Development of a balloon-borne instrument for CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; vertical profile observations in the troposphere

Mai Ouchi,Toshinobu Machida,Kensaku Shimizu,Osamu Uchino,Takehiko Sawada,Ryoichi Imasu,Isamu Morino,Yousuke Sawa,Hidekazu Matsueda,Tomoki Nakayama,Tomoaki Tanaka,Yutaka Matsumi

doi:10.5194/amt-12-5639-2019

Abstract

Abstract. 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.

Highlights

Atmospheric carbon dioxide (CO2) is one of the most important anthropogenic greenhouse gases for global warming
Atmospheric CO2 is measured by ground-based stations and ships using the flask sampling and continuous instrument methods such as nondispersive infrared absorption (NDIR) (Tanaka et al, 1983; Hodgkinson et al, 2013) and cavity ring-down spectroscopy (CRDS) (Winderlich et al, 2010)
The outlet port of the NDIR system was connected to the commercial CO2 instrument (LICOR, LI-840A) as a standard device, and the two instruments simultaneously measure the sample gas at 1010 hPa

Summary

Introduction

Atmospheric carbon dioxide (CO2) is one of the most important anthropogenic greenhouse gases for global warming. M. Ouchi et al.: Development of a balloon-borne instrument for CO2 vertical profile observations direct solar spectra in the near-infrared spectral region (Total Carbon Column Observing Network, TCCON) is used to observe the column-averaged mole fraction of CO2 in dry air (total column XCO2) (Wunch et al, 2011). Ouchi et al.: Development of a balloon-borne instrument for CO2 vertical profile observations direct solar spectra in the near-infrared spectral region (Total Carbon Column Observing Network, TCCON) is used to observe the column-averaged mole fraction of CO2 in dry air (total column XCO2) (Wunch et al, 2011) These observations have provided extensive information regarding the distribution and temporal variation of CO2 in the atmosphere (Pales and Keeling, 1965; Conway et al, 1988; Komhyr et al, 1989; Tans et al, 1989; Conway et al, 1994). More atmospheric CO2 measurements are needed to reduce the uncertainties in CO2 flux estimation using an inverse modeling

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