OMI Satellite/AIRPACT-3 Comparisons

(View additional imagery: CO from AIRS instrument)

Explanation of Images

Monthly Average NO₂ from OMI (Ozone Monitoring Instrument) and AIRPACT are for 1pm-2pm values only (when OMI passes over the region). Pixels with over 35% cloud cover are not included in the averaging function. An assumed GEOS-CHEM profile is used to add an estimated "below cloud" contribution to the Tropospheric Column derived from OMI.

OMI values are from the tropospheric NO₂ Vertical Column Data Product from NASA. AIRPACT values are taken from mixing ratio forecasts for all vertical layers and then vertically integrated into a single Vertical Column Density value. Ratios and Residuals are also calculated and provided to give a quantitative factor & difference between the satellite observations and the modeling system.

The OMI Tropospheric NO₂ algorithm assumes an annually averaged stratospheric contribution, which is subtracted from the total column measurement. Since seasonal changes in stratospheric NO₂ are not factored in, a shifting bias over the whole domain can be seen. Overall, this results in OMI Tropospheric NO₂ showing larger summer values and smaller winter values.

These AIRPACT results have been spatially averaged to the coarser OMI pixel resolution. Select from the monthly tabs below.

Additional satellite products links:

Mirador (http://mirador.gsfc.nasa.gov/) is a new search and order Web interface at NASA. It has a clean interface and employs the Google mini appliance for metadata keyword searches. Other features include quick response, data file hit estimator, Gazetteer (geographic search by feature name capability), and an interactive shopping cart.

Giovanni (http://disc.sci.gsfc.nasa.gov/giovanni) is a Web-based application developed by NASA that provides a simple and intuitive way to visualize, analyze and access vast amounts of Earth science remote sensing data without having to download the data.