CIMSS Satellite-Derived Proxy ABI Data

These pages describe how select MODIS (MODerate-resolution Imaging Spectroradiometer) data have been reformatted for use in ABI (Advanced Baseline Imager) studies. Most ABI bands can be simulated in this manner. The advantage of using real satellite observations is that the small-scale features are more realistic than calculated from numerical models. Of course the spectral simulations are not exact when just using a MODIS band to simulate the ABI, but most of these bands are spectrally similar. If a more accurate spectral simulation is needed, then Atmospheric InfraRed Sounder (AIRS), or NPOESS Atmospheric Sounder Testbed-Interferometer (NAST-I), data can be convolved with simulated ABI Spectral Response Functions (SRF).

A collection of visible, near-infrared (IR) and IR images based on the high-spatial resolution NASA MODIS hdf_data have been selected for several corresponding ABI bands to support ABI Government Field Test studies. These images include some interesting weather/environmental phenomena, such as:

  • Fire and Smoke
  • Mountain Waves (IR Only)
  • Dust Storms
  • Convective Clouds
  • Daytime Clouds

There are several steps in these ABI simulations:

  • The original MODIS hdf images for these various cases have been acquired from the NASA DAAC over the region of interest.
  • Only the select bands with similar central wavenumbers have been considered.
  • The IR bands have been de-striped with an algorithm from L. Gumley of CIMSS.
  • The MODIS image data have been averaged to appropriate ABI resolution. For the IR bands this is to 2 km.
  • Only subsets of the original MODIS file are provided. 1000 x 1000 Fields of View (at 1km) are used over the area of interest. This is to a avoid image edge effects.
  • The data are stretched from a minimum to maximum value, which is band-dependent and based on the stated ABI requirements. The draft bit-depth for the ABI bands is then used to define the quantization level. While the "science data from the focal plane arrays is digitized by 14-bit analog-to-digital converters (ADCs)", bit trimming is configurable on-orbit. Current plan:

    10 bits:

    0.47, 0.86, 1.38, 1.61, 2.26 µm

    11 bits:

    6.18, 6.95, 9.61, 13.3 µm

    12 bits:

    0.64, 7.34, 8.5, 10.35, 11.20, 12.30 µm

    14 bits:

    3.90

  • Finally, the image (and the corresponding navigation information) has been written to a Matlab (*.mat) file.
Not all future ABI bands can be closely represented by MODIS. In fact, we can only really represent two of the three water vapor channels (8,9,10) and not the 10.35 µm (band 13) at all. The following table shows the ABI bands and their proposed central wavelengths along with the MODIS bands chosen to represent them along with their central wavelengths, the resolution of those bands on ABI and the bitdepth simulated for ABI. 
 ABI   Center  MODIS   Center  ABI     ABI
 Band  Waveln  Band    Waveln  Res     Bitdepth
 No    (μm)    No      (μm)    (km)    
 01    0.47    3       0.47    1       10
 02    0.64    1       0.659   0.5     12
 03    0.865   2       0.865   1       10
 04    1.378   5       1.240   2       10
 05**  1.61    6       1.640   1       10
 06    2.25    7       2.130   2       10
 07    3.9     22      3.96    2       14
 08*   6.19    NA       NA     2       11
 09    6.95    27      6.78    2       11
 10    7.34    28      7.34    2       12
 11    8.5     29      8.55    2       12
 12    9.61    30      9.72    2       11
 13*   10.35   NA       NA     2       12
 14    11.2    31      11.0    2       12
 15    12.3    32      12.0    2       12
 16    13.3    33      13.4    2       11
                                * These bands don't appear in the data files because MODIS does not have a similar enough band.
  ** The 1.64μm band, band 6, on Aqua MODIS, appears to have several bad detectors. In the images collected here 4 of the 10 detectors were bad. So that band only appears for data collected for Terra MODIS.
Draft ABI data rates, before any compression. Total rate: 37.6 Mbps. This is assuming variable bit depth data, circular area, and a 5-minute full disk scan mode. Visible and Near-Infrared Bands 1-6 Infrared Bands 7-16

The above tables are from an ABI overview article:

Schmit, T. J., M. M. Gunshor, W. P. Menzel, J. J. Gurka, J. Li, and A. S. Bachmeier, 2005: Introducing the next-generation Advanced Baseline Imager on GOES-R. Bull. Amer. Meteor. Soc., 86, 1079-1096.

NOTICE:  The images, text, and other information on these web pages are proprietary information belonging to The Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison.   If the informationis of use to you, please give proper credit to CIMSS.  Thanks!

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