Assessment of Daily Atmospheric Turbidity Databases Using Aerosol Optical Depth and Direct Normal Irradiance Measurements

2016 ◽  
Author(s):  
L. Martin-Pomares ◽  
Jesus Polo ◽  
Daniel Perez-Astudillo ◽  
Dunia A. Bachour
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Atmospheric Turbidity ◽  
Direct Normal Irradiance

scholarly journals Comparison Between Atmospheric Turbidity Coefficients of Desert and Temperate Climates

10.14311/214 ◽  
2001 ◽  
Vol 41 (2) ◽  
Author(s):  
Hamdy K. Elminir ◽  
U. A. Rahuma ◽  
V. Benda
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Temperate Climate ◽  
Universal Relation ◽  
Energy Devices ◽  
Atmospheric Turbidity ◽  
Direct Normal Irradiance ◽  
Report Data ◽  
Linke Turbidity Factor ◽  
Desert Climate

Knowledge of the solar radiation available on the earth’s surface is essential for the development of solar energy devices and for estimating of their performance efficiencies. For this purpose it is helpful to study the attenuation of direct normal irradiance by the atmosphere, in terms of fundamental quantities, including optical thickness, relative optical air mass, water vapor content, and aerosol amount. In the present article, we will not deal with cloudy atmospheres because of their great variability in space and time, but will focus our attention on atmospheres characterized by the complete absence of condensed water. The objectives of this article are to report data on aerosol optical depth and atmospheric turbidity coefficients for a desert climate, and to compare them with those of a temperate climate. Aerosol optical depth, the Linke turbidity factor, TL, and ngström turbidity coefficients, _, are calculated from measurements of broadband filters at Helwan, Egypt, which has a desert climate. A linear regression model is to be determined between the Linke factor and the ngström turbidity coefficient. This relation is compared with similar relations reported for a temperate climate [Prague, Czech Republic]. This comparison is made to determine whether a universal relation exists between these two important coefficients, or whether the relation is location dependent.

scholarly journals Aerosol optical depth retrievals in central Amazonia from a multi-filter rotating shadow-band radiometer calibrated on-site

2019 ◽  
Vol 12 (2) ◽  
pp. 921-934
Author(s):  
Nilton E. Rosário ◽  
Thamara Sauini ◽  
Theotonio Pauliquevis ◽  
Henrique M. J. Barbosa ◽  
Marcia A. Yamasoe ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spectral Response ◽  
Monitoring Site ◽  
Direct Normal Irradiance ◽  
Central Amazonia ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Band Radiometer

Abstract. Extraterrestrial spectral response calibration of a multi-filter rotating shadow band radiometer (MFRSR) under pristine Amazonian Forest atmosphere conditions was performed using the Langley plot method. The MFRSR is installed in central Amazonia as part of a long-term monitoring site, which was used in the context of the GoAmazon2014/5 experiment. It has been operating continuously since 2011 without regular extraterrestrial calibration, preventing its application to accurate monitoring of aerosol particles. Once calibrated, the MFRSR measurements were applied to retrieve aerosol particle columnar optical properties, specifically aerosol optical depth (AODλ) and Ångström exponent (AE), which were evaluated against retrievals from a collocated Cimel Sun photometer belonging to the AErosol RObotic NETwork (AERONET). Results obtained revealed that pristine Amazonian conditions are able to provide MFRSR extraterrestrial spectral response with relative uncertainty lower than 1.0 % in visible channels. The worst estimate (air mass =1) for absolute uncertainty in AODλ retrieval varied from ≈0.02 to ≈0.03, depending on the assumption regarding uncertainty for MFRSR direct normal irradiance measured at the surface. The obtained root mean square error (RMSE ≈0.025) from the evaluation of MFRSR retrievals against AERONET AODλ was, in general, lower than estimated MFRSR AODλ uncertainty, and close to the uncertainty of AERONET field Sun photometers (≈0.02).

