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GOES-East/West Composite image of Sounder Channel 12 (upper-level moisture)

All available sectors from the GOES-East and GOES-West Sounders are spatially combined each hour for a few select representative infrared spectral bands. The four pieces (two in the east; two in the west) typically cover the western Atlantic, eastern US, western US, and eastern Pacific; however, schedule variations do occur, as do omissions during eclipse situations. For display, these images from GOES-East and GOES-West have been re-mapped to a common projection (mercator) at an effective resolution of 14 km; the nominal resolution of a field-of-view at the sub-satellite point for a GOES Sounder is 10 km. The color scheme, from warm reds to cool blues, is maintained for each band, but the range enhanced does vary with band (to emphasize gradients in each). Note the equivalent blackbody temperature scale at the bottom of each image. The current band selection follows:

Band
Number
Wavelength
(um)
Principal
Gas
Sounding
Purpose
3 14.1 CO2 upper-level temperature
5 13.4 CO2 lower-level temperature
8 11.0 window surface/cloud top temperature
10 7.5 H2O lower-level moisture
11 7.0 H2O midlevel moisture
12 6.5 H2O upper-level moisture
15 4.45 CO2 upper-level temperature
17 4.0 window surface temperature

Note the following characteristics while comparing the different bands. Window bands 8 and 17 have the same color enhancement applied; band 17 is more transparent, but is also sensitive to reflected solar radiation (contributing energy during the daytime). Windows range widely from warm surface values to cold cloud tops. Bands 3 and 12 both sense upper portions of the troposphere; note the smaller range of temperatures. Band 3 is sensitive to the thermal energy of that region, while band 12 is sensitive to the moisture content as well. Thus, in band 3, look for the large scale thermal pattern (cool troughs and warm ridges); in band 12, look for moist ("cool") plumes and dry ("warm") slots, often clearly indicative of dynamic features ranging from jet streams to mesoscale vorticity circulations. Note that band 11 provides a look at moisture at levels lower in the atmosphere than that from band 12 (temperature values are warmer in band 11, in agreement with the general lapse of temperature with height in the troposphere). Also notice how "clean" the radiometric signal is from band 11 (versus the noisier bands 3 or 12). Of all the water vapor channels, band 10 is influenced the most by radiation emitted from the surface. Band 15 has been included for monitoring purposes, with respect to the appropriateness of radiometric coefficients applied to the specific GOES Sounder instruments (especially historically with GOES-8); otherwise, band 15 is similar to band 3, but is within the shortwave rather than longwave CO2 absorption region.