Thin and thick cloud top height retrieval algorithm with the Infrared Camera and LIDAR of the JEM-EUSO Space Mission

TL;DR

This paper presents a cloud top height retrieval algorithm using infrared camera and LIDAR data for the JEM-EUSO space mission, crucial for cosmic ray detection under cloudy conditions.

Contribution

It introduces a novel retrieval algorithm tailored for JEM-EUSO's atmospheric monitoring system to accurately determine cloud top heights.

Findings

The algorithm meets technical requirements for cloud top height reconstruction.

Cloud coverage impacts UHECR arrival direction determination.

The combined use of IR camera and LIDAR improves atmospheric measurements.

Abstract

The origin of cosmic rays have remained a mistery for more than a century. JEM-EUSO is a pioneer space-based telescope that will be located at the International Space Station (ISS) and its aim is to detect Ultra High Energy Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) by observing the atmosphere. Unlike ground-based telescopes, JEM-EUSO will observe from upwards, and therefore, for a properly UHECR reconstruction under cloudy conditions, a key element of JEM-EUSO is an Atmospheric Monitoring System (AMS). This AMS consists of a space qualified bi-spectral Infrared Camera, that will provide the cloud coverage and cloud top height in the JEM-EUSO Field of View (FoV) and a LIDAR, that will measure the atmospheric optical depth in the direction it has been shot. In this paper we will explain the effects of clouds for the determination of the UHECR arrival direction. Moreover, since the cloud top height retrieval is crucial to analyze the UHECR and EHECR events under cloudy conditions, the retrieval algorithm that fulfills the technical requierements of the Infrared Camera of JEM-EUSO to reconstruct the cloud top height is presently reported.