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| Advanced Satellite Product Description
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It is important to note that specialized products using MODIS imagery can not be produced in real time due to the fact that the Terra platform is in polar orbit. With the combined use of both Terra and Aqua (both possessing the MODIS instrument), views of a given scene are available, at most, 4 times a day. The MODIS instrument can therefore provide "snapshots" of a region, allowing us to update our CI algorithms with higher resolution data in both the visible and infrared bands |
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The following examples utilized MODIS data from the Terra platform during a tornado outbreak in Tennessee and Alabama on November 10-11, 2002. These examples provide a demonstration of MODIS' advanced capabilities (e.g. higher spatial and spectral resolution) over the GOES instrument. The GIFTS (Geosynchronous Imaging Fourier Transform Spectrometer) instrument, to be launched in 2007, will provide real-time TOA radiances in over 3000 discrete spectral bands, allowing for an even further advancement in satellite imaging and profiling capabilities. Click here to learn more about this exciting future instrument.
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Benefits of Increased Spatial Resolution
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This example illustrates the benefits of 1 km. resolution MODIS vs. 4 km. GOES infrared data. A severe squall line with embedded supercell thunderstorms was present across MS, AL, and GA at this time (Nov. 11, 2002 04 UTC). Ahead of the squall line, boundary layer cumulus cloud lines were present, which developed into strong/severe thunderstorms an less than an hour later. These cumulus are clearly present in the MODIS 6.7-10.7 and 3.9-10.7 um band differences (bottom panels), but are not as clear in comparable GOES band differencing (top panels).
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| Benefits of Increased Spectral Resolution
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This example illustrates the benefits of having additional spectral bands detected by the MODIS instrument. The 8.5-10.8 um band difference, as documented by Strabala and Ackerman (1994), is useful for assessing the microphysical character of clouds. Values of this difference greater than zero indicate the presence of ice clouds; values near zero indicate mixed phase (liquid and ice); negative values indicate liquid water clouids or clear sky. The highest positive differences indicate the presence of high concentrations of small ice particles, which make the atmosphere more opaque in the 10.8 um band due to the difference between the refractive index of ice and water. This capability is not available with the GOES satellite because it does not have an 8.5 micron band.
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