Statistical estimates of the effect of the sea water scattering phase function on the characteristics of airborne hydrooptical lidar signals

2021 ◽  
pp. 171-177
Author(s):  
A.A. Lisenko ◽  
◽  
V.S. Shamanaev ◽  
Keyword(s):  
Sea Water ◽  
Water Layer ◽  
Single Scattering ◽  
Airborne Lidar ◽  
Statistical Estimates ◽  
Scattering Approximation ◽  
Coastal Sea ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Phase Functions

The effect of the scattering phase functions of sea water types by the Petzold classification on the characteristics of signals of an airborne lidar is investigated using the Monte Carlo method. It is shown that for pure and coastal waters, the single scattering approximation is applicable for solving the laser sensing equation. Based on the analysis of the results obtained in the closed numerical experiment, the method of reconstruction of the extinction coefficient of lidar signals by pure and coastal sea waters in the mixing water layer is proposed and substantiated. The obtained results can be used to expand the possibilities of lidar signal interpretation, especially in complex and ambiguous situations.

scholarly journals Modelling Laboratory Data of Bidirectional Reflectance of a Regolith Surface Containing Alumina

2011 ◽  
Vol 28 (3) ◽  
pp. 261-265 ◽  
Author(s):  
C. Bhattacharjee ◽  
D. Deb ◽  
H. S. Das ◽  
A. K. Sen ◽  
R. Gupta
Keyword(s):  
Laboratory Data ◽  
Size Composition ◽  
Single Scattering ◽  
Bidirectional Reflectance ◽  
Reflection Function ◽  
Versus Phase ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Phase Functions ◽  
Bidirectional Reflection

AbstractBidirectional reflectance of a surface is defined as the ratio of the scattered radiation at the detector to the incident irradiance as a function of geometry. Accurate knowledge of the bidirectional reflection function for layers composed of discrete, randomly positioned scattering particles is essential for many remote sensing, engineering, and biophysical applications, as well as for different areas of astrophysics. Computations of bidirectional reflection functions for plane parallel particulate layers are usually reduced to solving the radiative transfer equation by the existing techniques. In this work we present our laboratory data on bidirectional reflectance versus phase angle for two sample sizes of alumina, 0.3 and 1 μm, for the He–Ne laser at wavelengths of 632.8 nm (red) and 543.5 nm (green). The nature of the phase curves of the asteroids depends on the parameters like particle size, composition, porosity, roughness, etc. In the present study we analyze data which are being generated using a single scattering phase function, that is, Mie theory of treating particles as a compact sphere. The well-known Hapke formula, along with different particle phase functions such as Mie and Henyey–Greenstein, will be used to model the laboratory data obtained at the asteroid laboratory of Assam University.

scholarly journals Modeling of Aerosol Radiation-Relevant Parameters in the Troposphere of Siberia on the Basis of Empirical Data

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 414 ◽  
Author(s):  
Mikhail Panchenko ◽  
Svetlana Terpugova ◽  
Victor Pol’kin ◽  
Valerii Kozlov ◽  
Dmitry Chernov
Keyword(s):  
Complex Refractive Index ◽  
West Siberia ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Optical Characteristics ◽  
Asymmetry Factor ◽  
Size Spectrum ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Modal Radius

The paper presents the generalized empirical model of the aerosol optical characteristics in the lower 5-km layer of the atmosphere of West Siberia. The model is based on the data of long-term airborne sensing of the vertical profiles of the angular scattering coefficient, aerosol disperse composition, as well as the content of absorbing particles. The model provides for retrieval of the aerosol optical characteristics in visible and near IR wavelength ranges (complex refractive index, scattering and absorption coefficients, optical depth, single scattering albedo, and asymmetry factor of the scattering phase function). The main attention in the presented version of the model is given to two aspects: The study of the effect of the size spectrum of the absorbing substance in the composition of aerosol particles on radiative-relevant parameters (the single scattering albedo (SSA) and the asymmetry factor (AF)) and the consideration of different algorithms for taking into account the relative humidity of air. The ranges of uncertainty of SSA and AF at variations in the modal radius of the absorbing fraction at different altitudes in the troposphere are estimated.

scholarly journals A Method for Deriving the Mean Volume Scattering Phase Function for Zodiacal Dust

1985 ◽  
Vol 85 ◽  
pp. 215-218
Author(s):  
S.S. Hong
Keyword(s):  
Linear Combination ◽  
Phase Function ◽  
Dust Particles ◽  
Zodiacal Light ◽  
Volume Scattering ◽  
Zodiacal Dust ◽  
Scattering Phase ◽  
The Mean ◽  
Scattering Phase Function ◽  
Phase Functions

AbstractA linear combination of 3 Henyey-Greenstein phase functions is substituted for the mean volume scattering phase function in the zodiacal light brightness integral. Results of the integral are then compared with the observed brightness to form residuals. Minimization of the residuals provides us with the best combination of Henyey-Greenstein functions for the scattering phase function of zodiacal dust particles.

scholarly journals Application of a diode array spectroradiometer to measuring the spectral scattering properties of cloud types in a laboratory

2007 ◽  
Vol 7 (22) ◽  
pp. 5803-5813 ◽  
Author(s):  
A. R. D. Smedley ◽  
A. R. Webb ◽  
C. P. R. Saunders
Keyword(s):  
Single Scattering ◽  
Small Scale ◽  
Diode Array ◽  
Full Spectrum ◽  
Solar Radiation Incident ◽  
Scattering Phase ◽  
Set Up ◽  
Phase Functions ◽  
Mixed Phase Clouds ◽  
Ultraviolet Solar Radiation

