Publications

The impact of ENSO on regional rainfall is often opposite between these two major phases of ENSO in various regions around the world. However, the two ENSO patterns of rainfall are not always mirror images of one another. Essentially, the rainfall response can often be higher or lower in magnitude during one phase compared to the other, which is often described as an asymmetric response of precipitation to ENSO. We assess the ability of 50 coupled climate models in simulating the seasonal and regional differences in asymmetric response using observations and reanalysis data sets as reference. Model performance is found to be poor across all regions and season, mainly because of the inability of the models in simulating the observed skewness in the regional precipitation anomaly distribution

The issue of whether climate change is accelerating has sparked heated debate in recent months. Here, we examine for acceleration in warming rates and explore possible causes for regional differences. We find, the rate of global warming is accelerating, and show that regions with large population and low socioeconomic development experience reduced acceleration due to high local aerosol emissions. As we transition to clean-energy alternatives, rapid reduction in aerosol emissions without a concurrent reduction in greenhouse gas emissions could expose a large fraction of the world's most vulnerable people to a sudden acceleration of warming. This would also increase exposure to more intense and frequent heat extremes for highly vulnerable populations. These results call for targeted climate adaptation strategies that direct attention to low-socioeconomic aerosol masked regions.

Governments are targeting net-zero emissions later this century with the aim of limiting global warming in line with the Paris Agreement. However, few studies explore the long-term consequences of reaching net-zero emissions and the effects of a delay in reaching net-zero. We use the Australian Earth system model to examine climate evolution under net-zero emissions. We find substantial changes which differ regionally, including continued Southern Ocean warming and Antarctic sea ice reduction.

In the study, the performance of three high resolution data sets - GPM-IMERG satellite derived, ERA5 and IMDAA reanalysis precipitation - in determining the seasonal variations in precipitation-temperature scaling rates are investigated. When compared with the IMD data, IMERG and IMDAA capture the spatial variations and magnitude of scaling rates of daily precipitation extremes much better than ERA5

The major objectives of this study were three-fold. First, to analyse the seasonal cahnges in the apparent scaling rates over the Indian subcontinent and to determine the differences in the departure from the expected climate scaling rate using ERA5 reanalysis temperature and precipiatation data. Second, to use ERA5 data on pressure levels to determine the seasonal variations of the dynamic and thermodynamic contribution to precipitation extremes and find the factos that cause these deviations in scaling rates. Third, to further probe into these variations using composite analysis of the various climate variables as dynamic and thermodynamic indices to find the major driving factors behind extremes across seasons.

Analysing the performance of high resolution air-quality and meteorological parameters obtained from the forecasting system developed at IITM, Pune against observation data from the WIFEX campaign and to calculate statistical performance and skill score of model AQI output against CPCB observation data over Delhi-NCR during winter 2020-2021.