Aircraft observations of wind and temperature are very
important for upper air meteorology. In this article, the quality of the meteorological
information of an Automatic Dependent Surveillance-Contract (ADS-C) message is
assessed. The ADS-C messages broadcast by the aircraft are received at air
traffic control centres for surveillance and airline control centres for
general aircraft and dispatch management. A comparison is performed against a
global numerical prediction (NWP) model and wind and temperature observations
derived from Enhanced Surveillance (EHS) air-traffic control radar which
interrogates all aircraft in selective mode (Mode-S EHS). Almost 16 000 ADS-C
reports with meteorological information were compiled from the Royal Dutch
Airlines (KLM) database. The length of the data set is 76 consecutive days and
started on 1 January 2011. The wind and temperature observations are of good
quality when compared to the global NWP forecast fields from the European
Centre for Medium-Range Weather Forecasts (ECMWF). Comparison of ADS-C wind and
temperature observations against Mode-S EHS derived observations in the
vicinity of Amsterdam Airport Schiphol shows that the wind observations are of
similar quality and the temperature observations of ADS-C are of better quality
than those from Mode-S EHS. However, the current ADS-C data set has a lower
vertical resolution than Mode-S EHS. High vertical resolution can be achieved
by requesting more ADS-C when aircraft are ascending or descending, but could
result in increased data communication costs.
NB: Third author is my son – not me (GPK)