This study was conducted using a drone with advanced mobility to develop a unified sensor and communication system as a new platform for in situ atmospheric measurements. As a major cause of air pollution, particulate matter (PM) has been attracting attention globally. We developed a small, lightweight, simple, and cost-effective multi-sensor system for multiple measurements of atmospheric phenomena and related environmental information. For in situ local area measurements, we used a long-range wireless communication module with real-time monitoring and visualizing software applications. Moreover, we developed four prototype brackets with optimal assignment of sensors, devices, and a camera for mounting on a drone as a unified system platform. Results of calibration experiments, when compared to data from two upper-grade PM2.5 sensors, demonstrated that our sensor system followed the overall tendencies and changes. We obtained original datasets after conducting flight measurement experiments at three sites with differing surrounding environments. The experimentally obtained prediction results matched regional PM2.5 trends obtained using long short-term memory (LSTM) networks trained using the respective datasets.

https://www.mdpi.com/1424-8220/21/14/4881/pdf

Development of Drone-Mounted Multiple Sensing System with Advanced Mobility for In Situ Atmospheric Measurement: A Case Study Focusing on PM2.5 Local Distribution

Eastward airmass transport from the Asian summer monsoon (ASM) anticyclone in the upper troposphere and lower 20 stratosphere (UTLS) often involves eastward shedding vortices, which can cover most of the Japanese archipelago. We investigated the aerosol characteristics of these vortices by analysing data from two lidar systems in Japan, at Tsukuba (36.1°N, 140.1°E) and Fukuoka (33.55°N, 130.36°E), during the summer of 2018. We observed several events with enhanced particle signals at Tsukuba at 15.5-18 km altitude (at or above the local tropopause) during August-September 2018, with a backscattering ratio of ~1.10 and particle depolarization of ~5% (i.e., not spherical, but more spherical than ice crystals). These 25 particle characteristics may be consistent with those of solid aerosol particles, such as ammonium nitrate. Each event had a timescale of a few days. During the same study period, we also observed similar enhanced particle signals in the lower stratosphere at Fukuoka. The upper troposphere is often covered by cirrus clouds at both lidar sites. Backward trajectory calculations for these sites for days with enhanced particle signals in the lower stratosphere and days without indicate that the former airmasses originated within the ASM anticyclone, and the latter more from edge regions. Reanalysis carbon-monoxide 30 and satellite water-vapour data indicate that eastward shedding vortices were involved in the observed aerosol enhancements. Satellite aerosol data confirm that the period and latitudinal region were free from the direct influence of documented volcanic eruptions and high latitude forest fires. Our results indicate that the Asian Tropopause Aerosol Layer (ATAL) over the ASM 2 region extends east towards Japan in association with the eastward shedding vortices, and that lidar systems in Japan can detect at least the lower stratospheric portion of the ATAL during periods when the lower stratosphere is undisturbed by volcanic 35 eruptions and forest fires. The upper tropospheric portion of the ATAL is either depleted by tropospheric processes (convection and wet scavenging) during eastward transport or is obscured by much stronger cirrus cloud signals.

/pdf/lower-stratospheric-aerosol-measurements-in-eastward-4rmrz8tn2u.pdf

Lower-stratospheric aerosol measurements in eastward-shedding vortices over Japan from the Asian summer monsoon anticyclone during the summer of 2018

Capsule SummaryThis article introduces CUBE/Biak, a big-balloon air sampling campaign conducted in Indonesia, describing from the scientific scope in historical perspective through challenges in campaign coordination.

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/72228/1/bams-d-16-0289.1.pdf

Coordinated Upper-Troposphere-to-Stratosphere Balloon Experiment in Biak

Measuring techniques for concentration and stable isotopologues of CO2 in a terrestrial ecosystem: A review

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.

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

Balloon-borne tropospheric CO2 observations over the equatorial eastern and western Pacific

. A novel, practical observation system for measuring tropospheric carbon
dioxide ( CO2 ) concentrations using a non-dispersive infrared analyzer
carried by a small helium-filled balloon ( CO2 sonde) has been
developed for the first time. Vertical profiles of atmospheric CO2 can
be measured with a 240–400 m altitude resolution through regular onboard
calibrations using two different CO2 standard gases. The standard
deviations ( 1σ ) of the measured mole fractions in the laboratory
experiments using a vacuum chamber at a temperature of 298 K were
approximately 0.6 ppm at 1010 hPa and 1.2 ppm at 250 hPa. Two CO2 
vertical profile data obtained using the CO2 sondes, which were
launched on 31 January and 3 February 2011 at Moriya, were compared
with the chartered aircraft data on the same days and the commercial
aircraft data obtained by the Comprehensive Observation Network for TRace
gases by Airliner (COTRAIL) program on the same day (31 January) and 1 d before (2 February). The difference between the CO2 sonde data
and these four sets of in situ aircraft data (over the range of each balloon
altitude ±100  m) up to the altitude of 7 km was 0.6±1.2  ppm
(average ±1σ ). In field experiments, the CO2 sonde
detected an increase in CO2 concentration in an urban area and a
decrease in a forested area near the surface. The CO2 sonde was shown
to be a useful instrument for observing and monitoring the vertical profiles
of CO2 concentration in the troposphere.

/pdf/development-of-a-balloon-borne-instrument-for-co-2-vertical-gepyok5m3p.pdf

Development of a balloon-borne instrument for CO 2 vertical profile observations in the troposphere

We conducted continuous, high time-resolution measurements of CO2 and water vapour isotopologues ((16)O(12)C(16)O, (16)O(13)C(16)O and (18)O(12)C(16)O for CO2, and H2(18)O for water vapour) in a red pine forest at the foot of Mt. Fuji for 9 days from the end of July 2010 using in situ absorption laser spectroscopy. The δ(18)O values in water vapour were estimated using the δ(2)H-δ(18)O relationship. At a scale of several days, the temporal variations in δ(18)O-CO2 and δ(18)O-H2O are similar. The orders of the daily Keeling plots are almost identical. A possible reason for the similar behaviour of δ(18)O-CO2 and δ(18)O-H2O is considered to be that the air masses with different water vapour isotopic ratios moved into the forest, and changed the atmosphere of the forest. A significant correlation was observed between δ(18)O-CO2 and δ(13)C-CO2 values at nighttime (r(2)≈0.9) due to mixing between soil (and/or leaf) respiration and tropospheric CO2. The ratios of the discrimination coefficients (Δa/Δ) for oxygen (Δa) and carbon (Δ) isotopes during photosynthesis were estimated in the range of 0.7-1.2 from the daytime correlations between δ(18)O-CO2 and δ(13)C-CO2 values.

Mai Ouchi

Papers

Balloon-borne tropospheric CO2 observations over the equatorial eastern and western Pacific

Development of a balloon-borne instrument for CO 2 vertical profile observations in the troposphere

In situ measurement of CO2 and water vapour isotopic compositions at a forest site using mid-infrared laser absorption spectroscopy.