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Athira KS, Roxy MK, Dasgupta P, Saranya JS, Singh VK, Attada R. Regional and temporal variability of Indian summer monsoon rainfall in relation to El Niño southern oscillation. Sci Rep 2023; 13:12643. [PMID: 37542113 PMCID: PMC10403600 DOI: 10.1038/s41598-023-38730-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 07/13/2023] [Indexed: 08/06/2023] Open
Abstract
The Indian summer monsoon rainfall (ISMR) exhibits significant variability, affecting the food and water security of the densely populated Indian subcontinent. The two dominant spatial modes of ISMR variability are associated with the El Niño Southern Oscillation (ENSO) and the strength of the semi-permanent monsoon trough along with related variability in monsoon depressions, respectively. Although the robust teleconnection between ENSO and ISMR has been well established for several decades, the major drivers leading to the time-varying relationship between ENSO and ISMR patterns across different regions of the country are not well understood. Our analysis shows a consistent increase from a moderate to substantially strong teleconnection strength between ENSO and ISMR from 1901 to 1940. This strengthened relationship remained stable and strong between 1941 and 1980. However, in the recent period from 1981 to 2018 the teleconnection decreased consistently again to a moderate strength. We find that the ENSO-ISMR relationship exhibits distinct regional variability with time-varying relationship over the north, central, and south India. Specifically, the teleconnection displays an increasing relationship for north India, a decreasing relationship for central India and a consistent relationship for south India. Warm SST anomalies over the eastern Pacific Ocean correspond to an overall decrease in the ISMR, while warm SST anomalies over the Indian Ocean corresponds to a decrease in rainfall over the north and increase over the south of India. The central Indian region experienced the most substantial variation in the ENSO-ISMR relationship. This variation corresponds to the variability of the monsoon trough and depressions, strongly influenced by the Pacific Decadal Oscillation and North Atlantic Oscillation, which regulate the relative dominance of the two spatial modes of ISMR. By applying the PCA-Biplot technique, our study highlights the significant impacts of various climate drivers on the two dominant spatial modes of ISMR which account for the evolving nature of the ENSO-ISMR relationship.
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Affiliation(s)
- K S Athira
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India.
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
- College of Climate Change and Environmental Sciences, Kerala Agricultural University, Thrissur, India.
| | - M K Roxy
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India
| | - Panini Dasgupta
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India
- Department of Meteorology and Oceanography, College of Science and Technology, Andhra University, Visakhapatnam, India
- Future Innovation Institute, Seoul National University, Siheung, 15011, Seoul, Republic of Korea
| | - J S Saranya
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India
- College of Climate Change and Environmental Sciences, Kerala Agricultural University, Thrissur, India
- School of Earth and Environmental Sciences/Research Institute of Oceanography, Seoul National University, Seoul, 08826, Republic of Korea
| | - Vineet Kumar Singh
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune, India
- Department of Atmospheric and Space Sciences, Savitribai Phule Pune University, Pune, India
- Typhoon Research Center, Jeju National University, Jeju, South Korea
| | - Raju Attada
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
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Climate-catchment-soil control on hydrological droughts in peninsular India. Sci Rep 2022; 12:8014. [PMID: 35570220 PMCID: PMC9108094 DOI: 10.1038/s41598-022-11293-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 04/18/2022] [Indexed: 11/23/2022] Open
Abstract
Most land surface system models and observational assessments ignore detailed soil characteristics while describing the drought attributes such as growth, duration, recovery, and the termination rate of the event. With the national-scale digital soil maps available for India, we assessed the climate-catchment-soil nexus using daily observed streamflow records from 98 sites in tropical rain-dominated catchments of peninsular India (8–25° N, 72–86° E). Results indicated that climate-catchment-soil properties may control hydrological drought attributes to the tune of 14–70%. While terrain features are dominant drivers for drought growth, contributing around 50% variability, soil attributes contribute ~ 71.5% variability in drought duration. Finally, soil and climatic factors together control the resilience and termination rate. The most relevant climate characteristics are potential evapotranspiration, soil moisture, rainfall, and temperature; temperature and soil moisture are dominant controls for streamflow drought resilience. Among different soil properties, soil organic carbon (SOC) stock could resist drought propagation, despite low-carbon soils across the Indian subcontinent. The findings highlight the need for accounting feedback among climate, soil, and topographical properties in catchment-scale drought propagations.
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