Turbidity coefficients from normal direct solar irradiance in Central Spain

Bilbao, J.; Román, Roberto; Miguel, A. de

doi:10.1016/j.atmosres.2014.02.007

Cited by 24 publications

(11 citation statements)

References 36 publications

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“…This interpretation of the results is also supported by the enhancement of the positive correlation between PM COARSE and temperature levels during warm seasons: High temperatures prevailing throughout dry and sunny days, remove the soil's moisture, favoring dust resuspension (Vardoulakis and Kassomenos, 2008;Galindo et al, 2011;Mangia et al, 2011;Buchholz et al, 2014). Finally, the more frequent occurrence of Saharan dust intrusions during the warm seasons of the time interval 2010-2012 (Bilbao et al, 2014), may induce PM COARSE episodes combined with highly elevated temperatures, justifying positive correlations (Galindo et al, 2011;Mangia et al, 2011).…”

Section: Local Pm Sources and Meteorologysupporting

confidence: 61%

The Dependence of PM Size Distribution from Meteorology and Local-Regional Contributions, in Valencia (Spain) - A CWT Model Approach

Dimitriou

2015

Aerosol Air Qual. Res.

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This paper combines an analysis of hourly air pollution measurements and daily meteorological data with backward air mass trajectories, in order to elucidate local/regional sources and processes (e.g., atmospheric dispersion/stagnation, dust resuspension, etc.) defining PM levels and size distribution in Valencia (Spain). Four size fractions of PM (PM 10 , PM COARSE = PM 10 -PM 2.5 , PM 2.5 and PM 1 ) were independently studied. No chemical/physical interactions among the four different size categories were assumed. Wind dispersion of PM 2.5 and PM 1 was indicated, whereas atmospheric stagnation conditions triggered the accumulation of fine particles, mainly produced from local combustion. Wind blown dust enhanced PM COARSE concentrations, particularly throughout warm periods when dry land facilitates dust resuspension. Hourly air mass trajectory points were analyzed by Concentration Weighted Trajectory (CWT) model and Potential Source Contribution Function (PSCF) on a 0.5° × 0.5° resolution grid. The outcome of CWT model and PSCF identified Iberian Peninsula, France, North-West Africa and the Mediterranean as potential exogenous PM source areas. Extreme events of all PM fractions were primarily associated with the prevalence of South-South West airflows, whereas Saharan dust PM COARSE intrusions also emerged. The availability of hourly meteorological data and the analysis of the chemical species included in PM mass could further clarify the findings of this paper and remove uncertainties.

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Section: Local Pm Sources and Meteorologysupporting

confidence: 61%

The Dependence of PM Size Distribution from Meteorology and Local-Regional Contributions, in Valencia (Spain) - A CWT Model Approach

Dimitriou

2015

Aerosol Air Qual. Res.

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“…Therefore, in this analysis, the variability is explained based on the elevation of the radiant flux intensity throughout the day for each hour. Other factors may influence hourly turbidity fluctuation: meteorological conditions, local pollution, water vapor, aerosols that originated from seasonal forest fires, and local industrial activities (Bilbao et al, 2014).…”

Section: Diurnal and Seasonal Variation Of The Linke's Turbiditymentioning

confidence: 99%

Temporal variability of atmospheric turbidity and DNI attenuation in the sugarcane region, Botucatu/São Paulo/Brazil

