Effect of scattered light on the accuracy of thin clouds optical thickness measurement by a sun photometer

1994 ◽  
Author(s):  
Iosif L. Katsev ◽  
Eleonora P. Zege ◽  
Alexander S. Prikhach ◽  
Igor N. Polonsky
Keyword(s):  
Optical Thickness ◽  
Scattered Light ◽  
Thickness Measurement ◽  
Sun Photometer

Aerosol Optical Thickness Measurement with Elevation-Scanning Lidar

2015 ◽  
Vol 32 (7) ◽  
pp. 1364-1371
Author(s):  
Pavel I. Ionov ◽  
Andrew K. Mollner
Keyword(s):  
Optical Thickness ◽  
Thickness Measurement ◽  
High Accuracy ◽  
Sufficient Accuracy ◽  
Aerosol Optical Thickness ◽  
Calibration Standards ◽  
Accuracy Measurement ◽  
Scanning Lidar ◽  
Sun Photometer ◽  
High Accuracy Measurement

AbstractHigh-accuracy measurement of aerosol optical thickness (AOT) τa with an elevation-scanning lidar is demonstrated and the results are compared with a collocated Cimel 318 sun photometer. Linear regression of the time-coincident data from a 2-week measurement campaign with the two instruments is found to be τalidar = (1.00 ± 0.17)τaphot + (0.025 ± 0.019) (1σ). The method proved to have sufficient accuracy to measure AOTs of 0.1–0.2 commonly seen in relatively clear atmosphere. The measurement is absolute and thus does not depend on any external calibration standards.

scholarly journals High-Resolution Optical Thickness Measurement Based on Electro-Optic Dual-Optical Frequency Comb Sources

2017 ◽  
Vol 23 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Oscar E. Bonilla-Manrique ◽  
Pedro Martin-Mateos ◽  
Borja Jerez ◽  
Marta Ruiz-Llata ◽  
Pablo Acedo
Keyword(s):  
High Resolution ◽  
Optical Thickness ◽  
Frequency Comb ◽  
Thickness Measurement ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Electro Optic

Optical thickness measurement of stacked glass based on balanced cross-correlation

2021 ◽  
Author(s):  
Xiefen Long ◽  
He Huang ◽  
Haoran Gao ◽  
Renhao Zheng ◽  
Liandong Yu
Keyword(s):  
Optical Thickness ◽  
Cross Correlation ◽  
Thickness Measurement

scholarly journals Evolution of aerosol optical thickness over Europe during the August 2003 heat wave as seen from CHIMERE model simulations and POLDER data

2006 ◽  
Vol 6 (7) ◽  
pp. 1853-1864 ◽  
Author(s):  
A. Hodzic ◽  
R. Vautard ◽  
H. Chepfer ◽  
P. Goloub ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Forest Fires ◽  
Atmospheric Aerosol ◽  
Large Scale ◽  
Transport Model ◽  
Anthropogenic Sources ◽  
Chemistry Transport Model ◽  
Model Simulations ◽  
High Particle ◽  
Sun Photometer

Abstract. This study describes the atmospheric aerosol load encountered during the large-scale pollution episode that occurred in August 2003, by means of the aerosol optical thicknesses (AOTs) measured at 865 nm by the Polarization and Directionality of the Earth's Reflectances (POLDER) sensor and the simulation by the CHIMERE chemistry-transport model. During this period many processes (stagnation, photochemistry, forest fires) led to unusually high particle concentrations and optical thicknesses. The observed/simulated AOT comparison helps understanding the ability of the model to reproduce most of the gross AOT features observed in satellite data, with a general agreement within a factor 2 and correlations in the 0.4–0.6 range. However some important aerosol features are missed when using regular anthropogenic sources. Additional simulations including emissions and high-altitude transport of smoke from wildfires that occurred in Portugal indicate that these processes could dominate the AOT signal in some areas. Our results also highlight the difficulties of comparing simulated and POLDER-derived AOTs due to large uncertainties in both cases. Observed AOT values are significantly lower than the simulated ones (30–50%). Their comparison with the ground-based Sun photometer Aerosol Robotic Network (AERONET) measurements suggests, for the European sites considered here, an underestimation of POLDER-derived aerosol levels with a factor between 1 and 2. AERONET AOTs compare better with simulations (no particular bias) than POLDER AOTs.

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