Comparison of eddy dissipation rate estimated from operational radiosonde and commercial aircraft observations in the United States

The 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.