The atmospheric transparency measured with a LIDAR system at the Telescope Array experiment

TL;DR

This study used a LIDAR system to measure atmospheric transparency at the Telescope Array site over two years, providing data crucial for understanding atmospheric effects on cosmic ray observations.

Contribution

It presents the first detailed measurement of aerosol extinction and optical depth at this site, and develops an aerosol distribution model for cosmic ray fluorescence analysis.

Findings

Aerosol extinction coefficient at ground level: 0.033 km^{-1}

Vertical aerosol optical depth at 5 km: 0.035

Developed an aerosol distribution model for atmospheric attenuation

Abstract

An atmospheric transparency was measured using a LIDAR with a pulsed UV laser (355nm) at the observation site of Telescope Array in Utah, USA. The measurement at night for two years in $2007\sim 2009$ revealed that the extinction coefficient by aerosol at the ground level is $0.033^{+0.016}_{-0.012} \rm km^{-1}$ and the vertical aerosol optical depth at 5km above the ground is $0.035^{+0.019}_{-0.013}$. A model of the altitudinal aerosol distribution was built based on these measurements for the analysis of atmospheric attenuation of the fluorescence light generated by ultra high energy cosmic rays.