Revised optical air mass tables and approximation formula

Kasten, Fritz; Young, A. T.

doi:10.1364/ao.28.004735

Cited by 992 publications

(522 citation statements)

References 1 publication

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“…For the calculation of the airmass, m, we used the formula suggested by Hansen and Travis (1974). Results from different formulas (Young, 1994;Kasten and Young, 1989;Rosenberg, 1966), also taking into account atmospheric refraction and the effects of a spherical Earth on the atmospheric path of radiance, were compared. The average percentage difference of each airmass value calculated by the different formulae from their mean increased from 0.2% to 1.7% for the airmass range of 2-6 that we used.…”

Section: Methodsmentioning

confidence: 99%

Climatological aspects of aerosol optical properties in Northern Greece

et al. 2003

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Abstract.Measurements of aerosol optical properties (aerosol optical depth, scattering and backscattering coefficients) have been conducted at two groundbased sites in Northern Greece, Ouranoupolis (40 • 23 N, 23 • 57 E, 170 m a.s.l.) and Thessaloniki (40 • 38 N, 22 • 57 E, 80 m a.s.l.), between 1999 and 2002. The frequency distributions of the observed parameters have revealed the presence of individual modes of high and low values, indicating the influence from different sources. At both sites, the mean aerosol optical depth at 500 nm was 0.23. Values increase considerably during summer when they remain persistently between 0.3 and 0.5, going up to 0.7-0.8 during specific cases. The mean value of 65±40 Mm −1 of the particle scattering coefficient at 550 nm reflects the impact of continental pollution in the regional boundary layer. Trajectory analysis has shown that higher values of aerosol optical depth and the scattering coefficient are found in the east sector (former Soviet Union countries, eastern Balkan countries), whereas cleaner conditions are found for the NW direction. The influence of Sahara dust events is clearly reflected in the Angström exponents. About 45-60% of the observed diurnal variation of the optical properties was attributed to the growth of aerosols with humidity, while the rest of the variability is in phase with the evolution of the sea-breeze cell. The contribution of local pollution is estimated to contribute 35±10% to the average aerosol optical depth at the Thessaloniki site during summer. Finally, the aerosol scale height (aerosol optical depth divided by scattering coefficient) was found to be related to the height of the boundary layer with values between 0.5-1 km during winter and up to 2.5-3 km during summer.

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Section: Methodsmentioning

confidence: 99%

Climatological aspects of aerosol optical properties in Northern Greece

et al. 2003

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“…This introduces a negative fair weather bias in the recorded IWVs, since cloudy conditions are often associated with higher IWV values. The reported IWV value in the AERONET database is the zenith value, but the solar slant value can easily be returned using the optical air mass table based on a standard atmosphere (Kasten and Young, 1989).…”

Section: Cimel Sun Photometermentioning

confidence: 99%

“…One way forward is to compare coincident IWV values in the direction of the Sun (the so-called solar slant IWV). These solar slant IWVs are one step back in the CIMEL data process to obtain IWVs from the measured slant transmittance and are obtained by multiplying the (zenith) IWVs with the optical air mass as defined in Kasten and Young (1989). These CIMEL solar slant IWVs should then have no contributions from clouds, by definition.…”

Section: Solar Slant Integrated Water Vapour Measurementsmentioning

confidence: 99%

A multi-site intercomparison of integrated water vapour observations for climate change analysis

et al. 2014

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Abstract. Water vapour plays a dominant role in the climate change debate. However, observing water vapour over a climatological time period in a consistent and homogeneous manner is challenging. On one hand, networks of groundbased instruments able to retrieve homogeneous integrated water vapour (IWV) data sets are being set up. Typical examples are Global Navigation Satellite System (GNSS) observation networks such as the International GNSS Service (IGS), with continuous GPS (Global Positioning System) observations spanning over the last 15+ years, and the AErosol RObotic NETwork (AERONET), providing long-term observations performed with standardized and well-calibrated sun photometers. On the other hand, satellite-based measurements of IWV already have a time span of over 10 years (e.g. AIRS) or are being merged to create long-term time series (e.g. GOME, SCIAMACHY, and GOME-2).This study performs an intercomparison of IWV measurements from satellite devices (in the visible, GOME/SCIAMACHY/GOME-2, and in the thermal infrared, AIRS), in situ measurements (radiosondes) and ground-based instruments (GPS, sun photometer), to assess their use in water vapour trends analysis. To this end, we selected 28 sites world-wide for which GPS observations can directly be compared with coincident satellite IWV observations, together with sun photometer and/or radiosonde measurements. The mean biases of the different techniques compared to the GPS estimates vary only between −0.3 to 0.5 mm of IWV. Nevertheless these small biases are accompanied by large standard deviations (SD), especially for the satellite instruments. In particular, we analysed the impact of clouds on the IWV agreement. The influence of specific issues for each instrument on the intercomparison is also investigated (e.g. the distance between the satellite ground pixel centre and the co-located ground-based station, the satellite scan angle, daytime/nighttime differences). Furthermore, we checked if the properties of the IWV scatter plots between these different instruments are dependent on the geography and/or altitude of the station. For all considered instruments, the only dependency clearly detected is with latitude: the SD of the IWV observations with respect to the GPS IWV retrievals decreases with increasing latitude and decreasing mean IWV.

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“…Among the atmospheric parameters, air mass (AM) corrected with site elevation [13], aerosol optical depth (AOD), and precipitable water (PW) are considered to be the main factors impacting DNI spectrum, while others such as ambient temperature, air pressure, ozone and others have a minor impact [14]. Nevertheless, the impact of such atmospheric condition on the MJ device performance cannot be directly calculated, but it is necessary to estimate the spectral distribution of DNI first by means of a radiative transfer model and then calculate the performance of the device through its spectral response.…”

Section: Mapping the Solar Resource With The Spectral Characteristicsmentioning

confidence: 99%

Spectral classification of worldwide locations using SMR indexes

Núñez¹,

Jin²,

Antón³

et al. 2016

AIP Conference Proceedings

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Abstract. Spectral variation of solar irradiance can be analyzed by the means of component cells, being useful for multi junction (MJ) and concentrator photovoltaics (CPV) characterization by the use of component cells derived spectral indexes, namely, spectral matching ratios (SMRs). When enough spectral data is available, a location can be also characterized and a MJ solar cell can be locally tuned. The AERONET network of ground-based sun photometers is employed to obtain the atmosphere parameters for 34 sites worldwide. To conclude, the SMR indexes are obtained for every location, and a comparative analysis is completed for four architectures of MJ solar cells technologies (two lattice match and two metamorphic). Based on this information, some cluster of locations that share similar spectral features arise.

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Revised optical air mass tables and approximation formula

Abstract: We correct an error in a widely used air mass table by recalculating the values on the basis of the ISO Standard Atmosphere (1972) and revise its approximation formula.

Cited by 992 publications

References 1 publication

Climatological aspects of aerosol optical properties in Northern Greece

Climatological aspects of aerosol optical properties in Northern Greece

A multi-site intercomparison of integrated water vapour observations for climate change analysis

Spectral classification of worldwide locations using SMR indexes

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