Temporal and spatial variabilities of total ozone column over Portugal



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Antón, M. and Bortoli, D. and Costa, M. J. and Kulkarni, P. S. and Domingues, A. E. and Barriopedro Cepero, David and Serrano, A., A. and Silva, A. M. (2011) Temporal and spatial variabilities of total ozone column over Portugal. Remote sensing of environment, 115 (3). pp. 855-863. ISSN 0034-4257

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Official URL: http://dx.doi.org/10.1016/j.rse.2010.11.013


This paper focuses on the spatial-temporal structure of total ozone column (TOC) over Portugal. This relevant region of southwestern Europe has not been evaluated yet in detail due to the lack of continuous and well-covered ground-based TOC measurements. The data used in this study are derived from the NASA's Total Ozone Mapping Spectrometer (TOMS) for the period 1978-2005. The TOC spatial behavior shows no significant longitudinal variability (smaller than 3%). In contrast, the variation in latitude changes between 3.5% and 6% depending on the calendar month. The TOC in the northern Portugal is, on average, higher than that recorded in the South. The temporal variability was analyzed for three scales: long-term, seasonal and short-term. The long-term TOC changes are analyzed between 1978 and 1999 by means of linear least squares fits. The results show an annual TOC trend of (2.65 +/- 0.70)%/decade which is statistically significant at the 95% confidence level. This TOC decrease is smaller than the trends obtained in other midlatitudes regions which could be partially explained by the compensation due to the observed increase in the tropospheric ozone over the Iberian Peninsula. A trend analysis performed for each individual month shows a statistically significant TOC decline between March and October, with a maximum linear trend value of (-7.30 +/- 45)%/decade in May. The amplitude of the seasonal TOC cycle over Portugal shows a slight dependence in latitude, varying from 28.6 DU (37.5 degrees N) to 33.6 DU (41.5 degrees N). Finally, the short-term variability showed a notable seasonal behavior, with maximum day-to-day TOC changes in winter (similar to 6%) and minimum in summer (similar to 3%). In addition, the persistence (characterized by the autocorrelation coefficients) strongly decreases after a few days (except in summer months).

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© 2010 Elsevier Inc. The authors thank the NASA TOMS Science Team for the satellite data used in this paper. Manuel Anton thanks the Ministerio de Ciencia e Innovacion and Fondo Social Europeo for the award of a postdoctoral grant (Juan de la Cierva). Author (Pavan S Kulkarni) is thankful to the Geophysics Centre of the University of Evora (CGE-UE) for the fellowship in the project 'SPATRAM-MIGE Polar Project', funded by the Portuguese Science Foundation - FCT. This work was partially supported by Ministerio de Ciencia e Innovacion under project CGL2008-05939-C03-02/CLI and by Fundacao para a Ciencia e a Tecnologia though projects PROPOLAR and PTDC/CTE-ATM/102142/2008.

Uncontrolled Keywords:North-Atlantic oscillation; Stratospheric ozone; Interannual variability; Satellite measurements; Tropopause pressure; Tropospheric ozone; Nitrogen-dioxide; Central-Europe; Trends; Radiation
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
Sciences > Physics > Atmospheric physics
ID Code:24296
Deposited On:23 Jan 2014 09:34
Last Modified:10 Dec 2018 15:05

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