Talk:Moderate-Resolution Imaging Spectroradiometer

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The MODIS data processing chain is wanted![edit]

The MODIS data processing chain should also be described.

The short version of the story is, roughly:

  • L0 to L1A to L1B:
    • the satellite sends a sequence of packets, formatted as per CCSDS recommendations, which are received by the receiving station and, after any duplicate or damaged packets are removed, saved as an .pds file;
    • the data is then extracted out of the individual packets to be laid on swath (as in swath width), and an MxD01 (with x being “O” for MODIS/Terra and “Y” for MODIS/Aqua, respectively) file is formed;
    • the geolocation is then performed, resulting in an MxD03 file;
    • both the geolocation results and the original unpacked data-on-swath (MxD01) are needed to perform the calibration, resulting in an MxD02 — calibrated radiances — file;
  • L1B to L2:
    • the cloud mask is retrieved (MxD35);
    • the atmospheric variables (temperature and moisture profiles, the total amount of the atmospheric gases, etc.) are retrieved (MxD07); there, some ancillary data is used, in particular — the final reanalysis data, as published by NCEP;
    • with the atmospheric variables known, the accurate atmospheric correction is performed, resulting in the land surface (i. e., “no atmosphere”) reflectances product (MxD09);
  • L2 to L2G to L3:
    • the data on swath is first transferred to a kind of “intermediate” grid format, which allows for all the observations (i. e., up to four) of a given pixel of the grid to be saved (MxD09G);
    • a number of gridded products are then made, among those are BRDF model parameters (MCD43A1 for the “500 m” grid and MCD43B1 for the “1 km” one), Albedo (MCD43A3 and MCD43B3), etc.; the “C” letter here means that the product combines the data from both the MODIS/Terra and MODIS/Aqua sensors.

(But note that while the scheme outlined above is linear, the actual processing chain is more like a tree, with, e. g., some of the L3 products being all about atmosphere, and thus requiring no MxD09 processing. There're also much more products than mentioned above.)

Unfortunately, I cannot provide appropriate references just now, aside from Математические технологии оперативного регионального спутникового мониторинга характеристик атмосферы и подстилающей поверхности ч. 1. MODIS, which I co-authored.

Also of significance are:

PS. File naming conventions should also be described.

Ivan Shmakov (talk) 16:43, 17 July 2009 (UTC)

What replaced MODIS?[edit]

It says in the article it had a design life of 6 years and began in 2002, so I'm guessing they made something to supercede it. --I'ḏOne 05:02, 4 September 2010 (UTC)

Not yet, the satellites are still operational. I'm not sure if NASA has annonced anything to replace the satellites so far. Wonderworld1995268 (talk) 03:29, 5 September 2010 (UTC)
The NPOESS satellites were to supplement and then replace the Terra and Aqua satellites, but the project has folded. I guess that Joint Polar Satellite System is now ought to fill the role. — Ivan Shmakov (talk) 10:26, 31 March 2011 (UTC)