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Measurement program

Research projects




PhD works using Izaña DOAS data


Scientists involved


Stratospheric gases became a subject of major concern in the eighties when mechanisms of ozone depletion due to man-produced chemical were identified. Ozone concentration in the stratosphere basically depends on meridional transport of air, radiation available and amounts of NO2 and halogens.

Unpolluted, clear skies high stations constitute perfect locations for stratospheric measurements.

Measurement Program

DOAS stands for Differential Optical Absorption Spectroscopy. It is a technique suitable for the detection of minor gases in the atmosphere.  By collecting zenith diffuse light during twilight high quality measurements of stratospheric species can be performed.

INTA in agreement with AEMET (former INM) started a long-term stratospheric measurement program in 1993.  Since that date NO2 vertical column has been collected everyday at twilight. In 1999 a second instrument extended the spectral range to incorporate O3 data (vertical columns). BrO radical measurements (vertical columns) started in 2001 when an UV- spectrometer was deployed.

Twilight total column NO2 series (1193-2000) obtained at Izana by DOAS/UV-VIS technique

Research Projects

Izaña DOAS belongs to the NDACC (Network for the Detection of Atmospheric Comoposition Change) where Quality controlled data are stored.  Data are used for climatological studies, ozone comparison with instruments operating in different spectral ranges to improve the accuracy, potential impact of Saharan dust layers on ozone retrieval by optical methods, short scale events and satellite validation, long term trends, etc

At present Izaña-DOAS contributes to ESA satellites permanent validation through the project MULTI-TASTE coordinated by the Institut d'Aéronomie Spatiale de Belgique (IASB).


Differential absorption spectrometers are integrated at INTA. Algorithms, evaluation software and instrument control software are developed at INTA as well. For main specifications see Table I (from Gil et al., 2008).


Fitting light sensors and optical fibers of DOAS instruments on the terrace of the Izana's observation tower. 
 ARTIST and RASAS DOAS/UV-VIS intruments in the 6th floor of the observation tower.


Gil, M., O. Puentedura, M. Yela y E. Cuevas. “Behavior of NO2 and O3 columns during the eclipse of February 26, 1998, as measured by visible spectroscopy, J. Geophys. Res., V105, D3, 3583, 2000

Lambert, J-C, J. Granville, M. Allart, T. Blumenstock, T. Coosemans, M. de Maziere, U. Friess, M. Gil, F. Goutail, D.V. Ivonov, I. Kostadinov, E. Kyro, A. Petritoli, A. Piters, A. Richter, H.K. Roscoe, H. Schets, J. D. Shanklin, V. T. Soebijanta, T. Suortti, M. van Roozendael and C. Varotsos, Ground-Based Intercomparison of early Sciamachy O3  and NO2 columns First ENVISAT Validation Workshop, ESA/ESRIN, Italy, 9-13 Dec. 2002, ESA SP-531, 2003

Gil, M., M. Yela, E. Cuevas and V. Carreño, Sudden increases in the NO2 column caused by thunderstorms: A case study in the northern subtropical region. Atmospheric Chemistry and Physics Discussions, 4, 2263-2281, 2004

Blumenstock, T., S. Mikuteit, A. Griesfeller, F. Hase, G. Kopp, I. Kramer, M. Schneider, H. Fischer, M. Gil, J. R. Moreta, M. Navarro-Comas, U. Raffalski, E. Cuevas, B. Dix & G. Schwarz, Validation of MIPAS and SCIAMACHY data by ground-based spectroscopy at Kiruna, Sweden, and Izana, Tenerife island (AOD-191), ESA SP-562, 2004  (ISBN 92-9092-873-5)

