Monthly Averages of GOES-17 Brightness Temperatures for Bands 8, 10, and 13
Monthly means of full disk GOES-17 brightness temperatures1 for Bands 8, 10, and 13 have been computed from 2019 to 2021, totaling 36 months. This is an expansion of similar work that had been done for Band 13 for a single year. Band 8, centered on 6.2 µn, is sensitive to upper-level water vapor. While Band 10, centered on 7.3 µn, is sensitive to low-level water vapor. Band 13 is the clean longwave infrared window channel and observes at 10.3 µn.
Brightness temperature can be thought of as the amount energy (radiance) being reflected or emitted from Earth and measured by satellite sensors. These fields of averaged brightness temperature are useful for assisting forecasters in knowing what can be expected from satellite retrievals on monthly timescales, especially in remote Pacific regions where forecasters are heavily reliant on satellite data.
While a large amount of smoothing is expected for a monthly average, the resulting full disk fields are not homogenous. Certain patterns appear. The ITCZ is noticeable. Also, an area of warmer brightness temperature is visible west of Hawaii during winter months in the animations for Bands 8 and 10. This is likely associated with a synoptic high pressure for that region.
Reference to a Climatic Atlas created by Sadler et al. (1987) from the School of Ocean and Earth Science and Technology confirms potential for a synoptic high pressure region that is usual for that time of year. However, because the Sadler fields are derived surface measurements (temperature, pressure, wind, and stress), comparing them to GOES-17 ABI brightness temperatures is not exactly an “apples to apples” situation.
1 Brightness temperatures are computed from radiances.