Publication Date:
2017-12-29
Description:
Observations from aircraft are an important element of the global observing network. A promising new observation source, deriving wind and temperature measurements from air traffic management data, has previously been reported on by a small number of groups. This paper further investigates the error characteristics by comparing a year's worth of in situ observed winds and temperatures from a commercial British Airways Boeing 747 (B747) with the derived Mode-Selective (Mode-S) Enhanced Surveillance (EHS) observations from the Met Office network of Mode-S receivers. It is shown that whilst the winds and high altitude temperatures are of good quality they show error profiles with altitude that are different for ascent and descent. The data shows that the situation of the aircraft is critical to understand the biases; this is dependent on the aircraft, operator and airport, making corrections infeasible. Further understanding is gained by an intercomparison flight with the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe 146 aircraft. This showed a good comparison with Mode-S EHS winds, with a RMS difference between the FAAM data and B747 Mode-S EHS data of 1.5 ms −1 and 0.9 ms −1 for the u and v components respectively; Comparing the FAAM data and B747 flight data recorder (FDR) provided RMS differences of 0.6 ms −1 and 1.4 ms −1 respectively. This suggests that the data quality from Mode-S EHS is similar to that which can be achieved from a commercial aircraft. The temperature RMS differences were found to be 1.6 K and 0.5 K when the FAAM data is compared to the Mode-S EHS data and FDR data from the B747 respectively, suggesting that the temperature Mode-S EHS data are of an inferior quality.
Print ISSN:
0035-9009
Electronic ISSN:
1477-870X
Topics:
Geography
,
Physics
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