Korean Journal of Agricultural and Forest Meteorology (한국농림기상학회지)

Korean Society of Agricultural and Forest Meteorology (한국농림기상학회)
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Variability of Calibration Factors for Open-Path CO2/H2O Infrared Gas Analyzer and Its Effect on Long-Term Flux Measurement

개회로 CO2/H2O 적외선 기체 분석기 보정 인자의 변동성과 장기 플럭스 관측에 미치는 영향

  • Choi, Tae-jin (Department of Atmospheric Sciences and Global Environment Laboratory, Yonsei University) ;
  • Yun, Jin-I. (Department of Ecosystem and Engineering, Kyung Hee University) ;
  • Lim, Jong-Hwan (Division of Forest Ecology, Korea Forest Research Institute) ;
  • Park, Eun-Woo (National Instrumentation Center for Environmental Management, Seoul National University) ;
  • Kim, Joon (Department of Atmospheric Sciences and Global Environment Laboratory, Yonsei University)
  • 최태진 (연세대학교 대기과학과 ＆ 지구환경연구소) ;
  • 윤진일 (경희대학교 생태시스템 공학과) ;
  • 임종환 (임업연구원 산림생태과) ;
  • 박은우 (서울대학교 농업과학공동기기센터) ;
  • 김준 (연세대학교 대기과학과 ＆ 지구환경연구소)
  • Published : 2002.06.01
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Abstract

Calibration experiments were executed to document pertinent calibration methods for open-path infrared gas analyzer (OP-2) in field operations and to quantify their performance characteristics in continuous long-term flux measurements. Based on our results, we concluded: (1) flow rate of 2.0 L min$^{-1}$ can be used for calibration instead of the recommended 0.5 L min$^{-1}$ . Such faster flow rate brings the sampled air in the calibration hood at equilibrium within 5 min for $CO_2$ and 10 min for $H_2O$; (2) after reaching equilibrium, two-minute average sampling for related variables per each concentration may be sufficient; (3) use of four concentration is needed to derive the nonlinear calibration equation for water vapor with 1% uncertainty of flux measurement; and (4) the resultant calibration interval for OP-2 for both $CO_2$ and $H_2O$ is approximately one month.

Keywords

References

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