Model Used
All calculations have been done with the particle dispersion model FLEXPART. A detailed description can be found here: FLEXPART home
a) Tracer
Anthropogenic CO
based on the Edgar emission inventory, passive Tracer carried in the model for 20 days
Biomass burning CO
based on MODIS hot spots, no removal, carried for 20 days
CHBr3 with a lifetime of 15 days
based on Chlorophyll a, available for a region of 20 S - 30 N and 90 E - 160 E for November (averaged over 2003-2009) provided by Birgit Quack.
CHBr3 with a lifetime of 5 days
the same as above, but tracer are only kept in the model for 5 days.
SHIP tracer
this tracer is defined for experiments where a tracer is released from a shiptrack and further sampled by an aircraft. On specific locations tracer is released and followed 5 days. The release time can be seen in the Figure header, the various Releasepoints distributed over the ship route can be selected by a list menu and are called 1R to 24R. This is a purely passive tracer
b) Geographical Extent
The tracer can be viewed either on a global base, in an regional extent (-20 S to 30 N and 80E to 140 E) or in a local view: 100 - 120 E and 0 - 20 N
c) Type of plots
In principle a total column of the tracer as well as slices in a hight of 3, 5, 8 and 11 km can be plotted. For the SHIP tracer instead of the slices a sum over latitude or longitude can be viewed.
d) Release location
For the Ship tracer it is possible to view the distribution of the tracer released from the various position of a given Shiptrack.
Emission Information for anthropogenic CO and biomass burning CO
Emission tracer forecasts are calculated with the particle dispersion model FLEXPART based on Global Forecast System (GFS) data of the National Centre for Environmental Prediction (NCEP). Tracer masses are carried by particles following trajectories calculated using the GFS winds and stochastic components for turbulence and convection. These species are run as passive tracers for a duration of 20 days, after which tracer particles are dropped from the simulation. In addition, a biomass burning CO tracer is available; the emission algorithm ingests actual information on MODIS fire detections, landuse information, and emission factors.
As the emission basis, the EDGAR version 3.2 fast track inventory for the year 2000 with a resolution of 1 degree is used, excecpt for most of North America where the inventory of Frost and McKeen (2004) is used. This inventory is based on the U.S. EPA NEI-99 inventory (National Emissions Inventory, base year 1999, version 3) and has an original resolution of 4 km, plus point sources. For initializing FLEXPART, the high resolution has been kept for high-emission grid cells and strong point sources. Weaker sources were aggregated to coarser resolution. For Mexico City, an inventory provided by Jerome Fast was used, which has a resolution of 4.5 km. Again, the high resolution was kept for high-emission grid cells.
Meteorological input data
0.5°x0.5° resolution GFS data for the real-time analysis and up to 3 hour forecast, 1°x1° resolution GFS data for the forecast; the forecasts strongly benefit from the high-resolution 0.5°x0.5° analyses!
26 vertical levels, every 3 hours
Output resolution
1°x1° globally, 0.5°x0.5° for place of interest
18 vertical levels, every 3 hours
Update frequency and timing
4 times daily; forecasts will be started ca. 4 hours after analysis time and will be available ca. 9 hours after analysis time, i.e., forecasts based on 0-UTC meteorological analysis will be available at about 9 UTC (± hour, depending on the tracer).