FAAM CORE - Aircraft horizontal wind vectors

General

The data from the 5-hole turbulence probe should always be the first choice. However, due to the fact that the holes are located in radome of the aircraft and the design does not allow the installation of powerful heaters the turbulence probe is susceptible to icing. In situations where icing had occured, and low time resolution wind speed data are sufficient the aircraft horizontal wind vectors can be a valuable substitute.

Data

The aircraft horizontal wind vector calculations are completetly independent from the turbulence probe. The algorithmen uses the following variables from the core data as input:

  • true air temperature, deiced (TAT_DI_R)
  • heading (HDG_GIN)
  • ground speeds (VELN_GIN, VELE_GIN)
  • true air speed (TAS_RVSM)

The two vectors are stored as U_NOTURB and V_NOTURB variables in the core_faam netCDF. Although the time resolution for all the input parameters is 32Hz the wind vectors are only supplied as 1Hz. The inertia of the aircraft acts as a high-pass filter.

The quality flag for the data is derived from the the flag of the input variables. The formulas above are only valid for straight and level runs. Therefore all data points where the aircraft bank angle is greater than 1.5 degrees are flagged as unusable (Flag 3).

Links

Further Details

Contact Alan Woolley at FAAM