High‐resolution climate change projection of northeast monsoon rainfall over peninsular India

Abstract

In this study, projected changes in mean northeast monsoon (NEM) rainfall and associated extreme rainfall and temperature events, over peninsular India (PI) and its six subdivisions, are quantified. High-resolution dynamically downscaled simulations of the Weather Research and Forecasting (WRF) regional climate model driven by the boundary conditions from the Community Climate System Model version 4 (CCSM4) model (WRF-CCSM4) are compared with statistically downscaled simulations of NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP). Over PI, these downscaled simulations show low bias in mean NEM rainfall (≤ − 0.44 mm⋅day −1 ) and high pattern correlation coefficient (≥0.75), giving confidence in their future projections. Under future warming over PI, both downscaled simulations project future significant enhancement in NEM rainfall with WRF-CCSM4 projecting 1.98 mm⋅day −1 (83.78% change with respect to the present-day mean) whereas the multimodel ensemble (MME) of eight NEX-GDDP models project 0.67 ± 0.58 mm⋅day −1 (19.78%) by the midddle of the century and 1.42 ± 0.97 mm⋅day −1 (42.76%) by the end of the century. Analysis of extreme rainfall events shows that WRF-CCSM4 projects future enhancement (reduction) in extreme rainfall (R95p) days over 91.4% (8.6%) of grid-points over PI. In future, coastal areas of Karnataka and Andhra Pradesh will likely experience increased extreme rainfall occurrence by more than 25 days and 15-20 days respectively. Projected future enhancement in the mean and extreme NEM rainfall is attributed to the increased precipitable water under a warming climate. Future projection of extreme temperature indices shows an increase in minimum and maximum temperatures over PI during the NEM season. Over PI, future winter nights and days are found to be warmer than those in the present day and the temperature change in future winter nights is found to be larger than that in winter days. This climate change information would help decision-makers in evaluating existing policies and devising revised policies to reduce risk due to climate change.

Groundwater irrigation is critical for adapting wheat systems to warming temperatures in the Eastern Indo-Gangetic Plains in India

“…In addition, 15% of farmers reported that flooded fields were a main reason that they delayed wheat sowing, as they were unable to prepare fields when there was standing water. This is of concern given that within-season rainfall distributions are changing due to climate change, with some models projecting increases in end of season monsoon rainfall (Loo et al 2015, Jayasankar et al 2021. This could be problematic for the establishment of wheat if higher rainfall at the time of rice harvest and wheat planting leads to increases in water logging in fields.…”

Truly Absent or Sampling Gaps? Insights on the Potential Distribution of Duttaphrynus hololius (Günther, 1876) from Peninsular India

“…As mentioned above, our future climate analysis also shows that, with a steep decline in the suitable range, the southern and parts of the Western Ghats might act as a climate refugia for the D. hololius under the RCP 8.5 for 2070. The climate change analysis from the past studies for the Peninsular Indian region shows that increase in drought (Rehana and Naidu, 2021) and extreme rainfall events clubbed with warmer winter months (Jayasankar et al, 2021). Insofar as amphibians are ectothermic animals with an amphibious life cycle, events like erratic rainfall, warmer winter months, and increased temperature will only increase the species' vulnerability (Cushman, 2006;Buckley and Jetz, 2007), which is overwhelmed by human-induced land-use changes, especially in this case.…”

Assessment of climate change in west godavari district of andhra pradesh, India using water balance approach

“…The coastal Andhra plain has a large population, and the region receives enough rainfall during the monsoon and post-monsoon seasons to maintain it (Murthy , 2020). Due to unprecedented and erratic rainfall events and nonavailability of surface water, groundwater depletion, and salinity problems in coastal regions, they affect developmental activities and the living standards of the population (Jayasankar , 2021). Keeping this in mind, the current study was conducted in the West Godavari district of coastal Andhra Pradesh to examine the climate pattern utilizing water balance methodologies and historical data spanning the period 1901-2019.…”