Meteorologists get less data due to fewer flights

The dramatic restriction in the number of commercial aircraft flights around the globe — in a bid to control the spread of the novel coronavirus — has reduced the accuracy of weather predictions, say meteorologists.

After satellites, aircraft are the second-most important airborne element in forecasting, and with the number of flights down by between 40 and 65 per cent, forecasts aren’t quite as pinpoint, said Chris Scott, chief meteorologist for The Weather Network.

The number of flights is expected to fall even more in the coming days, affecting forecasting slightly more, according to The Weather Network.

An international agreement dating to 1991 ensures commercial aircraft feed their weather data into meteorologists’ computers, which also depend on ground stations, satellites and weather balloons. Most of the effect will be from the loss of wind and temperature data collected by planes at an altitude of 10 to 12 kilometres.

With so many of those aircraft grounded to ride out the COVID -19 crisis, the edge to that forecasting sensitivity is eroded but the effect shouldn’t concern the public, he said.

It might translate, overall, to about a nine per cent decrease in accuracy, said Scott, and even that’s variable.

“The results are very small, it’s not like we’re going to miss a major storm — you might have a low-pressure front shifted a bit from where we thought,” he said.

“In a seven-day forecast, it’s not going to be something that jumps way off the page.”

That reassurance even applies to southern Albertans accustomed to weather unpredictability and hairpin changes that exist because of the proximity of the Rocky Mountains, he said.

“This is more of a global thing and this isn’t going to change variability, so, from a local standpoint, there’s nothing to worry about,” said Scott.

An Alberta academic agreed with Scott’s assessment, saying some of the data lost from passenger planes might be replaced by more cargo aircraft flown by companies such as Fedex and UPS, which also collect data.

“You also have ships doing the same thing, and I doubt there’ll be fewer of those because they’re carrying cargo,” said Jeff Kavanaugh, an associate professor with the department of Earth and Atmospheric Science at the University of Alberta. And agencies such as the U.S. National Oceanic and Atmospheric Association will still track the progress of hurricanes.

Weather balloons can also be used to replace some of the lost data, added Kavanaugh.