Standardized Variability Index (SVI): A multiscale index to assess the
variability of precipitation
Abstract
Quantifying the spatiotemporal variability of precipitation is the
principal component for the assessment of the impact of climate change
on the hydrological cycle. A better understanding of the quantification
of variability and its trend is vital for water resources planning and
management. Therefore, a multitude of studies has been dedicated to
quantify the precipitation variability over the years. Despite their
importance for modeling precipitation variability, the studies mainly
focused on the amount of precipitation and its spatial patterns. The
studies investigating the spatial and temporal variability of
precipitation across the Indian subcontinent, in general, and at
multiscale, in particular, are limited. In this study, we introduce a
novel measure, Standardized Variability Index (SVI), based on
information entropy to investigate the spatiotemporal variability of
precipitation. The proposed measure is independent of the temporal
scale, the length of the data and can compare the precipitation
variability at multiple timescales. Distinct spatial patterns were
observed for information entropies at the monthly and seasonal scale.
Stations with statistically significant trends were observed and vary
from monthly to seasonal scale. There is an increase in the variability
of precipitation amount across Central India. Trend analysis revealed
there is changing behaviour in the precipitation amount as well as rainy
days, showing an increase in the probability of occurrence of extreme
events in the near future. In addition, coupling the mean annual
rainfall with SVI enables a relative assessment of the water resources
availability.