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. Plain Language Summary: We calculated a primary aviation turbulence metric, eddy dissipation rate (EDR), using operational high‐resolution radiosonde data and compared it with flight‐EDR observed from commercial airlines. EDR is an index for representing the intensity of turbulence. Analyzing 6 years of data (2012–2017) over the United States, we find that the horizontal distributions of both EDRs from radiosonde data and flight data show large values over the Rocky Mountains. However, they show large differences in vertical and temporal distributions in terms of their peak location and timing. We attribute these discrepancies to three factors. First, turbulence observed from the two data sets cannot be the same event, because the radiosonde and aircraft cannot coincide at the same location and time. Second, the sources of turbulence derived from radiosonde and flight observation may be different: static‐instability and dynamic‐instability for radiosonde‐EDR and flight‐EDR, respectively. Third, aircraft have limitations detecting fluctuation at scales smaller than the aircraft size. Given the limited global data on atmospheric turbulence, EDR estimated from operational radiosonde data can be a valuable resource for research and development for the aviation industry and numerical weather forecasting models. Key Points: Radiosonde‐derived turbulence is applied to aviation turbulence metricSpatiotemporal distributions of radiosonde‐ and flight‐turbulence are comparedCauses of discrepancies between radiosonde‐ and flight‐turbulence are discussed [ABSTRACT FROM AUTHOR]