Impact of Synoptic and Mesoscale Disturbances on the Beginning and End of the Summer Melt Season Over Sea Ice

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Synoptic and mesoscale weather events are hypothesized to provide the forcing that determines the magnitude, and often the sign, of the Arctic pack-ice surface energy budget (SEB). This is believed to occur through their impacts on the macro and microphysical structure of clouds, and on the thermodynamic and kinematic atmospheric structure within and above the Arctic boundary layer. Furthermore, these weather events are hypothesized to affect the onset of the summer melt season through their wintertime cumulative impact on the pack ice thermal structure, to determine the intensity of the summer melt, and to trigger the climatologically important transitions at the beginning and end of the summer melt season. Funds are provided to use historical data sets to deduce the impact of individual disturbances on the atmospheric boundary layer (ABL), SEB, and the melt season transitions; to diagnose the processes by which these impacts occur; to perform case studies of synoptic/mesoscale events triggering a seasonal transition through diagnoses of a mesoscale model; and to test the impacts of wintertime synoptic/mesoscale warming events on the timing of the onset of the subsequent melt season using a 1-D snow and ice model forced with atmospheric observations.