What

The UK Met Office has been providing predictions of upper air wind and temperature to support Continuous Descent Approaches into Stockholm airport in Sweden.

Where

The forecasts are provided on a grid covering an area of one degree of latitude by three degrees of longitude based around Stockholm.

When

From September 2007 forecasts are being generated for certain specific transatlantic flights. These flights arrive early in the morning, Swedish time. Forecasts generated are for up to an hour ahead.

Why

For many approaches into busy airports, step-wise descent profiles are standard practice. For approaches into particularly busy airports such as Heathrow in England, it is very common for aircraft to join “stacks” in which there are alternating phases of level and descending flight. However, it is recognised that continuous descent approaches allow considerable fuel savings (with associated reductions in CO2 emissions). In addition the noise footprint is considerably reduced and the chances of encountering a wake vortex from another approaching aircraft are reduced.

How

The WAFTAGE (Winds Analysed and Forecast for Tactical Aircraft Guidance over Europe) nowcasting tool is being used. WAFTAGE ingests measurements of wind and temperature, in this case from AMDAR equipped aircraft. In addition to generating forecasts, the work described includes verifying the forecasts against later AMDAR reports.