Precipitable Water Measurements with Sun Photometers

Bird, Richard E.; Hulstrom, R. L.

doi:10.1175/1520-0450(1982)021<1196:pwmwsp>2.0.co;2

Cited by 22 publications

(7 citation statements)

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“…The effect of water vapor on the broadband downwelling SW fluxes is considered in the flux calculations. The column precipitable water amount is obtained from either satellite remote sensing [e.g., Gao and Goetz , 1990; Kaufman and Gao , 1992; Bartsch and Fischer , 1997; Gao and Kaufman , 2003] or Sun photometer measurements [e.g., Volz , 1974; Bird and Hulstrom , 1982; Halthore et al , 1997; Morys et al , 2001]. Surface reflection is assumed to be Lambertian.…”

Section: Algorithm For Determination Of ωOmentioning

confidence: 99%

Estimation of aerosol single scattering albedo from solar direct spectral radiance and total broadband irradiances measured in China

Zhao

2007

J. Geophys. Res.

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[1] Aerosol single scattering albedo (w o ) is a primary factor dictating aerosol radiative effect. Ground-based remote sensing of w o has been employed most widely using spectral sky radiance measurements made from a scanning Sun photometer. Reliable results can be achieved for high aerosol loadings and for solar zenith angle >50°. This study presents an alternative method using spectral direct radiance measurements or aerosol optical depths together with total sky irradiance to retrieve w o . The method does not require sky radiance data that can only be acquired by the expensive scanning Sun photometer. The method is evaluated using extensive measurements by a suite of instruments deployed in northern China under the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE) project. The sensitivities of the retrieval to various uncertain factors were first examined by means of radiative transfer simulations. It was found the retrieval is most sensitive to cloud screening, total irradiance and the Angstrom Exponent (AE), but only weakly depends on surface albedo and the fine structure of aerosol size distribution. Using 1 year of rigorously screened clear-sky measurements made at the Xianghe site, the retrieved w o values were found to agree with those retrieved from the Cimel Sun photometer by the AERONET method to within $0.03 (RMS), and $0.003 (mean bias). As part of the differences originate from different sky views seen by the Sun photometers and pyranometer under comparison, a further test was conducted by using total sky irradiances simulated with the retrieved aerosol properties from the AERONET. The resulting estimates of w o agree to within 0.01-0.02 (RMS differences) and 0.002-0.003 (mean bias). These values are better measure of the true retrieval uncertainties, as they are free from any data mismatch. The characteristics of w o retrievals were discussed.Citation: Zhao, F., and Z. Li (2007), Estimation of aerosol single scattering albedo from solar direct spectral radiance and total broadband irradiances measured in China,

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Section: Algorithm For Determination Of ωOmentioning

confidence: 99%

Estimation of aerosol single scattering albedo from solar direct spectral radiance and total broadband irradiances measured in China

Zhao

2007

J. Geophys. Res.

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“…Standard solar spectrum is shown in Figure 1 The spectrum outside the atmosphere is so called air mass zero (AM0) meaning that the spectrum was measured with no air between the sun and the receiver [2,3] The variation of the amount of total solar radiation into the atmosphere depending on the wavelength is modelled by atmospheric effects. Many researchers may obtain the capability to produce accurate terrestrial spectra using a computer program [5][6][7].…”

Section: Basic Terms For Solar Irradiancementioning

confidence: 99%

Muğla Bölgesi̇ İçi̇n Aylik Toplam Güneş Işinim Mi̇ktarinin Hesaplanmasi

Eke

Kabakçı

2018

Mugla Journal of Science and Technology

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Calculation of the amount of energy from the sun as the energy source of the world is very important in terms of determining the efficiency of photovoltaic (PV) systems. At air mass zero solar spectral irradiance values have received a great deal of attention in recent years and are given in the wavelength range 0.2-4.0 µm. The amount of incoming sunlight can be calculated with different mathematical models. In this study, a mathematical modelling using SPCTRL 2 program will be discussed. The model has many variables in determining the quantity of sunlight coming in the atmosphere. With this model, the amount of solar energy falling on any on spot on the Earth's surface can be calculated and graphically modelled. In this study, direct, indirect and total (global) solar energy amounts coming from horizontal and sloping surfaces for Mugla were calculated depending on the wavelength. Horizontal and 30° inclined surfaces were calculated separately for winter, spring, summer and autumn seasons for Muğla Province. As a result, the amount of solar radiance for Muğla province was determined by mathematical modelling and the general conditions for the establishment of suitable photovoltaic system were determined.

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“…The basis for photometric precipitable water measurement was discussed by Fowle (1912Fowle ( , 1913Fowle ( , 1915, and recent applications have been given by Volz (1974), Pitts et al (1977), Bird and Hulstrom (1982), and others.…”

Section: Precipitable Water Vapor Measurementsmentioning

confidence: 99%

Interpretation of Mauna Loa atmospheric transmission relative to aerosols, using photometric precipitable water amouts

1985

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Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction.Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant.The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution.Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount.The remaining variability in the adjusted ATF is due mostly to aerosol extinction.The technique is applied to a 6-year period (1978"1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth.Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident.ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols.The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation "drought"

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Precipitable Water Measurements with Sun Photometers

Cited by 22 publications

References 0 publications

Estimation of aerosol single scattering albedo from solar direct spectral radiance and total broadband irradiances measured in China

Estimation of aerosol single scattering albedo from solar direct spectral radiance and total broadband irradiances measured in China

Muğla Bölgesi̇ İçi̇n Aylik Toplam Güneş Işinim Mi̇ktarinin Hesaplanmasi

Interpretation of Mauna Loa atmospheric transmission relative to aerosols, using photometric precipitable water amouts

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