The ongoing COVID-19 crisis continues to affect the activities of society as a whole, and the weather observing network is no exception.

The pandemic has led to a sharp fall in the number of flights around the world and therefore a loss of aircraft-based observations, including temperature, wind and humidity readings, which are used by global numerical weather prediction (NWP) centres.

Satellite observations from space agencies, such as the European Space Agency and EUMETSAT, have not been interrupted and continue to provide key observational data, and the Met Office surface observing network here in the UK is almost fully automated and is therefore also relatively resilient to this type of crisis.

In some cases, national meteorological services are working with private satellite companies to help mitigate some of the adverse effects of the continued loss of aircraft-based observations.  The Met Office has warmly welcomed the offer from the commercial satellite company, Spire, who have made their Radio Occultation (RO) data available to us free of charge for a limited period.

Dr John Eyre, Met Office Fellow, said “We have used RO data from other satellites for many years, and we know their value for improving our weather forecasts. The offer of data from Spire is very welcome. It will make a valuable contribution to mitigating the loss of other weather observations during the COVID-19 period”.

Spire Executive Vice President Corporate Development, Theresa Condor, said: “We are very glad that Spire could make a contribution of our weather data to the Met Office during this current crisis, demonstrating the kind of collaboration that is possible between public and private institutions to ensure the resilience of a critical service for people and businesses.”

Radio Occultation (RO) samples atmospheric temperature and moisture using a receiver on a satellite and by measuring signals sent by global navigation satellite systems (GNSS), such as those from GPS satellites. As the signal between the two satellites travels through the atmosphere, it is refracted; the magnitude of this refraction depends on the temperature and water vapour content of the atmosphere, allowing relevant weather information to be derived as the signal between the two satellites passes through different levels of the atmosphere.

The Spire data will be assimilated into Met Office Numerical Weather Prediction systems to help improve our forecasting capabilities.