occur. We hypothesize that long lived cyclones over thin ice have the greatest impact on sea ice, as opposed to cyclone strength and intensity. After identifying the time and location of the vRILEs using sea ice extent and concentration data from the National Snow and Ice Data Center (NSIDC), we analyze them in a composite sense. This is done separately for summer (JJA) and winter (DJF) events. In these composites we identify strong pre

ssure gradients across the vRILE in both seasons and negative anomalies in both mslp and tropopause potential temperature. These signals indicate the presence of a cyclone and a tropopause polar vortex, at least in a composite sense. We also use cyclone track products from both NCEP/NCAR and ERA-Interim reanalysis datasets.