The impact of weather on ALMA operations

ALMA, located in the Chilean Altiplano at the Atacama Desert, faces significant challenges due to extreme weather conditions and seasonal and daily variations. Besides the impact of winds and PWV, the observatory is subject to weather phenomena associated with ENSO, including the Altiplanic winter during the southern hemisphere summer and the Chilean winter during the winter hemisphere. These seasonal variations introduce additional complexities for observatory operations.

This research characterizes the past ten years' weather and climate at the Atacama Large Millimeter/submillimeter Array (ALMA) observatory and their impact on radio astronomy operations. The characterization considers the El Niño-Southern Oscillation (ENSO), and its impact on the intensity of both Altiplanic and Chilean winter. The methodology involves the analysis of in-situ weather station data, numerical forecasts, and considerations for optimizing observatory operations.

In particular, we examine the role of precipitable water vapor and phase rms as crucial factors affecting radio astronomy observations.

In conclusion, this study emphasizes the impact on operations due to weather variables and the climatology of Altiplano. Considering ENSO, Altiplanic, and Chilean winters, the changes in Phase RMS and the amount of precipitable water vapor add further insights into the complexities faced by ALMA in optimizing observatory operations. The findings from this study can aid in developing strategies to mitigate the effects of daily and seasonal variations of weather variables, ensuring optimal performance and data quality in radio astronomy observations at the ALMA observatory.