Winter 2008
GOES 10: New uses for an old satellite
photo by Maciek Smuga-Otto
The antenna in the foreground is SSEC's GOES-10 tracking antenna.
GOES-10 served as the western geostationary satellite for the U.S for nine years. In 2006, NOAA offered the services of GOES-10 to South American scientists to improve their weather analyses and forecasts. After capturing and archiving the GOES-10 data stream during the transfer from its position as GOES-West over the U.S. to 60° west longitude, SSEC now provides data product support for meteorologists in the Southern Hemisphere.
Operated by NOAA/NESDIS, GOES-10 scans the Southern Hemisphere using both imaging and sounding instruments. Before GOES-10 moved, the Southern Hemisphere had no GOES sounder coverage and irregular imager coverage. In addition to providing consistent imagery, GOES-10 carries the first operational geostationary sounder to routinely gather data over South America. The transfer of GOES-10 is part of the Global Earth Observation System of Systems (GEOSS) in the Americas project, which is a collaborative effort between NOAA and partners in the Americas and the Caribbean.
GOES-10 imagery demonstrates the value of having a satellite positioned at 60º W longitude, sampling the entire South American continent three to four times per hour. In its current position, the GOES-10 imager scans a full disk image every three hours and scans an “extended Southern Hemisphere” sector every 15 minutes. The sounder has 19 spectral bands and gathers observations over South America and its surrounding regions in four sectors over four hours. Data from GOES-10 allow Southern Hemisphere meteorologists to monitor convection and a variety of phenomena over the continent.
Funded by the NOAA Office of Systems Development, the SSEC Data Center recently installed a tracking antenna on the roof of SSEC. This antenna allows SSEC to directly receive GOES-10 data. CIMSS produces experimental Sounder products and posts them on a web page in near real time. The sounder products include Derived Product Images (DPI) of Cloud Top Pressure (CTP), Total Precipitable Water (TPW), and Lifted Index (LI). Animations of these DPIs, as well as select sounder and imager spectral bands, are also available. The CIMSS GOES-10 web page also has a Spanish language counterpart.
Figure 1: The left side of this image shows the coverage provided by GOES-12 when in rapid scan mode. The right side of the image shows the area covered by GOES-10 in its new position.
CIMSS scientists recently traveled to Cachoeira Paulista-Sao Paulo, Brazil to train South American meteorologists in remote sensing applications. With the support of the NOAA Office of International Affairs, CIMSS presented a weeklong workshop that included lectures and hands-on laboratory exercises directly dealing with the GOES-10 imager and sounder. Lectures covered topics such as: the fundamentals of remote sensing, how the imager and sounder collect the signal to build their images, and product production and applications. There were 33 participants from 12 countries including Argentina, Bolívia, Brazil, Chile, Colombia, Costa Rica, Equador, México, Paraguay, Peru, Uruguay and Venezuela
With the help of CIMSS researchers, Instituto Nacional de Pesquisas Espaciais (INPE) in Brazil
is able to generate a number of GOES-10 sounder products directly from their reception of the GOES-10
data stream. Some of these products include various level temperature and moisture information,
along with vertical profile information.
While in transit during the fall of 2006, SSEC used GOES-10 to collect a unique dataset of
one-minute imagery. The GOES-10 one-minute images allow researchers to closely monitor the evolution
of atmospheric features. The dataset includes many interesting examples of convection, clouds and
hurricanes. These data offer a preview of the improved temporal resolution imaging anticipated with
the next generation geostationary imager.
The History of GOES-10
Researchers have found many other uses for the GOES-10 data stream. SSEC’s Antarctic Meteorological Research Center (AMRC) uses data from the GOES-10 Imager to improve satellite composite imagery used to monitor weather-related aviation concerns over Antarctica. SSEC also provides GOES-10 data to the Washington DC Volcanic Ash Advisory Center (VAAC), so that volcanic ash plumes can be monitored. The GOES-10 sounder cloud information is being used to initialize a regional Numerical Weather Prediction (NWP) model. These activities are in addition to uses of the GOES-10 imager and sounder data in Central and South America.
The GOES-10 instruments still function well, but the satellite has exhausted its north-south station-keeping fuel. The lack of fuel means that the satellite inclination (or “wobble”) will continue to increase by about one degree per year. To overcome this wobble, NOAA recently began remapping the GOES-10 imager data before the radiance data are re-broadcast. Current GOES operational spacecraft (east and west) operate within a 0.5 degree inclination limit that allows the on-board Image Motion Compensation system to scan imagery as if from a “perfect GOES projection” from a fixed point in orbit. The inclination constraints shorten the life of operational GOES spacecraft. As part of the Extended GOES High Inclination (XGOHI) mission, the current generation of GOES ground system was enhanced to accommodate on-ground remapping to extend the life of retired spacecraft such as GOES-10.
