acquired from the online portal of the Department of Water Resources, Government
of Rajasthan, Rajasthan, India (www.waterresources.rajasthan.gov.in). The geographic position (latitude and longitude) and elevation details of the selected nine
stations are provided in Table 12.1. The main problem with the rainfall analysis is
missing records. The missing rainfall observations were filled in before executing
analysis. The normal ratio method has been executed to estimate the missing values
by choosing the rainfall amounts of three nearest stations. A distance matrix has been
structured for all stations based on their geographic positions to evaluate the
closeness of stations.
Further, a data quality check is essential before the investigation, as outliers can
greatly affect rainfall trends and patterns (You et al. 2008; Shahid et al. 2016). To
ensure homogeneity, the subjective double mass curve method and objective Student’s t test have been performed for rainfall time-series. The double mass curves of
all stations did not show any breakpoint and displayed a more or less straight line,
which indicates homogeneity in the data. Similarly, the Student’s t test did not
revealed any breakpoint or statistically significant difference in the rainfall timeseries at the 95% confidence level. Apart from this, the daily rainfall data have been
summed to obtain monthly, seasonal, and annual values. Seasonal analysis has been
completed for four seasons: winter (January–February), pre-monsoon (March–
May), monsoon (June–September), and post-monsoon (October–December), as
per categorization of the India Meteorological Department.
Methods
After preparation of the dataset, suitable statistical analyses such as sum, frequencies, percentage, mean, standard deviation (SD), coefficient of variation (CV),
skewness, and kurtosis have been performed for each station for the period
1961–2017. Then, the excess and deficit rainfall years and heavy rainy days were
identified as follows.
Table 12.1 Details of
selected nine stations over
Sahibi Basin in Rajasthan
Station
District Latitude
Longitude Altitude (m)
Bairath
Jaipur
27
27
0 N 76
11
0 E
430
Kotputli
Jaipur
27
43
0 N 76
13
0 E
360
Mundawar Alwar
27
52
0 N 76
33
0 E
310
Tijara
Alwar
27
57
0 N 76
51
0 E
293
Kotkasim
Alwar
28
02
0 N 76
43
0 E
259
Thanagaji
Alwar
27
24
0 N 76
19
0 E
417
Bansur
Alwar
27
42
0 N 76
21
0 E
357
Behrod
Alwar
27
53
0 N 76
17
0 E
323
Tapukara
Alwar
28
03
0 N 76
51
0 E
275
12 Trends and Pattern of Rainfall over Semiarid Sahibi Basin in Rajasthan, India
277
of Rajasthan, Rajasthan, India (www.waterresources.rajasthan.gov.in). The geographic position (latitude and longitude) and elevation details of the selected nine
stations are provided in Table 12.1. The main problem with the rainfall analysis is
missing records. The missing rainfall observations were filled in before executing
analysis. The normal ratio method has been executed to estimate the missing values
by choosing the rainfall amounts of three nearest stations. A distance matrix has been
structured for all stations based on their geographic positions to evaluate the
closeness of stations.
Further, a data quality check is essential before the investigation, as outliers can
greatly affect rainfall trends and patterns (You et al. 2008; Shahid et al. 2016). To
ensure homogeneity, the subjective double mass curve method and objective Student’s t test have been performed for rainfall time-series. The double mass curves of
all stations did not show any breakpoint and displayed a more or less straight line,
which indicates homogeneity in the data. Similarly, the Student’s t test did not
revealed any breakpoint or statistically significant difference in the rainfall timeseries at the 95% confidence level. Apart from this, the daily rainfall data have been
summed to obtain monthly, seasonal, and annual values. Seasonal analysis has been
completed for four seasons: winter (January–February), pre-monsoon (March–
May), monsoon (June–September), and post-monsoon (October–December), as
per categorization of the India Meteorological Department.
Methods
After preparation of the dataset, suitable statistical analyses such as sum, frequencies, percentage, mean, standard deviation (SD), coefficient of variation (CV),
skewness, and kurtosis have been performed for each station for the period
1961–2017. Then, the excess and deficit rainfall years and heavy rainy days were
identified as follows.
Table 12.1 Details of
selected nine stations over
Sahibi Basin in Rajasthan
Station
District Latitude
Longitude Altitude (m)
Bairath
Jaipur
27
27
0 N 76
11
0 E
430
Kotputli
Jaipur
27
43
0 N 76
13
0 E
360
Mundawar Alwar
27
52
0 N 76
33
0 E
310
Tijara
Alwar
27
57
0 N 76
51
0 E
293
Kotkasim
Alwar
28
02
0 N 76
43
0 E
259
Thanagaji
Alwar
27
24
0 N 76
19
0 E
417
Bansur
Alwar
27
42
0 N 76
21
0 E
357
Behrod
Alwar
27
53
0 N 76
17
0 E
323
Tapukara
Alwar
28
03
0 N 76
51
0 E
275
12 Trends and Pattern of Rainfall over Semiarid Sahibi Basin in Rajasthan, India
277