Towards an automatic wind speed and direction profiler for wide field adaptive optics systems

Abstract

Wide Field Adaptive Optics (WFAO) systems are among the most sophisticated adaptive optics(AO) systems available today on large telescopes. Knowledge of the vertical spatio-temporaldistribution of wind speed (WS) and direction (WD) is fundamental to optimize the performanceof such systems. Previous studies already proved that the Gemini Multi-ConjugatedAO system (GeMS) is able to retrieve measurements of the WS and WD stratification usingthe SLOpe Detection And Ranging (SLODAR) technique and to store measurements in thetelemetry data. In order to assess the reliability of these estimates and of the SLODAR techniqueapplied to such complex AO systems, in this study we compared WS and WD valuesretrieved from GeMS with those obtained with the atmospheric model Meso-NH on a richstatistical sample of nights. It has previously been proved that the latter technique providedexcellent agreement with a large sample of radiosoundings, both in statistical terms and onindividual flights. It can be considered, therefore, as an independent reference. The excellentagreement between GeMS measurements and the model that we find in this study proves therobustness of the SLODAR approach. To bypass the complex procedures necessary to achieveautomatic measurements of the wind with GeMS, we propose a simple automatic method tomonitor nightly WS and WD using Meso-NH model estimates. Such a method can be appliedto whatever present or new-generation facilities are supported byWFAO systems. The interestof this study is, therefore, well beyond the optimization of GeMS performance.