Abstract:
The primary objective of this research is to provide a comprehensive drought projection
in the Punjab Province of Pakistan. The reconnaissance drought index (RDI)
obtains drought duration and severity variables at selected sites with strong correlations.
Eleven stations have been selected to measure the prolonged and severe drought
periods. Out of the six marginal probability distributions considered, Log-normal and
Exponential distributions are identified as the most appropriate for this purpose. Three
Copula models, namely Clayton, Gumbel, and Galambos copulas, are utilized to find
the joint probabilities of drought variables. The selection of the best copula model
for joint distribution is of great importance in effectively capturing drought risk, especially
in assessing upper-tail dependency. Therefore, graphical and numerical statistical
techniques are employed to identify the optimal Gumbel copula. The assessment of
drought hazards involve a comparison of bivariate joint return periods within designated
temporal frames. As the return periods increase, droughts' duration and severity
also escalate. The contour lines in the severity-duration frequency (SDF) graph are
utilized to define the combination of drought duration and severity at the selected return
periods. Shorter return periods indicate a higher risk of drought duration and
severity reoccurring. This information can be highly instrumental in climate change
planning, given the frequent occurrence of droughts and water scarcity in the Punjab
province, which is primarily an agricultural region. Consequently, this research can aid
in developing irrigation agencies and enhance their planning efforts.
