Model parameterization

The BETR Global model includes a database of long-term average environmental conditions in the global environment. In dynamic calculations, many of these environmental parameters are varied on a monthly time resolution. The animations and maps on this page illustrate the parameters in the default BETR Global environmental database. If your internet connection is slow you may have to be patient while the animations load!

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1. Temperature

Temperature in the upper and lower atmosphere is taken from the NCEP/NCAR reanalysis of climate data, and is 15^o x 15^o averages for the years 1960 - 1999.

2. OH Radical Concentrations

Hydroxyl (OH) radicals are the primary oxidant responsible for degrading many organic chemicals in the atmosphere. Concentrations of OH radicals in the upper air compartment (free troposphere) and lower air compartment (boundary layer) of BETR Global have been taken from the paper by Spivakovsky et al. (2000).

3. Precipitation Rate

Precipitation rates, and average dry and wet periods used in BETR Global are from the NCEP/NCAR reanalysis dataset.

4. Atmospheric Circulation

Atmospheric circulation in BETR Global is also derived from averages of the years 1960 - 1999 from the NCEP/NCAR reanalysis. The animation below shows the calculated concentration of an inert, volatile tracer in the lower air compartment that was emitted as a pulse from southern Europe.

5. Ocean Circulation

BETR Global uses a description of ocean circulation derived from the NOAA drifting buoy dataset, as described in the supporting information of the paper by Armitage et al. (2009). The animation below shows the transport of an ocean tracer released as a pulse in the model region that includes the United Kingdom. Note that the total amount of the tracer goes down over time as a result of transfer to deep oceans.

6. River Flow Rates and Discharge to Oceans

Flow rates of fresh water between regions and discharge into the oceans is parametrized in BETR Global using the RivDIS database, which contains monthly averaged discharge measurements for 1018 stations located throughout the world. The period of record varies widely from station to station, but has a mean of 21.5 years. These data are available from the Distributed Active Archive Center maintained at Oak Ridge National Laboratory, USA.