Utility of silicone filtering for diffusive model CO₂ sensors in field experiments

Figures & data

Fig. 1 Schematic of laboratory experiment.

Fig. 2 (a) Time variations of given C _soil(t) (black solid line) by eq. (14) and C _{det_sil(t)} with Q _sil=2.01×10⁻¹⁰ and 10.04×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ (grey dashed line and black dashed line, respectively); (b) Time variation of the gap of C _{soil_sil(t)} from given C _soil(t), using Q _sil=2.01×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ and eq. (13). A negative value means that C _{soil_sil(t)} is smaller than the given C _soil(t). Five lines for five logging intervals (10 s, 1 min, 10 min, 30 min and 60 min) are shown; and (c) Time variation of the gap of C _{soil_sil(t)} from given C _soil(t), using Q _sil=10.04×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ and eq. (13). Lines are depicted as (b).

Fig. 3 (a) Time variations of given C _soil(t) (black solid line) by eq. (15) and C _{det_sil(t)} with Q _sil=2.01×10⁻¹⁰ and 10.04×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ (grey dashed line and black dashed line, respectively); (b) Time variation of the gap of C _{soil_sil(t)} from given C _soil(t), using Q _sil=2.01×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ and eq. (13); (c) Time variation of the gap of C _{soil_sil(t)} from given C _soil(t), using Q _sil=10.04×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹ and eq. (13). Lines are depicted as Fig. 2.

Fig. 4 (a) Time variation of C _{det_cel(t)} (solid line) and C _{det_sil(t)} (dashed line) responding to CO₂ concentration in the container. Black and grey arrows respectively indicate the time to infuse the N₂ and air-balanced CO₂ standard (1930 ppmv) gases; and (b) time variation of C _{soil_sil(t)} (grey line), C _{soil_sil(t)} calculated from 60-data (10 min) moving averages of C _{det_sil(t)} (dark grey line) and C _{soil_cel(t)} (black line). These variations are calculated with Q _sil=11.5×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹. Black solid lines do not denote the moving average of the grey solid line. C _{soil_sil(t)} and C _{soil_cel(t)} are calculated with eq. (13).

Fig. 5 Observed diurnal variations of CO₂ concentration in the field experiment. (a) C _{det_cel(t)} (solid line) and C _{det_sil(t)} (dashed line); (b) C _{soil_cel(t)} (black line), C _{soil_sil(t)} (grey line) and C _{soil_sil(t)} calculated from six-data (60 min) moving averages of C _{det_sil(t)} (dark grey line). These variations are calculated with Q _sil=11.5×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹. Black solid lines do not show the moving average of the grey solid line.

Fig. 6 Observed time variations of CO₂ concentration after rainfall in the field experiment. (a) C _{det_cel(t)} (solid line) and C _{det_sil(t)} (dashed line); and (b) C _{soil_cel(t)} (black line), C _{soil_sil(t)} (grey line) and C _{soil_sil(t)} calculated from 6-data (60 min) moving averages of C _{det_sil(t)} (dark grey line). These variations are calculated with Q _sil=11.5×10⁻¹⁰ mol m m⁻² s⁻¹ kPa⁻¹. Black solid lines do not show the moving average of the grey solid line.