Fig. 10

a Scatter plot of the hourly CO₂ flux in accordance with the temperature for non-vegetation urban (gray) and vegetation (red) sites from 2017 to 2018. The black solid line represents the median value of the CO₂ flux of all urban sites except for the vegetation site; the red solid line represents the CO₂ flux of the vegetation site. The gray vertical lines represent 18 and 24 ℃ (solid and dashed, respectively), which are threshold temperatures for non-vegetated and vegetated sites, respectively. b The same as a but with a narrower y-axis range.