100 Years of Progress in Boundary Layer Meteorology

Abstract

Over the last 100 years, boundary layer meteorology grew from the subject of mostly near-surface observations to a field encompassing diverse atmospheric boundary layers (ABLs) around the world. From the start, researchers drew from an ever-expanding set of disciplines—thermodynamics, soil and plant studies, fluid dynamics and turbulence, cloud microphysics, and aerosol studies. Research expanded upward to include the entire ABL in response to the need to know how particles and trace gases dispersed, and later how to represent the ABL in numerical models of weather and climate (starting in the 1970s–80s); taking advantage of the opportunities afforded by the development of large-eddy simulations (1970s), direct numerical simulations (1990s), and a host of instruments to sample the boundary layer in situ and remotely from the surface, the air, and space. Near-surface flux-profile relationships were developed rapidly between the 1940s and 1970s, when rapid progress shifted to the fair-weather convective boundary layer (CBL), though tropical CBL studies date back to the 1940s. In the 1980s, ABL research began to include the interaction of the ABL with the surface and clouds, the first ABL parameterization schemes emerged; and land surface and ocean surface model development blossomed. Research in subsequent decades has focused on more complex ABLs, often identified by shortcomings or uncertainties in weather and climate models, including the stable boundary layer, the Arctic boundary layer, cloudy boundary layers, and ABLs over heterogeneous surfaces (including cities). The paper closes with a brief summary, some lessons learned, and a look to the future.

Ramp‐Like PM Accumulation Process and Z‐Less Similarity in the Stable Boundary Layer

“…In the past 30 years, great achievements have been made in the experimental study of SBL, including short-term field experiments (radiosonde, tethered balloon, various remote sensing, and aircraft observation) and long-term observation of meteorological tower (LeMone et al, 2018;Sorbjan, 1986). For example, the famous SBL experiments Cooperative Atmosphere-Surface Exchange Study (CASES-99) (Poulos et al, 2002) and SHEBA (Grachev et al, 2013;Persson, 2012), the high meterological tower like Boulder Atmospheric Observation (BAO) 300-m tower in the United States (Kaimal & Gaynor, 1983;Sorbjan, 1986), Cabauw 213-m tower in the Netherlands (Nieuwstadt, 1984), and the Beijing 325-m tower in China (Al-Jiboori & Hu, 2005).…”

“…Similarity theory is very useful for studying SBL (LeMone et al, ; Sorbjan, ). Some previous studies focused on the SBL similarity have presented turbulent variances and covariances nondimensionalized by surface layer fluxes and as a function of , where is the atmospheric boundary height (Caughey et al, ; Mahrt et al, ).There are also semiempirical theories based on local similarity (LeMone et al, ; Stull, ). However, vertical turbulence is greatly suppressed in SBL and the turbulence motions cannot extend throughout the boundary layer, so the use of scaling length is less appropriate (Nieuwstadt, ).…”

Commentaries on Top-Cited Boundary-Layer Meteorology Articles

“…(i) a review of the modelling of stratocumulus clouds, emphasizing the mixed-layer model of Lilly (1968) and its assumptions; (ii) the three-dimensional model equations, including the use of Betts' liquid-water potential temperature as a thermodynamic variable, and the prescribed radiative flux divergence in terms of magnitude and height for each model grid column; (iii) a new and simpler subgrid turbulence parametrization scheme in which the subgrid eddy coefficient is proportional to the square root of the subgrid turbulence intensity. As noted by LeMone et al (2019), this accounted for the effects of pressure fluctuations and turbulent transport as well as buoyancy, shear, and dissipation on the eddy coefficient, and later came to be called the Deardorff TKE scheme (Moeng and Sullivan 2015); (iv) a 2-km deep domain, with 40 × 40 × 40 gridpoints, with a vertical grid spacing of 50 m set by the limit of computer resources at the time. D80 considers seven cases, including a dry PBL, a "dry cloud", a stratocumulus layer with no radiative cooling, and finally realistic stratocumulus with cloud-top radiative cooling, all with a specified PBL depth of between 1 and 1.5 km.…”

Characteristics and performance of wind profiles as observed by the radar wind profiler network of China

“…It is increasingly recognised that atmospheric wind profiles and vertical wind shear are crucial to better understanding the more frequent extreme rainfall events (Huuskonen et al, 2014;Nash and Oakley, 2001;Weber et al, 1990), the intensification of clear-air turbulence associated with aircraft safety (Williams and Joshi, 2013), complicated aerosolcloud-precipitation interaction (Fan et al, 2009;Guo et al, 2016aGuo et al, , 2019Lee et al, 2016) and persistent particulatepollution episodes (Yang et al, 2019;Zhang et al, 2020). For the wind speed in the planetary boundary layer (PBL), the most striking feature is that the turning of winds with height dominates the whole PBL and beyond, which can be explained in terms of force vectors (drag, pressure gradient force, Coriolis force) at the surface and the top of the PBL (pressure gradient force and Coriolis force) (LeMone et al, 2018). Under the influence of large-scale dynamic forcing and land surface processes, wind speed and direction will dramatically vary (Michelson and Bao, 2008), which poses a great challenge for models to simulate or forecast the variation in wind very well, especially in the PBL (Constantinescu et al, 2009;Guo et al, 2016b;Liu et al, 2017).…”