In situ measurements of trace gases and aerosol optical properties at a rural site in northern China during East Asian Study of Tropospheric Aerosols: An International Regional Experiment 2005

2007 ◽  
Vol 112 (D22) ◽  
Author(s):  
Can Li ◽  
Lackson T. Marufu ◽  
Russell R. Dickerson ◽  
Zhanqing Li ◽  
Tianxue Wen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Trace Gases ◽  
East Asian ◽  
Northern China ◽  
In Situ Measurements ◽  
Rural Site ◽  
Aerosol Optical Properties ◽  
Asian Study ◽  
East Asian Study

scholarly journals Spatial variation of aerosol optical properties around the high-alpine site Jungfraujoch (3580 m a.s.l.)

2012 ◽  
Vol 12 (15) ◽  
pp. 7231-7249 ◽  
Author(s):  
P. Zieger ◽  
E. Kienast-Sjögren ◽  
M. Starace ◽  
J. von Bismarck ◽  
N. Bukowiecki ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Light Scattering ◽  
In Situ Measurements ◽  
Swiss Alps ◽  
Aerosol Size Distribution ◽  
Horizontal Distance ◽  
Aerosol Optical Properties ◽  
Orographic Clouds

Abstract. This paper presents results of the extensive field campaign CLACE 2010 (Cloud and Aerosol Characterization Experiment) performed in summer 2010 at the Jungfraujoch (JFJ) and the Kleine Scheidegg (KLS) in the Swiss Alps. The main goal of this campaign was to investigate the vertical variability of aerosol optical properties around the JFJ and to show the consistency of the different employed measurement techniques considering explicitly the effects of relative humidity (RH) on the aerosol light scattering. Various aerosol optical and microphysical parameters were recorded using in-situ and remote sensing techniques. In-situ measurements of aerosol size distribution, light scattering, light absorption and scattering enhancement due to water uptake were performed at the JFJ at 3580 m a.s.l.. A unique set-up allowed remote sensing measurements of aerosol columnar and vertical properties from the KLS located about 1500 m below and within the line of sight to the JFJ (horizontal distance of approx. 4.5 km). In addition, two satellite retrievals from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) and the Moderate Resolution Imaging Spectroradiometer (MODIS) as well as back trajectory analyses were added to the comparison to account for a wider geographical context. All in-situ and remote sensing measurements were in clear correspondence. The ambient extinction coefficient measured in situ at the JFJ agreed well with the KLS-based LIDAR (Light Detection and Ranging) retrieval at the altitude-level of the JFJ under plausible assumptions on the LIDAR ratio. However, we can show that the quality of this comparison is affected by orographic effects due to the exposed location of the JFJ on a saddle between two mountains and next to a large glacier. The local RH around the JFJ was often higher than in the optical path of the LIDAR measurement, especially when the wind originated from the south via the glacier, leading to orographic clouds which remained lower than the LIDAR beam. Furthermore, the dominance of long-range transported Saharan dust was observed in all measurements for several days, however only for a shorter time period in the in-situ measurements due to the vertical structure of the dust plume. The optical properties of the aerosol column retrieved from SEVIRI and MODIS showed the same magnitude and a similar temporal evolution as the measurements at the KLS and the JFJ. Remaining differences are attributed to the complex terrain and simplifications in the aerosol retrieval scheme in general.

scholarly journals Spatial variation of aerosol optical properties around the high-alpine site Jungfraujoch (3580 m a.s.l.)

2012 ◽  
Vol 12 (5) ◽  
pp. 11105-11150
Author(s):  
P. Zieger ◽  
E. Kienast-Sjögren ◽  
M. Starace ◽  
J. von Bismarck ◽  
N. Bukowiecki ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Light Scattering ◽  
In Situ Measurements ◽  
Swiss Alps ◽  
Aerosol Size Distribution ◽  
Horizontal Distance ◽  
Aerosol Optical Properties ◽  
Orographic Clouds

