scholarly journals A Model Chain Application to Estimate Mixing Layer Height Related to PM10 Dispersion Processes

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
F. Guarnieri ◽  
F. Calastrini ◽  
C. Busillo ◽  
G. Messeri ◽  
B. Gozzini
Keyword(s):  
Wind Speed ◽  
Numerical Models ◽  
Central Italy ◽  
Mixing Layer ◽  
Meteorological Conditions ◽  
Air Pollutant ◽  
Limited Area ◽  
Near Surface ◽  
Layer Height ◽  
Mixing Layer Height

The mixing layer height (MLH) is a crucial parameter in order to investigate the near surface concentrations of air pollutants. The MLH can be estimated by measurements of some atmospheric variables, by indirect estimates based on trace gases concentration or aerosol, or by numerical models. Here, a modelling approach is proposed. The developed modelling system is based on the models WRF-ARW and CALMET. This system is applied on Firenze-Prato-Pistoia area (Central Italy), during 2010, and it is compared with in situ measurements. The aim of this work is to evaluate the use of MLH model estimates to characterize the critical episodes for PM10 in a limited area. In order to find out the meteorological conditions predisposing accumulation of PM10 in the atmosphere’s lower level, some indicators are used: daily mean wind speed, cumulated rainfall, and mean MLH estimates from CALMET model. This indicator is linked to orography, which has important consequences on local weather dynamics. However, during critical events the local emission sources are crucial to the determination of threshold exceeding of PM10. Results show that the modelled MLH, together with cumulative rainfall and wind speed, can identify the meteorological conditions predisposing accumulation of air pollutant at ground level.

scholarly journals The Relationship of PM Variation to Visibility and Mixing Layer Height under Haze/Fog Condition in Multi-Cities of Northeast China

2017 ◽  
Author(s):  
Hujia Zhao ◽  
Huizheng Che ◽  
Yanjun Ma ◽  
Yangfeng Wang ◽  
Hongbin Yang ◽  
...  
Keyword(s):  
Northeast China ◽  
Mixing Layer ◽  
Liaoning Province ◽  
Vertical Diffusion ◽  
Near Surface ◽  
Layer Height ◽  
Haze Pollution ◽  
Mixing Layer Height ◽  
High Concentrations ◽  
Fog Days

The variations of visibility, PM mass concentration and mixing layer height (MLH) at four major urban-industry regions (Shenyang, Anshan, Benxi and Fushun) in multi-cities of central Liaoning over northeast China were evaluated from 2009-2012 to characterize the dynamics effect on air pollution. The annual mean visibilities were about 13.7±7.8km, 13.5±6.5km, 12.8±6.1km and 11.5±6.8km in Shenyang, Anshan, Benxi and Fushun, respectively. The pollution load (PM×MLH) shown a weaker vertical diffusion in Anshan with a higher PM concentration in the near-surface. High concentrations of fine mode particles may be partially attributed to the biomass burning emissions from September in Liaoning Province and surrounding regions in Northeast China as well as the coal burning during the heating period with lower MLH in winter. The increasing wind speed has a similar change as the increasing of mixing layer height to make the effect on the aerosol vertical diffusion. The visibility on the non haze-fog days was about 2.5-3.0 times higher than that on hazy and fog days. The fine particle concentrations of PM2.5 and PM1.0 on the haze and fog days were ~1.8-1.9 times and ~1.5 times higher than that on no hazy-fog days. The MLH during fog pollution showed more declining trend than haze pollution compared with non haze-fog days. The results of this study could provide the useful information to better recognize the effects of vertical pollutants diffusion on air quality in the multi-cities of central Liaoning over Northeast China.

scholarly journals Detailed Assessment of the Effects of Meteorological Conditions on PM10 Concentrations in the Northeastern Part of the Czech Republic

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 497 ◽  
Author(s):  
Vladimíra Volná ◽  
Daniel Hladký
Keyword(s):  
Air Pollution ◽  
Wind Direction ◽  
Mixing Layer ◽  
Meteorological Conditions ◽  
Pollution Sources ◽  
Pollution Level ◽  
Layer Height ◽  
Wind Speeds ◽  
Average Maximum ◽  
Mixing Layer Height

