While 5G mobile networks promise to provide tremendous wireless speeds with low latency, they may also make it more difficult for meteorologists to provide weather forecasts. That's because 5G's neighboring frequencies are used by satellites that detect water vapor in the atmosphere, data that informs weather models used by meteorologists. From Nature:
Astronomers, meteorologists and other scientists have long worked to share the spectrum with other users, sometimes shifting to different frequencies to prevent conflicts. But "this is the first time we've seen a threat to what I'd call the crown jewels of our frequencies — the ones that we absolutely must defend come what may", says Stephen English, a meteorologist at the European Centre for Medium-Range Weather Forecasts in Reading, UK.
They include the 23.8-gigahertz frequency, at which water vapour in the atmosphere emits a faint signal. Satellites, such as the European MetOp probes, monitor energy radiating from Earth at this frequency to assess humidity in the atmosphere below — measurements that can be taken during the day or at night, even if clouds are present. Forecasters feed these data into models to predict how storms and other weather systems will develop in the coming hours and days.
But a 5G station transmitting at nearly the same frequency will produce a signal that looks much like that of water vapour. "We wouldn't know that that signal is not completely natural," says Gerth.