We will combine observational and modelling resources to quantify the impact of laas on sea ICE. A new arctic aerosol reanalysis dataset is under development with the utilization of a newly…

This is a $312,244 grant awarded by the National Aeronautics and Space Administration (NASA) to Western Washington University (WWU) to quantify the impact of light-absorbing aerosols (LAA) on Arctic sea ice. The project will develop a new Arctic aerosol reanalysis dataset that includes assimilation of Ozone Monitoring Instrument (OMI) Aerosol Index (AI) data over bright surfaces, which is an improvement over existing aerosol reanalysis products. The deposition fluxes from this new dataset will be evaluated against field measurements and then used as an input to the Navy Earth System Prediction Capability (NAVY-ESPC) global climate model to examine the response of sea ice processes to the albedo forcing from LAA. The research will also estimate the direct radiative effect of aerosols over the Arctic and the relative importance of the aerosol albedo effect on sea ice changes. There is no set-aside designation for this award.

We will combine observational and modelling resources to quantify the impact of laas on sea ICE. A new arctic aerosol reanalysis dataset is under development with the utilization of a newly available OMI AI data assimilation capability. Unlike traditional aerosol reanalysis products, this new arctic aerosol reanalysis product includes the assimilation of OMI-AI data over bright surfaces, supplementing the normally assimilated modis and misr aerosol datasets that have proven extremely limited near the poles because of retrieval challenges over bright surfaces. The aerosol deposition fluxes from this product will be evaluated against refractory black carbon (RBC), elemental carbon/organic carbon (EC/OC) and dust measurements over snow and ICE from available campaigns and field works, including the currently ongoing mosaic project. The deposition fluxes from the new arctic aerosol reanalysis product will then be used as an input in the navy earth system prediction capability (navy-espc), a global atmosphere-ocean-sea ICE coupled model, to help understand the responses of sea ICE processes to the LAA-induced albedo forcing. The espc model has an explicit treatment of surface snow/ICE with consideration of aerosol and melt pond processes. The ability of the model to turn on and off the deposition fluxes on snow/ICE constrained by the arctic aerosol reanalysis product will allow US to examine the responses of the fully-coupled model to the albedo effect of laas. Similarly, we will estimate the direct radiative effect of aerosols over the arctic, and the relative importance of the aerosol albedo effect on sea ICE changes. Navy-espc also has the capability of assimilating ocean and atmosphere data, which allows constraining of the models large-scale weather patterns so the aerosol-sea ICE physical processes can be isolated from local meteorology. We will use radiative flux data from ceres and arise, as well as sea ICE thickness data from icesat and icesat-2 for navy-espc evaluation. In addition, broadband albedo and radiative flux changes due to the deposition of LAA onto snow/ICE covered areas will also be studied by examining long-term variations of upward shortwave TOA flux over the arctic region using data collected from the ceres sensors.