Megacity Impacts on Regional and Global Environments (MIRAGE) is part of the Mexico City Pollution Outflow Field Campaign. The WRF mesoscale model real-time forecast support for the March 2006 field campaign is available from these web pages.

The National Center for Atmospheric Research has established a Strategic Initiative to study the Megacities Impacts on Regional and Global Environments (MIRAGE). The goal of MIRAGE is to characterize the chemical/physical transformations and the ultimate fate of pollutants exported from urban areas, and to assess the current and future impacts of these exported pollutants on regional and global air quality, ecosystems, and climate.

As part of the MIRAGE Initiative, plans are being developed for an observational campaign to examine the chemical and physical transformations of gases and aerosols in the polluted outflow from Mexico City. This MIRAGE field campaign will coordinate and integrate observations from ground stations, aircraft, and satellites to provide a rich data base for improving regional and global models of the transport and transformations of aging urban pollutants.

The field campaign is scheduled for 1 - 28 March 2006. This WRF Realtime Forecast site will be used to test the realtime forecast products prior to the experiment, and will be the source of daily forecasts during the MIRAGE experiment.

ARW model configuration

The ARW model is integrating two grids using two-way interaction, and a scalar representing the CO release from the Mexico City metropolitan region is being transported within the meterological simulation to allow tracking of the Mexico City plume. We are using WRFV2.1.1 with bug fixes to the KF convective parameterization and to the YSU PBL as outlined in the latest release WRFV2.1.2.

mirage arw domains The ARW output can be viewed online here.

Coarse grid

dx = dy = 9 km, dz is variable
399 x 300 x 37 grid (399 west-east (x) grid cells by 300 south-north (y) grid cells with 37 vertical levels)
Mercator map projection
Time step (dt) = 60 seconds (acoustic step = 10 s)
WSM-3 "simple ice" microphysics
RRTM long-wave radiation scheme
Dudhia short-wave scheme (10 minutes between radiation scheme calls)
Monin-Obukhov surface layer scheme
Noah land-surface model
YSU PBL scheme
Kain-Fritsch cumulus parameterization scheme
Forecast frequency and length: Daily 4-day forecasts, starting at 0 UTC (1900 local time)
Initialization: Interpolation from the NCEP GFS 0Z analysis.
Boundary conditions: Interpolation from the NCEP GFS 0Z forecast.

Fine grid

dx = dy = 3 km, dz is variable and the same as coarse grid
429 x 399 x 37 grid (429 west-east (x) grid cells by 399 south-north (y) grid cells with 37 vertical levels)
Mercator map projection
Time step (dt) = 20 seconds (acoustic step = 3 1/3 s)
WSM-3 "simple ice" microphysics
RRTM long-wave radiation scheme
Dudhia short-wave scheme (10 minutes between radiation scheme calls)
Monin-Obukhov surface layer scheme
Noah land-surface model
YSU PBL scheme
No cumulus parameterization scheme
Forecast frequency and length: Daily 2-day forecasts, starting at 0 UTC (1900 local time)
Initialization: Interpolation from the NCEP GFS 0Z analysis.
Boundary conditions: From the ARW 9 km (coarse) grid, with feedback to the coarse gird (2-way interactive).

WRF-Chem model configuration

The WRF-Chem model integrates a single domain.  The WRF-Chem solver used in MIRAGE is based on the ARW meteorological model and the chemistry solver.

mirage chem domains The WRF-Chem output can be viewed online here.

Coarse grid

dx = dy = 6 km, dz is variable
130 x 130 x 30 grid (130 west-east (x) grid cells by 130 south-north (y) grid cells with 30 vertical levels)
Mercator map projection
Time step (dt) = 30 seconds (acoustic step = 7.5 s)
Kessler (warm-rain) microphysics
RRTM long-wave radiation scheme
Dudhia short-wave scheme (30 minutes between (meteorological) radiation scheme calls)
Monin-Obukhov surface layer scheme
Noah land-surface model
YSU PBL scheme
No cumulus parameterization scheme
Forecast frequency and length: Daily 2-day forecasts, starting at 0 UTC (1900 local time)
Initialization: Interpolation from the NCEP GFS 0Z analysis.
Boundary conditions: Interpolation from the NCEP GFS 0Z forecast.

Chemistry

Modified RADM2 mechanism
FTUV radiation
Biogenic emissions every 30 minutes
Photolysis timestep = 30 minutes
Chemistry timestep = 3 minutes
Dry Deposition
No aerosols

Advanced Research WRF & WRF-Chem

WRF-ARW model: Bill Skamarock
WRF-Chem: Xuexi Tie, Sasha Madronich
Forecast Production: Sherrie Fredrick
Website: Kristin Conrad

Further Information on ARW and WRF-Chem

For more information on the Mesoscale & Microscale Meteorology Division's Advanced Research WRF model, please visit http://www.mmm.ucar.edu/facilities/wrf/wrf.php

For information on all the WRF development efforts, please visit wrf-model.org.

Information on the chemistry component of WRF-Chem can be found on the WRF Working Group 11 (Atmospheric Chemistry) web page.

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