The H2020 SOLARNET project includes a study to investigate the possibility to set-up systems for the
forecast of the optical turbulence in the day-time regimes at the two sites of Roque de los Muchachos
Observatory (ORM, La Palma) and Teide Observatory (TO, Tenerife), with a particular attention to the site
that will be selected for the European Solar Telescope (EST) [RF1]. More precisely the study (hereafter
referred to as the proposed study) aims to upgrade to day-time conditions the method to forecast the optical
turbulence (C N2 profiles and integrated astroclimatic parameters) that was developed by the INAF partner
for night-time ground-based astronomy.
The technique implies the use of a mesoscale model (Meso-Nh) developed by the Centre National des
Recherches Meteorologiques (CNRM) and Laboratoire d’Aerologie (LA) in Toulouse (France), and a
dedicated code (Astro-Meso-NH) created by Elena Masciadri of INAF-Osservatorio Astrofisico di Arcetri
(INAF-OAA), to forecast the optical turbulence [RF2]. The Astro-Meso-Nh code is in continuous evolution
since more than a decade. It is now managed by the Optical Turbulence team of INAF-OAA and the
applications of this code evolved in the time. The most recent version of the code is described in [RF3]. The
application to day-time conditions implies new challenges, because the turbulence in day-time presents
different features with respect to those developed in night-time, and it is characterised by different typical
values for C N2 and derived astroclimatic parameters. This study can lead to the development and
implementation of an operational and automatic system for the optical turbulence forecast for EST and other
solar telescopes operated at the ORM and TO sites.
INAF-OAA has already developed an equivalent system for the Large Binocular Telescope (ALTA Center
project – alta.arcetri.astro.it) that runs nightly providing a complete description of the atmosphere conditions
(including the optical turbulence). The system is used for the science operations of LBT and in particular to
optimize the use of instrumentation supported by the adaptive optics. Such a tool can be considered as a
reference with respect to a potential similar tool to be conceived for the EST. The final and ultimate goal of
this activity is to develop and implement an operational and automatic system for the optical turbulence
forecast for EST and other solar telescopes operated at the ORM and TO sites.
This report deals with the availability of optical turbulence measurements above the ORM and TO sites. We
are interested on the information on the vertical stratification and integrated values of the monitored
quantities. Measurements are very important for the proposed study, because they are required to calibrate
the Astro-Meso-Nh model and to validate it for day-time conditions, i.e. to quantify the performances of the
model
