Hurricane Sandy turned west in 2012 before making landfall in New Jersey. Without microwave sensor data, forecasters would have called for the storm to make landfall 24 hours later than it did and to strike Maine. Credit: National Weather Service

BOSTON – Anyone who thinks the international weather community has given up the fight to protect key portions of the radio frequency spectrum from 5G interference is mistaken.

After losing a battle at the International Telecommunication Union’s World Radiocommunication Conference 2019 in Egypt, meteorologists, atmospheric scientists, aerospace engineers and radio frequency experts met at the American Meteorological Conference to plan their next campaign.

“We are really deeply worried about this microwave spectrum,” said Wenjian Zhang, World Meteorological Organization assistant secretary-general. “We face the danger that this critical band will be polluted by 5G.”

In the last 20 years, passive microwave sensors on weather satellites have detected faint signals emitted by water vapor in the atmosphere from 23.6 to 24 GHz. Data drawn from those sensors “is the most significant contributor to reduced forecast error,” according to Developing a Sustainable Spectrum Approach to Deliver 5G Services, a paper released Jan. 13 by the Aerospace Corp.’s Civil Spectrum Management Group.

Those signals are “absolutely key to knowing what is going on in the atmosphere,” said David Lavers, a European Centre for Medium-Range Weather Forecasts scientist.

World Radiocommunication Conference delegates agreed to allow 5G technologies to operate from 24.25-27.5 GHz as long as equipment limits the strength of signals spilling over into the adjacent band.

Meteorologists, who say the limits do not go far enough to protect weather observations, are calling for further dialogue between the weather and telecommunications communities.

“Until the dialogue happens, I don’t think the two sides are going to arrive at good solutions,” said David Lubar, Aerospace  Civil Spectrum Management Group senior project leader.

Meteorologists and atmospheric scientists said they are not seeking to hinder 5G rollout, noting its promising weather-related applications.

“We need new technology for telecommunications but we also need to protect satellite frequencies because weather forecasts protect life and property,” Zhang said. With any new technology, it’s important to evaluate both the costs and benefits, he added.

One potential solution posed in the new Aerospace paper is spectrum time-sharing. Networks could switch from 5G to 4G or a different wireless frequency for a few seconds whenever a satellite with a passive microwave sensor passes overhead.

Debra Werner is a correspondent for SpaceNews based in San Francisco. Debra earned a bachelor’s degree in communications from the University of California, Berkeley, and a master’s degree in Journalism from Northwestern University. She...