Government researchers have confirmed that the sharp drop in air traffic during the coronavirus pandemic has affected the quality of weather forecast models by sharply reducing the amount of atmospheric data regularly collected by commercial airliners.
In one study, researchers showed that when a short-term forecasting model received less data on temperature, wind and humidity from aircraft, forecasting skill (the difference between forecasted weather conditions and what had actually happened) was worse.
The researchers and others had suspected this would be the case because atmospheric observations from passenger and cargo flights are among the most important data used in forecast models. Observations are made by instruments aboard thousands of airliners, mostly based in North America and Europe, as part of a program that has been in place for decades. They are transmitted in real time to forecasting organizations around the world, including the National Weather Service.
In the first few months of the pandemic, when air traffic globally declined by 75% or more, the number of sightings dropped by roughly the same percentage.
“With every type of observation that goes into weather models, we know they have an impact on improving overall accuracy,” said one of the researchers, Stan Benjamin, principal investigator at the Global Systems Laboratory, which is part of the National Oceanic and Atmospheric. Administration, in Boulder, Colorado. “If you’ve really lost a lot of sightings, there might be a skill downturn in general.”
While researchers have shown that the loss of data helps make the model less accurate, NOAA said so far it has not seen an impact on the kind of short-term forecasts that companies use. to make business decisions or that a person could use to decide if they should take an umbrella when they go out.
“We are not directly seeing an obvious reduction in forecast accuracy as we continue to receive valuable data from passenger and freight aircraft as well as many other data sources,” said a statement from the agency. These other sources include satellites, ocean buoys, and instruments carried aloft by weather balloons.
The amount of data coming from planes has also increased in recent months with the resumption of air travel, the agency said. The daily number of passenger plane flights in the United States is now at about 50 percent of pre-pandemic levels. Cargo plane flights were not as affected.
Dr. Benjamin, along with two colleagues working in the lab, Eric P. James from the University of Colorado and Brian D. Jamison from Colorado State University, simulated conditions during the pandemic in April by taking data from 2018 and 2019 and by eliminating 80%. before feeding it into a forecast model developed by NOAA called Rapid Refresh.
They compared the resulting errors to those if the model did not contain any aircraft data.
“We had to look to see if 80% is 80% impact,” said Dr. Benjamin. “But it’s not that much. They found that removing 80 percent of the data produced errors that accounted for 30 to 60 percent of the errors that would have resulted from no data at all. The study was published in the Journal of Applied Meteorology and Climatology.
In addition, the World Meteorological Organization, which in the spring was concerned about the loss of on-board observation data, announced this week that it had signed an agreement with a group in the aviation industry to expand the program of ‘observation. to cover regions of the world where little data is currently collected.
The agreement with the International Air Transport Association calls for adding more airlines and aircraft to the program, including those with routes in Africa and other less guarded areas.
Currently, about 40 airlines are participating in the program and, in total, about 3,500 aircraft are equipped with the necessary equipment to make and transmit observations. In the United States, Delta, United, American and Southwest and United Parcel Service and FedEx freight carriers are involved.