A new era in satellite monitoring of the Western Hemisphere began on November 19 with the successful launch of the GOES-R satellite. GOES-R is the latest in a sequence of GOES (Geostationary Operational Environmental Satellite) satellites that began in 1975. Both polar-orbiting and geostationary satellites gather crucial data for incorporation in computer forecast models, but it’s the geostationary birds--stationed at fixed spots tens of thousands of miles above the surface--that furnish most of the satellite imagery we’ve seen on television and the Internet since the first GOES satellite was sent into space in 1975. The new satellite and three more that will follow (collectively referred to as the Geostationary Operational Environment Satellite–R Series) will provide a huge leap forward in temporal and spatial resolution, with more frequent and precise images than ever before gathered by a U.S. geostationary satellite.
Figure 1. A rocket bearing the GOES-R satellite hurtles into space from NASA’s Kennedy Space Center at 6:42 PM EST Saturday, November 19, 2016. As with previous launches, NASA worked with NOAA to develop and launch GOES-R. See embedded video of the launch at bottom. Image credit: NOAA.
When do we see the first pictures? Although GOES-R will be in a test mode until about one year after launch (i.e., till November 2017), we won’t have to wait that long to get a peek at its offerings. The satellite should begin providing researchers with initial imagery in the next couple of months from its vantage point 22,500 miles above the equator near 89.5°W, roughly the longitude of St. Louis, Memphis, and New Orleans. This location will allow GOES-R to observe tropical cyclones in both the western North Atlantic and eastern North Pacific. According to the GOES-R Product Readiness and Operations Team, data from 16 wavelength channels, including visible and infrared images, will be made public starting in May 2017 at the following tempos:
Full-disk images (spanning most of the Western Hemisphere): every 15 minutes Continental U.S.: every 5 minutes Mesoscale (regional) areas of interest: every minute
The Advanced Baseline Imager (ABI) aboard GOES-R is comparable to the Advanced Himawari Imager aboard Japan’s Himawari-8 and -9 satellites. Tropical weather watchers have been marveling at the crystal-clear images of Northwest Pacific typhoons and Southwest Pacific cyclones gathered from Himawari-8 since July 2015 (Himawari-9 was launched on November 2 of this year). Himawari’s visible images boast a top horizontal resolution of 500 meters (1640 feet). That’s about four city blocks!
Figure 2. Visible (top) and infrared (bottom) images of Super Typhoon Meranti in the Philippine Sea on September 11, 2016, as gathered by Japan’s Himawari-8 satellite. The GOES-R Advanced Baseline Imager is expected to gather data of comparable quality. Image credit: CIMSS Satellite Blog.
The crisp, frequent imagery from GOES-R is expected to be a particular boon to forecasters keeping tabs of fast-changing weather features, including supercell thunderstorms as well as the cores of rapidly intensifying tropical storms and hurricanes. “We are hopeful that the improved resolution will help in resolving tropical cyclone features such as emerging eyes, which should lead to better analyses of current intensity,” said Chris Velden (University of Wisconsin–CIMSS) in an email.
GOES-R also includes a Geostationary Lightning Mapper (GLM), a groundbreaking operational sensor--the first of its type on any geostationary satellite--that will detect in-cloud, cloud-to-cloud, and cloud-to-ground activity throughout the Americas. The GLM also will allow forecasters to monitor lightning activity over the open ocean where traditional land-based lightning mapping systems can’t operate. With a resolution of around 10 kilometers (6 miles), GLM data will help forecasters watch for pockets of strong thunderstorms that may help contribute to the intensification of a tropical cyclone.
Figure 3. At top is two different modes of simulated GOES-R satellite imagery for Hurricane Wilma (October 19, 2005), as compared to the same type of output from the lower-resolution GOES-12 satellite (bottom). GOES-R infrared data, as depicted in (b), will feed into a new Hurricane Intensity Estimation (HIA) algorithm, the latest iteration of the Advanced Dvorak Technique that allows for automated estimates of tropical cyclone intensity based on infrared satellite imagery. Image credit: GOES-R.
Giving the models more to chew on Over time, GOES-R should pay big dividends for numerical forecasting models, which often lean heavily on satellite data for their starting-point initializations. Scientists are still exploring the best ways to assimilate various types of satellite data into existing models, including the smorgasbord of new data soon to come from GOES-R. In a paper recently accepted by Monthly Weather Review, Velden and colleagues describe a new technique designed to allow the HWRF model to assimilate winds inferred from cloud motion (atmospheric motion vectors, or AMVs) of the type that GOES-R will produce. “These enhanced AMVs can provide a better initial state for the model,” said Velden. Since GOES-R has more imaging bands than its predecessors, it will be able to better specify the heights of AMVs.
Figure 4. Left: Atmospheric motion vectors (AMVs) for Hurricane Katrina (2005) as produced from GOES-12 data (4 km resolution, every 15 minutes). Right: a simulation of the enhanced AMVs that GOES-R will be able to produce (2 km resolution, every 5 minutes). Image credit: “GOES-R Impacts on Satellite Data Assimilation,” UCAR/COMET (free registration required to view module).
One feature that didn’t make it to GOES-R from the previous GOES generation is the sounder, an instrument designed to produce vertical profiles of atmospheric conditions similar to those gathered by balloon-borne radiosondes. The original plan was to include an advanced sounder aboard GOES-R, but the sounder was dropped in 2006 because of tight budgets. Along with its many other benefits, the wealth of high-resolution data from the GOES-R imager will help fill in some of the information that the aborted sounder would have provided for assimilation into computer models.
Next in the queue Three more satellites in the GOES-R series are forthcoming: GOES-S, GOES-T, and GOES-U. If all goes well, forecasters will be drawing on data from these four launches until at least 2036. After its year-long testing phase, GOES-R will be shifted to serve as either the western or eastern satellite in the GOES constellation (GOES West or GOES East). That choice will depend on how well the two current satellites in those positions, GOES-15 and GOES-13, continue to function. (Each satellite has both a numeric and alphabetic suffix, with GOES-R to be designated as GOES-16 once it goes into geostationary orbit.) Another satellite, GOES-14, remains in space as a backup but isn’t being used at present. NOAA’s satellite agency, NESDIS, is structured to accommodate 24/7 operational data from only two satellites at a time.
We’ll be back with a new post on Tuesday. Thanks go to Chris Velden (UW/CIMSS/SSEC) and Michael Folmer (NOAA Center for Weather and Climate Prediction) for background used in this post. You can follow the steps in GOES-R’s transition to data-gathering mode at an updates page maintained by NOAA/NESDIS.
Video 1. GOES-R heads into space aboard a United Launch Alliance Atlas V rocket on November 19, 2016, from Cape Canaveral Air Force Station in Florida. Image credit: NASA.