Abstract. In the last few years diode array spectroradiometers have become useful complements to traditional scanning instruments when measuring visible and ultraviolet solar radiation incident on the ground. This study describes the application of such an instrument to the problem of measuring the radiation scattered by different cloud-types in a laboratory environment. Details of how the instrument is incorporated into the experimental set-up are given together with the development of the system as a whole. The capability to measure a full spectrum for each scattering angle is an undoubted advantage, although the limited sensitivity impacts on the usefulness for optically thin clouds. Nevertheless example results are presented: (1) scattering phase functions at a range of wavelengths recorded simultaneously for water clouds, showing spectral deviation at the rainbow angle and verification of Mie theory; (2) likewise for mixed phase clouds, with evidence of both halo and rainbow features in a single scattering function; and, (3) detail of the forward scattering region in a glaciated cloud showing a barely perceptible halo feature, with implications for the small-scale structure of the ice crystals produced.

scholarly journals Pyramidal ice crystal scattering phase functions and concentric halos

1996 ◽  
Vol 14 (11) ◽  
pp. 1192-1197 ◽  
Author(s):  
C. Liu ◽  
P. R. Jonas ◽  
C. P. R. Saunders
Keyword(s):  
Three Dimensional ◽  
Ice Crystals ◽  
Ice Crystal ◽  
Three Dimensional Model ◽  
Model Calculations ◽  
Scattering Phase ◽  
The Common ◽  
Scattering Phase Function ◽  
Phase Functions ◽  
Solar Angle

Abstract. Phase functions have been calculated using the Monte Carlo/geometric ray tracing method for single hexagonal pyramidal ice crystals (such as solid and hollow bullets) randomly oriented in space and horizontal plane, in order to study the concentric halo formations. Results from three dimensional model calculations show that 9° halo can be as bright as the common 22° halo for pyramidal angle of 28°, and the 18°, 20°, 24° and 35° halos cannot be seen due to the strong 22° halo domination in the scattering phase function between 18° and 35°. For solid pyramidal ice crystals randomly oriented horizontally, the 35° arc can be produced and its intensity depends on the incident ray solar angle and the particle aspect ratio.

Modeling of Spectral Properties and the Scattering Phase Function for Lightweight Heat Protection Spacecraft Materials

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Valery V. Cherepanov ◽  
Oleg M. Alifanov
Keyword(s):  
Optical Properties ◽  
Spectral Properties ◽  
Material Structure ◽  
Scattering Pattern ◽  
High Temperature Materials ◽  
Heat Protection ◽  
Angular Scattering ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Phase Functions

This work gives a brief description of the statistical model that takes into account when calculating the physical, in particular, the optical properties of some ultraporous nonmetallic high-temperature materials, the real regularities of the material structure, and the physical properties of substances constituting the material. For the spectral part of the model, some tests are presented, confirming its adequacy. The simulation of the spectra and the scattering of monochromatic radiation pattern by using the representative elements of the model and the material as a whole are carried out. It is found that despite the fact that the scattering pattern based on the use of representative elements of a material can be approximated by the classical distributions, this is not true for the material as a whole. Calculations of the angular scattering probability density of the materials are carried out, and the approximations of obtained distributions that extend the class of modeling scattering phase functions (SPF) are proposed.

scholarly journals Aerosol direct radiative effect in the Po Valley region derived from AERONET measurements

2008 ◽  
Vol 8 (16) ◽  
pp. 4925-4946 ◽  
Author(s):  
M. Clerici ◽  
F. Mélin
Keyword(s):  
Regional Climate ◽  
Single Scattering ◽  
Radiative Effect ◽  
Aerosol Model ◽  
Po Valley ◽  
Spatial Gradients ◽  
Clear Sky ◽  
Scattering Phase ◽  
Absorbing Aerosols ◽  
Scattering Phase Function

Abstract. The aerosol direct radiative effect (ADRE) affecting the Po Valley and the adjacent North Adriatic Sea is studied using 10-year series of measurements collected at two AERONET sites located in the western part of the Valley (Ispra), and on a platform (AAOT) offshore Venice. This region is characterized by a high, mostly continental, aerosol load with comparable average aerosol optical thickness τa at both locations (0.21 at 500 nm) and more absorbing aerosols at Ispra. A dynamic aerosol model accounting for the changes in scattering phase function with τa is used for radiative transfer calculations, together with boundary conditions representative of terrestrial and marine surfaces. A sensitivity analysis allows the construction of an error budget for the daily ADRE estimates, found to be of the order of 20% and mostly due to uncertainties on aerosol single scattering albedo and τa. The daily radiative efficiencies, normalized by τa at 500 nm, increase from December to June, from −17 to −24 W m−2 τa−1 at top-of-atmosphere (TOA) and −33 to −72 W m−2 τa−1 at surface for the Po Valley, and from −15 to −32 (TOA) and −35 to −65 W m−2 τa−1 (surface) for the AAOT site. The average of log-transformed ADRE for TOA, surface and atmosphere are −5.2, −12.2 and +6.8 W m−2 for the Po Valley case, and −6.5, −13.0 and +6.5 W m−2 for the AAOT site but these values can be much higher for individual days. Concurrent clear-sky days give indications on the regional atmospheric heating spatial gradients. Differences between the atmospheric ADRE at the two locations average 6.3 W m−2 with a gradient positive towards the inner valley in 65% of the cases. This study confirms the importance of duly considering the radiative impact of aerosols on the regional climate.

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