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Synoptic and Mesoscale Modulation of Dynamic and Thermodynamic Impacts on Central Arctic Sea Ice During MOSAiC

Active Dates 9/1/2020-8/31/2024
Program Area Atmospheric System Research
Project Description
Synoptic and Mesoscale Modulation of Dynamic and Thermodynamic Impacts on Central Arctic Sea Ice During MOSAiC

Ola P. G. Persson, Cooperative Institute for Research in Environmental Sciences (CIRES), Univ. of Colorado,
                               Boulder CO USA 80309 (Principal Investigator)

Amy Solomon, Cooperative Institute for Research in Environmental Sciences (CIRES), Univ. of Colorado, 
                               Boulder CO USA 80309 (Co-Investigator)

Jennifer K. Hutchings, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 
                               Corvallis, OR USA 97331-5503 (Co-Investigator)

This project will utilize the year-long observations from the Atmosphere Radiation Measurement (ARM) Mobile Facility (AMF) at the ongoing Multidisciplinary Observatory for Studies of Arctic Climate (MOSAiC) field program (Oct 2019 - Oct 2020), and combine these with other MOSAiC observations, ERA5 reanalyses (ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate), and a research, coupled, air-ice-ocean mesoscale model (CAFS: NOAA’s Coupled Arctic Forecast System) currently being run at NOAA/PSL by CIRES project participants.  Specifically, we will use data from the vertically-pointing and scanning Ka-band radars and the boundary layer 1290 MHz wind profiler currently with the AMF at MOSAiC, data from microwave radiometers, and data from ARM broadband radiation sensors onboard the R/V Polarstern and at the Central Observatory (CO) flux tower site.   Additional key data for these analyses include 4X daily rawinsondes, CIRES basic meteorological parameters and energy budget and momentum flux measurements at the CO 4-level flux tower and mast and at three CIRES distributed network sites, and the 70+ GPS buoys coordinated by Oregon State University. 

These data sources will be combined in a coupled analysis.  Understanding the evolution of synoptic and mesoscale atmospheric structure will rely on overlaying time-height sections of radar-derived cloud properties, serial rawinsonde diagnostics, and time-series of near-surface observations. Analysis of spatial structural features will rely on combined analysis of time-to-space conversion of the rawinsonde data, scanning radar data, ERA-5 reanalysis, and observations from the distributed network. To examine dynamic impacts on the sea ice, observations of floe movements and ice divergence/deformation from the distributed sites and GPS buoys will be examined and related to wind and turbulence/stress data from the three distributed sites and the CO on a ~20-30 km spatial scale and smaller.  Similar atmospheric parameters will be obtained from the scanning Ka-band radar using, for instance, the Velocity Azimuth Display (VAD) technique when sufficient backscatter exists, and calculated from the ERA-5 reanalysis. An ice momentum equation will be used as a basis for understanding the role of atmospheric forcing on ice motion and deformation.  Understanding the atmospheric events and processes producing observed sea-ice motion, including divergence/deformation, will be a focus of this study. To study thermodynamic impacts on the sea ice, analyses will include examining time series of the surface energy budget (SEB) and its various terms, identifying the synoptic/mesoscale atmospheric events that contribute significantly to the long-term (e.g., monthly) SEB means, and understanding the processes associated with events producing cloud forcing not associated with stratocumulus clouds.  We expect microphysical structure and temperature to be important modulating features, though boundary-layer stability, and snow cover/snowfall may also be important.

The coupled air-ice-ocean CAFS model will be run on identified events as case studies. The model will be examined for its ability to reproduce observed air-ice thermodynamic and dynamic interactions and the associated processes, such as lower tropospheric divergence/deformation, cloud macro and microphysics, and surface radiation.  Approximately 20 cases will be examined with the model.

The project has the potential to significantly expand our understanding of the processes by which atmospheric events impact the sea-ice, and differentiate between the thermodynamic impacts on the sea-ice energy budget and the dynamic impacts on sea-ice motion. Many events demonstrating significant ice motion and energy fluxes have occurred during the currently ongoing MOSAiC project, providing ample cases.  The project should inform development of air-ice coupled models that are necessary for operations and safety as human presence increases in the Arctic.
Award Recipient(s)
  • University of Colorado Boulder (PI: Persson, Ola)