Santos

Escobedo

2016

Atmospheric Research

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In this study, attenuation of direct normal solar irradiance (DNI) in Botucatu / São Paulo, an area under the influence of local and adjacent agricultural burning, is expressed using the Linke's turbidity factor (TL) in the period from 1996 to 2008. Two methodologies represented as TL Dj and TL Li were used. Temporal variability (hourly average for the season and monthly average) is presented. Turbidity was correlated with wind speed and air temperature. Frequency distribution and cumulative frequency are analyzed to determine turbidity predominance levels in the local atmosphere. Optical depth information of aerosols at 550 nm (AOD 550nm) and water vapor were obtained by the Terra satellite using the MODIS sensor. The highest degree of DNI transmission is observed in the morning. Close to solar noon, transmission is smaller (greatest TL value). Diurnal TL variability is more evident in the hot period than in the cold period. May and June were the months of lowest DNI attenuation (highest atmospheric transparency). The highest DNI attenuation occurs in spring (TL Dj = 4.22 ± 0.05 and TL Li = 4.65 ± 0.06) and summer (TL Dj = 4.27 ± 0.14 and TL Li = 4.69 ± 0.15). Wind speed and air temperature were positively correlated with TL. In N 28% of hours of clear sky, turbidity exceeded the value of 4.0. The region of Botucatu seems to be influenced by water vapor and aerosols from different origins. This study concludes that these factors significantly reduce DNI incidence on the surface, with higher atmospheric transparency in the cold period and lower atmospheric transparency in the warm period.

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“…The Å ngströ m turbidity coefficient does not incorporate the optical depth of water vapor or other participating gasses and therefore provides an uncontaminated measure of atmospheric aerosol loading. However, a and b are known to exhibit daily fluctuations driven by atmospheric processes such as photochemical activity, local emissions, mesoscale circulation, wind ventilation, and changes in temperature resulting from phase changes in the atmosphere (Bilbao et al, 2014). As a result, capturing the intra-daily variability in AOD requires highly resolved temporal data of AOD, which is typically not available without a ground-based sunphotometer in close proximity (e.g., NASA's Aeronet network).…”

Section: Aerosol Loadingmentioning

confidence: 98%

“…Gueymard (2014) also evaluated the impact of on-site atmospheric water vapor estimation methods on the accuracy of local solar irradiance predictions. Bilbao et al (2014), proposed a method for deriving Å ngströ m's turbidity coefficient and the AOD at 550 nm from broadband DNI observations over Castilla y Leó n (Spain), from July 2010 to December 2012.…”

Section: Introductionmentioning

confidence: 99%

Impact of local broadband turbidity estimation on forecasting of clear sky direct normal irradiance

2015

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Clear-sky modeling is of critical importance for the accurate determination of Direct Normal Irradiance (DNI), which is the relevant component of the solar irradiance for concentrated solar energy applications. Accurate clear-sky modeling of DNI is typically best achieved through the separate consideration of water vapor and aerosol concentrations in the atmosphere. Highly resolved temporal measurements of such quantities is typically not available unless a meteorological station is located in close proximity. When this type of data is not available, attenuating effects on the direct beam are modeled by Linke turbidity-equivalent factors, which can be obtained from broadband observations of DNI under cloudless skies. We present a novel algorithm that allows for a time-resolved estimation of the average daily Linke turbidity factor from ground-based DNI observations under cloudless skies. This requires a method of identifying clear-sky periods in the observational time series (in order to avoid cloud contamination) as well as a broadband turbidity-based clear-sky model for implicit turbidity calculations. While the method can be applied to the correction of historical clear-sky models for a given site, the true value lies in the forecasting of DNI under cloudless skies through the assumption of a persistence of average daily turbidity. This technique is applied at seven stations spread across the states of California, Washington, and Hawaii while using several years of data from 2010 to 2014. Performance of the forecast is evaluated by way of the relative Root Mean Square Error (rRMSE) and relative Mean Bias Error (rMBE), both as a function of solar zenith angle, and benchmarked against monthly climatologies of turbidity information. Results suggest that rRMSE and rMBE of the method are typically smaller than 5% for both historical and forecasted CSMs, which compare favorably against the 10-20% range that is typical for monthly climatologies.

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Turbidity coefficients from normal direct solar irradiance in Central Spain

Cited by 24 publications

References 36 publications

The Dependence of PM Size Distribution from Meteorology and Local-Regional Contributions, in Valencia (Spain) - A CWT Model Approach

The Dependence of PM Size Distribution from Meteorology and Local-Regional Contributions, in Valencia (Spain) - A CWT Model Approach

Temporal variability of atmospheric turbidity and DNI attenuation in the sugarcane region, Botucatu/São Paulo/Brazil

Impact of local broadband turbidity estimation on forecasting of clear sky direct normal irradiance

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