Analysis of the distribution of precipitable water vapor in the Chajnantor area

TL;DR

This study provides a comprehensive long-term analysis of precipitable water vapor in the Chajnantor region, crucial for astronomical observations, by integrating diverse datasets and validating measurement conversion methods.

Contribution

It offers the most extensive dataset to date for the region, compares atmospheric conditions across sites, and validates a method to convert radiometer data to PWV.

Findings

Average PWV ratio of 0.68 between Cerro Chajnantor and Llano

Validated method for converting atmospheric opacity to PWV

Rich dataset spanning 2005-2014 with multiple instruments

Abstract

In this work, we present results from a long-term precipitable water vapor (PWV) study in the Chajnantor area, in northern Chile. Data from several instruments located at relevant sites for sub-millimeter and mid-infrared astronomy were processed to obtain relations between the atmospheric conditions among the sites. The data used for this study can be considered the richest dataset to date, because of the geographical sampling of the region, including sites at different altitudes, a time span from 2005 to 2014, and the different techniques and instruments used for the measurements. We validate a method to convert atmospheric opacity from 350 $\mu$m tipper radiometers to PWV. An average of 0.68 PWV ratio between Cerro Chajnantor and Llano of Chajnantor was found.