Abstract. This paper presents results of the extensive field campaign CLACE 2010 (Cloud and Aerosol Characterization Experiment) performed in summer 2010 at the Jungfraujoch (JFJ) and the Kleine Scheidegg (KLS) in the Swiss Alps. The main goal of this campaign was to investigate the vertical variability of aerosol optical properties around the JFJ and to show the consistency of the different employed measurement techniques considering explicitly the effects of relative humidity (RH) on the aerosol light scattering. Various aerosol optical and microphysical parameters were recorded using in-situ and remote sensing techniques. In-situ measurements of aerosol size distribution, light scattering, light absorption and scattering enhancement due to water uptake were performed at the JFJ at 3580 m (a.s.l.). A unique set-up allowed remote sensing measurements of aerosol columnar and vertical properties from the KLS located about 1500 m below and within the line of sight to the JFJ (horizontal distance of approx. 4.5 km). In addition, two satellite retrievals from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) and the Moderate Resolution Imaging Spectroradiometer (MODIS) as well as back trajectory analyses were added to the comparison to account for a wider geographical context. All in-situ and remote sensing measurements were in clear correspondence. The ambient extinction coefficient measured in-situ at the JFJ agreed well with the KLS-based LIDAR (Light Detection and Ranging) retrieval at the altitude-level of the JFJ under plausible assumptions on the LIDAR ratio. However, we can show that the quality of this comparison is affected by orographic effects due to the exposed location of the JFJ on a saddle between two mountains and next to a large glacier. The local RH around the JFJ was often higher than in the optical path of the LIDAR measurement, especially when the wind originated from the south via the glacier, leading to orographic clouds which remained lower than the LIDAR beam. Furthermore, the dominance of long-range transported Saharan dust was observed in all measurements for several days, however only for a shorter time period in the in-situ measurements due to the vertical structure of the dust plume. The optical properties of the aerosol column retrieved from SEVIRI and MODIS showed the same magnitude and a similar temporal evolution as the measurements at the KLS and the JFJ. Remaining differences are attributed to the complex terrain and simplifications in the aerosol retrieval scheme in general.

scholarly journals Measurement report: Comparison of airborne, in situ measured, lidar-based, and modeled aerosol optical properties in the central European background – identifying sources of deviations

2021 ◽  
Vol 21 (22) ◽  
pp. 16745-16773
Author(s):  
Sebastian Düsing ◽  
Albert Ansmann ◽  
Holger Baars ◽  
Joel C. Corbin ◽  
Cyrielle Denjean ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Aerosol Particle ◽  
In Situ Measurements ◽  
Light Extinction ◽  
Aerosol Optical Properties ◽  
Central European ◽  
Lidar Ratio ◽  
Aerosol Mixing State

Abstract. A unique data set derived from remote sensing, airborne, and ground-based in situ measurements is presented. This measurement report highlights the known complexity of comparing multiple aerosol optical parameters examined with different approaches considering different states of humidification and atmospheric aerosol concentrations. Mie-theory-based modeled aerosol optical properties are compared with the respective results of airborne and ground-based in situ measurements and remote sensing (lidar and photometer) performed at the rural central European observatory at Melpitz, Germany. Calculated extinction-to-backscatter ratios (lidar ratios) were in the range of previously reported values. However, the lidar ratio is a function of the aerosol type and the relative humidity. The particle lidar ratio (LR) dependence on relative humidity was quantified and followed the trend found in previous studies. We present a fit function for the lidar wavelengths of 355, 532, and 1064 nm with an underlying equation of fLR(RH, γ(λ))=fLR(RH=0,λ)×(1-RH)-γ(λ), with the derived estimates of γ(355 nm) = 0.29 (±0.01), γ(532 nm) = 0.48 (±0.01), and γ(1064 nm) = 0.31 (±0.01) for central European aerosol. This parameterization might be used in the data analysis of elastic-backscatter lidar observations or lidar-ratio-based aerosol typing efforts. Our study shows that the used aerosol model could reproduce the in situ measurements of the aerosol particle light extinction coefficients (measured at dry conditions) within 13 %. Although the model reproduced the in situ measured aerosol particle light absorption coefficients within a reasonable range, we identified many sources for significant uncertainties in the simulations, such as the unknown aerosol mixing state, brown carbon (organic material) fraction, and the unknown aerosol mixing state wavelength-dependent refractive index. The modeled ambient-state aerosol particle light extinction and backscatter coefficients were smaller than the measured ones. However, depending on the prevailing aerosol conditions, an overlap of the uncertainty ranges of both approaches was achieved.

scholarly journals The measurement of aerosol optical properties at a rural site in Northern China

2008 ◽  
Vol 8 (8) ◽  
pp. 2229-2242 ◽  
Author(s):  
P. Yan ◽  
J. Tang ◽  
J. Huang ◽  
J. T. Mao ◽  
X.J. Zhou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Urban Area ◽  
Northern China ◽  
Entire Period ◽  
Rural Site ◽  
Aerosol Optical Properties ◽  
Absorption Coefficients ◽  
Air Masses ◽  
Scattering Coefficients ◽  
The Mean

