Geology Reference
In-Depth Information
Fig. 7.19 Sensitivity of the reference evapotranspiration to meteorological variables
annual ANN ET
0
estimation with that of standard ET
0
equations, which indicates
the modeling capability of ANN in both Beas and Santa Monica Stations, with
available meteorological data sets as inputs. Figure
7.18
shows the annual ANN
ET
0
estimation at the Brue catchment with that of pan evaporation during the
3 years 1995, 1996, and 1998. (The pan evaporation data for the year 1997 was not
available for comparison.)
7.4.2.4 Reference Evapotranspiration Sensitivity to Meteorological
Variables
This study also performed sensitivity analysis for reference evapotranspiration with
meteorological variables such as net solar radiation, relative humidity, air temper-
ature, and wind speed in a simple and practical way, as discussed in Goyal [
10
] and
Xu et al. [
29
]. A plot is made with the relative changes of an input variable against
the resultant relative change of ET
0
and the curve is known as the
sensitivity
curve.
'
Seven input scenarios are generated for each meteorological variable with
variation from
'
30 to +30 %. The sensitivity curve of the study is shown in
Fig.
7.19
. It has been found that the most sensitive variable is relative humidity,
followed by net solar radiation, air temperature, and wind speed. The sensitivity of
wind velocity is observed to be quite close to that of air temperature. Relative
humidity is observed as the most sensitive variable, with an inversely proportional
effect on ET
0
with values of 68
−
65 % corresponding to a
30 to 30 % variation.
-
−
Wind velocity had the least effect with values of 8
7%.
-