scholarly journals Study of Linke Turbidity Factor over Bode, Bhaktapur

2020 ◽  
Vol 6 (2) ◽  
pp. 66-73
Author(s):  
P. M. Shrestha ◽  
N. P. Chapagain ◽  
I. B. Karki ◽  
K. N. Poudyal
Keyword(s):  
Sea Level ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Meteorological Parameters ◽  
Research Work ◽  
Solar Insolation ◽  
Annual Average ◽  
Atmospheric Turbidity ◽  
Linke Turbidity Factor ◽  
One Year

The daily aerosol optical depth (AOD) data are derived from AERONET over Bode, Bhaktapur (27.68° N, 85.39° E, 1297 m above sea level) for a period of one year 2013. Annual mean of Atmospheric turbidity factors are calculated. The effect of different physical as well as meteorological parameters on the Linke turbidity factor was analyzed. The yearly mean of solar insolation, Angstrom exponential (α),Angstrom coefficient of turbidity (β) and Linke turbidity (LT) were found 4.70 ± 1.10kWh/m2/day, 1.13 ± 0.21 ,0.18 ± 0.14 and 5.70 ± 2.46 respectively. Annual average of visibility is 2.98 ± 2.13 km. Result of this research work is beneficial for the further identification, impact and analysis of atmospheric turbidity at different places.

scholarly journals Aerosol Optical Depth retrievals in Central Amazonia from a Multi-Filter Rotating Shadow-band Radiometer on-site calibrated

2018 ◽  
Author(s):  
Nilton E. Rosário ◽  
Thamara Sauini ◽  
Theotonio Pauliquevis ◽  
Henrique M. J. Barbosa ◽  
Marcia A. Yamasoe ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spectral Response ◽  
Monitoring Site ◽  
Direct Normal Irradiance ◽  
Central Amazonia ◽  
Mean Square Errors ◽  
Term Monitoring ◽  
Band Radiometer

Abstract. Extraterrestrial spectral response calibration of a Multi-Filter Rotating Shadow band Radiometer (MFRSR) under Amazonian Forest atmosphere pristine conditions using the Langley plot method was performed and evaluated. The MFRSR is installed in central Amazonia as part of a long-term monitoring site, which was used in the context of the GoAmazon2014/5 Experiment. It has been operating continuously since 2011 without regular extraterrestrial calibration, preventing its application to accurate monitoring of aerosol particles. Once calibrated, the MFRSR measurements were applied to retrieve aerosols particles columnar optical properties, specifically Aerosol Optical Depth (AODλ) and Ångström Exponent (AE), which were evaluated against retrievals from a collocated CIMEL sunphotometer belonging to the AErosol RObotic NETwork (AERONET). Results obtained revealed that Amazonian pristine conditions are able to provide MFRSR extraterrestrial spectral response with relative uncertainty lower than 1.0 % at visible channels. The worst estimate (air mass = 1) for absolute uncertainty in AODλ retrieval varied from ~ 0.02 to ~ 0.03, depending on the assumption regarding uncertainty for MFRSR direct-normal irradiance measured at the surface. Obtained Root Mean Square Errors (RMSE ~ 0.025) from the evaluation of MFRSR retrievals against AERONET AODλ were, in general, lower than estimate MFRSR AODλ uncertainties, and close to AERONET field sunphotometers (~ 0.02).

scholarly journals Improving direct normal irradiance retrieval in cloud-free, but high aerosol load conditions by using aerosol optical depth

2017 ◽  
Vol 26 (5) ◽  
pp. 475-483
Author(s):  
M. Boraiy ◽  
M. Korany ◽  
Y. Aoun ◽  
S.C. Alfaro ◽  
M. El-Metwally ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Direct Normal Irradiance ◽  
Load Conditions

scholarly journals Climatological Aspects of Aerosol Physical Characteristics in Tunisia Deduced from Sun Photometric Measurements

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Mabrouk Chaâbane ◽  
Chafai Azri ◽  
Khaled Medhioub
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Climatic Data ◽  
Weather Patterns ◽  
Annual Variations ◽  
Microphysical Properties ◽  
Atmospheric Turbidity ◽  
Long Time ◽  
Photometric Measurements ◽  
Aerosol Emissions

Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977–2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions.

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