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Lightning strikes near a cell transmission tower. shaunl/Grist/Getty Images
This story was first published in Grist and is reproduced here as part of the Climate Desk collaboration.
When you hear wireless internet providers talk about “expanding the 5G cellular Network,” your first thought is probably, “Oh good.” That’s because there’s a lot of wireless data streaming to the world’s many smartphones, tablets, and laptops. But scientists are increasingly worried that all that mobile device bandwidth will come at a cost—our ability to forecast the weather quickly and accurately.
While most people know that they’re paying their wireless provider to connect them to the internet, they may not realize that wireless providers are tapping into a finite resource: a narrow band of radio frequencies known as spectrum (not the cable company). SpectrumThe -range radio wavelengths are special for a few reasons. For one thing, they can transmit data through solid objects—such as the walls of your house or windows of your car—making them ideal for wireless communication. But they are also important because the Earth’s atmosphere naturally emits radio waves, which can be picked up by satellite sensors and translated into weather data like temperature and precipitation.
The problem is, the radio wave frequency used by wireless cellular networks is similar to the ones used to monitor atmospheric conditions; the 24 GHz band is increasingly being used for telecommunications—notably for 5G cellular networks. The 23.8 GHz band is reserved to scientific purposes, including weather satellites. These two spectrum bands are becoming more common, and can cause interference, making dissemination of climate and weather information slower and less accurate.
Wireless data bandwidth can look a lot like a highway in a city growing. Traffic will get worse unless more highway lanes are built as the population grows. As more and more people receive wireless service, the signal can slow if companies don’t look to expand bandwidth for mobile devices. Many companies are asking for the FCC’s auction of additional spectrum bands for wireless communication.
But atmospheric scientists say auctioning off additional spectrum bands could reduce their ability to give communities a heads-up about extreme weather events like hurricanes and tropical storms—events in which time is of the essence in order to save lives.
“This would degrade the forecast skill by up to 30 percent,” said Neil Jacobs, former acting administrator of the National Oceanic and Atmospheric Administration (NOAA), in a 2019 federal hearing about interference between cellular and scientific spectrum bands. “This would result in the reduction of hurricane track forecast lead time by roughly two to three days.”
Timely and preciseExtreme weather makes it even more important to have accurate information about the weather. For example, in 2012, the National Hurricane Center was able give Louisiana information about the weather. An accurate prediction for when and where Category 1 Hurricane Isaac would make landfall about two days in advance of the storm. Although the initial warning was issued five days prior, it miscalculated by 250 miles the location of the storm’s landfall. The Federal Emergency Management Agency and state still had two days to notify people about the danger and issue evacuation orders.
The storm caused damage of $612 million and killed at least five people in the state. Without that forecast correction, it’s likely many more lives would have been lost.
But getting a storm’s theoretical timing and trajectory right is notoriously tricky. Atmospheric water vapor—a crucial component in weather forecasting and climate modeling—primarily releases radiation in the 23.8 GHz frequency spectrum band. A 2021 Hearing before the House Committee on Science, Space, and Technology, David Lubar, Senior Project Leader of the Civil Systems Group at the Aerospace Corporation, described the water vapor monitoring as “trying to hear a whisper in San Francisco while standing 500 miles away in San Diego.”
Federal law and international agreements stipulate that the 23.8 GHz spectrum should be reserved. Radio astronomy observations and earth science are the only ones allowed. Sensors on some satellite systems operated by the big federal agencies like the National Atmospheric and Ocean Administration, or NOAA, and National Aeronautics and Space Administration, or NASA, are Design to pick up these signals. Interference from adjacent spectrum bands—also known as “out-of-band” emissions—has been a concern of the remote sensing community for It takes a long time. This problem is magnified for satellite sensors that rely upon extremely sensitive measurements to provide accurate forecasting data.
Scientists feel excluded from the decision-making process because the FCC continues to sell nearby spectrum bands for commercial use.
“The FCC process is very complex and confusing for the scientific community, and most scientists do not have the resources available to them or advocates for such a process,” Bill Mahoney, Director of Research Applications Laboratory at the National Center for Atmospheric Research, said in the same hearing.
However, there are some things the government could do in order to limit interference from spectrum bands. Here are some examples 2019 auction in which the FCC issued 2,904 commercial licenses to use the 24 GHz spectrum band, the commission Limitations proposed on spectrum interference. These out-of band emissions standards were considerably less stringent that what the scientific community had advocated.
Experts fear that commercial spectrum interference could cause US weather forecasting accuracy to drop to levels not seen in the 1970s.
This is the result of a severe weather eventForecasting accuracy can be very costly. While the FCC’s 2019 auction of the 24 GHz spectrum band generated $2 billion in revenue for the Department of the Treasury, the costs from severe weather could be much greater. During the 2021 hearing, Mahoney noted that out-of-band emissions are degrading forecasting accuracy “during a period when our country is facing significant increases in billion-dollar weather disaster events.”
Some proposals have been made to preserve weather forecast accuracy despite interference, as commercial spectrum allocation is likely to continue. The government could limit interference from spectrum bands. Similar to sound-proofing a studio to make sure you don’t bother your neighbors, “out-of-band” emissions can be reduced. In the 2021 hearing, Lubar recommended adding devices to satellite sensors that “would identify the interference contamination, do some significant computation on the spacecraft, and flag that data so that it doesn’t contaminate the downstream weather process.” Presently, however, there is no funding allocated for NASA’s or NOAA’s joint satellite missions to provide such an instrument.
As the FCC considers future proposals to share additional bands, a spectrum mitigation plan is likely to be required. The agency is especially interested in sharing the 1675 MHz to 1680MHz frequency band. That’s the same band used by NOAA’s Geostationary Operational Environmental satellite to provide real-time weather information—notably for severe weather and flooding.
