| Autor: |
Deutscher, Nicholas M., Naylor, Travis A., Caldow, Christopher G. R., McDougall, Hamish L., Carter, Alex G., Griffith, David W. T. |
| Jazyk: |
angličtina |
| Rok vydání: |
2020 |
| ISSN: |
1867-8548 |
| Popis: |
Open-path measurements of atmospheric composition provide spatial averages of trace gases that are less sensitive to small-scale variations and the effects of meteorology. In this study we introduce improvements to Open-Path Near Infrared (OP-NIR) Fourier Transform Spectrometer measurements of CO2 and CH4. In an extended field trial, the OP-NIR achieved measurement repeatability six times better for CO2 (0.26 ppm) and ten times better for CH4 (2.0 ppb) over a 1.55 km one-way path than its predecessor. The measurement repeatability was independent of pathlength up to 1.55 km, the longest distance tested. Comparisons to co-located in situ measurements under well-mixed conditions characterise biases of 2.67 % for CO2 and 2.46 % for CH4 relative to in situ measurements calibrated to World Meteorological Organisation – Global Atmosphere Watch (WMO-GAW) scales. The OP-NIR measurements can detect signals due to local photosynthesis and respiration, and local point sources of CH4. The OP-NIR is well-suited for deployment in urban or rural settings to quantify atmospheric composition on kilometre scales. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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