## 3 Results
### Seasonal, Daily, and Hourly Variations  
The micrometeorological measurement was performed from summer to winter (19 July 2019 to 23 July 2020). The subsoil measurement system of CO\({}_{2}\) using FTIR started on 23 July 2019, sustaining approximately two days of continuous measurement on each visit due to power supply limitation. Meanwhile, the auxiliaries data both from the subsoil monitoring system and lattice tower which include soil temperature at various depth (Figure 5a), air pressure at different depth (Figure 5b), Soil Water Content (Figure 5c), precipitation (Figure 5c), CO\({}_{2}\) molar fraction at 1 and 6 m depth (Figure 5d), and friction velocity (Figure 5d) were measured continuously and simultaneously during monitoring periods. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{CO\({}_{2}\) (100 to 60,000 ppm)} & \multicolumn{3}{c}{**Residuals by Section (ppm)**} & \multicolumn{3}{c}{**Residual Standard Error (ppm)**} & **Adjusted R\({}^{2}\)** \\ \cline{2-7}  & Min & 1Q & Median & 3Q & Max & \\ \cline{2-7}  & \(-\)81.94 & \(-\)18.07 & \(-\)3.33 & 7.58 & 109.58 & 57.84 on 15 degrees of freedom & 1 \\ \hline \multicolumn{7}{c}{**Residual Standard Error (ppm)**} \\ \cline{2-7}  & 1 & 2 & 3 & 4 & 5 & \\ \cline{2-7}  & \(-\)5.97 & 21.23 & \(-\)19.23 & 7.76 & \(-\)3.4 & 17.62 on 3 degrees of freedom & 0.9999 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The residual error and the adjusted R\({}^{2}\) of the two polynomial model fitting of CO\({}_{2}\) and CH\({}_{4}\) (Resolution: 1 cm\({}^{-1}\)). Figure 5: Time-series graph showing the daily max of temperature at various depth (35 m, 0 m, \(-\)1 m, and \(-\)6 m) (**a**), the daily average of atmospheric pressure measured at 35 and 0 m, and the soil-air pressure measured at 6m depth (**b**), soil water content (SWC) (**c**), precipitation (**c**), CO\({}_{2}\) molar fraction (**yc**) at 1 and 6 m depth (**d**), and friction velocity (**d**). Overall, the atmospheric temperature ranged from \(-2\)\({}^{\circ}\)C to 38 \({}^{\circ}\)C (Figure 5a). The atmospheric temperature at 35 m shows a clear seasonal pattern where it was highest in summer 2019 at 38 \({}^{\circ}\)C, and it started to decline significantly during the Autumn. The Temperature variations at \(-1\) m and \(-6\) m were found at 14.98-19.80 \({}^{\circ}\)C and 9.73-11.13 \({}^{\circ}\)C, respectively. The diurnal atmospheric temperature variations are also considered more significant than soil temperature (0 m), subsoil temperature at \(-1\) m, and \(-6\) m.  
Even though there is a small difference in magnitude between the atmospheric pressure (35 m) and soil-air pressure (\(-6\) m) around 150 mbar, the general pattern seasonally over the monitoring periods is similar. Although small differences in magnitude were identified, the daily average of atmospheric pressure (35 m and 0 m) and soil-air pressure (\(-6\) m) shows a visually similar general pattern (Figure 5b). The atmospheric pressure at 35 m high indicates the lowest value, followed by soil air pressure at 6 m depth and soil interface (0 m) consecutively. The atmospheric pressure ranged from 0.933 to 0.998 at 35 m, 0.971 to 1.026 bar at 0 m, and 0.964 to 1.021 at \(-6\) m. It is clear that the highest atmospheric pressure (35 m) was found in Summer and the lowest in winter. The daily average of soil water content (Figure 5c) demonstrates a clear correlation with precipitation and anticorrelation with temperature and very pronounced seasonal variation. The average lowest SWC occurred in summer at around 10%, with some spikes due to the rainfall episodes. However, this increase in SWC of approximately 20% lasted only around five days after the rainfall. During the winter, the average SWC remained high at around 40% due to more frequent rainfall and low temperatures. A slight reduction of SWC by approximately 5% was identified from January to February due to less frequent rain events.