Exploring temporal and spatial variation of nitrous oxide flux using several years of peatland forest automatic chamber data

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S8. N2O budgets and seasonal contributions
Figure S1: Distribution of daily mean N2O flux in Chambers 1-6.The chamber-specific mean, median and 70 % percentile that was used to define high-flux days, are shown as vertical lines.
Figure S2: a) Daily mean N2O flux, b) soil surface temperature and temperature at 5 cm depth with highlighted freezing periods (soil surface temperature < 0 °C), c) soil moisture and water table level (WTL), and (d) daily precipitation from March 2016 to March 2017 in Chamber 2. The shown temporal dynamics of N2O flux were measured in a year with relatively wet summer and warm winter.Data are not gap-filled.Figure for Chamber 1 is presented in the manuscript (Fig. 6).

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Figure S3: a) Daily mean N2O flux, b) soil surface temperature and temperature at 5 cm depth with highlighted freezing periods (soil surface temperature < 0 °C), c) soil moisture and water table level (WTL), and (d) daily precipitation from March 2016 to March 2017 in Chamber 3. The shown temporal dynamics of N2O flux were measured in a year with relatively wet summer and warm winter.Data are not gap-filled.Figure for Chamber 1 is presented in the manuscript (Fig. 6).

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Figure S4: a) Daily mean N2O flux, b) soil surface temperature and temperature at 5 cm depth with highlighted freezing periods (soil surface temperature < 0 °C), c) soil moisture and water table level (WTL), and (d) daily precipitation from March 2016 to March 2017 in Chamber 4. The shown temporal dynamics of N2O flux were measured in a year with relatively wet summer and warm winter.Data are not gap-filled.Figure for Chamber 1 is presented in the manuscript (Fig. 6).

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Figure S5: a) Daily mean N2O flux, b) soil surface temperature and temperature at 5 cm depth with highlighted freezing periods (soil surface temperature < 0 °C), c) soil moisture and water table level (WTL), and (d) daily precipitation from March 2016 to March 2017 in Chamber 5.The shown temporal dynamics of N2O flux were measured in a year with relatively wet summer and warm winter.Data are not gap-filled.Figure for Chamber 1 is presented in the manuscript (Fig. 6).

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Figure S6: a) Daily mean N2O flux, b) soil surface temperature and temperature at 5 cm depth with highlighted freezing periods (soil surface temperature < 0 °C), c) soil moisture and water table level (WTL), and (d) daily precipitation from March 2016 to March 2017 in Chamber 6.The shown temporal dynamics of N2O flux were measured in a year with relatively wet summer and warm winter.Data are not gap-filled.Figure for Chamber 1 is presented in the manuscript (Fig. 6).

Figure S9 :
Figure S9: Response of predicted N2O flux to different environmental conditions for Chamber 3 visualized using Accumulated Local Effects (ALE).Figures illustrate how the predicted N2O flux values deviate from the mean predicted flux (ALE value= 0) along the gradients of a) soil moisture at 7 cm depth, b) soil moisture at 20 cm depth, c) water table level (WTL), d) precipitation, e) air temperature, f) soil surface temperature and g) soil temperature at 5 cm.ALE responses for unlagged and lagged variables (1-7 days) are included.Responses for chamber 1 are presented in the manuscript (Fig. 9).

Figure S10 :
Figure S10: Response of predicted N2O flux to different environmental conditions for Chamber 4 visualized using Accumulated Local Effects (ALE).Figures illustrate how the predicted N2O flux values deviate from the mean predicted flux (ALE value = 0) along the gradients of a) soil moisture at 7 cm depth, b) soil moisture at 20 cm depth, c) water table level (WTL), d) precipitation, e) air temperature, f) soil surface temperature and g) soil temperature at 5 cm.ALE responses for unlagged and lagged variables (1-7 days) are included.Responses for chamber 1 are presented in the manuscript (Fig. 9).

Figure S11 :
Figure S11: Response of predicted N2O flux to different environmental conditions for Chamber 5 visualized using Accumulated Local Effects (ALE).Figures illustrate how the predicted N2O flux values deviate from the mean predicted flux (ALE value = 0) along the gradients of a) soil moisture at 7 cm depth, b) soil moisture at 20 cm depth, c) water table level (WTL), d) precipitation, e) air temperature, f) soil surface temperature and g) soil temperature at 5 cm.ALE responses for unlagged and lagged variables (1-7 days) are included.Responses for chamber 1 are presented in the manuscript (Fig. 9).

Figure S12 :
Figure S12: Response of predicted N2O flux to different environmental conditions for Chamber 6 visualized using Accumulated Local Effects (ALE).Figures illustrate how the predicted N2O flux values deviate from the mean predicted flux (ALE value = 0) along the gradients of a) soil moisture at 7 cm depth, b) soil moisture at 20 cm depth, c) water table level (WTL), d) precipitation, e) air temperature, f) soil surface temperature and g) soil temperature at 5 cm.ALE responses for unlagged and lagged variables (1-7 days) are included.Responses for chamber 1 are presented in the manuscript (Fig. 9).

Figure S13 :
Figure S13: Measured and predicted N2O fluxes plotted against time.Figures (a-f) show predicted values from random forest with conditional inference trees separately for six chambers.Points are colored by the used data with out-of-bag (OOB) data, evaluation data within training period (30 % of first three years of data) and prediction in time data (outside model training period, fourth year of data) different types of evaluation datasets, and daily means of measured fluxes.