Comparison of Eddy Dissipation Rate Estimated From Operational Radiosonde and Commercial Aircraft Observations in the United States

Abstract

AbstractThe one‐third power of the energy dissipation rate (EDR), a primary aviation turbulence metric, is calculated using high vertical‐resolution radiosonde data (HVRRD) and compared with flight‐EDR observed from commercial airlines. Comparisons are made along the main flight routes over the United States and at z = 20–45 kft for 6 years (2012–2017). The horizontal distributions of moderate‐or‐greater (MOG) ratio of HVRRD‐EDR show large values over the Rocky Mountains, consistent with those of flight‐EDR. Vertically, the MOG ratios of HVRRD‐EDR show local peaks at z = 20–23 kft and 41–44 kft, while those of flight‐EDR at z = 23–26 kft and 35–41 kft. Temporally, HVRRD‐EDR has maximum MOG values in JJA and minimum values in DJF at z = 20–30 kft, which is opposite to the flight‐EDR. At z = 30–40 kft, HVRRD‐EDR shows nearly no seasonal variation but flight‐EDR has large values in MAM and small values in JJA. At z = 40–45 kft, HVRRD‐EDR (flight‐EDR) shows large values in MAM and small values in SON (DJF). Discrepancies in spatiotemporal distributions between the two data sets likely stem from: (a) turbulence observed from the two data sets cannot be the same event, (b) the limitation of HVRRD‐EDR in capturing shear‐instability under statically stable condition (i.e., Kelvin‐Helmholtz instability) which probably accounts for most flight‐EDR events at upper levels, and (c) limitation in aircraft measurements response to fluctuations at smaller scales than the aircraft size.