Investigation of Atmospheric Turbidity at Ghadaa (Algeria) Using Both Ground Solar Irradiance Measurements and Space Data

Djafer, Djelloul; Irbah, Abdanour; Philippe, Keckhut; Zaiani, Mohamed; Meftah, Mustapha

doi:10.4236/acs.2019.91008

Cited by 3 publications

(6 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We can explain it by winds of the south sectors (Sirocco) during the summer season that characterize the Sahara of North Africa. This kind of winds brings particles of dust and sand with them, which increases the Angström coefficient [1,19,20,32,41].…”

Section: Resultsmentioning

confidence: 99%

“…We note that there is a temporal extremum of β (middle plot in Figure 8) while there is an extremum in both humidity and temperature at the same time (bottom plot in Figure 9). These seasonal variations are most likely related to the African monsoon [1,20,32,41,42]. ± 0.04 0.12 ± 0.05 0.15 ± 0.04 0.11 ± 0.03 September 0.14 ± 0.05 0.13 ± 0.04 0.11 ± 0.06 0.11 ± 0.06 0.12 ± 0.03 0.14 ± 0.04 October 0.12 ± 0.05 0.14 ± 0.04 0.09 ± 0.04 0.09 ± 0.04 0.14 ± 0.04 0.16 ± 0.08 November 0.12 ± 0.06 0.13 ± 0.05 0.02 ± 0.03 0.02 ± 0.02 0.14 ± 0.05 0.11 ± 0.04 December 0.11 ± 0.03 0.11 ± 0.05 0.03 ± 0.05 0.03 ± 0.03 0.12 ± 0.06 0.11 ± 0.05 Finally, we compared the Angström coefficient obtained with ESRA 2 model with the frequency of occurrence of aerosols over Tamanrasset observed from space.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Study of Atmospheric Turbidity in a Northern Tropical Region Using Models and Measurements of Global Solar Radiation

et al. 2021

View full text Add to dashboard Cite

Radiative transfer in the Earth’s atmosphere under clear-sky conditions strongly depends on turbidity due to aerosols and hydrometeors. It is therefore important to know its temporal radiative properties for a given site when the objective is to optimize the solar energy that is collected there. Turbidity can be studied via measurements and models of the global solar radiation reaching the ground in cloudless conditions. These models generally depend on two parameters, namely the Angström turbidity coefficient and the Linke factor. This article aims to do a comparative study of five models of global solar radiation, all dependent on the Linke factor, based on real data. The measurements are provided by the Tamanrasset Meteorological Center (Algeria), which has a long series of global solar radiation data recorded between 2005 and 2011. Additional data from AERONET and MODIS onboard the TERRA satellite were also used to perform the comparison between the two estimated parameters and those obtained from AERONET. The study shows that the ESRA models are the most reliable among the five models for estimating the Linke factor with a correlation coefficient R of the data fits of 0.9995, a RMSE of 13.44 W/m2, a MBE of −0.64 W/m2 and a MAPE of 6.44%. The maximum and minimum statistical values were reached, respectively, in June and during the autumn months. The best correlation is also observed in the case of ESRA models between the Linke parameter and the joint optical thickness of aerosols and the total column-integrated water vapor. The Angström turbidity coefficient β, calculated from the Linke factor and MODIS data, has values less than 0.02 at 9% of the cases, and 76% present values ranging between 0.02 and 0.15 and 13% higher than 0.15. These β values are validated by AERONET measurements since a very good correlation (R≈0.87) is observed between the two datasets. The temporal variations of β also show a maximum in June. Satellite observations confirm more aerosols during the summer season, which are mostly related to the African monsoon.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Study of Atmospheric Turbidity in a Northern Tropical Region Using Models and Measurements of Global Solar Radiation

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In the atmosphere, solar radiation undergoes significant attenuation due to two primary mechanisms: scattering and absorption by air molecules, hydrometeors, and aerosol particles. These processes result in a remarkable reduction in the direct solar component and a moderate increase in the diffuse component [4,[6][7][8][9][10][11][12][13][14][15]. The attenuation processes of solar radiation exhibit significant variability due to factors such as the apparent motion of the sun, changes in meteorological conditions, and fluctuations in aerosol properties with time across different regions [8].…”

Section: Introductionmentioning

confidence: 99%

“…Since the introduction of the Linke turbidity factor by [40] and the Ångström turbidity coefficient by [41], numerous researchers have proposed various models, including those by [22,45,[52][53][54][55][56][57][58]. These empirical equations have been used to quantify the impacts of air pollutants and aerosols on horizontal visibility degradation and the reduction in solar radiation received at the Earth's surface under different weather conditions and locations [4,6,8,11,[13][14][15]19,20,22,35,43,[59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. The extent of the application of all these indices at both regional and global scales remains unclear.…”

