Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe, and Xinglong in North China
<p>Atmospheric <span class="inline-formula">CO<sub>2</sub></span> mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using Picarro G2301 cavity ring-down spectroscopy instruments. The measurement system is described com...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/11741/2021/acp-21-11741-2021.pdf |
| Summary: | <p>Atmospheric <span class="inline-formula">CO<sub>2</sub></span> mole fractions are observed at Beijing (BJ), Xianghe
(XH), and Xinglong (XL) in North China using Picarro G2301 cavity ring-down
spectroscopy instruments. The measurement system is described comprehensively
for the first time. The geographical distances among these three sites are within
200 <span class="inline-formula">km</span>, but they have very different surrounding environments: BJ is
inside the megacity; XH is in the suburban area; XL is in the countryside on a
mountain. The mean and standard deviation of <span class="inline-formula">CO<sub>2</sub></span> mole fractions at BJ,
XH, and XL between October 2018 and September 2019 are
<span class="inline-formula">448.4±12.8</span>, <span class="inline-formula">436.0±9.2</span>, and
<span class="inline-formula">420.6±8.2</span> <span class="inline-formula">ppm</span>, respectively. The seasonal variations of
<span class="inline-formula">CO<sub>2</sub></span> at these three sites are similar, with a maximum in winter and a
minimum in summer, which is dominated by the terrestrial ecosystem. However,
the seasonal variations of <span class="inline-formula">CO<sub>2</sub></span> at BJ and XH are more affected by human
activities as compared to XL. Using <span class="inline-formula">CO<sub>2</sub></span> at XL as the background,
<span class="inline-formula">CO<sub>2</sub></span> enhancements are observed simultaneously at BJ and XH. The diurnal
variations of <span class="inline-formula">CO<sub>2</sub></span> are driven by the boundary layer height,
photosynthesis, and human activities at BJ, XH, and XL. We also compare the
<span class="inline-formula">CO<sub>2</sub></span> measurements at BJ, XH, and XL with five urban sites in the USA, and it is
found that the <span class="inline-formula">CO<sub>2</sub></span> mean concentration at BJ is the largest. Moreover,
we address the impact of the wind on the <span class="inline-formula">CO<sub>2</sub></span> mole fractions at BJ and
XL. This study provides an insight into the spatial and temporal variations of
<span class="inline-formula">CO<sub>2</sub></span> mole fractions in North China.</p> |
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| ISSN: | 1680-7316 1680-7324 |