MOZART-4
MOZART-4 (available Jan 2006) will incorporate a number of improvements over MOZART-2:Improved Chemical Mechanism
John Orlando, Geoff Tyndall: The chemical mechanism used in MOZART-4 has been expanded from the MOZART-2 mechanism described by Horowitz et al [2003], and now includes a more complete description of anthropogenic hydrocarbon chemistry. A lumped C4H10 hydrocarbon species in use previously has been replaced by three separate species, "bigene" (C4H8), a lumped alkene species representing mostly 2-methylpropene and 2-butene; "bigalk" (C5H12), a lumped alkane representing the butanes, pentanes, and hexanes; and "toluene" (C7H8), a lumped aromatic compound representing mostly benzene, toluene, and the xylenes. Additional oxidation products of these species have also been included. The terpene oxidation mechanism in MOZART-4 has also been updated to reflect recent laboratory data. These changes result in 17 new species and 22 new reactions. The new MOZART species are: BIGENE, BIGALK, TOLUENE, ENEO2, ALKO2, ALKOOH, MEK, MEKO2, MEKOOH, CRESOL, TOLO2, TOLOOH, XOH, TERPO2, TERPOOH, BIGALD, GLYOXAL
New photolysis scheme (FTUV)
The FTUV (Fast TUV) model is a new radiative transfer model to calculate photolysis rates. The detailed description and its application is given by Tie et al. [2003]. The model is based on the Tropospheric Ultraviolet-Visible Model (TUV) developed by Madronich [1989]. TUV is a state-of-the-art radiation transfer model, and is widely used by the scientific community. TUV calculates spectral irradiance, spectral actinic flux, and photodissociation rates (J-values) for the wavelength range between 121 and 750 nm. The wavelength resolution used by TUV is sufficiently expensive as to prohibit the coupling of TUV with three-dimensional global CTMs. In order to couple the radiative transfer model (TUV) into MOZART-4 and to investigate the effect of clouds and aerosols on photolysis rates and oxidants, we have developed a simple TUV model, which is about 8 times faster than the full TUV. We refer to this model as Fast-TUV (FTUV). In FTUV, we utilize the same physical processes as the TUV model, except that the number of wavelength bins between 121-750 nm is reduced from 140 to 17 bins.
References:
Tie, X., S. Madronich, S. Walters, P. Rasch, and W. Collins, Effect of Clouds on photolysis and oxidants in the troposphere, J. Geophys. Res., 108,4642, doi: 10.1029/2003JD003659, 2003.Madronich, S., Photodissociation in the atmosphere 1. Actinic flux and the effect of ground reflections and clouds, J. Geophys. Res., 92, 9740-9752, 1989.