WASHINGTON — Do you ever wake up expecting a nice cool day only to discover a humid scorcher instead? Many people around the world are probably wondering why their local weather team can’t get the forecast right lately. A new study says with fewer planes in the sky, thanks to COVID-19, global weather data is becoming less accurate.
Researchers working with the American Geophysical Union report the world lost between 50 and 75 percent of its aircraft weather observations in March, April, and May. The drop-off began when nations started grounding commercial flights due to the pandemic.
These aircraft are constantly recording things like air temperature, relative humidity, air pressure, and wind during their flights. With fewer planes reporting in, meteorologists now have less information to build their forecasts with.
Correct weather forecast key for industries
Ying Chen of the Lancaster Environment Centre in the U.K. says getting the weather right is more important than you may think. Inaccurate forecasts can damage the economy, affecting farmers and their crops.
The researcher adds proper forecasting is critical for your power grid. Wind turbines rely on correct wind speeds and electric companies depend on accurate temperatures to predict how much power customers will be using — like on hot days when air conditioners are switched on.
“If this uncertainty goes over a threshold, it will introduce unstable voltage for the electrical grid,” Chen says in a media release. “That could lead to a blackout, and I think this is the last thing we want to see in this pandemic.”
The study finds countries whose air traffic has been heavily impacted by COVID-19 are having the most problems with weather forecasts; those include the United States, China, and Australia. Some isolated regions like the Sahara Desert, Greenland, and Antarctica are also having issues.
Forecast models are more accurate with more meteorological data in them. The Aircraft Meteorological Data Relay program typically makes use of over 3,500 planes and 40 commercial airlines.
Chen says the March-May 2020 forecasts are less reliable than ones taken during the same months in 2017, ’18, and ’19. They are providing less accurate readings on temperature, relative humidity, windspeed, and air pressure.
In February, before most air travel was halted, the report finds 2020 forecasts relying on aircrafts had actually improved by 35 degrees Fahrenheit over past years. During the pandemic, that improvement in accuracy has vanished.
The results are having a bigger impact on long-term weather predictions. Surface pressure and wind speed forecasts four to eights days away are much more inaccurate than ones looking at the next three days.
Getting back on the ground
One region that is surprisingly unaffected by the pandemic is Western Europe. Despite losing up to 90 percent of their air traffic, the study finds the region’s forecasts remain reliable.
Chen suspects it’s because the Europeans rely more on ground stations and weather balloons to take measurements. There are over 1,500 meteorological stations throughout that part of Europe, which create a dense network of data to use.
“It’s a good lesson which tells us we should introduce more observation sites, especially in the regions with sparse data observations,” the study author explains. “This will help us to buffer the impacts of this kind of global emergency in the future.”
Concerns about hurricane season
Since March, April, and May were relatively dry months in 2020, the weather inaccuracies haven’t really impacted rain forecasts.
Chen warns the drop in air travel may cause big problems during hurricane and monsoon seasons. He adds these missing measurements often catch early warning signs of major weather events around the world.
The study appears in the AGU’s journal Geophysical Research Letters.