 |
| Titel |
Direct-sun total ozone data from a spectroradiometer: methodology and comparison with satellite observations |
| VerfasserIn |
M. Antón, R. Román, A. Valenzuela, F. J. Olmo, L. Alados-Arboledas |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1867-1381
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 3 ; Nr. 6, no. 3 (2013-03-12), S.637-647 |
| Datensatznummer |
250017837
|
| Publikation (Nr.) |
 copernicus.org/amt-6-637-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| A methodology to obtain the total ozone column (TOC) from the
direct-sun spectral measurements of a Bentham spectroradiometer located at Granada
(Spain) is presented in this paper. The method relies on the differential
absorption technique using two pairs of direct irradiance at adjacent
wavelengths between 305 and 340 nm. The extraterrestrial constant was
determined from the extrapolation to zero air mass of each wavelength pair
(Langley plot method). We checked the strong influence of the cloud cover on
the Bentham TOC measurements using simultaneous sky images taken with an
all-sky camera. Thus, reliable TOC data are exclusively obtained during
cloud-free conditions or partly cloudy conditions without the solar disk
obstructed. In this work, the hourly TOC averages retrieved by the Bentham
instrument with a standard deviation smaller than 3% (~ 10
Dobson Unit) are selected as high-quality TOC data. The analysis of the
diurnal TOC variations during cloud-free days in late spring and summer
showed different TOC values between the morning and afternoon periods. Thus,
while the mornings exhibit an almost stable pattern, the afternoons display
a monotonic TOC increase which could be partially related to photochemical
processes in the lower troposphere associated with the formation of surface
ozone. Finally, the Bentham TOC measurements were compared against the
satellite data derived from three satellite instruments: OMI, GOME and
SCIAMACHY. The mean absolute values of the relative differences between
satellite and ground-based data were smaller than 3%, highlighting the
high reliability of the retrieval method proposed in this paper to derive
TOC data. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|