Fig. 1.
Timeseries of gas concentrations and meteorological conditions, taken at 11 m above the ground surface (1 m above the canopy) between 13 May and 5 June 2007. The orange shaded area indicates the pre-irrigation period (13–21 May), while the blue shaded area shows the post-irrigation period (26 May–5 June). The gray shaded area (20 May at noon to 22 May at noon) represents the period with ‘northerly’ winds.
Fig. 2.
Mean diurnal evolution of (a) O3, (b) NO, (c) NO2, (d) total VOC mixing ratios, (e) wind speed, (f) wind direction, (g) temperature and (h) specific humidity at 11 m above the ground (1 m above the canopy) for the pre-(orange) and post-(blue) irrigation periods. The vertical shaded areas indicate sunrise and sunset times for Davis, including both the ‘Northerly winds’, pre- and post-irrigation periods. The shaded area represents the standard error of the mean.
Fig. 3.
Vertical profiles of (a) O3, (b), NO, (c) NO2, (d) total VOC mixing ratios, (e) mean wind speed, (f) wind direction, (g) temperature, and (g) specific humidity, averaged between 10:00 and 17:00 LT for the ‘Northerly winds’, pre-(orange) and post-(blue) irrigation periods. The green dashed line indicated the bottom of the canopy, the black dashed line indicates the canopy crown and the red line indicates the approximate height of the roughness sublayer. The shaded areas are the standard error of the means.
Fig. 4.
Observed and calculated vertical profiles of (a) friction velocity (b) vertical velocity standard deviation () and, (c) sensible heat, averaged between 10:00 and 17:00 LT pre-(orange) and post-(blue) irrigation periods. The vertical velocity standard deviation, as calculated from Raupach (1989a) for neutral conditions (solid line), is normalized by the locally calculated from EC observations pre and post irrigation. The shaded area represents the standard deviation of the mean. See Fig 3 for a description of the horizontal lines.
Fig. 5.
Mean vertical profiles of eddy diffusivity of (a) momentum, and (b) heat, averaged between 10:00 and 17:00 LT pre-(orange) and post-(blue) irrigation periods. The shaded area represents the standard deviation of the mean. See Fig. 3 for a description of the horizontal lines.
Fig. 6.
Mean vertical profile of fluxes of (a, d) O3, (b, e) NO and (c, f) NO2 calculated via the K c OBS, MOST, MOST + RSL and ILNF methods, averaged for the pre-and post-irrigation periods (pre irrigation top row, post irrigation bottom row), between 10:00 and 17:00 LT. See Fig. 3 for a description of the shaded area and horizontal lines.
Fig. 7.
Vertical profile of the deposition velocity of (a, b) O3, (c, d) NO and (e, f) NO2 calculated via the K c OBS, MOST, MOST + RSL and ILNF methods, averaged for the pre-and post-irrigation periods, between 10:00 to 17:00 LT. See Fig. 3 for a description of the shaded area and horizontal lines.
Fig. 8.
Vertical profile of (a) τ (b) τNO and (c) τt for the pre-and post-irrigation periods, averaged between 10:00 to 17:00 LT. Please note that τ is in minutes, while τNO and τt are in seconds. See Fig. 3 for a explanation of the three horizontal dashed lines.
Fig. 9.
Vertical profile of (a) evaporative fraction and, (b) water vapour deficit averaged between 10- 17 LT for the pre and post irrigation periods. See Figure 3 for an explanation of the horizontal lines.
Table 1.
Ratio of estimated and observed and sensible heat.
[i] Mean estimates of and sensible heat were calculated by the MOST and MOST + RSL methods at 1.25 hc within 10-17 LT for the pre- and post-irrigation periods; Δ represents the resulting difference between the ratio estimate of MOST + RSL and MOST values with respect to the KC OBS method in percentage.
Table 2.
Ratio of mean fluxes calculated by MOST or MOST + RSL compared to fluxes calculated by the KC OBS method at 1.25 hc for the three main species, averaged within 10–17 LT.