Statistical structure of the atmospheric optical turbulence at Teide Observatory from recalibrated generalized SCIDAR data

The characterization of the optical turbulence structure at an astronomical site requires a proper data base of the refractive-index structure constant, C-N(2)(h). Our team has been obtaining generalized SCIntillation Detection and Ranging (SCIDAR) observations to monitor C-N(2)(h) from 2002 November-2009 January at Teide Observatory (Tenerife, Canary Islands, Spain). The Teide C-N(2)(h) data base includes useful data from 153 nights of generalized SCIDAR measurements obtained at the 1.5-m Calos Sanchez Telescope. The overestimation of the turbulence strength as a consequence of generalized SCIDAR data processing has been analysed for all double stars and analysis-plane combinations used in our observations. If this overestimation of the turbulence is not taken into account, the median total seeing and isoplanatic angle derived from the turbulence profiles in the data base are 0.70 and 2.47 arcsec, respectively. We have recalibrated all the derived C-N(2)(h), correcting for this overestimation. The statistical optical turbulence structure above Teide Observatory is derived by combining the 93 662 individual C-N(2)(h) that constitute the data base at this site. More than 85 per cent of the total optical turbulence is concentrated in low-altitude layers (< 5 km above sea level). The optical turbulence structure presents an evolution of the layers in both strength and altitude. Only the turbulence concentration at the observatory level shows a similar turbulence strength over a standard year. The median values of total seeing and isoplanatic angle of epsilon(0) = 0.64 arcsec and theta(0) = 2.83 arcsec demonstrate the excellent quality of the Teide Observatory astronomical site for the implementation of adaptive optics systems.