Protecting Scientific Use of the Spectrum

May 2, 2016 · 0 comments

by Ya’el Seid-Green, AMS Policy Program

There has been much talk recently about the Federal Communications Commission (FCC) proceedings to sell the radio frequencies of 1675-1680 MHz, currently used for GOES data transmission, on the open market. A comment period on the proposal closes June 21st. More information can be found here.

The radio spectrum is a limited resource of great value both within and beyond our scientific community. The weather, water, and climate community uses radio spectrum to conduct scientific research, collect observations, and transmit data that contribute to oceanic, atmospheric, and hydrologic research, models, products, and services. Spectrum is also used to support mobile broadband networks, a sector with enormous growth potential and value for the United States economy.

The scientific community uses the radio spectrum in three distinct ways:

  • Passive remote sensing: Measuring the natural radio emissions of the environment and space (receiver only). Example: GPM Microwave Imager on the Global Precipitation Measurement Mission Core Spacecraft
  • Active remote sensing: Emitting radio waves and measuring the return emissions (transmitter and receiver). Example: Cloud Profiling Radar on CloudSat
  • Data transmission: Transmitting data from satellites and ground-observation stations. Example: GOES VARiable (GVAR) service on the GOES system satellites

Observations are made using ground-based, airborne, and space-based platforms to determine wind profiles, rainfall estimates, wave heights, and ocean current direction, among others. Further information on active and passive sensing instruments is available here: https://earthdata.nasa.gov/user-resources/remote-sensors.

With the advent and rapid growth of mobile commercial technologies, interference on and competition for the radio spectrum has increased. The signals of commercial terrestrial users of spectrum are often much stronger than the signals being measured or transmitted by the weather, water, and climate communities. This can cause radio frequency interference (RFI) that degrades or entirely destroys the data being collected and transmitted for scientific and operational uses.

In addition, there is pressure for federal agencies to relocate off certain spectrum bands to free up additional space for commercial users. In 2010, President Obama set a target of freeing up 500 MHz of spectrum for wireless broadband services. (See also, the Report to the President: Realizing the Full Potential of Government-Held Spectrum to Spur Economic Growth, available here.) The potential benefits to the U.S. economy from freeing up spectrum for commercial use are considerable. Mobile broadband is a rapidly growing segment of the economy, and in 2015 the FCC auctioned off the frequencies of 1695-1710, 1755-1780, and 2155-2180 MHz (collectively the “AWS-3” bands) for mobile telecommunication use for a combined $44.9 billion.

There are several challenges in understanding spectrum allocation policy. First, several different agencies are responsible for allocating and regulating spectrum: the International Telecommunications Union (ITU), within the U.N., allocates spectrum internationally; the National Telecommunications and Information Administration (NTIA) manages Federal use of the spectrum; and the Federal Communications Commission (FCC) manages non-Federal use of the spectrum. This bifurcated regulatory system can make decision-making and management of spectrum use challenging.

Second, given the diverse and complex sources of data that go into weather, water, and climate products, it is often hard for end users to understand how radio spectrum management issues may impact the products and services they rely on for creating value-added products or for making management decisions (see the joint letter sent to the FCC by the AMS and National Weather Association). Finally, it is often difficult to determine the value of scientific and operational uses of the spectrum. Because of this valuation problem, there is concern that earth science uses of the spectrum are not being taken fully into account in spectrum management decisions (see the National Research Council report, A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum).

Although the FCC proceedings regarding 1675-1780 MHz have received the most attention in our community recently, issues around spectrum allocation and management are only going in grow in scope and frequency as pressure on the spectrum increases. An AMS Ad Hoc Committee is working to update the AMS Statement on radio frequency allocations, and there are several bills under consideration in Congress that focus on spectrum management concerns. As a community, we must be prepared to communicate the importance of spectrum for earth observations, science, and services, and the resulting societal applications. We need to be actively engaged in exploring management strategies, policy options, and technology innovations that will allow the nation and the world to gain the maximum benefit from our use of the radio spectrum.