Cloud Cover and Aurora Contamination at Dome A in 2017 from KLCAM

TL;DR

This study uses long-term all-sky camera data to statistically analyze cloud cover and aurora contamination at Dome A, Antarctica, demonstrating its high potential for astronomical observations despite frequent auroral activity.

Contribution

It provides the first extensive quantitative assessment of cloud cover and aurora contamination at Dome A using automated all-sky camera data from 2017.

Findings

Cloud cover was absent 83% of the time, indicating excellent observing conditions.

Aurorae were detected in nearly 45% of images, but can be mitigated with filters.

Dome A ranks highly among observatory sites for clear sky availability.

Abstract

Dome A in Antarctica has many characteristics that make it an excellent site for astronomical observations, from the optical to the terahertz. Quantitative site testing is still needed to confirm the site's properties. In this paper, we present a statistical analysis of cloud cover and aurora contamination from the Kunlun Cloud and Aurora Monitor (KLCAM). KLCAM is an automatic, unattended all-sky camera aiming for long-term monitoring of the usable observing time and optical sky background at Dome~A. It was installed at Dome~A in January 2017, worked through the austral winter, and collected over 47,000 images over 490 days. A semi-quantitative visual data analysis of cloud cover and auroral contamination was carried out by five individuals. The analysis shows that the night sky was free of cloud for 83 per cent of the time, which ranks Dome~A highly in a comparison with other observatory sites. Although aurorae were detected somewhere on an image for nearly 45 per cent of the time, the strongest auroral emission lines can be filtered out with customized filters.