Arctic Transport Potential
Arctic Transport Potential
This page describes two projects focused on identifying transport patterns for emissions to reach the Arctic. The two projects are similar but with distinct geographic foci. One is a Joint Fire Science Program project looking at contiguous U.S. (CONUS) emissions sources and the other is a U.S. State Department funded effort (as part of a larger USDA project) focused on emissions from Russia.
Lead: Sim Larkin, USFS AirFire
Co-Is: T. Strand, Scion; S. Brown, J. DeWinter, S. Raffuse, STI; P. Dolwick, EPA; R. Solomon, USFS
P. Lahm, USFS; E. Sasser, EPA
R. Draxlar, NOAA; B. Kinder, USFS
The basic question behind each project is the same:
What are the conditions required for emissions to be transported from their source locations to the Arctic?
This question is important for determining what emissions have the potential for transport to the Arctic, but it also defines the reverse:
When do emissions have no potential for transport to the Arctic?
Knowing when emissions have no transport potential is important, particularly for black carbon, as this knowledge allows for focusing mitigation efforts and research on the areas and emissions sources that can affect the Arctic. The focus here is on necessary conditions for transport to the Arctic; determining sufficient conditions requires considerations such as chemistry, deposition, and rain, that each have their own modeling uncertainties. By focusing only on necessary conditions, this modeling effort can rule out areas, timing, and emissions sources that are not of interest for Arctic impacts; but cannot properly state that an area, timing, or emissions source is a definite cause of impacts to the Arctic. This approach can be considered conservative in what is ruled out.
A 30-year climatology of Arctic Transport Potential was created using historical meteorology model runs. Additionally a real-time (daily) forecast system was created. Areas examined include both CONUS and Eurasia. For all of the modeling, the HYSPLIT trajectory model is used. As discussed below, different model setups are needed for the climatology and for the real-time forecasts; additional, but more minor differences occur between the CONUS and Eurasian modeling.
For the climatological runs, HYSPLIT is run using the North American Regional Reanalysis (NARR) dataset embedded within the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Global Reanalysis for full northern hemisphere coverage. Trajectories are released every 6 hours from a grid of points at the following height levels: 500, 1000, 1500, 2000, 2500, 3000, and 5000m above ground level (AGL) and run out for 10 days. The release locations over CONUS are every other grid cell within the NARR dataset (approximately 64 km); over Eurasia, the release points are every 1 degree aligned with the global reanalysis. See Larkin et al. 2012 for technical details of the CONUS modeling. Eurasian modeling details are in preparation.
Daily forecasts are generated from the U.S. National Weather Service’s Global Forecast System (GFS) model runs. Trajectories are released every 3 hours from every GFS land grid cell in the U.S. and Canada for North America, and between 38N and the Arctic circle elsewhere, at the same starting heights as the climatological runs and run out for 4 days. Interpretation of the daily forecasts is based on which height levels reach the Arctic. Smaller fires and lower intensity fires such as prescribed burns are generally limited in their ability to loft smoke high into the atmosphere, and higher atmospheric levels are generally more capable of transporting emissions to the Arctic quickly. Therefore, we display information for the daily forecasts based on what the lowest level of the atmosphere that is reaching the Arctic because the lower the level of the atmosphere with transport, the smaller the fire that may be able to produce emissions that can reach that transport level.
Daily forecasts of Arctic Transport Potential (both North America and Eurasia)
CONUS work: Final report to the Joint Fire Science Program (pdf on JFSP site 11.3MB)