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A comparison of Mode‐S Enhanced Surveillance observations with other in situ aircraft observations
Author(s) -
Stone E. K.
Publication year - 2018
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.3238
Subject(s) - mode (computer interface) , altitude (triangle) , environmental science , descent (aeronautics) , meteorology , remote sensing , computer science , geology , geography , mathematics , geometry , operating system
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 article 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 show 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 and 0.9 m/s for the u and v components respectively. Comparing the FAAM data and B747 flight data recorder (FDR) provided RMS differences of 0.6 and 1.4 m/s 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 and 0.5 K when the FAAM data were 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.