Weather- and Space-Weather-Driven Variability of ADS-C Reports in New Zealand Airspace

Surveillance and route conformance monitoring for air traffic are supported by information shared via Automatic Dependent Surveillance Contracts (ADS-C). This includes parameters for aircraft position and altitude, which are applied to trigger event reports if the observed values exceed defined limits (e.g., due to offsets). A rate of such event reports compared to the number of ADS-C records is calculated in the present study for the New Zealand airspace and analyzed via a composite analysis to describe variability according to local time, latitude, and distance. Since this analysis indicates the impact of large-scale processes, weather and space weather phenomena are investigated in more detail. Flight tracks are presented in combination with tropospheric and ionospheric parameters to discuss increased rates of event reports via disturbances. Further categories of geometry, weather, and space weather are identified from these results, and the corresponding impacts are summarized in an overview. The occurrence of event reports can be attributed to both tropospheric and ionospheric disturbances, and a correlation to solar flux and geomagnetic activity measurements is indicated. Thus, the study provides a first insight into the variability of ADS-C records with respect to weather and space weather in the New Zealand airspace.