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The Effects of Pacific Decadal Oscillation and El Niño-Southern Oscillation on Annual Floods in Godavari River Basin, India
  • Sunil Gurrapu,
  • Ashwini Ranada,
  • J P Patra
Sunil Gurrapu
National Institute of Hydrology

Corresponding Author:[email protected]

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Ashwini Ranada
National Institute of Hydrology
J P Patra
National Institute of Hydrology

Abstract

Indian summer monsoon rainfall is strongly influenced by various large-scale atmosphere-ocean oscillations including Pacific Decadal Oscillation (PDO), and El Niño-Southern Oscillation (ENSO). Researchers have shown that the negative phase of PDO or La Niña episodes of ENSO produce higher magnitude rainfall and hence relatively wetter years. So, it is imperative to have better knowledge of flood characteristics in the Indian watersheds for optimal planning and design of various infrastructure, and for optimal planning and management of reservoir operations. Traditionally, such information is estimated using flood frequency analysis (FFA) for small and medium sized projects. However, the adequacy of traditionally accepted assumption that the annual peak flows are independent and identically distributed (i.i.d.) is questioned globally \cite{Gurrapu_2016,Milly_2008}. This study evaluates the influence of PDO and ENSO and flood characteristics in Godavari River, India. The results indicate that the flood magnitude and frequency at majority of the selected gauges in Godavari River Basin is significantly influenced by PDO and ENSO, higher magnitude floods are associated with negative phase of PDO and La Niña episodes of ENSO. A few gauges are inversely related to these teleconnections. The influence of these teleconnections on regional climate is spatially variable across India and so are the contrasting results. The results from this study benefits the design engineers for efficient design of water resources infrastructures and water managers for optimal planning and management of reservoir operations. 
24 Dec 2022Submitted to ESS Open Archive
26 Dec 2022Published in ESS Open Archive