GEOS-CHEM Near-Real-Time (NRT) Simulations

Last Updated April 10, 2006. As of April 1 2007, the GMAO GEOS-4 met fields have been turned off. GEOS-5 is now the operational GMAO data product. The GEOS-Chem model has not yet been validated with GEOS-5. Scientific validation is ongoing but will likely take at least a couple of months. Therefore there will be no NRT simulations for the time being.

Harvard University - Atmospheric Chemistry Modeling Group:
Solène Turquety (stu@fas.harvard.edu),Carine Saüt (csaut@fas.harvard.edu),Bob Yantosca (bmy@sol.harvard.edu), Rynda Hudman (hudman@fas.harvard.edu) and Daniel Jacob (djacob@fas.harvard.edu)

NASA Goddard Space Flight Center - Global Modeling and Assimilation Office (GMAO): Steven Pawson (spawson@gmao.gsfc.nasa.gov) and Eric Nielsen (nielsen@gmao.gsfc.nasa.gov)

University of Washington - Department of Atmospheric Sciences: Lyatt Jaeglé (jaegle@atmos.washington.edu)

Data Products | About the NRT runs

NRT GEOS-CHEM Products : Interactive Web Interface

Near real time assimilation browser:
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Ground-station browser:
 View latest comparison plot at CPO
View latest comparison plot at MBO
Upper tropospheric observations from the EOS Microwave Limb Sounder (MLS):
 View comparison to weekly upper tropospheric MLS O3 and CO observations Follow link and scroll down to "MLS weekly tropospheric data plots"

NOTE: You may encounter problems with INTERNET EXPLORER using this site. We recommend that you use either NETSCAPE or MOZILLA.
Please report any bugs/comments to Lyatt Jaeglé (jaegle@atmos.washington.edu).

NEW: Near real time comparison to observations at three west coast sites. Follow the new option above, "Ground-station browser", to view real-time observations of CO, ozone and NOy from the Jaffe research group, and compare them to the GEOS-CHEM NRT simulation! These observations are made continuously at two sites: Cheeka Peak Observatory (48.3 N, 124.6 W, 480 m) in Washington State and Mt. Bachelor Observatory (43.8N, 121.7W, 2.7 km) in Oregon. We are also extracting NRT results at Whistler Summit in Canada.

The maintenance of this web-site is made possible by funding from the National Science Foundation under grant ATM 0238530.

QUICKSTART GUIDE to NRT simulation browser

Here you can view output from the daily near-real-time simulations which are generated with the GEOS-CHEM model. You can choose to plot timeseries data (CO, NOx,O3, HNO3, PAN, acetone, sulfate, dust, sea-salt), columns (CO, NO2, HCHO, O3), or chemical quantities (OH, NO2, NO).
Simply press the "Start NRT browser" button to see maps of the various products calculated with the GEOS-CHEM chemical transport model. You can then adjust the day, hour, tracer, latitude, longitude, altitude and plot the results again. You also have the options of generating an animation or a postscript file. The curtain display option together with the 'Zonal Average' or 'Meridional Average' plot type allows you to enter (latitude, longitude, altitude) along a proposed flighttrack and then sample it along that flight track. All dates are indicated in GMT time.

ABOUT THE GEOS-CHEM Near-Real-Time (NRT) SIMULATIONS

We are producing daily detailed ozone–aerosol–CO–CO2–methane simulations with the GEOS–CHEM model. These GEOS–CHEM simulations are being generated at Harvard University using the GEOS–4 first-look assimilated data product at 2° latitude by 2.5° longitude horizontal resolution and 55 vertical levels. The GEOS-4 meteorological assimilated fields are generated at NASA's Global Modeling and Assimilation Office (GMAO). The simulations lag the present by only 2-3 days, and hence have been dubbed "near-real-time", or NRT for short.

The GEOS–CHEM NRT simulations serve 3 purposes:

  1. To monitor over the course of ICARTT any large deviations between the aircraft observations and our understanding of ozone and aerosol processes that may cause alteration of flight plans,

  2. To provide vertical shape information for NO2 and HCHO concentrations to support near-real-time retrievals of SCIAMACHY column data for these two gases (by Dalhousie University), and

  3. To generate a set of preliminary findings by the end of ICARTT.
    4.

The NRT simulations include our most detailed GEOS–CHEM representation of coupled nonlinear ozone–NOx–VOC–aerosol chemistry [Park et al 2004], CO2 [Suntharalingam, 2004], and methane [Xiao et al 2004]. Anthropogenic emissions in the United States will be from the EPA NEI 1999 inventory. Fires in North American and Northern Asia will be included in the simulation on the basis of MODIS satellite observations.

Output from the NRT simulations are posted to this website (maintained by Lyatt Jaeglé at the University of Washington) and consists of 3 different kinds of quantities:

Personnel at Harvard responsible for generating NRT simulations:

Reference: Chemical forecasting and near-real-time CTM analysis in support of INTEX–NA, D. J. Jacob, 2004.