FLYSAFE - meteorological hazard nowcasting, driven by the needs of the pilot

The FLYSAFE project is a European Commission funded project aiming at improving flight safety through the development of a Next Generation Integrated Surveillance System (ISS). The ISS will provide information to the pilot on a number of external hazards, with particular emphasis on weather, air traffic and terrain. In many current aircraft information about these three hazards is provided on independent warning systems and there can be considerable difficulty in, for example, avoiding turbulence without increasing the risk of a mid-air collision. The NGISS will have the capability of displaying information about all three hazards on a single screen, facilitating rapid pilot appreciation of the situation and the instigation of avoiding action.

One particularly innovative feature of the NGISS is that it is coupled to ground facilities which are being designed to provide the best possible nowcast of the most dangerous meteorological hazards. This is made possible by the development of so-called Weather Information Management Systems (WIMSs). The WIMSs are best thought of as expert systems which bring together all available information about the hazard under consideration and provide an optimised nowcast for aircraft at risk. In addition, information concerning hazards which fall outside the scope of the WIMSs will be made available to aircraft in flight.

Four WIMSs are being developed, covering Clear Air Turbulence, Icing, Thunderstorms and Wake Vortices. This selection of the most severe hazards was not without debate, and at various stages WIMSs addressing volcanic ash and poor visibility have also been considered. However as mentioned earlier, information concerning these hazards will be made available without specialised processing on the ground.

All WIMSs will generate products on three scales – the global scale, the European scale and the Terminal Manoeuvring Area (TMA) scale. For the global scale, considerable reliance will be placed on products from the London World Area Forecast Centre, which will generate gridded products which will also support flight planning.

The update rate of forecasts from the WIMS will be scale and product dependent and have not been finalised but update rates for TMA scale forecasts of 10 minutes are under consideration. Similarly the length of forecasts are scale and product dependent.

The input are meteorological data from observations (SYNOP, radar, satellite, lightning sensors, aircraft etc) and numerical models.

CAT WIMS

The CAT WIMS will address shear induced CAT, mountain wave induced CAT and CAT caused by severe thunderstorms. For the latter cause, considerable reliance will be placed on the thunderstorm WIMS. Accurate nowcasts of both shear induced CAT and mountain wave induced CAT are critically dependent on accurate nowcasts of wind and temperature and for this purpose the WAFTAGE nowcasting tool will be further developed.

ICE WIMS

As mentioned earlier, the global icing information will be derived from the existing WAFC icing product, for European scale information it is planned to use the German ADWICE system. Icing information on the local scale (TMA) will be derived from locally available high-resolution observational data sets (e.g. for Paris and other locations).

Output are relevant parameters describing the icing situation, like estimate for super-cooled liquid water content (SLWC), temperature and icing type.

Thunderstorm WIMS

For the TMA, the Cb properties like location, size, track, its meteorological characterisation like rain, hail, wind, turbulence, lightning, and its future evolution are described in terms of Cb objects. For the European scale, object-oriented data or meteorological parameters on grids may be used. As mentioned earlier, for the global scale (over areas with low data density), simple Cb measures are provided on a grid by the London WAFC. The thunderstorm WIMS uses meteorological data from sensors installed at the airport, in addition to the data sources available to all WIMSs.

Wake Vortex WIMS

The Wake Vortex (WV) WIMS provides forecast meteorological parameters used for WV predictions in RVSM airspace and in the TMA (approach and take-off/climbing). For the TMA the WIMS further produces predictions of WV trajectories and strength and minimum safe time separations for two consecutive aircraft classes between the Final Approach Fix and the runway threshold or – for departures – for the take-off and climb phases. The WV WIMS uses local meteorological measurements from equipment installed at the airport, and ground-based WV monitoring data in addition to the data sources available to all WIMSs . It computes the future meteorological parameters in the RVSM airspace. It also computes the future meteorological parameters, the resulting WV behaviour, and the required safe aircraft separations in the TMA.

On-board data fusion

After the WIMS products have been uplinked to the aircraft, they are combined with data from on-board sensors where appropriate. For example on-board measurements of turbulence can be combined with data from the CAT WIMS. This process will mean that the information provided to the pilot is the most up-to-date available.