|GOES-R IFR Probabilities computed from MODIS data (upper left) and from GOES-East data (lower left); Ceiling and visibility observations (upper right) and 10.7-micrometer brightness temperatures from GOES-East (lower right)
GOES-R IFR Probabilities can be computed using GOES-East Imager data (the Imager has 5 radiometric channels), with a nominal resolution of 4 kilometers at the sub-satellite point (The Equator, at 75 degrees W for GOES-East; Actual resolution in the upper midwest is closer to 5 or 6 kilometers). IFR Probabilities can also be computed using MODIS data from Terra or Aqua; the MODIS instrument yields information at 36 different radiometric channels, with a nadir resolution of 1 km. Thus, small-scale features, such as river valleys, or ridge-tops, are far more likely to be visible in the data. However, MODIS data are available infrequently because Terra and Aqua are polar orbiters, and each satellite passes over a location in the upper Midwest only 2 times daily.
The strength of GOES-R IFR imagery is its temporal resolution. Routine imaging every 15 minutes is typical, and that allows observations of fog development, as shown in the loop below. The increase in GOES-R IFR probabilities alerts the forecaster to a region of interest, where more vigilant monitoring of sky conditions may be warranted. The surface observations do show decreasing visibilities and ceilings where the IFR probabilities are increasing; that is, the IFR probabilities and actual observations are consistent.
|GOES-R IFR Probabilities computed using GOES-East imager data and surface observations of visibility and ceiling from 0400 UTC to 1400 UTC on 26 July 2012.
The ABI (Advanced Baseline Imager) on GOES-R will have twice the resolution of the current GOES Imager (that is, 2 kilometer for infrared channels at the subsatellite point) and higher temporal resolution as well.