October 31, 2016
As GOES-R launches into space, will its data make it back to Earth?
Posted by Timia Crisp
The first in a new series of United States government weather satellites is scheduled to launch on 16 November. This satellite series is a substantial upgrade and will provide operational meteorologists a notable improvement in monitoring weather hazards as they evolve. The Geostationary Operational Environmental Satellite R-Series (GOES-R) is a set of four satellites that will provide coverage over the Western Hemisphere for the next two decades. Compared to legacy geostationary weather satellite imagery, the spatial, spectral, and temporal resolutions will be much improved. GOES-R series satellites will be able to routinely provide imagery of developing storms as fast as every 30 seconds, with visible imagery resolving the clouds of weather systems down to 0.5 km.
Ensuring this data makes it in front of government and non-government weather forecasters and researchers is an integral part of the capabilities of the satellite. The U.S. government has invested in a GOES-R Rebroadcast (GRB) service that will transmit data to any entity with a configured ground system at a bandwidth of 31 Mbps, an increase from approximately 2 Mbps with current GOES. GRB receiving systems are reasonably affordable to those that need them. Academic institutions and industry partners can access the imagery with their own antennas to support customers and the public.
This satellite-to-antenna method of delivery has a substantial advantage that alternatives cannot match. Direct-to-user broadcast services are least likely to be interrupted or impacted by a failure of an interconnected system, like the Internet. In a disaster, when Internet connectivity may be slow or nil, a GRB ground system is essentially the only way to collect imagery, especially at such a high bandwidth.
But this capability is under threat. The radio frequency spectrum has a limited number of bands that are available for transmitting information in an increasingly connected and wireless world. Under pressure from the wireless broadband industry, the Federal Communications Commission (FCC) is considering whether to open the government-owned 1675 to 1680 MHz portion of the spectrum to wireless customers. With GRB services in the adjacent 10 MHz, strong and likely overwhelming signals from cell towers could interfere with the substantially (millions of times) weaker GRB signal, threatening environmental intelligence. Data and derived products from weather satellites that impact warnings, evacuations, and flight routes could be intermittent, frustrating decision makers and creating uncertainty about rapidly evolving atmospheric conditions.
For that reason, the FCC has received numerous comments from citizens and entities, including academic institutions, industry groups, non-profit organizations, emergency managers, and foreign governments, that are deeply concerned about the FCC auctioning the spectrum adjacent to GOES-R GRB and Data Collection System (DCS) bands. Forcing the weather community and the weather-sensitive industries to rely on the Internet for data, particularly after a disaster, could imperil business, property, and lives.
FCC proceedings take several years. Though the original comment period, on whether to proceed with rulemaking, has closed, if the FCC decides to proceed with the rulemaking process, there will be a new opportunity for the interested communities and enterprise to submit additional comments. It is unclear at this time when the decision to continue with rulemaking for the 1675 to 1680 MHz portion of the spectrum might be made.
Protecting portions of the radio frequency spectrum in order to ensure a timely, consistent, and reliable transmission of weather information is an effort that will require the attention of the unique public and private interests that support meteorological research, forecasting, and emergency response in the years ahead. The demand for wireless broadband continues to grow, and as such, there will inevitably be renewed pressure to share bands. But we must be careful to not unnecessarily surrender portions of the spectrum that deliver critical information on meteorological and environmental hazards.
Jordan Gerth is an associate researcher with the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin’s Space Science and Engineering Center.