Mesoscale variability of the aerosol distribution as determined from ceilometer measurements

2020 ◽  
Author(s):  
Matthias Wiegner ◽  
Alexander Geiß ◽  
Ina Mattis ◽  
Fred Meier ◽  
Thomas Ruhtz
Keyword(s):  
Air Quality ◽  
Mixing Layer ◽  
Radiation Budget ◽  
Transport Models ◽  
Layer Height ◽  
Aerosol Distribution ◽  
Two Cities ◽  
Spatial Differences ◽  
Mixing Layer Height ◽  
Highly Correlated

<p>The spatial distribution of aerosol particles is relevant for studies on the radiation budget, for the verification of chemistry transport models, or for air quality studies just to name a few. As the distribution is highly variable the requirements to measurements are very demanding. As a consequence it is often assumed that the aerosol distribution is "relatively homogeneous", i.e., measurements at one site are representative for a larger area.</p><p>By exploiting 2 years of measurements from 12 ceilometers located in the area of Munich and Berlin, Germany, we have investigated the spatial differences between locations separated between 3~km and 50~km. For this purpose we have used the mixing layer height (MLH), a quantity often used when the vertical aerosol distribution should be described by a single parameter. The MLH was determined by the COBOLT-algorithm (Geiß et al., 2017). It was found that the MLHs at different locations inside the two cities are highly correlated and agree within a few tens of meters. However, the maximum extension of the mixing layer from April to September was found to be significantly larger in Berlin compared to Munich.</p><p><br>Geiß, A., Wiegner, M., Bonn, B., Schäfer, K., Forkel, R., von Schneidemesser, E., Münkel, C., Chan, K. L., and Nothard, R. (2017): Mixing layer height as an indicator for urban air quality?  Atmos. Meas. Tech., 10, 2969-2988, https://doi.org/10.5194/amt-10-2969-2017, 2017.</p>

Application of continuous remote sensing of mixing layer height for assessment of airport air quality

2010 ◽  
Author(s):  
Klaus Schäfer ◽  
Costas Helmis ◽  
Stefan Emeis ◽  
George Sgouros ◽  
Ralf Kurtenbach ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Air Quality ◽  
Mixing Layer ◽  
Layer Height ◽  
Mixing Layer Height

Impact of mixing layer height on air quality in winter

2020 ◽  
Vol 197 ◽  
pp. 105157 ◽  
Author(s):  
B.S. Murthy ◽  
R. Latha ◽  
Arpit Tiwari ◽  
Aditi Rathod ◽  
Siddhartha Singh ◽  
...  
Keyword(s):  
Air Quality ◽  
Mixing Layer ◽  
Layer Height ◽  
Mixing Layer Height

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 Ground-Based Remote Sensing of the ABL Structure in Moscow and Its Use to Estimate Pollutant Surface Emission Rates

2014 ◽  
Vol 53 (5) ◽  
pp. 1272-1281 ◽  
Author(s):  
Valery F. Kramar ◽  
Evgeniya Baykova ◽  
Margarita Kallistratova ◽  
Rostislav Kouznetsov ◽  
Sergei Kulichkov
Keyword(s):  
Air Quality ◽  
High Surface ◽  
Mixing Layer ◽  
Pollutant Emissions ◽  
Horizontal Wind ◽  
Emission Rates ◽  
Layer Height ◽  
Surface Emission ◽  
Convective Mixing ◽  
Mixing Layer Height

AbstractCurrently used methods to estimate surface pollutant emissions require a set of specific air-sampling surveys. Data from a network of ground-based sodars and a network of air-quality stations in Moscow, Russia, are used to estimate the emission rates of carbon monoxide (CO) and nitric oxide (NO). The sodar network, consisting of three “LATAN-3” Doppler sodars and three “MTP-5” microwave temperature profilers, is used to measure the vertical profiles of vertical and horizontal wind velocity, wind direction, and temperature, which are used to determine the average mixing-layer height. The network of ground-based air-quality stations, consisting of 17 automated stations distributed uniformly across Moscow, continuously measured the CO and NO concentrations. This study focuses on an anticyclonic episode of high surface pressure over Moscow during 30 July–1 August 2012. After sunrise, the solar-induced convection effectively moderated the pollutant levels in the lowest 100–200 m. After sunset, convective mixing stopped and the wind weakened, which allowed CO and NO to reach hazardous levels. With an assumption of an average mixing-layer height of 150 m, the resulting estimate of surface emission of CO is ~6 μg m−2 s−1, whereas that for NO is ~0.6 μg m−2 s−1.

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.

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