This article assessed the links between PM10 pollution and meteorological conditions over the Czech-Polish border area at the Třinec-Kosmos and Věřňovice sites often burdened with high air pollution covering the years 2016–2019. For this purpose, the results of the measurements of special systems (ceilometers) that monitor the atmospheric boundary layer were used in the analysis. Meteorological conditions, including the mixing layer height (MLH), undoubtedly influence the air pollution level. Combinations of meteorological conditions and their influence on PM10 concentrations also vary, depending on the pollution sources of a certain area and the geographical conditions of the monitoring site. Gen1erally, the worst dispersion conditions for the PM10 air pollution level occur at low air temperatures, low wind speed, and low height of the mixing layer along with a wind direction from areas with a higher accumulation of pollution sources. The average PM10 concentrations at temperatures below 1 °C reach the highest values on the occurrence of a mixing layer height of up to 400 m at both sites. The influence of a rising height of the mixing layer at temperatures below 1 °C on the average PM10 concentrations at Třinec-Kosmos site is not as significant as in the case of Věřňovice, where a difference of several tens of µg·m−3 in the average PM10 concentrations was observed between levels of up to 200 m and levels of 200–300 m. The average PM10 hourly concentrations at Třinec-Kosmos were the highest at wind speeds of up to 0.5 m·s−1, at MLH levels of up to almost 600 m; at Věřňovice, the influence of wind speeds of up to 2 m·s−1 was detected. Despite the fact that the most frequent PM10 contributions come to the Třinec-Kosmos site from the SE direction, the average maximum concentration contributions come from the W–N sectors at low wind speeds and MLHs of up to 400 m. In Věřňovice, regardless of the prevailing SW wind direction, sources in the NE–E sector from the site have a crucial influence on the air pollution level caused by PM10.

scholarly journals Impact of mixing layer height variations on air pollutant concentrations and health in a European urban area: Madrid (Spain), a case study

2020 ◽  
Vol 27 (33) ◽  
pp. 41702-41716 ◽  
Author(s):  
Pedro Salvador ◽  
Marco Pandolfi ◽  
Aurelio Tobías ◽  
Francisco Javier Gómez-Moreno ◽  
Francisco Molero ◽  
...  
Keyword(s):  
Urban Area ◽  
Mixing Layer ◽  
Air Pollutant ◽  
Layer Height ◽  
Pollutant Concentrations ◽  
Mixing Layer Height ◽  
Air Pollutant Concentrations

scholarly journals Mixing layer height as an indicator for urban air quality?

2017 ◽  
Author(s):  
Alexander Geiß ◽  
Matthias Wiegner ◽  
Boris Bonn ◽  
Klaus Schäfer ◽  
Renate Forkel ◽  
...  
Keyword(s):  
Air Quality ◽  
Mixing Layer ◽  
Clear Correlation ◽  
Emission Sources ◽  
Near Surface ◽  
Layer Height ◽  
Diurnal Cycles ◽  
Pollutant Concentrations ◽  
Novel Approach ◽  
Mixing Layer Height

Abstract. The mixing layer height (MLH) is a measure for the vertical turbulent exchange within the boundary layer, which is one of the controlling factors for the dilution of pollutants emitted near the ground. Based on continuous MLH measurements with a Vaisala CL51 ceilometer and measurements from an air quality network, the relationship between MLH and near surface pollutant concentrations have been investigated. In this context the uncertainty of the MLH retrievals and the representativeness of ground-based in-situ measurements are crucial. We have investigated this topic by using data from the BAERLIN2014 campaign in Berlin, Germany, conducted during June and August 2014. To derive the MLH three versions of the proprietary software BL-VIEW and a novel approach COBOLT were compared. It was found that the overall agreement is reasonable if mean diurnal cycles are considered. The main advantage of COBOLT is the continuous detection of the MLH with a temporal resolution of 10 minutes and a lower number of cases when the residual layer is misinterpreted as mixing layer. We have calculated correlations between MLH as derived from the different retrievals and concentrations of pollutants (PM10, O3 and NOx) for different locations in the metropolitan area of Berlin. It was found that the correlations with PM10 are quite different for different sites without showing a clear pattern, whereas the correlation with NOx seems to depend on the vicinity of emission sources in main roads. In case of ozone as a secondary pollutant a clear correlation was found. We conclude that the effects of the heterogeneity of the emission sources, chemical processing and mixing during transport exceed the differences due to different MLH retrievals. Moreover, it seems to be unrealistic to find correlations between MLH and near surface pollutant concentrations representative for a city like Berlin, in particular when traffic emissions are dominant. Nevertheless it is worthwhile to use advanced MLH retrievals for ceilometer data, e.g. for the validation of chemical transport models.

scholarly journals Mixing layer height as an indicator for urban air quality?

