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Copula based analysis of meteorological drought and catchment resilience across Indian river basins
Author(s) -
Jha Vibhuti Bhushan,
Gujrati Ashwin,
Singh R P
Publication year - 2021
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6758
Subject(s) - copula (linguistics) , return period , gumbel distribution , drainage basin , joint probability distribution , environmental science , climatology , streamflow , hydrology (agriculture) , structural basin , geography , statistics , extreme value theory , mathematics , econometrics , geology , cartography , flood myth , paleontology , archaeology , geotechnical engineering
Drought analysis is an important part of risk management plan. Drought is usually characterized by variables such as severity and duration. Using standardized precipitation index (SPI) at an aggregated scale of 12 months, we construct different copula models for different river basins of India. Based on goodness of fit tests, suitable distributions are selected for duration and severity. These marginal distributions are then used to construct copula models from amongst‐Frank, Gumbel, Clayton and Student's t copula. It is found that for some river basins Frank copula can capture the dependence structure between duration and severity whereas for others Gumbel copula is effective. Exceedance probability, conditional probability and joint return period of different drought events are calculated which allude to differing drought resilience and persistence conditions in river basins. The river basins in the western India have a longer joint return period and smaller exceedance probability compared to the river basins in south India. We explore the conjunctive use for joint return period and exceedance probability to qualitatively assess the resilience of river basins to meteorological drought. The results suggest that the drought events in the south Indian river basins are less severe and more frequent whereas the ones in Central and Western India are severe and longer. The results of this study can provide useful information for drought mitigation strategies at a national scale.