The resistance law for stably stratified atmospheric planetary boundary layers

• Published in: Quarterly journal of the Royal Meteorological Society Vol. 147; no. 737; pp. 2233 - 2243
• Main Authors: Kadantsev, Evgeny, Mortikov, Evgeny, Zilitinkevich, Sergej
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.04.2021; Wiley Subscription Services, Inc
• Subjects: Atmosphere; Boundary layers; Climate models; cross‐isobaric angle; eddy viscosity; friction velocity; geostrophic drag coefficient; large‐eddy simulation; Meteorology; Modelling; Planetary boundary layer; resistance law; static stability; Stratification
• ISSN: 0035-9009; 1477-870X
• DOI: 10.1002/qj.4019

The resistance law for stably and neutrally stratified atmospheric planetary boundary layers (PBL) entered textbooks on boundary‐layer meteorology but, until now, remains practically unused in modelling applications. This is not surprising. The law has been formulated and validated only for idealised cases, such as truly neutral PBL – implying neutral stratification across the entire atmosphere, nocturnal stable PBL – stably stratified near the surface but developed against the neutrally stratified free flow, and (more recently) conventionally neutral PBLs – neutrally stratified near the surface but developed against stable stratification in the free flow. We derive and validate the general formulation of the resistance law accounting for the integral effect on PBL of stable stratifications at the surface and in the free atmosphere. Such long‐lived stable PBLs, typical of wintertime at high latitudes, were until recently overlooked in boundary‐layer meteorology, not to mention weather and climate models. The proposed general formulation of the resistance law covers long‐lived stable PBLs and opens up prospects for their improved modelling. The resistance law for atmospheric planetary boundary layers (PBL) expresses the friction velocity and the cross‐isobaric angle through external parameters but it is barely practically used due to its formulation and validation only for rarely observed idealised cases. This study presents the general formulation accounting for the integral effect on PBL of stable stratifications at the surface and in the free atmosphere that improves general applicability of the resistance law in weather and climate modelling.