DOC in Throughfall and Canopy leachate
The mean DOC concentration in TF was 13.96 (± 8.12)
mg.L-1 for the studied hillslope. The observed
variation between events substantially reflects the variations found in
the BP (r = 0.9434) (figure 5). For CL data, there is a reduction in the
correlation to BP DOC (r = 0.6332) and the significance of variation
between events, with a posteriori variant group alteration.
BP DOC exerted a strong influence on field-values (TF) since its
start-value for through-canopy increases. The TF DOC showed a moderate
and significant linear model in inversely proportional relationship to
the precipitation intensity (Table 3). The time range of antecedent
rainfall which on showed best explanatory capacity was 15-days, followed
by the 10-days range, both presenting significant linear models with an
inversely proportional relationship.
Combined by multiple regression, the two independent variables with best
individual adjustments (RfI and 15-days AcR) showed a high explanatory
capacity of TF DOC concentration through a significant linear model,
which increase considerably when the concentration of the previous
compartment (BP DOC) was added to the model.
For the CL data, the modulation of the values increased the similarity
inversely proportional to the 15-days AcR and the rainfall intensity,
demonstrating a more pronounced pre-wash and dilution effects
(respectively) for the dry deposition than was observed in wet
deposition (BP DOC). The 30-days range for antecedent rain proved not to
be relevant, as observed for TF.
Spatial analysis indicated that variability remains high within each
slope position, resulting in similar averages and a non-significant
variation between areas in a hillslope-scale analysis for both TF and CL
data (figure 6). The spatial heterogeneity is extremely punctual,
reflecting local details of rain interception, washing and crossing
processes.