Lambert, J.C., M. Van Roozendael, S.B. Andersen, J. P. Burrows, C. de Clerq, I. de Semdt, V. Dorokhov, N.F. Elansky, M. Gil, F. Goutail, G. Held, F. Hendrick, B.A.K.Hoiskar, D.V. Ionocv, P.V.Johnston, I. Kostadinov, K. Kreher, E. Kyrö, J. Leveau, D. Loyola, J-F. Müller, A. Petritoli, G. Pinardi, U,. Platt, J-P. Pommereau, O. Puentedura, A. Richter, H.K. Roscoe, V. Semenov, S. Slijkhuis, R.J.D. Spurr, Yu.M. Timofeyev, K.K. Tornkvist, G. Vaughan, T. Wagner, S. Wahl, F. Wittrock and M. Yela, End-to-end validation of EPS/METOP GOME-2 Trace gas data, EUMETSAT Polar System/MetOp RAO Workshop, ESA-SP 618, 2006

Lambert, J.-C., J. Granville, C. Lerot, F. Hendrick, M. Van Roozendael, S.B. Andersen, V. Dorokhov, P. Gerard, M. Gil, F. Goutail, A.N. Gruzdev, G. Held, D. V. Ionov, P. V. Johnston, I. Kostadinov, K. Kreher, E. Kyrö, J. Leveau, M. Navarro-Comas, A. Petritoli, J.-P. Pommereau, A. Richter, H. K. Roscoe, V. K. Semenov, K. Stebel, G. Vaughan, T. Wagner, F. Wittrock, and M. Yela. GDP 4.0 transfer to SGP 3.0 for SCIAMACHY NO2 column processing: verification with SDOAS/GDOAS prototype algorithms and delta-validation with NDACC/UV-Visible network data. (ACVE-3), ESA SP-642, 2006

Gil, M., Yela, M,  L. N. Gunn, A. Richter, I. Alonso, M. P. Chipperfield, E. Cuevas, J. Iglesias, M. Navarro, O. Puentedura, and S. Rodrıguez, NO2 climatology in the northern subtropical region: diurnal, seasonal and interannual variability Atmos. Chem. Phys. 8, 1635–1648, 2008


Yela, M., S. Rodriguez,  M. Gil, E. Cuevas, C. Parrondo and A. Redondas, NO2  and O3  at subtropical regions, Third European Ozone  Symposium in the Arctic region, Procc., Ed. G. Amanatidis, European Commision, pp 235-238,  Schliersee, Alemania, 1995

Yela, M., M. Gil, M. Navarro, S. Rodriguez, E. Cuevas and C. Romero,  Meridional transport in the subtropics during winter as seen by  NO2 column record, Polar Stratospheric Ozone 1997, Air Pollution Report 66, EUR 18032EN, Ed. N.R.P. Harris, I. Kilbane-Dawe and G.T. Amanatidis, pp 88-91, 1998.

Gil, M., M. Yela, A. Redondas, V. Carreño, E. Cuevas, M. Schneider, O. Puentedura, M. Navarro, F. Hase  y T. Blumenstock, Intercomparación de instrumentos de medida de la columna total de ozono en el Observatorio subtropical de Izaña (28ºN, 16ºW), 2ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica, Lagos, 2000

Gil, M., O Puentedura  M. Yela and F. Hendrick, Diurnal and seasonal variation of BrO in the Northern Subtropics, IUGG, Sapporo, Japón 2003

Olga Puentedura, Manuel Gil, Mónica Navarro, François Hendrick, Martyn Chipperfield and Emilio Cuevas. An estimation of the Bromine Monoxide content in the free troposphere of north subtropical regions. IAMAS, Beijing, China. 2-11 August, 2005.

