Statistical estimations of the vapor content and optical thickness of the atmosphere using reanalysis and radiosonding data as applied to millimeter telescopes
A.Yu. Shikhovtsev, P.G. Kovadlo
Institute of Solar-Terrestrial Physics of the Siberian Branch of the RAS, Irkutsk, Russia
Keywords: astroclimate, atmosphere, water vapor, millimeter radiation, inversion layers
Abstract
Possibilities of astronomical millimeter and submillimeter observations strongly depend on the precipitable water vapor (PWV), which determines the radiation absorption. The precise determination of PWV within large regions is one of key astroclimate problems. In this work, we refine estimates of PWV content for different sites based on processing ERA5 reanalysis and radiosounding data and test the previously proposed technique for correcting PWV values taking into account the characteristic water vapor vertical scale and relative altitude difference of grid nodes. In addition, the spatial distribution of the nighttime atmospheric optical thickness at a wavelength of 3 mm averaged over December - February 2013-2022 was derived for the first time for Russia and the adjacent territory. Our results can serve the basis for selecting an astronomic site for a new large millimeter telescope within the Eurasian Sub-Millimeter and Millimeter Telescope Project.
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