Section: Introductionmentioning

confidence: 99%

The Variation in Atmospheric Turbidity over a Tropical Site in Nigeria and Its Relation to Climate Drivers

SoneyeArogundade,

Rappenglück

2024

Atmosphere

View full text Add to dashboard Cite

Atmospheric turbidity exhibits substantial spatial–temporal variability due to factors such as aerosol emissions, seasonal changes, meteorology, and air mass transport. Investigating atmospheric turbidity is crucial for climatology, meteorology, and atmospheric pollution. This study investigates the variation in atmospheric turbidity over a tropical location in Nigeria, utilizing the Ångström exponent (α), the turbidity coefficient (β), the Linke turbidity factor (TL), the Ångström turbidity coefficient (βEST), the Unsworth–Monteith turbidity coefficient (KAUM), and the Schüepp turbidity coefficient (SCH). These parameters were estimated from a six-month uninterrupted aerosol optical depth dataset (January–June 2016) and a one-year dataset (January–December 2016) of solar radiation and meteorological data. An inverse correlation (R = −0.77) was obtained between α and β, which indicates different turbidity regimes based on particle size. TL and βEST exhibit pronounced seasonality, with higher turbidity during the dry season (TL = 9.62 and βEST = 0.60) compared to the rainy season (TL = 0.48 and βEST = 0.20) from May to October. Backward trajectories and wind patterns reveal that high-turbidity months align with north-easterly air flows from the Sahara Desert, transporting dust aerosols, while low-turbidity months coincide with humid maritime air masses originating from the Gulf of Guinea. Meteorological drivers like relative humidity and water vapor pressure are linked to turbidity levels, with an inverse exponential relationship observed between normalized turbidity coefficients and normalized water vapor pressure. This analysis provides insights into how air mass origin, wind patterns, and local climate factors impact atmospheric haze, particle characteristics, and solar attenuation variability in a tropical location across seasons. The findings can contribute to environmental studies and assist in modelling interactions between climate, weather, and atmospheric optical properties in the region.

show abstract

“…The on-orbit polarization correction method depends on establishing the correlation between the polarization state of the incident light and the polarization-sensitive device. It is realized by calibrating the Mueller matrix of the instrument and by measuring the Stokes vector of polarized light [ 11 , 12 , 15 , 16 , 17 , 18 , 19 ]. The key to on-orbit polarization calibration is to determine the polarization calibration factor by ground calibration in the laboratory and on-orbit measurements by the instrument.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Correction of Polarization Response Calibration Error of Limb Atmosphere Ultraviolet Hyperspectral Detector

Huang

et al. 2022

Sensors

View full text Add to dashboard Cite

A UV hyperspectral instrument was designed with a polarization measurement channel for real-time in-orbit polarization correction to reduce the influence of polarization on the detection accuracy of atmospheric radiation. One of the prerequisites for in-orbit polarization calibration is accurately calibrating the instrument’s polarization properties in the laboratory. This study first introduces the calibration method and measuring device of the polarization characteristics of the ultraviolet (UV) hyperspectral detector and conducts a polarization calibration test of the instrument. The two main error sources introduced by the calibration device were emphatically analyzed, and the correction method of the error sources was deduced theoretically. Finally, the polarization calibration results of the UV hyperspectral detector were corrected, and the uncertainty analysis of the corrected calibration results was about 1.4%, which provides effective ground polarization calibration data for the on-orbit polarization correction of the instrument.

show abstract

Investigation of Atmospheric Turbidity at Ghadaa (Algeria) Using Both Ground Solar Irradiance Measurements and Space Data

Abstract: Four radiometric models are compared to study the Angström turbidity coefficient β over Ghardaïa (Algeria). Five years of global irradiance measurements and space data recorded with MODIS are used to estimate β. The models are referenced as Dog

Cited by 3 publications

References 31 publications

Study of Atmospheric Turbidity in a Northern Tropical Region Using Models and Measurements of Global Solar Radiation

Study of Atmospheric Turbidity in a Northern Tropical Region Using Models and Measurements of Global Solar Radiation

The Variation in Atmospheric Turbidity over a Tropical Site in Nigeria and Its Relation to Climate Drivers

Analysis and Correction of Polarization Response Calibration Error of Limb Atmosphere Ultraviolet Hyperspectral Detector

Contact Info

Product

Resources

About