Gil, M., J. F. Lopez-Herreros, S. Chueca, O. Serrano, S. Alonso, E. Cuevas, P. M. Romero, M. Navarro, J. Andrey, C. Córdoba-Jabonero, M. Yela, A. Redondas, S. Rodriguez, M. Schneider, I. Kramer, T. Blumenstock and C. Pérez, A. El proyecto TROMPETA (TROpical Monitoring PhasE in The Atmosphere): Interacción aerosoles-radiación-ozono en la atmósfera subtropical, The TROMPETA (TROpical Monitoring PhasE in The Atmosphere) Project: Aerosols-Radiation-Ozone interaction in the Subtropics, Procc. de la 5ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica, 30/1-3/2, Sevilla 2006

Puentedura, O., M. Gil, M. Navarro,  Bromine Monoxide Vertical Column at Izaña Observatory (28ºN,16ºW), SCOUT-O3, Progress Meeting, Heraclion, 2007
Andrey, J., M. Gil and E. Cuevas, A review of Saharan dust specific extinction coefficient (SEC), RECTA, Torremolinos, Málaga, 2008

Puentedura O., M. Gil and E. Cuevas, Discrepancy between satellite and high mountain ground-based BrO seasonality in the Subtropics: Evidence of Marine Boundary Layer BrO? 35th Annual European Meeting on Atmospheric Studies by Optical Methods, Maynooth, Ireland, 2008

GEOMON UV-Vis team. Monitoring the stratosphere in GEOmon and NDACC. GEOMON Annual meeting, WMO, Geneve, 2009

GEOMON UV-Vis team. Monitoring the stratosphere in GEOmon and NDACC. Geophys. Res. Abstract VII, EGU 2009-10636,Vienna 2009

Hendrick, F., O. Puentedura, P. V. Johnston, M. De Mazière, M. Gil, K. Kreher, and M. Van Roozendael. Long-term ground-based UV-visible observations of stratospheric BrO at 60°N, 28°N, and 45°S reveal a decline. 3rd GEOMON Progress meeting. Geneve, Switzerland 26-29 January 2009.

F. Hendrick, P. V. Johnston, O. Puentedura, A. Rozanov, M. De Mazière, M. Gil, K. Kreher, B.-M. Sinnhuber, and M. Van Roozendael. Trend Analysis Of Stratospheric BrO Using Ground-Based Uv-Visible And SCIAMACHY Limb Observations At 60°N, 44°N, 28°N, And 45°S. European Geosciences Union General Assembly, 2009. Vienna, Austria, 2009.

F. Hendrick, M. De Mazière, N. Theys, M. Van Roozendael, A. Rozanov, B.-M. Sinnhuber, H. Bovensmann, P. V. Johnston, K. Kreher, O. Puentedura and M. Gil. Trend Analysis Of Stratospheric BrO: Comparison Between Sciamachy Limb And Ground-Based Uv-Visible Observations. ESA Atmospheric Science Conference 2009 (7-11 September, Madrid). Accepted.

PhD works using Izaña DOAS  data

Study of the NO2-O3 system at low latitudes by Ground-Based observations by using the ground-based absorption spectroscopy in the UV.Vis region (Estudio del sistema O3-NO2 en latitudes bajas basado en observaciones desde tierra utilizando la técnica de espectroscopía de absorción UV-Visible), Margarita Yela-Gonzalez,  U. de Salamanca, 1999

Bromine Monoxide remote sensing in the Subtropical atmosphere by Differential Absorption Spactroscopy (Detección remota de monóxido de Bromo en la atmósfera subtropical mediante espectroscopia de absorción diferencial), Olga Puentedura-Rodríguez, Universidad Complutense de Madrid., 2004


NO2 Vertical Column:  1993 to date

O3 Vertical column: 1999 to date

BrO Vertical column: 2001 to date

Data in molec/cm2 between 50º and 93º Solar Zenith Angle.  For long term studies only twilight data around 90º (± 1º) are provided. Ancilliary data are O4, Color index, and Raman scattering which provide information on atmospheric conditions (presence of dust and/or clouds) and H2O

Scientists involved

RASAS Instrument (NO2, O3):     Dr. Manuel Gil-Ojeda (INTA)

EVA Instrument (NO2):     Dr. Margarita Yela-González (INTA)

ARTIST spectrometer (BrO):     Dr. Olga Puentedura-Rodriguez (INTA)

Analysis software:          Mrs. Mónica Navarro-Comas (INTA)

Instrument control software:    Eng. Javier Iglesias-Méndez (INTA)