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A long-awaited international deal governing how the world's technology companies should roll out 5G technology poses serious risks to the accuracy of weather forecasts, according to federal agencies and the World Meteorological Organization.

Negotiators from around the world announced a deal last month at a meeting in Sharm el-Sheikh, Egypt, for how to roll out 5G technology that operates using specific radio frequency bands.

Studies completed by U.S. government agencies such as the National Oceanic and Atmospheric Administration, NASA and the Navy had warned that 5G equipment operating in the 24-gigahertz frequency band could interfere with transmissions from polar-orbiting satellites used to gather weather data. This could make forecasts much less reliable, the reports found.

Specifically, these highly technical analyses concluded that if deployed widely and without adequate constraints, telecommunications equipment operating in the 24 GHz frequency band would bleed into the frequencies that National Oceanic and Atmospheric Administration and NASA satellite sensors also use to sense the presence and properties of water vapor in the atmosphere, significantly interfering with the collection and transmission of critical weather data.

The National Oceanic and Atmospheric Administration report, for example, warned of a potential loss of 77.4% of data coming from microwave sounders mounted on the agency's polar-orbiting satellites.

The agency's microwave sounders operate at a frequency of 23.6 to 24 GHz, which is close to the frequency that the Federal Communications Commission auctioned off the use of for about $2 billion beginning this past March.

The key concerns about 5G interference focus on what are known as baseline interference limits, often referred to as out-of-band emission limits.

Going into the negotiations in Egypt, the United States took a negotiating position that worried scientists at National Oceanic and Atmospheric Administration and at NASA, as it called for a limit of up to -20 decibel watts of interference (the lower the limit, the more buffer room there is). European regulators and the World Meteorological Organization, a United Nations agency, took a stricter line, arguing for interference limits of up to -55 decibel watts.

The newly agreed-upon standard represents a middle ground and will be introduced in two stages. The first stage, which will be in effect until Sept. 1, 2027, will be -33 decibel watts. It will tighten to -39 decibel watts after that.

The idea is to help spur the technological development of the 5G sector -- a key priority of President Donald Trump's administration -- in the near term, without causing too much harm to weather forecasting once the technology is more mature and deployed widely.

However, reaction to the outcome of the meeting was mixed. At the meeting in Egypt, a representative of the World Meteorological Organization read a statement of concern, as did negotiators for many European nations, according to reporting by Nature News.

"Because the U.S. position was so high, any lower threshold is welcome news. But it's not where we are completely confident that there will not be interference," said Jordan Gerth, a meteorologist who chairs the Radio Frequency Allocations Committee for the American Meteorological Society.

The most important data that goes into computer models used for weather forecasting comes from the microwave sounders mounted on polar-orbiting satellites. Any degradation of this data could harm forecast accuracy by introducing blind spots in the models. Neil Jacobs, the acting administrator of the National Oceanic and Atmospheric Administration, has warned that if his agency's study proves correct, the quality of weather forecasting could decline by up to 30%, going back to the accuracy of 1980.

The data is especially useful for making near- to medium-range forecasts and allows measurements to be taken across regions that have no surface-weather stations, such as the oceans or remote land regions.

The European Center for Medium-Range Weather Forecasts in the U.K., which has a weather model that typically outranks the U.S. for its accuracy, released a statement recently to criticize the outcome of the 5G meeting.

The statement says the agreement "falls far short of ensuring 5G applications do not interfere with weather observations," and it compares the 5G agreement to the world's lack of action in response to decades of scientific warnings on climate change.

"It is worrying and disheartening to watch history repeat itself and science losing to other societal pressures," the organization stated. "Watching the cost society now has to pay for having ignored global warming warnings, one would have hoped that the voice of atmospheric science would have carried more weight."

The agreement reached in Egypt falls far short of ensuring 5G applications do not interfere with weather observations at 24 GHz.

Renee Leduc, a consultant with Narayan Strategy who specializes in radio frequency issues, said she is "very concerned" about a deterioration of computer modeling accuracy with this deal, especially during the early phase as companies rapidly deploy 5G networks.

"We need our weather models to be improving, not getting worse, and that's something that President Trump has said himself," she said.

In case forecasts are degraded because of 5G interference, the National Oceanic and Atmospheric Administration is considering plans to avoid worst-case scenarios. For example, it could use water-vapor-sensing channels only over oceans and could exclude land, which would be the likely source of interference.

A Section on 12/01/2019

Print Headline: 5G accord raises worry on quality of weather data


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