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Ann. Geophys., 20, 565-574, 2002
www.ann-geophys.net/20/565/2002/
© European Geosciences Union 2002
Measurements and estimation of the columnar optical depth of tropospheric aerosols in the UV spectral region
V. E. Cachorro1, R. Vergaz1, M. J. Martin1, A. M. de Frutos1, J. M. Vilaplana2, and B. de la Morena2
1Grupo de Optica Atmosférica-Universidad de Valladolid (GOA-UVA), Depto. de Optica y Fisica Aplicada, Depto de Fisica Aplicada I, Valladolid, Spain
2Estación de Sondeos Atmosféricos ESAT “El Arenosillo", INTA, Huelva, Spain
Correspondence to: V. E. Cachorro
(chiqui@baraja.opt.cie.uva.es)
Abstract. We report values of the
columnar tropospheric aerosol optical depth at UV wavelengths based on
experimental measurements of the direct spectral irradiances carried out by a
commercial spectroradiometer (Li1800 of Licor company) covering the range from
300–1100 nm at two stations with different climate characteristics in Spain.
The first station is located in a rural site in north central Spain with
continental climate. The data extend from March to the end of October of 1995.
The other station is a coastal site in the Gulf of Cádiz (southwest Spain) of
maritime climate type. This study is mainly focused on the capability of
estimating aerosol optical depth values in the UV region based on the extracted
information in the visible and near infrared ranges. A first method has been
used based on the Ångström turbidity parameters. However, since this method
requires detailed spectral information, a second method has also been used,
based on the correlation between wavelengths. A correlation has been
established between the experimental aerosol optical depth values at 350 nm and
500 nm wavelengths. Although the type of aerosol seems to be the key factor
that determines the quality of these estimations, the evaluation of the
associated error is necessary to know the behaviour of these estimations in
each area of study.
Key words. Atmospheric composition
and structure (aerosols and particles; transmission and scattering of
radiation; troposphere – composition and chemistry)
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