10.3 microns - Total Operational Weather Readiness - Satellites (TOWR-S)
GOES-R 10.3 um (Channel 13)
GOES-R ABI Fact Sheet Band 13 (“Clean” Longwave Infrared Window Band)
The “need to know” Advanced Baseline Imager reference guide for the NWS forecaster
By: The Cooperative Institute for Meteorological Satellite Studies (CIMSS)
The 10.3 µm atmospheric “clean” infrared window band is less sensitive than other infrared window channels to water vapor and, hence, improves atmospheric moisture corrections, cloud particle size estimation, and surface property characterization in derived products. The 10.3 µm band does have a very small sensitivity to ozone, while the 11.2 µm longwave window does not. In general, the 10.3 µm band may be used much like the traditional infrared window band. Typically, this band is slightly warmer than the traditional longwave window due to less moisture absorption in the lower troposphere.
Source: Schmit et al., 2005 in BAMS, the ABI Weather Event Simulator (WES) Guide, Lindsey et al., 2012.
Figure 1: The Advanced Himawari Imager (AHI) 10.4 μm band image for Typhoon Maysak from March 31, 2015, at 06 UTC. Credit: CIMSS and JMA
|In a Nutshell:|
|GOES-R ABI Band 13 (approximately 10.3 μm central, 10.2 μm to 10.4 μm)|
|Also similar to AHI Band 13|
|Not available on current GOES imager or sounder|
|"Clean" longwave infrared window band|
|Both day and night|
|Uses Similar to:|
|GOES-R ABI bands 11, 14, and 15|
Table 1: Overview of the 10.3 μm channel
Figure 2: The left panel shows the MTSAT infrared window band, while the right panel is of the JMA’s AHI longwave window centered at 10.4 µm. There is improved spatial resolution from the AHI, approximately by a factor of four. Both images are from November 3, 2015, at approximately 19:30UTC, and each are shown in their native projection. This case is of the Mount Rinjani volcano in Indonesia. While MTSAT does show the plume (in the center of the image), the Himawari data (from JMA) depicts the plume more clearly and uniquely shows the hot spot associated with this event. This image was made in McIDAS-X. Warmer brightness temperatures (K) are denoted as darker shades of gray, while the colder values are denoted as white. Credit: SSEC and ASPB.
Did You Know? Should the 10.3 μm or 11.2 μm band be the “default” atmospheric longwave IR window band?
According to Lindsey et al.: “Since the 10.3 μm band is cleaner than the 11.2 μm band, we recommend that forecasters default to the 10.3 μm band when simply looking at a window IR for estimates of radiating temperatures or subjective cloud identification and classification. But when a more detailed physical retrieval is being designed, characteristics of both bands need to be carefully considered. That said, … all bands from the ABI… are planned to be available for use by forecasters and others."
|GOES-R Baseline Product||Used?|
|Aerosol Optical Depth|
|Clear Sky Mask|
|Cloud & Moisture Imagery||x|
|Cloud Optical Depth|
|Cloud Particle Size Distribution|
|Cloud Top Phase|
|Cloud Top Height|
|Cloud Top Pressure|
|Cloud Top Temperature|
|Rainfall Rate / QPE|
|Legacy Vertical Moisture Profile||x|
|Legacy Vertical Temperature Profile||x|
|Derived Stability Indices||x|
|Total Precipitable Water||x|
|Downward Shortwave Radition: Surface|
|Reflected Shortwave Radiation: TOA|
|Derived Motion Winds|
|Fire / Hot Spot Characterization|
|Land Surface Temperature|
|Sea Surface Temperature||x|
|Volcanic Ash: Detection & Height|
Table 2: List of GOES-R baseline products that use the 10.3 μm channel
Tim's Topics: During the early formulation phase of the ABI, in the late 1990s, this spectral band was not included. In fact, the ABI was originally only eight spectral bands. Dr. Paul Menzel suggested the 10.3 μm band based on his experience with a similar band from a research sensor, the MAS (MODIS Airborne Sensor) on the NASA ER-2 high-altitude research aircraft. The data revealed the utility of this clean longwave infrared window for seeing through some clouds to ice (when differenced with a 8.6 μm band). The NOAA research council added the 10.3 μm band to the suite of ABI bands as a result. Several other international geostationary imagers now have, or will have, this spectral band.
Tim Schmit is a research meteorologist with NOAA NESDIS in Madison, Wisconsin.
Figure 3: The clear-sky weighting function (or contribution function) represents the layer of the atmosphere where the satellite-sensed radiation originates. This figure depicts the weighting functions for United States standard atmosphere scenes without the presence of clouds for window bands on the ABI. All of these weighting functions peak at the surface, suggesting that the surface temperature and emissivity dominate the brightness temperature in cloud-free scenes. Credit: CIMSS
Ward's Words: Though the weighting functions peak at the surface, longwave infrared window bands brightness temperatures are not necessarily representative of the two-meter shelter temperature, particularly during the day and over land, when certain land surfaces can warm substantially compared to the air temperature. Because of the water vapor absorption in infrared window bands, they do not provide a great estimate of the “skin” temperature. There are baseline products that exist to provide this information, though users can also estimate some quantities. For example, sea surface temperature is approximately twice the ABI Band 14 brightness temperature less than the ABI Band 15 brightness temperature based on regression algorithms developed with polarorbiting satellite imagers.
Bill “Hima-Ward-i” Ward is the ESSD Chief in NWS Pacific Region and a former Guam forecaster.
|ABI Band||Approximate Central Wavelength (µm)||Band Nickname||Type||Nominal Sub Satellite Pixel Spacing (km)|
|13||10.3||"Clean" Longwave Window||IR||2.0|
|15||12.3||"Dirty" Longwave Window||IR||2.0|
Table 3: Comparison of GOES-R channels
ABI Bands Quick Information Guides: http://www.goes-r.gov/education/ABI-bands-quick-info.html
J. Appl. Remote Sensing: http://spie.org/Publications/Journal/10.1117/1.JRS.6.063598
ABI Weighting Function page: http://cimss.ssec.wisc.edu/goes/wf/ABI/
CIMSS Satellite Blog: http://cimss.ssec.wisc.edu/goes/blog/archives/20096
CIMSS Satellite Blog: http://cimss.ssec.wisc.edu/goes/blog/archives/19897
GOES-R COMET training: http://www.goes-r.gov/users/training/comet.html
GOES-R acronyms: http://www.goes-r.gov/resources/acronyms.html