83rd Annual

Thursday, 13 February 2003
Channel selection for the next generation geostationary Advanced Baseline Imagers
Timothy J. Schmit, NOAA/NESDIS/ORA, Madison, WI; and W. P. Menzel, J. Sieglaff, J. P. Nelson III, M. K. Griffin, and J. J. Gurka
Poster PDF (137.8 kB)
The Advanced Baseline Imager (ABI) will be the next generation geostationary imager on GOES-R, beginning in approximately 2012. This imager will have a minimum of eight spectral bands and a maximum of eighteen spectral bands. The minimum eight bands would be similar to the five bands on the current GOES-8 -11 imagers (0.64, 3.9, 6.15, 11.2, and 12.3 Ám), plus a snow/cloud-discriminating 1.6 Ám band, a mid-tropospheric 7.0 Ám water vapor band, and a 13.3 Ám band useful for determining cloud heights. This CO2-sensitive band is similar to those on the GOES-12/N/O/P imagers.

Four additional bands were identified as being needed to meet and enhance opportunities for NWS (National Weather Service) weather and climate research and applications. Two of these bands are centered in infrared windows at 8.5 Ám and 10.35 Ám. The 8.5 Ám band, in conjunction with the 11.2 Ám band, will enable detection of volcanic dust cloud containing sulfuric acid aerosols. The 8.5 Ám band can be combined with the 11.2 and 12.3 Ám channels to derive cloud phase during both the day and night. The 10.35 Ám band will help to derive low-level moisture, cloud particle size and surface properties. Another visible band at 0.86 Ám is suggested to help with the detection of aerosols and vegetation. Also, a near-infrared channel at 1.38 Ám is proposed to detect very thin cirrus not detected by other bands.

Six more bands, in addition to the previous 12 bands are being evaluated. In order of priority, they are: 0.47, 9.7, 0.555, 2.3, 3.7, and 7.4 Ám. Because small particle scattering is most effective at the shortest wavelengths, a "blue" channel (0.47 Ám) would be particularly valuable for aviation applications (e.g., visibility). The thermal infrared ozone channel (9.7 Ám) will provide information on the dynamics of the atmosphere near the tropospause and total ozone estimates. If the 0.555 Ám band is added, it can be used with the 0.64 and 0.47 Ám bands to produce "true color" imagery for a range of applications, including dust and water turbidity. The 2.3 and 3.7 Ám bands can be used for determining cloud properties. The 7.4 Ám band can show another layer of atmospheric flow and SO2 properties (without ash interference). Taken as a whole, the additional bands are intended to improve moisture, volcanic and conventional cloud, aerosol, visualization and surface sensing capabilities.

Simulated GOES Advanced Baseline Imager examples will be shown for the bands in the visible, near infrared and infrared (IR) regions. The visible/near IR bands will be spectrally simulated from aircraft data, the NASA AVIRIS (Airborne Visible InfraRed Imaging Spectrometer). The AVIRIS is a high-spectral sensor with approximately 200 bands between 0.4 and 2.4 Ám. The advantage of using hyperspectral data to simulate broadband channels is that any spectral response can be applied to test sensitivities. Also, realistic meteorological scenes can be used. MODIS (MODerate-resolution Imaging Spectroradiometer) data will be used for the IR simulations.

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