Journal of Energy Bioscience 2012, Vol.3, No.1, 1-12
9
Figure 9 Seasonal wind profiles with spatial variations and
frequency of occurrence of wind speeds for Himachal Pradesh
the range of 1~3.25 m/s were seen during Monsoon
season (June to August) with high elevation zones of
Lahual Spiti, Kinnaur, Kullu and Shimla districts
showing above 2.5 m/s. Wind speeds declined during
post-monsoon and winter seasons (October to
February) and ranged as 0.75~2.25 m/s over the
region, although high elevations zones showed above
2
m/s. During summer and pre-monsoon (March to
May), wind speeds showed an increasing trend in the
range of 1.25~3 m/s, high elevation zones having
wind speeds appreciably above 2.5 m/s. Hence, the
districts of Lahual Spiti, Kinnaur, Kullu and Shimla
with annually consistent wind speeds above 2 m/s are
suitable candidates for detailed wind exploration.
4.2.1
Validation of seasonal and regional variations in
wind speed
Long term surface measurement based monthly
average wind speeds at 10 IMD sites with data
availability in Himachal Pradesh are shown in Figure 10.
Monthly variations of surface wind measurements are
consistent with the observations on seasonal wind
profiles (Figure 9) based on CRU data. Most of the
stations recorded peak wind speeds during the
monsoon season. Winter months witnessed calm
breeze awaiting a surge in the forthcoming summer.
Figure 10 Monthly average wind speeds at IMD stations with
data availability
Daily wind speeds in Himachal Pradesh were also
studied. The daylight average wind speeds (8:30~17:30
hrs) were higher than the dark hours (17:30~8:30 hrs) for
all the months recorded by IMD. These trends were
observed in most of the sites although exceptions due to
the micro climatic influences on wind speeds were
noticed at certain stations.
The IMD sites were mostly located in low and middle
elevation zones ranging from tropical to
wet-temperate (< 3 500 m) which experience wind
speeds below 2 m/s according to wind profiles based
on CRU data. None of the available IMD sites
represent high elevation zone where higher wind
speeds (> 2 m/s) were investigated. Most of the IMD
sites (except Shimla) measured wind speeds below 10 m,
and hence the assumption of standardized
measurements for data (mast height) sparse stations
could be an underestimate according to power law in
Equation 1. Hence, the actual wind speeds in many of
the data sparse sites may be higher at 10 m. AWS
wind speed measurements installed at 22 stations
spread across Himachal Pradesh (shown in Figure 2)
