Contents lists available at ScienceDirect Journal of Hydrology journal homepage: www.elsevier.com/locate/jhydrol Research papers Understanding the linkage between soil moisture variability and temperature extremes over the Indian region Naresh G. Ganeshi a,b , Milind Mujumdar a, ⁎ , R. Krishnan a , Mangesh Goswami a,c a Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune 411008, India b Savitribai Phule Pune University, Pune 411007, India c Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon 425001, India ARTICLE INFO This manuscript was handled by Marco Borga, Editor-in-Chief, with the assistance of Yadu Pokhrel, Associate Editor Keywords: Temperature extremes Soil moisture memory Soil moisture-temperature coupling North-central India Generalized extreme value distribution Surface energy partitioning ABSTRACT Soil moisture (SM) and near-surface temperature variations are known to be linked through land–atmosphere interactions. While previous investigators have examined the association between temperature extremes and large-scale atmospheric circulation variability, the role of land–atmosphere coupling on temperature extremes over the monsoon-dominated region of India is not well understood. This study presents an analysis of hydro- meteorological datasets for the 67-year period (1948–2014) to assess the impact of long-term soil moisture changes on temperature extremes over the Indian region. Firstly, our findings show that the hot-spot of land–atmosphere coupling located across north-central India (NCI) is a region where SM variations can sig- nificantly influence temperature extremes. We further note that the NCI region experienced a significant de- clining trend in SM (about 1.1 mm/decade) during 1948–2014, in association with the decreasing trend of monsoon precipitation. Our findings suggest that the long-term decrease of SM over the NCI has favored in- creased incidence of temperature extremes through strengthening (weakening) of sensible (latent) heat fluxes; while the loss of soil moisture memory has additionally promoted increased variability of temperature extremes. The frequency, duration and variability of extreme temperatures are found to increase significantly by 1–2 occurrences, 5–6 days and 43%, respectively, in association with a decrease of 10 mm SM over NCI. The Generalized Extreme Value (GEV) distributions are fitted to extreme temperature duration (ExTD) using SM as a covariate to quantify the role of SM on temperature extremes over NCI. GEV analysis reveals that drier SM conditions (10th percentile) lead to an increase in the 67-year return value of ExTD by 9–10 days, relative to wet SM conditions (90th percentile) over NCI. Furthermore, it is interesting to note that the rise in temperature extremes over NCI in the recent three decades has been more prominent during the monsoon and post-monsoon seasons as compared to the pre-monsoon months. 1. Introduction The linkage between global warming and long-term changes in the frequency, severity and duration of extreme temperature events has been a topic of great scientific interest and societal importance (Baldwin et al., 2019; Patz et al., 2005; Fischer and Schär, 2010; Im et al., 2017; IPCC special report, 2018; Shiva et al., 2019). Anthro- pogenic climate change is recognized as the dominant cause for the increasing trend of global mean temperature since the 19th century. However, variations in extreme temperatures over different areas of the globe can be influenced by interactions involving atmospheric dy- namics, land–atmosphere feedbacks, water vapour and cloud feedbacks with radiation and other processes (see IPCC, 2014; Perkins-Kirkpatrick et al., 2016; Perkins, 2015). The enhancement of hot extremes under climate change assumes greater significance, particularly over densely inhabited regions such as South Asia, which are highly vulnerable to extreme temperature con- ditions (Sheikh et al., 2015). Heat waves over India are a distinctive type of weather event, which is defined by the India Meteorological Department (IMD), as a continuous spell of abnormally hot weather. Heat waves over the Indian region occur during the pre-monsoon months from March to June (Ratnam et al., 2016), and sometimes even during July as well (Raghavan, 1966). Severe heat waves in the region are known to exert adverse physiological, sociological and agricultural impacts (Im et al., 2017; Patz et al., 2005). There is considerable spatial variability in the maximum number of heat wave occurrences across https://doi.org/10.1016/j.jhydrol.2020.125183 Received 22 November 2019; Received in revised form 21 May 2020; Accepted 9 June 2020 ⁎ Corresponding author at: Centre for Climate Change Research (CCCR), Indian Institute of Tropical Meteorology (IITM), Dr. Homi Bhabha Road, Pashan, Pune 411008, India. E-mail address: mujum@tropmet.res.in (M. Mujumdar). Journal of Hydrology 589 (2020) 125183 Available online 21 June 2020 0022-1694/ © 2020 Elsevier B.V. All rights reserved. T