Characterization of the planetary boundary layer height and structure by Raman lidar: comparison of different approaches

Abstract

Abstract.The planetary boundary layer (PBL) includes the portion of the atmosphere which is directly influenced by the presence of the earth's surface. Aerosol particles trapped within the PBL can be used as tracers to study the boundarylayer vertical structure and time variability. As a result of this, elastic backscatter signals collected by lidar systems can be used to determine the height and the internal structure of the PBL.The present analysis considers three different methods to estimate the PBL height. The first method is based on the determination of the first-order derivative of the logarithm of the range-corrected elastic lidar signals. Estimates of the PBL height for specific case studies obtained through this approach are compared with simultaneous estimates from the potential temperature profiles measured by radiosondes launched simultaneously to lidar operation. Additional estimates of the boundary layer height are based on the determination of the first-order derivative of the range-corrected rotational Raman lidar signals. This latter approach results to be successfully applicable also in the afternoon-evening decaying phase of the PBL, when the effectiveness of the approach based on the elastic lidar signals may be compromised or altered by the presence of the residual layer. Results from these different approaches are compared and discussed in the paper, with a specific focus on selected case studies collected by the University of Basilicata Raman lidar system BASIL during the Convective and Orographically-induced Precipitation Study (COPS).

Overview: Tropospheric profiling: state of the art and future challenges – introduction to the AMT special issue

“…Results obtained considering pilot instrumentation should be extended to instrument networks, such as ground-based weather radars (Maiello et al, 2014) or microwave radiometers (Güldner, 2013). Several authors pointed out that instrument synergy should be better exploited to overcome intrinsic limitations and reduce the uncertainties of products, such as the PBL height Summa et al, 2013), atmospheric refractivity (Hurter and Maier, 2013), aerosol profiles (Marcos et al, 2013), and rainfall rates (Réchou et al, 2014). The availability of near-real-time data and smart information and communications technology tools is recognized as crucial for applications such as flight trajectory prediction , weather nowcasting (Hurter and Maier, 2013), and hazard early warning (Adachi et al, 2013).…”

“…Using data from a field campaign conducted at the Haute Provence Observatory (France), the authors address the consistency of wind profile measurements made by different active remote sensors (lidars and a 72 MHz radar) with balloon radio soundings, in light of the upcoming European Space Agency wind Doppler lidar mission (ADMAeolus), currently scheduled for launch in 2015. Summa et al (2013) consider three different methods for estimating the planetary boundary layer (PBL) height based on (i) radiosonde profiles, (ii) elastic and (iii) Raman lidar signals. Using data collected during the Convective and Orographically-induced Precipitation Study (COPS), they demonstrate that the latter approach is successfully applicable also in the afternoon-evening decaying phase of the PBL, when the effectiveness of the elastic lidar approach may be altered by the presence of the residual layer.…”

Characterisation of boundary layer turbulent processes by the Raman lidar BASIL in the frame of HD(CP)<sup>2</sup> Observational Prototype Experiment

“…The evolution of the instantaneous CBL height z i (black dots in Fig. 4) was determined through the application of a conventional approach based on the detection of the strongest gradient in the aerosol backscatter signal (see, among others, Haeffelin et al, 2012;Milroy et al, 2012;Summa et al, 2013). Within the considered time interval, z i is found to be characterised by a limited variability, with a mean value z i of 1290 m a.g.l, and a standard deviation of 75 m. The minimum and maximum values of z i during the observation period are 1140 and 1440 m a.g.l., respectively.…”

A new methodology for PBL height estimations based on lidar depolarization measurements: analysis and comparison against MWR and WRF model-based results

“…The PBL structure is especially complex during the sunrise and sunset when the mixing and residual layers coexist. Furthermore, the coupling of advected aerosol layers in the free troposphere with aerosol in the PBL or the presence of clouds leads to under-or overestimation of the PBL height Summa et al, 2013).…”