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Online Versus Offline Air Quality Modeling On Cloud-resolving Scales


Computational advances now allow air quality forecast models to fully couple the meteorology with chemical constituents within a unified modeling system – online – that allows two-way interactions. The more common approach is the offline system, which only allows one-way coupling from the meteorology – sampled at fixed time intervals – to the chemistry. To study the information loss between online and offline numerical forecasts, a next-generation nonhydrostatic air quality modeling system has been developed that can be used both offline or online. First, a control online air quality simulation is conducted and the meteorology and chemical data are saved at a 10 s time interval. Subsequently, three offline simulations are conducted with meteorological data updates at 10, 30, and 60 min time intervals. Analysis of the wind velocity power spectrum and chemical profiles indicate that the offline simulations are susceptible to large errors in the vertical mass distribution.

Article / Publication Data
Available Metadata
Accepted On
July 16, 2004
Fiscal Year
Publication Name
Geophysical Research Letters
Published On
January 01, 2004
Publisher Name
Amer Geophysical Union
Print Volume
Print Number
Submitted On
April 16, 2004


Not available


Authors who have authored or contributed to this publication.

  • Stuart A. McKeen - Not Positioned Csl
    Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder
    NOAA/Global Systems Laboratory