Measuring Regional Atmospheric CO2 Concentrations in the Lower Troposphere with a Non-Dispersive Infrared Analyzer Mounted on a UAV, Ogata Village, Akita, Japan.

We have developed a simple measuring system prototype that uses an unmanned aerial vehicle (UAV) and a non-dispersive infrared (NDIR) analyzer to detect regional carbon dioxide (CO₂) concentrations and obtain vertical CO₂ distributions. Here, we report CO₂ measurement results for the lower troposphere above Ogata Village, Akita Prefecture, Japan (about 40° N, 140° E, approximately −1 m amsl), obtained with this UAV system. The actual flight observations were conducted at 500, 400, 300, 200, 100, and 10 m above the ground, at least once a month during the daytime from February 2018 to February 2019. The raw CO₂ values from the NDIR were calibrated by two different CO₂ standard gases and high-purity nitrogen (N₂) gas (as a CO₂ zero gas; 0 ppm). During the observation period, the maximum CO₂ concentration was measured in February 2019 and the minimum in August 2018. In all seasons, CO₂ concentrations became higher as the flight altitude was increased. The monthly pattern of observed CO₂ changes is similar to that generally observed in the Northern Hemisphere as well as to surface CO₂ changes simulated by an atmospheric transport model of the Japan Meteorological Agency. It is highly probable that these changes reflect the vegetation distribution around the study area. [ABSTRACT FROM AUTHOR]