Connection of Quasi-Resonant Amplification to the Delay in Atmospheric Residence Times Over India

T V Lakshmi Kumar,Humberto Barbosa,R K Mall,V Brahmananda Rao,G Purna Durga,Savita Patwardhan,Ashwini Kulkarni,K Koteswara Rao

doi:10.3389/feart.2021.615325

Abstract

Mean monthly Atmospheric Residence Times (ART), deduced from the global climate models of Coupled Model Intercomparison Project 5 (CMIP5) under RCP4.5 and RCP8.5 emission scenarios over Indian landmass, show a perceptible increase by the end of the 21st century. India, being a tropical country, faces prolonged ART, particularly during the June month of Southwest monsoon season (June to September) which will be an indicative measure of the increased frequency of extreme weather events. Here we show a possible connection of quasi-resonant amplification (QRA) to the recent (August 2018) Kerala heavy rains that resulted in severe floods and claimed more than 400 mortalities. Remarkable delay in residence times over India during June is shown to have an association with QRA evidenced by the higher magnitudes of amplitudes at the wavenumbers six and seven from the 19 global climate models of CMIP5 under the RCP4.5 and RCP8.5 scenarios.

Highlights

The atmospheric residence times (ART) are defined as the time that the moisture stays in the atmosphere before it precipitates (Chahine, 1992)
We estimated the ART using the gridded rainfall data developed by India Meteorological Department (IMD) based on the wide rain gauge network (Pai et al, 2014) and the precipitable water vapor data from European Center for Medium-Range Weather Forecasting Reanalysis (ERA) and National Center for Environmental Protection (NCEP) gridded data set
The ART are much higher over India’s other regions, such as peninsular India and northwestern parts of India, which might be due to the low SW monsoon activity

Summary

Introduction

The atmospheric residence times (ART) are defined as the time that the moisture stays in the atmosphere before it precipitates (Chahine, 1992). Van Der Ent and Tuinenburg (2017) studied the ART using atmospheric moisture tracking models and reported the global average residence times as 8.9 ± 0.4 days Van Der Ent and Tuinenburg (2017) used the method to estimate the residence times is slightly different by Chahine (1992), Trenberth (1998) where they have not considered the horizontal transport of water vapor in estimating the residence time. Van Der Ent and Tuinenburg (2017) termed the residence times obtained by Chahine (1992), Trenberth (1998) as the residence times for moisture recycling (Wang et al, 2018). We can find more details on QRA link to Residence Times

Methods

Results

Conclusion