Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid

Atmospheric pollution caused by aerosols deteriorates air quality, increasing public health risks. Anthropogenic aerosols are usually located within the atmospheric boundary layer (ABL), which presents a daytime evolution that determines the air pollutants’ vertical mixing of those produced near the...

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Main Authors: Francisco Molero, Pedro Salvador, Manuel Pujadas
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Atmosphere
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Online Access:https://www.mdpi.com/2073-4433/15/12/1451
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author Francisco Molero
Pedro Salvador
Manuel Pujadas
author_facet Francisco Molero
Pedro Salvador
Manuel Pujadas
author_sort Francisco Molero
collection DOAJ
description Atmospheric pollution caused by aerosols deteriorates air quality, increasing public health risks. Anthropogenic aerosols are usually located within the atmospheric boundary layer (ABL), which presents a daytime evolution that determines the air pollutants’ vertical mixing of those produced near the surface and, therefore, their ground-level concentration from local sources. Precise and complete characterization of the mixing layer is of crucial importance for numerical weather forecasting and climate models, but traditional methods such as radiosounding present some spatial and temporal limitations. Better resolutions have been obtained using lidar, which provides the aerosol vertical distribution. A particular type of lidar, the ceilometer, has demonstrated continuous measurement capabilities, providing vertical profiles with sub-minute time resolution and several-meter spatial resolution. Advanced methods, such as the recently developed STRATfinder algorithm, are required to estimate the ABL height in the presence of residual layers. More complex situations occur due to the advection of aerosols (e.g., due to long-range transport of desert dust, volcanic eruptions, or pyrocloud convection), producing a lofted layer in the free troposphere that may remain decoupled from the local ABL but can also be mixed. Aerosol-based methods for determination of the ABL height are challenging in those situations. The main objective of this research is the assessment of the impact of Saharan dust intrusions on the ABL using ceilometer signals, over a period of four years, 2020–2023. The ABL height database, obtained from ceilometer measurements every hour, is analyzed based on the most frequent synoptic patterns. A reduction in the ABL height was obtained from high dust load days (1576 ± 876 m) with respect to low dust load days (1857 ± 914 m), although it was still higher than clean days (1423 ± 772 m). This behavior is further studied discriminating by season and synoptic patterns. These results are relevant for health advice during Saharan dust intrusion days.
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spelling doaj-art-d14f701f594d4230995ac4300a2aad3e2025-08-20T02:00:54ZengMDPI AGAtmosphere2073-44332024-12-011512145110.3390/atmos15121451Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over MadridFrancisco Molero0Pedro Salvador1Manuel Pujadas2Centro de Investigaciones Energéticas, Medioambientales y Tecnologicas (CIEMAT), Avda Complutense, 40, 28040 Madrid, SpainCentro de Investigaciones Energéticas, Medioambientales y Tecnologicas (CIEMAT), Avda Complutense, 40, 28040 Madrid, SpainCentro de Investigaciones Energéticas, Medioambientales y Tecnologicas (CIEMAT), Avda Complutense, 40, 28040 Madrid, SpainAtmospheric pollution caused by aerosols deteriorates air quality, increasing public health risks. Anthropogenic aerosols are usually located within the atmospheric boundary layer (ABL), which presents a daytime evolution that determines the air pollutants’ vertical mixing of those produced near the surface and, therefore, their ground-level concentration from local sources. Precise and complete characterization of the mixing layer is of crucial importance for numerical weather forecasting and climate models, but traditional methods such as radiosounding present some spatial and temporal limitations. Better resolutions have been obtained using lidar, which provides the aerosol vertical distribution. A particular type of lidar, the ceilometer, has demonstrated continuous measurement capabilities, providing vertical profiles with sub-minute time resolution and several-meter spatial resolution. Advanced methods, such as the recently developed STRATfinder algorithm, are required to estimate the ABL height in the presence of residual layers. More complex situations occur due to the advection of aerosols (e.g., due to long-range transport of desert dust, volcanic eruptions, or pyrocloud convection), producing a lofted layer in the free troposphere that may remain decoupled from the local ABL but can also be mixed. Aerosol-based methods for determination of the ABL height are challenging in those situations. The main objective of this research is the assessment of the impact of Saharan dust intrusions on the ABL using ceilometer signals, over a period of four years, 2020–2023. The ABL height database, obtained from ceilometer measurements every hour, is analyzed based on the most frequent synoptic patterns. A reduction in the ABL height was obtained from high dust load days (1576 ± 876 m) with respect to low dust load days (1857 ± 914 m), although it was still higher than clean days (1423 ± 772 m). This behavior is further studied discriminating by season and synoptic patterns. These results are relevant for health advice during Saharan dust intrusion days.https://www.mdpi.com/2073-4433/15/12/1451Saharan dustatmospheric boundary layerceilometeraerosolsatmospheric pollution
spellingShingle Francisco Molero
Pedro Salvador
Manuel Pujadas
Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
Atmosphere
Saharan dust
atmospheric boundary layer
ceilometer
aerosols
atmospheric pollution
title Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
title_full Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
title_fullStr Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
title_full_unstemmed Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
title_short Impact of Saharan Dust Intrusions on Atmospheric Boundary Layer Height over Madrid
title_sort impact of saharan dust intrusions on atmospheric boundary layer height over madrid
topic Saharan dust
atmospheric boundary layer
ceilometer
aerosols
atmospheric pollution
url https://www.mdpi.com/2073-4433/15/12/1451
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AT pedrosalvador impactofsaharandustintrusionsonatmosphericboundarylayerheightovermadrid
AT manuelpujadas impactofsaharandustintrusionsonatmosphericboundarylayerheightovermadrid