An Evaluation of Calibration Techniques for In Situ Carbon Dioxide Measurements Using a Programmable Portable Trace-Gas Measuring System
| العنوان: | An Evaluation of Calibration Techniques for In Situ Carbon Dioxide Measurements Using a Programmable Portable Trace-Gas Measuring System |
|---|---|
| المؤلفون: | Stephen P. Oncley, Sean P. Burns, Johannes Ruppert, Britton B. Stephens, Anthony C. Delany, Joel Schröter, Jielun Sun, S. R. Semmer, Gordon D. Maclean |
| المصدر: | Journal of Atmospheric and Oceanic Technology. 26:291-316 |
| بيانات النشر: | American Meteorological Society, 2009. |
| سنة النشر: | 2009 |
| مصطلحات موضوعية: | Hydrology, Atmospheric Science, Nonlinear system, Reproducibility, System of measurement, Calibration, Environmental science, Ocean Engineering, Sensitivity (control systems), Mole fraction, Standard deviation, Remote sensing, Trace gas |
| الوصف: | The construction and deployment of a portable trace-gas measurement system (TGaMS) is described. The air-collection system (dubbed HYDRA) collects air samples from 18 different locations and was connected to either one or two LI-COR LI-7000 gas analyzers to measure CO2. An in situ “field calibration” method, that uses four calibration gases with an uncertainty on the order of ±0.1 μmol mol−1 relative to the WMO CO2 mole fraction scale, revealed CO2 output from the LI-7000 had a slightly nonlinear relationship relative to the CO2 concentration of the calibration gases. The sensitivity of the field-calibrated CO2 to different forms of the field-calibration equation is investigated. To evaluate TGaMS performance, CO2 from collocated inlets, portable gas cylinders, and nearby independent CO2 instruments are compared. Results are as follows: 1) CO2 measurements from HYDRA multiple inlets are feasible with a reproducibility of ±0.4 μmol mol−1 (based on the standard deviation of the CO2 difference between collocated inlets when HYDRA was operating with two LI-7000s); 2) CO2 differences among the various field-calibration equations were on the order of ±0.3 μmol mol−1; and 3) comparison of midday hourly CO2 measurements at 30 m AGL between TGaMS and an independent high-accuracy CO2 measurement system (within 300 m of TGaMS) had a median difference and standard deviation of 0.04 ± 0.81 μmol mol−1 over two months. |
| تدمد: | 1520-0426 0739-0572 |
| DOI: | 10.1175/2008jtecha1080.1 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::f23c190b2445534519341bc84cce9cf1 https://doi.org/10.1175/2008jtecha1080.1 |
| رقم الانضمام: | edsair.doi...........f23c190b2445534519341bc84cce9cf1 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15200426 07390572 |
|---|---|
| DOI: | 10.1175/2008jtecha1080.1 |