Why we need airtravel for an accurate weather forecast

By:

Joana Kollert

Flying is bad for the climate – this is an uncontested fact. However, air traffic is necessary for weather forecasts, as airplanes send live data to weather stations. COVID-19 has caused a massive decline in air travel, hereby affecting the quality of weather forecasts.

Density of meteorological airplane data from AMDAR on 23 March 2020 (Stewart Taylor, EUMETNET)

Density of meteorological airplane data from AMDAR on 2 March 2020 (Stewart Taylor, EUMETNET)

Globally, the aviation industry is responsible for about 2.4% of all anthropogenic CO2 emissions. While this small contribution may suggest that an individual’s choice to fly (or not) is negligible in the grand scheme of things, it is also true that transport choices have the highest mitigation potential amongst individual consumption options.

COVID-19 has hugely damaged the aviation industry; international air traffic has declined by about 85% . Passengers were either not allowed to fly due to travel restrictions, or scared to fly due to the risk of infection. This is good news for the climate, but not for weather predictions!

In order for weather models to calculate the forecast for the following days, they first need to know the current state of the atmosphere as accurately as possible. This means recording the current weather at as many locations and altitudes as possible; the more readings, the more accurate the weather forecast. Information about the current atmospheric state comes from a range of sources – weather stations, ships & buoys, weather balloons, satellites – but also from aircrafts.

For example, the global Deutscher Wetterdienst Weathermodel “ICON” receives 10% of its measurements from aircrafts. According to the European Center for Medium-Range Weather Forecasts, on average, the decline in aircraft measurements reduces the accuracy of forecast models by about 4%.

Weighing the benefit of reduced air traffic for the climate with the disadvantage for weather forecasts nevertheless seems inappropriate; I would still rather be caught in an unexpected rainshower tomorrow than in a flood in 10 years.