Abstract

The continuous spectrum of the direct solar radiation from λ = 330 to 2690 nm, penetrating a cloudless atmosphere and arriving on the earth surface, is determined by measuring the solar irradiance in ten selected discrete spectral ranges defined by interference filters. Heretofore knowledge of the extraterrestrial solar spectrum has been required as well as of the transmittance functions to describe the spectral optical properties of the atmosphere. A set of appropriate and simple functions is given and discussed, which allows calculation of the molecular, aerosol, oxygen, and ozone optical thicknesses. The influence of atmospheric water vapor is considered through line by line calculations. The dominant and most fluctuating extinction parameters are the aerosol optical thickness and the content of precipitable water vapor. These are obtained by measurements with two sun photometers, developed according to the WMO recommendation. To test the derived solar spectrum at ground level the photometers are also run with nine broadband filters. The values observed differ little from those obtained by integration of the deduced spectral irradiance. Furthermore, the integral value of the resulting entire spectrum agrees reasonably well with the total direct irradiance gained from actinometer measurements.

© 1988 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Evaluation of the applicability of solar and lamp radiometric calibrations of a precision sun photometer operating between 300 and 1025 nm

Beat Schmid, Paul R. Spyak, Stuart F. Biggar, Christoph Wehrli, Jörg Sekler, Thomas Ingold, Christian Mätzler, and Niklaus Kämpfer
Appl. Opt. 37(18) 3923-3941 (1998)

Determination of the atmospheric-water-vapor content in the 940-nm absorption band by use of moderate spectral-resolution measurements of direct solar irradiance

Victoria E. Cachorro, Pilar Utrillas, Ricardo Vergaz, Plinio Durán, Angel M. de Frutos, and Jose A. Martinez-Lozano
Appl. Opt. 37(21) 4678-4689 (1998)

Multiwavelength sun-photometers for accurate measurements of atmospheric extinction in the visible and near-IR spectral range

Claudio Tomasi, Franco Prodi, Monica Sentimenti, and Giulio Cesari
Appl. Opt. 22(4) 622-630 (1983)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (8)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (3)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (18)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription