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International MODIS/AIRS Processing Package

 University of Wisconsin-Madison AIRS Utility Plus Single FOV Retrieval Software Package for Direct Broadcast v1.0 release        10 March 2009

  This direct broadcast software package was created by Elisabeth Weisz at the University of Wisconsin-Madison. It contains software that will create these products from input AIRS Level 1B Radiance files and Direct Broadcast MODIS Geolocation and cloud mask files:

  • MODIS/AIRS collocations as described in Nagle, Frederick W. and Robert E. Holz, 2009: Computationally Efficient Methods of Collocating Satellite, Aircraft, and Ground Observations. Accepted to the J. of Atmos. and Ocean Tech.
  • AIRS cloud mask using collocated MODIS cloud mask pixels.
  • AIRS single field-of-view retrievals of temperature, moisture, ozone, surface emissivity and cloud top pressure.

The AIRS utility package includes scripts that can be run independently, or as part of the main processing script which calls the collocation, cloud mask and retrieval software in a processing chain. MODIS geolocation and cloud mask files are required as part of this processing. NOTE: This collocation will work only for Direct Broadcast full MODIS passes ONLY. It will not work correctly on standard DAAC 5 minute MODIS granules.

Several changes have been made to the UW AIRS single FOV regression retrieval. It is now valid under all-sky (clear and cloudy) conditions. Regression coefficients have been calculated using the latest version of the SARTA forward model (v1.07 as of Jan 2008, see http://asl.umbc.edu/pub/packages/sarta.html). Surface emissivities are retrieved as 6 emissivity eigenvector coefficients, and then converted to full spectrum (2378 AIRS channels). This is done under clear-skies only. Cloud top pressure (ctp) is now retrieved. Quality flags based on retrieved cloud optical thickness (cot) are now provided as well. The quality flag is a measure of cloudiness, and therefore at the same time a measure of the reliability of the retrieval results. Possible values are:

  • 0=clear
  • 1=thin clouds (cot < 0.5)
  • 2=medium clouds(0.5 < cot < 1)
  • 3=thick clouds (1 < cot < 1.5)
  • 4=opaque clouds (cot > 1.5)
  • 5=bad cloud top retrieval (i.e., cloud top retrieval above 90 hPa)

More information is provided in the release README file that is included with the package. To download the software, please select the DOWNLOAD NOW link below.

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