While it’s well-known that the coronavirus has all but halted the travel industry, the disruption has had a rather unusual side effect: it’s reducing our ability to forecast the weather accurately.
Contemporary meteorology is heavily driven by computer models that rely on data collected not only by ground-based monitoring stations, weather balloons, and satellites but also by commercial aircraft. As they fly around the world, planes measure weather indicators like temperature, humidity, and air pressure with their onboard sensors, and they contribute that data to the World Meteorological Organization’s (WMO) Aircraft Meteorological Data Relay (AMDAR) program. According to the WMO, “The data collected is used for a range of meteorological applications, including public weather forecasting, climate monitoring and prediction, early warning systems for weather hazards and, importantly, weather monitoring and prediction in support of the aviation industry.”
In May, the WMO released a report warning that the pandemic travel slowdown might drastically affect weather forecasting. In an academic study published by Dr. Ying Chen of the University of Lancaster in the United Kingdom last week, that’s been proven to be true. Before the pandemic, several thousand aircraft from the 43 airlines that participate in the AMDAR program recorded some 800,000 observations each day. But given the reduction in flights due to the pandemic, the number of daily observations measured has decreased by between 50 and 75 percent.
According to the study, which compared meteorological forecasts to recorded weather data from March to May 2020, predictions were far more likely to be inaccurate during this period than in previous months, “suggesting that the COVID-19 pandemic imperils weather forecasting of surface temperature, RH, pressure and wind speed due to the lack of aircraft observations during the global lockdown.”
The errors in forecasting might not seem like such a big deal for short-term forecasts, such as what the weather will be like over the weekend. Still, it has potentially dangerous repercussions in long-term forecasting, especially regarding hurricane predictions. The 2020 hurricane season is expected to be more active than years past, meaning that the computer models that predict the intensity and paths of the storms will be crucial to saving lives. Given that those models rely on the data collected by monitoring systems such as AMDAR, their accuracy will likely diminish because of the lack of flights.
While stop-gap measures like launching new weather balloons might help acquire more meteorological data, weather forecasting will likely remain less accurate than usual until we get more planes back in the air—something that’s not likely to happen until a COVID-19 vaccine is developed and travel can continue unimpeded.