A Review of Atmospheric Aerosol Impacts on Regional Extreme Weather and Climate Events

Abstract

Atmospheric aerosols are essential constituents of the atmosphere and also interact with radiation and clouds. Substantial progress has been made since the industrial era majorly for observing, understanding, and modeling processes and these research efforts have helped to identify how aerosol optical properties have contributed to radiative forcing that influence regional and global climate. Research findings have also helped to quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols as well as various other ways aerosol has contributed to global warming both at the regional and global scale. Several aerosol inventories have been developed to quantify different aerosol species including the emission, life span, sizes, and transportation from one region to another and as well as the influence of the surrounding environment on aerosol characteristics. In recent times new metrics have been developed for adequate measurements to quantifying aerosol radiation and cloud interaction including Aerosol Instantaneous Radiative Forcing (IRF) which is the changes that occur in the Earth's energy balance due to the direct interaction of aerosols with incoming solar or outgoing infrared radiation and can lead to warming or cooling of the atmosphere, depending on the aerosol type (e.g., sulfate aerosols cause cooling). Rapid adjustment also referred to as a swift in atmospheric response to changes in radiative forcing, including adjustments in temperature, humidity, and cloud cover. It occurs almost immediately, influencing local and regional climate conditions alongside aerosol or greenhouse gas emissions. On the other hand, after taking into consideration quick corrections and feedbacks, the Effective Radiative Forcing (ERF) represents the net change in Earth's energy balance. By recording both short- and long-term feedbacks, it offers a more thorough knowledge of the total impact of aerosols or other agents on climate. These metrics are employed to precisely estimate net radiation perturbation, even though the actual measurement values of these three recently developed metrics continue to fluctuate inexplicably throughout the regions. This review provides information on various aspects of aerosol properties especially those that are related to radiation, cloud interaction, and extreme events. The new paradigm shifts to a modeling approach, theoretical considerations, and finetuned observational methodology are essential tools to be considered. Scattering and absorption of aerosol show different mechanisms involved when aerosols interact with short and long-wave radiation but aerosol absorption ability might not only be limited to certain aerosol species as entailed in research consensus and these might be one of the major constraints of surface radiative fluxes from aerosol-radiation interactions. The influence of anthropogenic aerosols on cloud liquid water content and cloud fraction was also considered and it has been discovered that these complex processes are less clear, and the influence on mixed-phase and ice clouds remains to be well understood. Observed changes in surface temperature increase due to radiation perturbation and the radiative fluxes both at the Top of the Atmosphere and at the surface are the major driving force for global warming and also impacts weather and climate extreme events. It is also very important to measure with high sense of accuracy the changes in the surface temperature. The degree of aerosol-induced warming on global circulation as the major carrier of moisture for precipitation processes is yet to be fully explored. The extreme events associated with flood events and as well as drought associated with extreme temperature and heat waves are key areas for current and future research. In summary, if we must consider importance and the usage of the three invented metrics for accurate and scientific quantification over the traditional Direct and Indirect aerosol radiative forcing then there is a need for proper understanding and a better research approach to allay the fear of uncertainty in this regard. The application of new technological tools and as well as new parametrization schemes development that express micro aerosol-climate interaction and processes that are smaller and cannot be resolved or captured explicitly on regional and global scales are important factors to be considered.