MétéoSuisse - Cost 722

Foggy patches at the airport Zurich early in the morning (Photo C. Schmutz).

Short Range Forecasting Methods of Fog, Visibility and Low Clouds (COST Action 722)

Switzerland is contributing with different tasks to COST Action 722. MeteoSwiss is coordinating these tasks in a mandate from SER (for the member see the management committee in the section people). The Cost Action is currently planned to last until the end of 2006, with a chance of prolongation for a few months until mid 2007. There are three different working groups active at the moment: WG1 - initial data, WG2 - models and WG3 - statistical methods. The Swiss contributions are in the working groups WG2 and WG3.

Working Group 2:

MeteoSwiss and the University of Basel have a research contract with the SER for the project 1-DEFOP (1-Dimensional Ensemble Fog Prediction in Complex Terrain). A 1-dimensional fog forecasting model is developed with the aim to run 1-D ensembles in order to make probabilistic visibility forecasts. The initial and boundary conditions for the 1-D ensembles are taken from different limited area weather forecast models such as aLMo from MeteoSwiss.

The company 'Analysen und Konzepte' is assigned by the SER to further develop the so-called 'Topographisches Grenzschichtmodell'.

Working Group 3:

MeteoSwiss has the task to answer the following question: Which are the relevant predictors for statistical fog or visibility models? This task was executed by applying stepwise backward selection methods on one side and by utilizing subjective methods on the other side.

An Airbus 340 from Swiss international airlines just seconds before touching down on RWY 14 in Zurich on a foggy morning (Photo C. Schmutz).

1-DEFOP

First results are already available. The following Figures show a fog case at the airport of Zurich in autumn 2004. The fog prediction in this case is quite good.

Ensembles-Predictions, Liquid water content.

Observed visibilities.

Sensors at the airport Zurich

Different sensors were installed at the airport Zurich for the project 1-DEFOP. Some of the remain permanent while others were used temporary during the fog season 2004/2005.

Installation of ground humidity and ground temperature sensors in the immediate vicinity of the runways. (Photo C. Schmutz)

Radiometer MTP-5 for the remote sensing of the temperature profile in the lowest 1000m of the atmosphere at the MET observatory of the airport Zurich. (Photo C. Schmutz)