Open AccessBehavior of NO 2 and O 3 columns during the eclipse of February 26, 1998, as measured by visible spectroscopy
Author(s) -
Gil M.,
Puentedura O.,
Yela M.,
Cuevas E.
Publication year - 2000
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jd900973
Subject(s) - occultation , zenith , solar eclipse , solar zenith angle , eclipse , differential optical absorption spectroscopy , observatory , depth sounding , solar irradiance , physics , atmospheric sciences , absorption (acoustics) , environmental science , altitude (triangle) , optics , remote sensing , astrophysics , astronomy , geology , geometry , oceanography , mathematics
Observations of the NO 2 and O 3 columns using zenith‐viewing differential absorption spectroscopy in the visible range (450–540 nm) were carried out at Izaña Observatory (Tenerife, 28°N, 16°W, 2370 m above sea level.) during the eclipse of February 26, 1998 (95% occultation over the station). Ozone has been retrieved using two different spectral ranges to minimize the effect of the continuous change of the solar spectrum shape as the Sun is being occulted. Small variations before the maximum phase in agreement with previous observations are found, but because of the change in the shape of the solar spectrum, it cannot conclusively be determined whether the ozone changes are real or due to interferences with changing Fraunhofer lines. The difficulties in observing small changes of absorbing gases during solar eclipse when using remote sensing technique that uses the solar UV and visible radiation as the source are discussed. NO 2 displays an increase in phase with the degree of solar occultation, as compared to a non eclipse day of 1.55±0.09. A simple model assuming that changes over short times scales are only due to changes in photodissociation, using O 3 and temperatures obtained from an ozone sounding station close to the observatory, reproduces the observed variation when the NO 2 bulk is assumed to be at an altitude of 28 km. Correction for differences between local solar zenith angle (SZA) and the SZA where the absorption takes place is taken into account.