Comparison of analytical descriptions of nocturnal low-level jets within the Ekman model framework
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This study focuses on the inertial oscillation aspect of the nocturnal low-level jet (NLLJ). In the context of the Ekman model solutions, conceptual NLLJ inertial oscillation analytical frameworks proposed by Blackadar in 1957 and Shapiro and Fedorovich and van de Wiel et al. in 2010 are compared. Considering a NLLJ produced via direct numerical simulation over flat terrain with no baroclinic influence as a reference case, the deficiencies of each framework in representing a realistic NLLJ are assessed. The Blackadar theory results in unrealistic wind profiles near the surface. While extensions of Blackadar’s framework by Shapiro and Fedorovich and van de Wiel et al. produce more realistic NLLJs, the simpler approach taken by van de Wiel et al. does not describe the NLLJ wind hodograph at later times sufficiently in qualitative terms.
KeywordsAnalytical model Blackadar’s theory Low-level jet Inertial oscillation
The authors gratefully acknowledge support through the National Science Foundation (USA) Grant AGS-1359698. The authors are also grateful to anonymous reviewers for their helpful insights on the work.
- 4.Beyrich F, Kalass D, Weisensee U (1997) Influence of the nocturnal low-level-jet on the vertical and mesoscale structure of the stable boundary layer as revealed from doppler-sodar-observations. In: Acoustic remote sensing applications, Springer, New York, pp 236–246Google Scholar
- 5.Blackadar AK (1957) Boundary layer wind maxima and their significance for the growth of nocturnal inversions. Bull Am Meteorol Soc 38(5):283–290Google Scholar
- 7.Ekman VW (1905) On the influence of the earth’s rotation on ocean currents. Ark Mat Astron Fys 2:1–53Google Scholar
- 9.Geurts B (2004) Elements of direct and large-eddy simulation. RT Edwards, PhiladelphiaGoogle Scholar
- 11.Markowski P, Richardson Y (2011) Mesoscale meteorology in midlatitudes. Wiley, New YorkGoogle Scholar
- 14.Shapiro A, Fedorovich E (2010) Analytical description of a nocturnal low-level jet. Q J R Meteorol Soc 136(650):1255–1262Google Scholar