Role of Aerosols Behind High Precipitation Over The Himalayan Region

Rising atmospheric greenhouse gases have been blamed for climate change, which has resulted in a hotter climate. Aerosol-enhanced high precipitation events are microscopic particles that flow between the ground surface and the stratosphere in solid, liquid, or gaseous phases (from 0.001m to 100m). Atmospheric aerosols are produced by biomass burning, mineral dust, volcanic eruptions, and incomplete combustion of fossil fuels. Particulate emissions can change cloud systems’ physical and dynamical features, intensifying rainfall events over orographic regions downstream of polluted urban centres. The Indo-Gangetic Plain, one of the world’s most polluted areas, is upwind of the Himalayan foothills. As a result, the region offers a unique chance to investigate the impact of aerosol and the relation between aerosol and monsoon.

Aerosol-Enhanced high Precipitation Events in the Himalayan Foothills:

Anthropogenic aerosols’ absorption and scattering of incoming solar radiation influence the microclimatic system. The impacts of aerosol on weather and climate are essential for comprehending the anthropogenic impact on the Earth system. Aerosols can directly impact the atmosphere by interacting with arriving and outgoing air. Aerosol–radiation interactions are a type of outgoing radiation  Cloud microphysical and macrophysical properties can be altered by aerosols. Aerosol–cloud interactions (ACIs) are indirect impacts of aerosol that influence precipitation and the weather.

Aerosol-enhanced high precipitation events occur in Himalayan foothills. Extreme weather events well over steeper mountains can cause catastrophic floods and landslides, which can have terrible consequences for the people. Most of these rain occurrences occur inside large-scale continental atmospheric circulation, such as monsoon depressions, low-pressure systems, and extratropical disturbances. The Indo-Gangetic Plain (IGP) is located to the south of the Himalayan, and Aerosol-enhanced high precipitation events occur there. 

During the day, the aerosol-enhanced conditional instability mechanism suppresses convection in the lower atmosphere, avoiding the use of moist static energy. This surplus energy is carried towards the orography during the night, increasing the intensity of aerosol-enhanced high precipitation events. Moderate Resolution Imaging Spectroradiometer data will not be available if there is a thick cloud cover during the aerosol-enhanced high precipitation event.

Impacts of Aerosol

Climate change, agriculture, satellite remote sensing, and public health are all affected by light-absorbing aerosols like black carbon particles. They can change cloud characteristics and precipitation patterns, influencing the Earth-atmosphere system’s hydrodynamic balance. There are a variety of impacts of aerosol on health, including short-term acute symptoms such as asthma and bronchitis and long-term persistent discomfort and infection of the respiratory system, which can lead to cancer. Apart from greenhouse gases, scientists evaluate the impact of aerosol in climate change agents that affects the atmospheric equilibrium state and thus directly influence global climate model predictions. A preliminary study of how aerosols influence various climate system components contributes to the uncertainty in global climatic model estimates.

Relation between Aerosol and Monsoon:

Droughts/floods becoming more severe and decreasing air quality due to more aerosols in Asia monsoon areas seem to be the two most serious problems affecting nearly 60% of the world’s population. These two risks have generated a huge corpus of the function of aerosols in influencing Asian monsoon weather and climate during the last decade. Aerosols limit surface insolation and lessen the land-ocean thermal contrast on a continental scale, preventing the development of monsoons. Aerosol radiative changes lower the atmosphere’s thermodynamic stability and convective potential, resulting in lower temperatures, enhanced atmospheric stability, and weaker wind and atmospheric circulation. Lau (2016) presented a new perspective, suggesting that natural aerosols, especially dust and carbonaceous aerosols from natural sources, must be considered an integral part of the core relation between aerosol and monsoon weather and climate system. Consistent elevated heat pumps indicate substantial relation between aerosol and monsoon associated with aerosol advection and higher precipitation downwind of the intensifying south-west monsoon. The Indian relation between aerosol and monsoon, with no modification in anthropogenic aerosol emissions.

Conclusion

Significant aerosol effects and trends were appropriately integrated into climate models. In that case, the ongoing dispute over climate change owing to Greenhouse gases and the recent slowdown in global warming could be better explained. Warming and higher precipitation should have resulted from the accumulation of Greenhouse gases. There seem to be plenty of both natural and anthropogenic aerosols in monsoon regions. Their fundamental efforts to the distribution of heat sources and sinks, as well as the formation of clouds and precipitation, a new framework that treats natural aerosols with the same status as temperature, moisture, clouds, and precipitation, is needed to gain a better understanding of the roles of the relation of aerosol-monsoon on climate change.