Abstract
Results of monitoring optical-turbulence profiles and velocity of the turbulence layers at San Pedro Mártir, Mexico, are presented. The data were collected during 11 nights in April-May 1997 and 16 nights in May 2000 using the Generalized Scidar of Nice University installed on the 1.5-m and 2.1-m telescopes. The statistical analysis of the 6414 turbulence profiles obtained shows that the seeing produced by the turbulence in the first 1.2 km, not including dome seeing, at the 1.5-m and the 2.1-m telescopes have median values of 0 to z 0. hss'' 63 and 0 to z 0. hss'' 44, respectively. The dome seeing at those telescopes have median values of 0 to z 0. hss'' 64 and 0 to z 0. hss'' 31. The turbulence above 1.2 km and in the whole atmosphere produces seeing with median values of 0 to z 0. hss'' 38 and 0 to z 0. hss'' 71. The temporal correlation of the turbulence strength drops to 50% in time lags of 2 and 0.5 hours, approximately, for altitudes below and above 16 km above sea level, respectively. The turbulence above ∼ 9 km remained notably calm during 9 consecutive nights, which is encouraging for adaptive optics observations at the site. The 3016 profiles of the turbulent-layer velocity that are analyzed show that the fastest layers are found between 10 and 17 km, where the tropopause and the jet stream are located, with median speed of 24.4 m s-1. In the first 2.2 km and above 17 km, the turbulent layers move relatively slowly, with median speeds of 2.3 and 9.2 m s-1. The median of the wavefront coherence-time is 6.5 ms, in the visible. The results obtained here places San Pedro Mártir among the best suited sites for installing next generation optical telescopes.
