Objective verification of global in‐flight icing forecasts using satellite observations: Verification of WAFS icing forecasts using satellite observations

Abstract

The two World Area Forecast Centres (WAFC) are responsible for issuing global gridded forecasts of in‐flight icing to the aviation community. These forecasts are vital for flight planning and safety; therefore, the performance of these forecasts needs to be assessed and improvements made where necessary. New satellite instruments can detect additional information about cloud properties to then identify areas conducive to icing. At the Met Office, data from multiple geostationary satellites are combined to produce a gridded satellite icing potential product with coverage over Europe, Asia and Australasia. Recent satellite launches will give near‐global coverage of these observations. The present paper details an objective verification framework to routinely verify icing potential forecasts using the satellite‐inferred icing product as a source of truth data. To allow a fair comparison, the best method to appropriately match the forecast and truth data is investigated. This methodology includes processing the multilevel forecasts into a single field to best replicate the satellite observations and producing a time window of maximum icing potential observations to allow temporal flexing in the verification. Verification results of the mean icing forecasts issued by WAFC London are presented for the 12‐month period March 2016–February 2017 in order to illustrate how this methodology has been used.