Figure 9 Correlation of
parameter α of PDC and FFDC of 224 catchments with catchment
physical characteristics CIM .
There is a relationship between parameter α of PDC and FFDC of 224
catchments and catchment physical characteristics CIM (Figure
9 ). From Figure 9 (b), it can be seen that there is a
significant correlation (negative correlation) between the seasonal
index - Concentration ratio index based on monthly precipitation
(CIM ) and α of FFDC, but this correlation is not as tight
as Pmax*αp . In order to analyze
the mechanism by which CIM affects the shape of the PDC curves,
we conducted further research on the correlation between values αof PDC and CIM based on the previous research conducted in
Section 4.1 (α of PDC is not related to the factors mentioned
that affect β ), which indicates that α of PDC has a
tighter correlation with CIM (Figure 9 (a)). Therefore,
based on the previous analysis of the impact of precipitation on fast
flow, CIM has impacts on the curve of PDC, which in turn affects
the curve shape of FFDC.
For total flow and fast flow, the
base flow index (BFI ) can be considered as the main influencing
factor (but not the only) on the shape of normalized FDCs (TFDC and
SFDC), Pmax*αp influences the
shape of FFDC curves. CIM indirectly affects the change of fast
flow through influencing precipitation. However, because the
precipitation process is relatively complex, CIM has more influence on
the shape of PDC than on FFDC.