By grounding flights, the coronavirus could make your weather forecast less accurate

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Flight bans and cancellations mean less data is flowing into weather models.

The unprecedented downturn that has hit airlines worldwide due to the coronavirus pandemic is having ripple effects that may make weather forecasts less accurate. The reason? Fewer planes flying deprives weather models of prized data used to simulate future conditions.

Few people realize that when they’re on a commercial flight, be it an Airbus or a Boeing, the aircraft they’re flying in is constantly sending data on the air mass surrounding the plane back to the ground. This data then gets piped into computer models at weather centers in the United States, where it’s used as an input to the Global Forecast System (GFS) model, as well as in Europe, where the European model takes advantage of such data, as well.

Commercial flights are the equivalent of thousands of extra weather balloons launched each day, providing crucial data on air pressure, temperature, wind speed and direction, and, in some cases, humidity where such information is scarce, such as high above the open North Pacific Ocean. In terms of the density of measurements, aircraft soundings, as such data is known, dwarf the volume of the twice-a-day weather balloons launched from 900 weather stations around the world.

In the United States, more than 3,500 commercial aircraft provide more than 250 million observations per year, according to National Weather Service spokesperson Susan Buchanan.

Both the National Oceanic and Atmospheric Administration (NOAA), the Weather Service’s parent agency, and the European Center for Medium-Range Weather Forecasting (ECMWF) are closely watching the decline in flights to see whether it cuts into their models’ reliability.

The loss of data is particularly acute in Europe, where flight restrictions have gone into effect throughout the European Union, and U.S. airlines have announced steep capacity cuts in an attempt to stay in business.