International Journal of Geosciences, 2021, 12, 233-252 https://www.scirp.org/journal/ijg ISSN Online: 2156-8367 ISSN Print: 2156-8359 DOI: 10.4236/ijg.2021.123014 Mar. 22, 2021 233 International Journal of Geosciences Using Longwave Infrared Hyperspectral Imaging for a Quantitative Atmospheric Tracer Monitoring in Outdoor Environments Eitan Hirsch, Eyal Agassi, Alon Manor Environmental Physics Department, Environmental Sciences Division, Israel Institute for Biological Research, Ness Ziona, Israel Abstract Quantitative real-time retrieval of concentration-lengths (CL) through ga- seous plumes is an important tool for environmental monitoring, enabling remote monitoring of emissions from industrial facilities and risk assessment in scenarios of toxic gas releases. The adoption of LWIR (Long Wave Infra- Red) hyperspectral imaging as a leading technique for remote gas plume de- tection paved the way for an introduction of a precise CL estimation and two-dimensional (2D) mapping. A novel methodology for evaluating and characterizing the performance of a retrieval algorithm is presented. The al- gorithm utilizes state-of-the-art retrieved hyperspectral 2D mapping and is applied on a series of localized atmospheric tracer gas (SF 6 ) releases in moni- tored environmental conditions. The retrieved CL distributions are compared to a numeric atmospheric T&D (Transport and Diffusion) model. Satisfactory agreement between retrieved and simulated CL prediction is manifested, and the uncertainty involved is quantified. Possible sources for the remained dis- crepancies between retrieved and simulated CL values are characterized, and methods to minimize them are discussed. Keywords Hyperspectral, Infrared, Gaseous Plumes, Concentration-Length, Quantification, Atmospheric Transport and Diffusion (T&D) Model 1. Introduction Standoff sensing of hazardous gaseous plumes is a well-known technique. Some of the most common applications are detection and identification of CWAs and TICs (Chemical War Agents and Toxic Industrial Compounds), detection of How to cite this paper: Hirsch, E., Agassi, E. and Manor, A. (2021) Using Longwave Infrared Hyperspectral Imaging for a Quan- titative Atmospheric Tracer Monitoring in Outdoor Environments. International Jour- nal of Geosciences, 12, 233-252. https://doi.org/10.4236/ijg.2021.123014 Received: January 29, 2021 Accepted: March 19, 2021 Published: March 22, 2021 Copyright © 2021 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access