2017 ◽  
Vol 10 (8) ◽  
pp. 2969-2988 ◽  
Author(s):  
Alexander Geiß ◽  
Matthias Wiegner ◽  
Boris Bonn ◽  
Klaus Schäfer ◽  
Renate Forkel ◽  
...  
Keyword(s):  
Air Quality ◽  
Mixing Layer ◽  
Clear Correlation ◽  
Emission Sources ◽  
Near Surface ◽  
Layer Height ◽  
Diurnal Cycles ◽  
Pollutant Concentrations ◽  
Novel Approach ◽  
Mixing Layer Height

Abstract. The mixing layer height (MLH) is a measure for the vertical turbulent exchange within the boundary layer, which is one of the controlling factors for the dilution of pollutants emitted near the ground. Based on continuous MLH measurements with a Vaisala CL51 ceilometer and measurements from an air quality network, the relationship between MLH and near-surface pollutant concentrations has been investigated. In this context the uncertainty of the MLH retrievals and the representativeness of ground-based in situ measurements are crucial. We have investigated this topic by using data from the BAERLIN2014 campaign in Berlin, Germany, conducted from June to August 2014. To derive the MLH, three versions of the proprietary software BL-VIEW and a novel approach COBOLT were compared. It was found that the overall agreement is reasonable if mean diurnal cycles are considered. The main advantage of COBOLT is the continuous detection of the MLH with a temporal resolution of 10 min and a lower number of cases when the residual layer is misinterpreted as mixing layer. We have calculated correlations between MLH as derived from the different retrievals and concentrations of pollutants (PM10, O3 and NOx) for different locations in the metropolitan area of Berlin. It was found that the correlations with PM10 are quite different for different sites without showing a clear pattern, whereas the correlation with NOx seems to depend on the vicinity of emission sources in main roads. In the case of ozone as a secondary pollutant, a clear correlation was found. We conclude that the effects of the heterogeneity of the emission sources, chemical processing and mixing during transport exceed the differences due to different MLH retrievals. Moreover, it seems to be unrealistic to find correlations between MLH and near-surface pollutant concentrations representative for a city like Berlin (flat terrain), in particular when traffic emissions are dominant. Nevertheless it is worthwhile to use advanced MLH retrievals for ceilometer data, for example as input to dispersion models and for the validation of chemical transport models.

scholarly journals Lidar-based remote sensing of atmospheric boundary layer height over land and ocean

2014 ◽  
Vol 7 (1) ◽  
pp. 173-182 ◽  
Author(s):  
T. Luo ◽  
R. Yuan ◽  
Z. Wang
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Marine Boundary Layer ◽  
Mixing Layer ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Lidar Measurements ◽  
Mixing Layer Height ◽  
Atmospheric Radiation Measurement ◽  
Atmospheric Boundary Layer Height

Abstract. Atmospheric boundary layer (ABL) processes are important in climate, weather and air quality. A better understanding of the structure and the behavior of the ABL is required for understanding and modeling of the chemistry and dynamics of the atmosphere on all scales. Based on the systematic variations of the ABL structures over different surfaces, different lidar-based methods were developed and evaluated to determine the boundary layer height and mixing layer height over land and ocean. With Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) micropulse lidar (MPL) and radiosonde measurements, diurnal and season cycles of atmospheric boundary layer depth and the ABL vertical structure over ocean and land are analyzed. The new methods are then applied to satellite lidar measurements. The aerosol-derived global marine boundary layer heights are evaluated with marine ABL stratiform cloud top heights and results show a good agreement between them.

scholarly journals Erratum to: Observed and Modelled Convective Mixing-Layer Height at Dome C, Antarctica

2014 ◽  
Vol 153 (1) ◽  
pp. 163-164 ◽  
Author(s):  
Giampietro Casasanta ◽  
Ilaria Pietroni ◽  
Igor Petenko ◽  
Stefania Argentini
Keyword(s):  
Mixing Layer ◽  
Layer Height ◽  
Convective Mixing ◽  
Mixing Layer Height
Sign in / Sign up

Export Citation Format

Share Document