Study of the planetary boundary layer height in an urban environment using a combination of microwave radiometer and ceilometer

Abstract

The Planetary Boundary Layer () is an important part of the atmosphere that is relevant in different atmospheric fields like pollutant dispersion, and weather forecasting. In this study, we analyze four and five-year datasets of measurements gathered with a ceilometer and a microwave radiometer to study the PBL structure respectively, in the mid-latitude urban area of Granada (Spain). The methodologies applied for the Height ( ) detection (gradient method for ceilometer and the combination of parcel method and temperature gradient method for microwave radiometer) provided a description in agreement with the literature about the structure under simple scenarios. Then, the behavior is characterized by a statistical study of the convective and stable situations, so that the was obtained from microwave radiometer measurements. The analysis of the statistical study shows some agreement with other studies such as daily pattern and yearly cycle, and the discrepancies were explained in terms of distinct latitudes, topography and climate conditions. Finally, it was performed a joint long-term analysis of the residual layer (RL) provided by ceilometer and the stable and convective layer heights determined by microwave radiometer, offering a complete picture of the evolution by synergetic combination of remote sensing techniques. The PBL behavior has been used for explaining the daily cycle of Black Carbon (BC) concentration, used as tracer of the pollutants emissions associated to traffic.The measurement campaign was carried out at the Andalusian Institute of Earth System Research (IISTA-CEAMA). This station is part of European Aerosol Research Lidar Network -EARLINET (Pappalardo et al., 2014) since 2004 and at present is an active station of ACTRIS (http://actris2.nilu.no/). This station is located at Granada, a medium sized (population of around 238 000 inhabitants over an area of 88 km²) nonindustrialized city in the Southeastern Spain at about 50 km away from the Mediterranean coast (Granada, 37.16°N, 3.61°W, 680 m a.s.l.) (INE, 2017). Granada is surrounded by mountains and dominated by Mediterranean-continental conditions, which are responsible for large seasonal temperature differences, providing cool winters and hot summers. The most humid period goes from late autumn to early spring.The rest of the year is characterized by rain scarcity. It is worthy to note that the Southeastern Spain is usually affected by mineral dust outbreaks from the Saharan Desert (North Africa) (e.g. Lyamani et al.,

Detection of Upper and Lower Planetary-Boundary Layer Curves and Estimation of Their Heights from Ceilometer Observations under All-Weather Conditions: Case of Athens, Greece

“…The purpose of developing this algorithm was to estimate MLH under all-weather conditions. Though various algorithms have been developed for specific purposes (e.g., [43,[53][54][55][56]), the distinction with the present one is that our code can be applied at any part of the world with small modifications. On the other hand, Vaisala have produced the BL-View software package [57], which can detect MLH, but it is a commercial product sold separately from the ceilometer itself.…”

Sources and physicochemical characteristics of submicron aerosols during three intensive campaigns in Granada (Spain)

“…Planetary Boundary Layer height (PBLH) was determined using temperature profiles measured at UGR with a Microwave Radiometer (MWR, RPG-HATPRO, Radiometer Physics GmbH) (Navas-Guzmán et al, 2014, Moreira et al, 2018a. The parcel method (Bravo-Aranda et al, 2017;Collaud-Coen et al, 2014;Holzworth, 1964) was used to obtain the PBLH in convective situations (during the day), and the temperature gradient method (Collaud- Coen et al, 2014;Stull, 1988) was employed to obtain the PBLH in stable conditions (during the night) (Moreira et al, 2018a).…”

“…However, BCUB was the same in both spring campaigns (~700 ng m -3 ) but higher in autumn (~ 1500 and 1800 ng m -3 in AC-1 and AC-2, respectively). Thus, differences between seasons might be explained by the lower emissions and higher PBLH during spring (leading to greater mixing) than during autumn (Granados-Muñoz et al, 2012;Moreira et al, 2018aMoreira et al, , 2018b, when the PBLH is 56 % lower. In particular, the higher concentration of particles during AC-2 might be related to the BB contribution along with a shallower PBLH (Fig.…”

Estimating the urban atmospheric boundary layer height from remote sensing applying machine learning techniques

“…Toledo et al, 2017;Bravo-Aranda et al, 2017;Moreira et al, 2019;Vivone et al, 2021), ceilometers (e.g. Haeffelin et al, 2012;Caicedo et al, 2017;Lee et al, 2019;Uzan et al, 2020;Moreira et al, 2020a;, Doppler lidars (e.g. Manninen et al, 2018;Marques et al, 2018;Moreira et al, 2019) and microwave radiometers (e.g.…”