Some results of measurements of turbulent fluctuations of the aerosol scattering coefficient in the surface atmospheric layer

2004 ◽  
Author(s):  
Nadezhda A. Shefer ◽  
Andrey P. Rostov
Keyword(s):  
Scattering Coefficient ◽  
Atmospheric Layer ◽  
Surface Atmospheric Layer ◽  
Turbulent Fluctuations ◽  
Aerosol Scattering

scholarly journals Tropospheric aerosol scattering and absorption over Central Europe: a closure study for the dry particle state

2013 ◽  
Vol 13 (10) ◽  
pp. 27811-27854 ◽  
Author(s):  
N. Ma ◽  
W. Birmili ◽  
T. Müller ◽  
T. Tuch ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Direct Measurement ◽  
Radiative Forcing ◽  
Control Measure ◽  
Atmospheric Stability ◽  
Scattering Coefficient ◽  
Particle State ◽  
Air Mass ◽  
Aerosol Scattering ◽  
Tropospheric Aerosol

Abstract. This work analyses optical properties of the dry tropospheric aerosol measured at the regional GAW observation site Melpitz in East Germany. For a continuous observation period between 2007 and 2010, we provide representative values of the dry-state scattering coefficient, the hemispheric backscattering coefficient, the absorption coefficient, single scattering albedo, and the Ångström exponent. Besides the direct measurement, the aerosol scattering coefficient was alternatively computed from experimental particle number size distributions using a Mie code. Within pre-defined limits, a closure could be achieved with the direct measurement. The achievement of closure implies that such calculations can be used as a high-level quality control measure for data sets involving multiple instrumentation. All dry optical properties showed significant annual variations, which were attributed to corresponding variations in the regional emission fluxes, the intensity of secondary particle formation, and the mixed layer height. Air mass classification showed that atmospheric stability is a major factor influencing the dry aerosol properties at the GAW station. In the cold season, temperature inversions limit the volume available for atmospheric mixing, so that the aerosol optical properties near the ground proved quite sensitive to the geographical origin of the air mass. In the warm season, when the atmosphere is usually well-mixed during day-time, considerably less variability was observed for the optical properties between different air masses. This work provides, on the basis of quality-checked in-situ measurements, a first step towards a climatological assessment of direct aerosol radiative forcing in the region under study.

scholarly journals New correction method for the scattering coefficient measurements of a three-wavelength nephelometer

2021 ◽  
Vol 14 (7) ◽  
pp. 4879-4891
Author(s):  
Jie Qiu ◽  
Wangshu Tan ◽  
Gang Zhao ◽  
Yingli Yu ◽  
Chunsheng Zhao
Keyword(s):  
Relative Humidity ◽  
Radiative Forcing ◽  
Correction Method ◽  
High Accuracy ◽  
Scattering Coefficient ◽  
Observation Data ◽  
Machine Learning Model ◽  
Aerosol Scattering ◽  
Direct Radiative Forcing ◽  
Essential Parameter

Abstract. The aerosol scattering coefficient is an essential parameter for estimating aerosol direct radiative forcing and can be measured by nephelometers. Nephelometers are problematic due to small errors of nonideal Lambetian light source and angle truncation. Hence, the observed raw scattering coefficient data need to be corrected. In this study, based on the random forest machine learning model and taking Aurora 3000 as an example, we have proposed a new method to correct the scattering coefficient measurements of a three-wavelength nephelometer under different relative humidity conditions. The result shows that the empirical corrected values match Mie-calculation values very well at all three wavelengths and under all of the measured relative humidity conditions, with more than 85 % of the corrected values having less than 2 % error. The correction method obtains a scattering coefficient with high accuracy and there is no need for additional observation data.

scholarly journals PARAMETRIZATION OF THE HEAT AND MASS EXCHANGE PROCESS IN THE SURFACE ATMOSPHERIC LAYER

2021 ◽  
Vol 3 (72) ◽  
pp. 21-26
Author(s):  
B. Kantsyrev
Keyword(s):  
Mass Exchange ◽  
Numerical Models ◽  
Exchange Process ◽  
Computational Grid ◽  
Modeling Processes ◽  
Atmospheric Layer ◽  
Surface Atmospheric Layer ◽  
Mass Exchange Process ◽  
Heat And Mass Exchange

When constructing numerical models of the atmosphere and the surface atmospheric layer (PAS) interacting with it, the “parametrization” approach is used, that is, the representation of processes with scales smaller than the scale of the cells of the computational grid intended for modeling processes of larger scales.

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