Long-term changes in tropospheric temperature in India: Insights from radiosonde measurements, reanalysis data and CMIP6 model projections

• Published in: Atmospheric research 2024-10, Vol.309, p.107583, Article 107583
• Main Authors: Kumar, Rahul, Kuttippurath, Jayanarayanan
• Format: Article
• Language: English
• Subjects: Climate Change; India; Radiosonde; Reanalysis; Tropospheric temperature; Vertical trends
• ISSN: 0169-8095
• DOI: 10.1016/j.atmosres.2024.107583

The continuous rise in greenhouse gases (GHGs) in the atmosphere is one of the major factors responsible for the global warming and enhanced tropospheric temperature. In this context, we examine the long-term spatiotemporal changes in the tropospheric temperature (1000–100 hPa) in India using radiosonde measurements and the reanalysis data from European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5), Modern-Era Retrospective analysis for Research and Application Version 2 (MERRA2) and National Center for Environmental Prediction (NCEP) for the period 1980–2020. We also investigate the future projections of tropospheric temperature in the Shared Socio-economic Pathways (SSPs) 2–4.5 and 5–8.5 by using the Coupled Model Intercomparison Project 6 (CMIP6) results for the period 2015–2100 over India. Our analysis shows a significant positive trend (0.01–0.04 °C/yr) in the annual mean temperature in the upper troposphere (500–100 hPa) in India during the period 1980–2020. The warming trends are also noticeable in the middle and lower troposphere of India. Among the regions, the northeast, north central and northwest India exhibit significant warming of about 0.01–0.06 °C/yr in the upper troposphere (500–100 hPa). On the other hand, most regions show a decline in temperature at the tropopause (100 hPa), which is stronger in the interior peninsular, north central and east coast of India, at about −0.05 ± 0.01°C/yr. All reanalysis data show consistent warming and cooling trends in the respective regions as observed from the radiosondes, albeit slight differences in their values. The future high emission scenario of SSP5–8.5 shows a warming trend of about 0.04–0.08 °C/yr at 1000–200 hPa by the end of the century, which is highest at 250 hPa. The increasing trend in tropospheric temperature is a serious concern, which calls for adaptation and mitigation measures to alleviate the impacts of this accelerated warming in India. [Display omitted] •Tropospheric warming of 0.01–0.04 °C/yr is found in India during 1980–2020.•Northeast India shows high trends of about 0.024 ± 0.01 °C/yr at 700 hPa.•Northwest India shows a trend of 0.03 ± 0.014 °C/yr at both 500 and 700 hPa.•The SSP5–8.5 scenario shows a high warming of 0.04–0.08 °C/yr in 2015–2100.