| VII. Review Paper: WHAT MIGHT AN ASTRONOMER EXPECT FROM AN ASTROCLIMATIC STATION? Casiana Muñoz-Tuñon |
abstract to be communicated later |
| VII.1 METEOROLOGY: FROM SITE TESTING TO THE MICROCLIMATOLOGY OF ASTRONOMICAL OBSERVATORIES T. J. Mahoney, C. Muñoz-Tuñon, A. M. Varela and A. G. de Gurtubai |
Apart from the restricted needs of site testing and telescope security,
much useful microclimatological
information could be through i) continuous monitoring of surface meteorology
at several sites within a given observatory, ii) the
pooling of reduced meteorological data into a common observatory database,
iii) the regular comparison of the sensors (thermometers, hygrometers,
barometers, anemometer, etc.), and iv) the establishment of
possible collaborations
with national meteorological institutes with a view to obtaining
access to and help with the interpretation of professional meteorological
databases.
Such a programme would be an essential first step in providing the necessary
continuous coverage of surface and synoptic meteorology for characterizing
observatory microclimates and the climates of their surroundings,
as well as providing essential information for "nowcasting" and short-term
weather forecasting at observatories. |
| VII.2 SITE TESTING AND SITE MONITORING FOR EXTREMELY LARGE TELESCOPES Andreas Quirrenbach |
The next generation of extremely large telescopes (ELTs, 30m
to 100m diameter) will rely heavily on the performance of advanced adaptive
optics (AO) systems. These systems will probably employ tomographic wavefront sensing and
multi-conjugate correction. It is also likely that multiple laser guide stars (LGSs) will
be needed to achieve full sky coverage. The design and operation of ELTs sets new demanding
requirements on the knowledge about the site. For a detailed evaluation of the performance
of multi-conjugate AO, seasonal statistics on the turbulence and wind profiles must be known.
The requirements on lasers for sodium LGS systems depends on the column density of the sodium
layer. In addition, experience with the operation of LGS systems shows that nearly photometric
conditions are required, since cirrus layers produce intolerable levels of backscattering.
Altogether this requires a very comprehensive site testing program, which will influence not
only the site selection but also the details of the telescope / AO system design. For optimum
operation the same information should be available in near-real time during all observations.
We will discuss the requirements on site surveys and site monitoring for ELTs, and describe
possible techniques to obtain these data. Particular attention will be paid to the needs of
the CELT project, a joint University of California / Caltech study for a possible future 30m
telescope.
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| VII.3 ANTARTIC SITE TESTING J.W.V. Storey, M.C.B. Ashley & M.G. Burton |
We have developed a suite of self-contained automated instruments for year-long site testing on the Antarctic plateau. The instruments include a UV/Visible sky brightness spectrometer, a near-IR sky brightness monitor, and a mid-IR sky brightness monitor. To this we have added a Remtech acoustic radar and a low-power version of the sub-mm tipper originally developed by NRAO and CMU. The complete suite of instruments operates within a total power budget of 50 watts.
These instruments have operated at the South Pole as part of the Automated Astrophysical Site Testing Observatory (AASTO). We have already shown that the IR sky brightness at the Pole can be 100 times lower than that at temperate sites, and a further set of data will taken in 2000. The AASTO will then be deployed to remote sites on the Antarctic plateau.
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| VII.4 ESO WEATHER_WATCH, AN AUTOMATED SERVICE FOR OBSERVATORY OPERATION Marc Sarazin |
ESO Visiting Astronomers, Telescope Operation and Observatory Maintenance Teams have now access to a new service which should improve observing efficiency as well as safety of operation. A Weather_Watch mailing list has been created which allows subscribers to receive emails each time a change is forecasted in the observing conditions of the next 48h at La Silla and Paranal Observatories.
The messages are generated at ESO headquarters on the basis of the outcome of ECMWF meteorological forecasts, after adjustment to local conditions by Kalman filtering, and of satellite based cloud cover analysis.
The data fusion process in operation is briefly described and the selection criteria for issuing warnings are discussed.
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| P.VII.1 (poster) A MINIMAL WEATHER STATION SET-UP FOR USEFUL OBSERVATORY MICROCLIMATE CHARACTERIZATION T.J. Mahoney, C. Muñoz-Tuñon, A.M. Varela & A.G. de Gurtubai |
A profile is presented of a minimally equipped weather station and
the mode of its operation that would
be useful for characterizing an observatory's microclimate in terms of
latitude, altitude, continentality/oceanicity and topography. The need
for long-term (over decades, not years) continuous monitoring is
stressed. Reference is made to the GTC and other meteorological monitoring
campaigns and suggestions offered on how these can be used as a basis
for further campaigns aimed at characterizing the long-term microclimatology
of astronomical observatories.
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