Abstract. Atmospheric aerosols constitute one of the largest sources of uncertainty in the estimation of radiative forcing for climate. From April 2003 to January 2005, in situ measurements of aerosol optical properties were conducted at a rural site in Northern China, Shangdianzi Global Atmosphere Watch (GAW) regional station (SDZ), about 150 km from Beijing. Mean values (standard deviation, S.D.) of scattering and absorption coefficients for the entire period are 174.6 Mm−1 (189.1 Mm-1) and 17.5 Mm−1 (13.4 Mm-1), respectively. These values are approximately one third of the reported values for scattering coefficients and one fifth of those for absorption coefficients obtained in the Beijing urban area. The mean single scattering albedo (SSA) for the entire period was estimated as 0.88 (0.05), which is about 0.07 higher than the values reported for the Beijing urban area, and also higher than the values (0.85) used in a reported climate simulation for China and India. Both the absorption and scattering coefficients showed a seasonal cycle with the lowest values in winter, while the highest values occurred in summer for absorption coefficients and in fall for scattering coefficients. The mean SSA values were lowest in spring and highest in winter. The daily variations of aerosol absorption and scattering coefficients were strongly influenced by synoptic changes throughout the observation period. A trajectory cluster analysis was applied to discern the source characteristics of aerosol optical properties for different air masses. The cluster-mean aerosol scattering coefficients, absorption coefficients and SSA were all high when the air masses moved from SW and SE-E directions to the site and aerosols were influenced with heavy pollution from the dense population centers and industrial areas. The cluster-mean SSA for air masses coming from the polluted areas was not only higher than those with trajectories from the "clean" directions, but also higher than the reported values for the regions with high pollution emissions (such as the Beijing urban area). This fact might reflect the substantial secondary aerosol production during transport. The characteristics of aerosol optical properties measured at this rural site suggest significant impacts of human activities on the regional aerosol.

scholarly journals The measurement of aerosol optical properties at a rural site in Northern China

2007 ◽  
Vol 7 (5) ◽  
pp. 13001-13033 ◽  
Author(s):  
P. Yan ◽  
J. Tang ◽  
J. Huang ◽  
J. T. Mao ◽  
X. J. Zhou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Urban Area ◽  
Northern China ◽  
Entire Period ◽  
Rural Site ◽  
Aerosol Optical Properties ◽  
Absorption Coefficients ◽  
Air Masses ◽  
Scattering Coefficients ◽  
The Mean

Abstract. Atmospheric aerosols contribute one of the largest sources of uncertainty in the estimation of climate forcing. During the period from April 2003 to January 2005, in situ measurements of aerosol optical properties were conducted at a rural site in Northern China, Shangdianzi Global Atmosphere Watch (GAW) regional station (SDZ). Based on the daily average data, the means (standard deviation, S.D.) of scattering and absorption coefficients for the entire period were 174.6 Mm−1 (189.1 Mm−1) and 17.5 Mm−1 (13.4 Mm−1), respectively. These values were approximately one third of the reported values for scattering coefficients and one fifth of those for absorption coefficients obtained in the Beijing urban area. The mean single scattering albedo (SSA) for the entire period was 0.88 (0.05), which was about 0.07 higher than the values reported for the Beijing urban area, and also higher than the values (0.85) used in the climate model simulation for China and India. Both the absorption and scattering coefficients showed the lowest values in winter (11.2 Mm−1 and 128.9 Mm−1, respectively), while the highest values appeared in summer for absorption coefficients (22.1 Mm−1) and in fall for scattering coefficients (208.2 Mm−1). The mean SSA were lowest in spring (0.85) and highest in winter (0.90). The daily variations of aerosol absorption and scattering coefficients were strongly influenced by synoptic changes throughout the observation period. A trajectory cluster analysis was applied to discern the source characteristics of aerosol optical properties for different air masses. The cluster mean scattering coefficients, absorption coefficients and SSA were all high when the air masses moved from SW and SE-E directions to the site and aerosols were influenced with heavy pollution from the dense population centers and industrial areas. The cluster mean SSA for air masses coming from the polluted areas was not only higher than those with the trajectories from the "clean" directions, but also higher than the reported values for the regions with high pollution emissions (such as Beijing urban area). This fact might reflect the substantial secondary aerosol production during the transport. The characteristics of aerosol optical properties measured at this rural site suggest the significant impacts of human activities on the regional aerosol.

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