The Atmospheric Monitoring System of the JEM-EUSO space mission

Abstract

Abstract. An Atmospheric Monitoring System (AMS) is a mandatory and key device of a space-based mission which aims to detect Ultra-High Energy Cosmic Rays (UHECR) and Extremely-High Energy Cosmic Rays (EHECR) from Space. JEM-EUSO has a dedicated atmospheric monitoring system that plays a fundamental role in our understanding of the atmospheric conditions in the Field of View (FoV) of the telescope. Our AMS consists of a very challenging space infrared camera and a LIDAR device, that are being fully designed with space qualification to fulfil the scientific requirements of this space mission. The AMS will provide information of the cloud cover in the FoV of JEM-EUSO, as well as measurements of the cloud top altitudes with an accuracy of 500 m and the optical depth profile of the atmosphere transmittance in the direction of each air shower with an accuracy of 0.15 degree and a resolution of 500 m. This will ensure that the energy of the primary UHECR and the depth of maximum development of the EAS ( Extensive Air Shower) are measured with an accuracy better than 30% primary energy and 120 g/cm 2 depth of maximum development for EAS occurring either in clear sky or with the EAS depth of maximum development above optically thick cloud layers. Moreover a very novel radiometric retrieval technique considering the LIDAR shots as calibration points, that seems to be the most promising retrieval algorithm is under development to infer the Cloud Top Height (CTH) of all kind of clouds, thick and thin clouds in the FoV of the JEM-EUSO space telescope.

The Atmospheric Science of JEM-EUSO

“…To fully monitor the atmosphere and to retrieve the cloud coverage and cloud top height in the EUSO FoV, an Atmospheric Monitoring System (AMS) will be part of the instrument [2,3]. The AMS is also needed to estimate the effective UHECR & EHECR exposure of the telescope and for the reconstruction of main parameters of the UHECR & EHECR events under cloudy conditions.…”

The Spanish Infrared Camera onboard the EUSO-Balloon (CNES) flight on August 24, 2014

“…JEM-EUSO will use the atmosphere as a detector [3]. Therefore, information about properties of the Earth's atmosphere and presence of clouds is highly needed [4]. The telescope includes an Atmospheric Monitoring system (AMS) which provides information on the clouds and aerosol distribution, as well as their optical properties within the telescope Field of View (FoV) [5,6].…”

Implementation in OFFline of the reconstruction code of the Infrared Camera of the JEM-EUSO Space Mission.

“…Due to the variable nature of the atmosphere an on-time Atmospheric Monitoring (AM) system is one of the most important tasks, and a key element of the space-based mission. Such a dedicated on-site AM system has been designed for the understanding of the atmospheric conditions in the Field of View (FoV) of the main telescope [4,5,6,7]. The EUSO AM system consists of a Long Wave Infrared (LWIR) camera [8,9] and a LIDAR.…”