Day 6

Research suggests COVID-19 is affecting weather forecasts, but scientists are divided

Weather forecast models rely on data collected from commercial airlines, among other sources like satellites and weather balloons. But since the COVID-19 pandemic slowed down the world in March, the number of commercial flights has fallen drastically, meaning less data is available.

Weather forecast models rely, in part, on data collected from commercial airlines

According to a new study from Lancaster University, the grounding of many commercial flights during the coronavirus pandemic has had a negative effect on weather forecasts. (Justin Tang/The Canadian Press)

New research out of Lancaster University says the pandemic has made weather forecasts less reliable — and can potentially be detrimental to agriculture and our ability to predict more severe weather patterns.

Weather forecast models rely on data collected from commercial airlines, among other sources like satellites and weather balloons. Information like wind speed, atmospheric pressure are collected from thousands of flights a day and used to help forecast weather patterns.

But since the COVID-19 pandemic slowed down the world in March, the number of commercial flights has fallen drastically. Less data means inaccuracies, the study says.

"In my study, I do find that the accuracy of the forecast is going down," author Ying Chen said. 

Chen is a researcher at the Lancaster Environment Centre. He says temperature and pressure are off from forecasts due to the lack of data, and vary depending on area. Regions without a lot of air traffic to begin with are often less accurate, for example.

"For surface temperature accuracy going down by two degrees Celsius, it is significant," Chen says.

Some weather forecasts rely on data sourced from commercial aircrafts to make predictions. (Eric Foss/CBC)

There are areas where the difference is much less stark, Chen says. Places like Western Europe, where there are still frequent flights and lots of weather stations, are still able to predict pretty accurately. 

"For a global scale, maybe [it's] not remarkable," he said. But for areas with very little air traffic — like Greenland or Siberia — the difference is much bigger.

"If we're talking about a specific region ... such as southeast China, I would say the difference is really large."

Language in study 'a bit overdramatic'

The idea that less data from planes might mean less accurate forecasts has floated around since the beginning of April, but some meteorologists are skeptical of whether it makes any difference at all.

Doug Gillham, a meteorologist with The Weather Network, says much of the forecasting has been right on target, just as it was pre-pandemic. But there are drop-offs, or discrepancies, in the models.

"This happens all the time, but it seems the drop-offs are happening more frequently and the drop-offs are bigger than what we were seeing pre-pandemic," Gillham said.

"Now I can't prove to you that's due to the lack of data from airplanes," Gillham said, adding that more difficult weather patterns seem to be harder to predict without the data from planes.

Not all meterologists believe commercial airplanes are crucial to making weather predictions, but The Weather Network's Doug Gillham says it could mean less accurate long-term forecasts. (Ben Nelms/CBC)

The loss of data won't affect tomorrow's forecast accuracy, for example, but the forecast five to 10 days out might suffer a bit, he adds.

Bruce Ingleby with the European Centre for Medium-Range Weather Forecasts is much more skeptical. While he agrees that less data for the models to use could mean less accuracy, much of the forecasts rely primarily on data from satellites, which are unaffected by the pandemic.

When Chen's study was published last week, Ingleby and other researchers he talked to from other weather agencies weren't sure about it.

"It seemed to use rather sensational language — 'imperils weather forecasts' — which is a bit overdramatic. [Myself] and others are not sure it should have been published," Ingleby said.

He said while it's interesting and important to look at how less aircraft data affects the modelling, Ingleby says the study is flawed. 

"We don't think that study was particularly careful and it hasn't taken fully into account the variability. It's looking at one particular forecast system," he said. 

"Aircraft data does have an impact, but we think that study overstates it."

What the study does, however, is show a need for further diversification of where the data comes from, Chen says.

"If we can introduce a stronger observation that works … then for the future we may have a stronger ability to compensate in this kind of global emergency."

Written and produced by Kyle Myzuka.

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