Retrieval of optical depth and particle size distribution of tropospheric and stratospheric aerosols by means of Sun photometry

1997 ◽  
Vol 35 (1) ◽  
pp. 172-182 ◽  
Author(s):  
B. Schmid ◽  
C. Matzler ◽  
A. Heimo ◽  
N. Kampfer
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Optical Depth ◽  
Stratospheric Aerosols

scholarly journals Sensitivity of particle loss to the Kelvin effect in LES of young contrails

2016 ◽  
Author(s):  
Aniket R. Inamdar ◽  
Alexander D. Naiman ◽  
Sanjiva K. Lele ◽  
Mark Z. Jacobson
Keyword(s):  
Particle Size ◽  
Survival Rate ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Optical Depth ◽  
Particle Loss ◽  
Mean Particle Size ◽  
Kelvin Effect ◽  
The Impact ◽  
Exponential Relation

Abstract. Different treatments of the Kelvin effect in LES modeling of early contrails are shown to cause variations in the survival rate of ice particles by up to a factor of 4 and in optical depth and mean particle size by up to 50 %. The Kelvin effect which varies exponentially with particle size, can reduce or even suppress the impact of other important ambient parameters, such as ice supersaturation, on particle survival rate. Lowering or neglecting the Kelvin effect is shown to substantially alter the evolution of the ice particle size distribution and delay the onset of particle loss. A strongly Kelvin effect dependent exponential relation between particle survival rate and particle size is shown for high EIsoot (O(1015)).

scholarly journals The Truncated Geometric Approximation and the Size Distribution of Small Atmospheric Particles

2011 ◽  
Vol 28 (6) ◽  
pp. 779-786 ◽  
Author(s):  
J. G. DeVore
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Optical Depth ◽  
Power Law ◽  
Spherical Particles ◽  
Simple Relationship ◽  
Nasa Goddard Space ◽  
Geometric Approximation ◽  
Power Law Function

Abstract This paper describes a simple relationship between the slope of particulate optical depth as a function of wavelength and the size distribution of spherical particles. It is based on approximating extinction using a truncated geometric optics relationship and is applicable when optical depth decreases with wavelength. The new relationship suggests that extinction versus wavelength measurements are most sensitive to particles that are comparable in size to the wavelength. When optical depth is expressed as a power-law function of wavelength, the resulting particle size distribution is also a power-law function of size, with the two exponents reproducing the well-known relationship between the Ångström and Junge exponents. Examples of applying the new relationship are shown using both numerical calculations based on Mie theory and measurements from the Aerosol Robotic Network (AERONET) sun photometer at NASA Goddard Space Flight Center (GSFC). Since the truncated geometric approximation makes no assumptions per se concerning the form of the particle size distribution, it may find application in supplementing solar aureole profile measurements in retrieving the size distributions of particles in thin clouds—for example, cirrus—or when they are present.

scholarly journals Observation and Inversion of Aerosol Particle Size Distribution over Yinchuan Area

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 992
Author(s):  
Jiandong Mao ◽  
Yali Ren ◽  
Juan Li ◽  
Qiang Wang ◽  
Yi Zhang
Keyword(s):  
Particle Size ◽  
Singular Value Decomposition ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Singular Value ◽  
Truncated Singular Value Decomposition ◽  
Regularization Algorithm ◽  
Value Decomposition

Particle size distribution is one of the important microphysical parameters to characterize the aerosol properties. The aerosol optical depth is used as the function of wavelength to study the particle size distribution of whole atmospheric column. However, the inversion equation of the particle size distribution from the aerosol optical depth belongs to the Fredholm integral equation of the first kind, which is usually ill-conditioned. To overcome this drawback, the integral equation is first discretized directly by using the complex trapezoid formula. Then, the corresponding parameters are selected by the L curve method. Finally the truncated singular value decomposition regularization method is employed to regularize the discrete equation and retrieve the particle size distribution. To verify the feasibility of the algorithm, the aerosol optical depths taken by a sun photometer CE318 over Yinchuan area in four seasons, as well as hazy, sunny, floating dusty and blowing dusty days, were used to retrieve the particle size distribution. In order to verify the effect of truncated singular value decomposition algorithm, the Tikhonov regularization algorithm was also adopted to retrieve the aerosol PSD. By comparing the errors of the two regularizations, the truncated singular value decomposition regularization algorithm has a better retrieval effect. Moreover, to understand intuitively the sources of aerosol particles, the backward trajectory was used to track the source. The experiment results show that the truncated singular value decomposition regularization method is an effective method to retrieve the particle size distribution from aerosol optical depth.

Retrieval of aerosol particle size distributions in the stratosphere from SCIAMACHY limb observations and comparison to balloon-borne measurements and ECHAM5-HAM simulations

2021 ◽  
Author(s):  
Christine Pohl ◽  
Alexei Rozanov ◽  
Elizaveta Malinina-Rieger ◽  
Terry Deshler ◽  
Ulrike Niemeier ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aerosol Particle ◽  
Atmospheric Chemistry ◽  
Physical Models ◽  
Climate Modelling ◽  
Distribution Width ◽  
Aerosol Particle Size ◽  
Stratospheric Aerosols

<p>Stratospheric aerosols play an important role in the climate system and the atmospheric chemistry. They alter the radiative budget of the Earth affecting the global temperature and interact with stratospheric trace gases leading to ozone depletion. Effects are most noticeable after vulcanic eruptions enhancing the amount of aerosols in the stratosphere. Thus, vertically and spatially resolved knowledge about stratospheric aerosols, such as the particle size distribution and extinction coefficient, is crucial for the initialization of climate models, investigation of geoengineering, validation of aerosol micro-physical models, and improvement of trace gas retrievals. We present an algorithm to retrieve aerosol particle size distribution parameters (mode radius and distribution width, number density) from limb observations of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric ChartograpHY) operated aboard Envisat between 2002 and 2012. SCIAMACHY retrieved particle size distribution profiles are compared with in-situ balloon-borne measurements from Laramie, Wyoming. Both data-sets show good agreement. The stratospheric plume evolution after the eruption of Sarychev in the Kuril Islands, Russia, in June 2009 is investigated and compared to the output from the aerosol-climate modelling system ECHAM5-HAM.</p>

Effects of Particle Size Distribution on Corrosion Rate of Carbon Steel in Soil

2020 ◽  
Vol 69 (4) ◽  
pp. 102-106
Author(s):  
Shota Ohki ◽  
Shingo Mineta ◽  
Mamoru Mizunuma ◽  
Soichi Oka ◽  
Masayuki Tsuda
Keyword(s):  
Particle Size ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Particle Size Distribution ◽  
Size Distribution
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