Geoscience Reference
In-Depth Information
Figure 7.14.
The influence that
λ
has on different rain gauges used
to calculate extreme daily rainfall in the Ardèche drainage basin
Drainage basin
Gradex average
Gradex of rainfall recorded in
basin
ARVE
12.8
11.5
FIER
13.8
12.1
AIN
13.9
12.4
SAONE
10.8
7.6
ISERE
14.7
10.2
EYRIEUX
35.1
29.7
DROME
17.2
12.9
ARDECHE
38.6
29.1
CEZE
35.3
23.1
DURANCE
15.5
11.4
GARD
37.0
23.6
Table 7.3.
A comparison of the different estimations of the basin gradex values
7.3.2.2.
Precipitation is stationary
Sometimes, and this is often the case in urban hydrology, rainfall is said to be
stationary (same average and same variance for each measurement site within the
drainage basin) and that the spatial structure of the rainfall is said to be homogenous
and isotropic (the correlation coefficient only depends on distance). If the term
a
is said to be zero, then the interpolation equation becomes:
∗
G
n
G
=
R
(
x
,
ω
)
=
λ
R
(
x
,
ω
)
o
i
i
i
1
