Wildfire smoke aerosol modeling in the Arctic

Description

Wildfires in Siberia, Alaska, and Northern Canada are a major source of air pollution in the Arctic. We have been able to successfully predict the atmospheric effects of wildfire smoke. WRF/Chem Version 3.1 represents the core of the so-called UAFSmoke system. The system accounts for modeling of the chemistry and aerosol transport in online fashion with the meteorological forecast model. UAFSmoke includes detection of wildfire location and area using data from direct and airborne observations and thermal anomalies from the MODIS instrument. In addition, the sub-grid scale plume rise dynamics above fires have been embedded online in WRF/Chem as a further major progress in modeling wildfire effects in the atmosphere. The plume model is initiated with fire emissions derived from above-ground biomass fuel load data in 1-km resolution. Smoke concentration from UAFSmoke runs coincide well with measured particulate concentrations. Aerosol and radiation measurements at the ARM North Slope of Alaska (NSA) sites of Barrow and Atqasuk clearly show a strong wildfire smoke signal during extreme wildfire years. In 2004 the aerosol optical depth (AOD) at ARM NSA increased by orders of magnitude due to smoke transported from Interior Alaska to the Arctic. The ARM measurements constitute a reference for WRF/Chem evaluation in support of modeling aerosol effects over the Arctic.