On the Impact of ENSO Cycles and Climate Change on Telescope Sites in Northern Chile

TL;DR

This study analyzes how ENSO cycles and climate change affect observational conditions at northern Chilean telescope sites, revealing temperature rises and ENSO-related variations that impact astronomical observations.

Contribution

It provides new insights into the correlation between ENSO phases, climate change, and observational conditions at Chilean observatories, aiding long-term planning.

Findings

Temperature has risen over the last decade at all sites.

ENSO phases influence water vapour density and temperature.

El Niño correlates with drier conditions and higher temperatures.

Abstract

The Atacama desert stands as the most arid, non-polar, region on Earth and has accommodated a considerable portion of the world's ground-based astronomical observatories for an extended period. The comprehension of factors important for observational conditions in this region, and the potential alterations induced by the escalating impact of climate change, are, therefore, of the utmost significance. In this study, we conduct an analysis of the surface-level air temperature, water vapour density, and astronomical seeing at the European Southern Observatory (commonly known by its acronym, ESO) telescope sites in northern Chile. Our findings reveal a discernible rise in temperature across all sites during the last decade. Moreover, we establish a correlation between the air temperature and water vapour density with the El Ni\~no Southern Oscillation (ENSO) phases, wherein, the warm anomaly known as El Ni\~no (EN) corresponds to drier observing conditions, coupled with higher maximum daily temperatures favouring more challenging near-infrared observations. The outcomes of this investigation have potential implications for the enhancement of the long-term scheduling of observations at telescope sites in northern Chile, thereby aiding in better planning and allocation of resources for the astronomy community.