Abstract
The height of the atmospheric boundary layer (ABLH) or the mixing layer height (MLH) is a key parameter characterizing the planetary boundary layer, and the accurate estimation of that is critically important for boundary layer related studies, which include air quality forecasts and numerical weather prediction. Aerosol lidar is a powerful remote sensing instrument frequently used to retrieve the ABLH through detecting the vertical distributions of aerosol concentration. Presently available methods for ABLH determination from aerosol lidar are summarized in this review, including a lot of classical methodologies as well as some improved versions of them. Some new recently developed methods applying advanced techniques such as image edge detection, as well as some new methods based on multi-wavelength lidar systems, are also summarized. Although a lot of techniques have been proposed and have already given reasonable results in several studies, it is impossible to recommend a technique which is suitable in all atmospheric scenarios. More accurate instantaneous ABLH from robust techniques is required, which can be used to estimate or improve the boundary layer parameterization in the numerical model, or maybe possible to be assimilated into the weather and environment models to improve the simulation or forecast of weather and air quality in the future.
Highlights
The atmospheric boundary layer (ABL), called the planetary boundary layer (PBL), is the turbulent layer that is directly influenced by the Earth’s surface and responds to surface impact over a short period of time [1]
The mixing layer height (MLH) is identical to the height of the lower stable surface layer, the ABL height (ABLH) is identical to the height of upper layer, a residual aerosol layer (RL) which is a remnant of the daytime convective boundary layer (CBL)
Liu et al [138] proposed a two-wavelength algorithm called particle distribution method (PDM) to determine the ABLH based on the particle distribution, which is established by using the aerosol color ratio (CR) and depolarization ratio (DR)
Summary
The atmospheric boundary layer (ABL), called the planetary boundary layer (PBL), is the turbulent layer that is directly influenced by the Earth’s surface and responds to surface impact over a short period of time [1]. Lidar technique shows several advantages including high temporal resolution and wide vertical spatial coverage, the instrument can possibly be operated continuously in an almost automated status. This paper gives a new review of presently available methods for the aerosol lidar measurements of ABLH or MLH with some real cases based on the MPL profiles over SACOL (Semi-Arid Climate Observatory and Laboratory) in China. The reference ABLH is defined by the theta-gradient method (the altitude where the maximum of the theta gradient occurs [42,55]) based on the potential temperature profiles provided by a nearby radiosonde site (35.87◦N, 104.15◦E; 1875 m above sea level (90.8 m lower than SACOL)), which is approximately 8.83 km from SACOL (detail descriptions about lidar system over SACOL, and the radiosonde-provided profiles of atmospheric variables see Dang et al [56]).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
