Black carbon (BC) has several direct, indirect, semi-direct, and microphysical effects on the Earth’s climate system. Analyses of the decade-long measurement of BC aerosols at Varanasi (from 2009 to 2021) was done to understand its impact on radiative balance. General studies suggest that the daily BC mass concentration (mean of 9.18±6.53 µg m–3) ranges from 0.07 to 46.23 µg m–3 and show a strong interannual and intra-annual variation over the 13-year study period. Trend analyses suggest that the interannual variability of BC shows significant decreasing trend (-0.47 µg m–3 yr-1) over the station. The decreasing trend is maximum during the post-monsoon (-1.86 µg m–3 yr-1) and minimum during the pre-monsoon season (-0.31 µg m–3 yr-1). The radiative forcing caused specifically by BC (BC-ARF) at the top of the atmosphere (TOA), surface (SUR), and within the atmosphere (ATM) is found to be 10.3 ± 6.4, -30.1 ± 18.9, and 40.5 ± 25.2 Wm−2, respectively. BC-ARF shows strong interannual variability with a decreasing trend at the TOA (–0.47 Wm–2 yr-1) and ATM ((–1.94 Wm–2 yr-1) forcing, while it showed an increasing trend at the SUR (1.33 Wm–2 yr-1). To identify the potential source sectors and the transport pathways of BC aerosols, concentrated weighted trajectories (CWT) and potential source contribution function (PSCF) analyses have been conducted over the station. These analyses revealed that the primary source of pollution at Varanasi originate from the upper IGP, lower IGP, and central India.

A unique approach of a well-established Hot-Dry-Windy Index (HDWI) method is established to build the forecasting framework of dust storms. This method is successfully used for forecasting wildfire incidences. The approach calculates the likelihood of a dust storm by postulating that it arises from a synergistic interplay of elevated temperatures, arid atmospheric conditions, and powerful winds, similar to the conditions that are necessary for a wildfire occurrence. The approach has been effectively evaluated for eight distinct dust storm events that took place in important desert places around the world. The results regularly shown its capacity to precisely determine the source of dust storms within a limited time frame. The proposed strategy provides a multitude of advantages compared to other alternatives currently suggested for the same objective.

The recent emergence of compelling evidence (Mudiar et al., 2018, 2021a 2021b) regarding a significant impact of cloud electrification on rain microphysical processes raises curiosity on the potential dynamical implications of cloud electrification. In this study, the consequence of cloud electrification has been explored from a perspective of interaction between cloud microphysics and dynamics using observational data and numerical models in a tropical condition. It is shown that the strongly electrified (SE) clouds exhibit a reduced value of rain intercept parameter, N0 relative to the weakly electrified (WE) counterpart facilitated by the in-cloud electric field. This process results in a reduction in rain evaporation rate in the warm phase of the cloud, thereby enhancing the surface rain intensity. From a dynamical perspective, the reduced rain evaporation rate gives positive feedback to storm energetics by reducing latent cooling. The reduced latent cooling delays the downdraft thereby facilitating an invigoration of convection. This electrically induced invigoration is termed ‘Dynamical Invigoration of Electrified Storms’.