TEMPO gridded NO2 total column PROXY

Description

This is a “fast” proxy dataset for the TEMPO early adopters community, aimed to familiarize users on the planned file structure and content of TEMPO level 3 (L3) NO2 data before real data are available from the mission after launch. The procedure for generating the “fast” proxy L3 NO2 product is the same as the level 2 (L2) product, except for the regridding step at the end of the L3 procedure. Hourly model (truth) profiles and monthly-average hourly trace gas (a-priori) profiles from the NASA Goddard Earth Observing System version 5 Earth system model (GEOS-5 ESM) with GEOS-Chem as a chemical module (G5NR-chem; ~12.5 x 12.5 km2 resolution) are sampled at the TEMPO footprint (2.0 x 4.75 km2 at the center of the Field of Regard) to represent the true state of the atmosphere and climatological conditions, respectively. Scattering weights are based on calculations from pre-computed lookup tables as a function of viewing geometry, surface reflectance, cloud fraction, and cloud pressure. True slant column densities are calculated from the NO2 truth profiles multiplied by the scattering weights in each model layer. A similar set of calculations are performed using the climatological model profiles to derive air mass factors from the slant column and vertical column densities. A statistical noise model is then applied to add random noise, primarily as a function of radiance, to the true slant column densities, which are divided by the climatological air mass factors to derive the proxy NO2 vertical column density product at the TEMPO footprint. Lastly, a geometric regridding procedure is applied, which weights the contributions of each L2 pixel to the target L3 polygon based on the geometric overlap, to generate the L3 product on a regular grid at 0.05° resolution. Overall, the “fast” proxy methodology accounts for retrieval physics/sensitivity/uncertainty, but not by the operational retrieval algorithms. The proxy product is not intended for supporting scientific publications, operational decisions, etc. Permission is needed to access the data.

Resources

Name Format Description Link
21 TEMPO project page http://tempo.si.edu
34 Mission Logo https://asdc.larc.nasa.gov/static/images/project_logos/tempo.png

Tags

  • atmosphere
  • atmospheric-chemistry
  • air-quality
  • earth-science

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