Water-salt-organic interactions within atmospheric aerosol: a molecular dynamics study
Date Issued
March 2021
Author(s)
Advisor
Abstract
This thesis's focal point is to advance our knowledge regarding the interactions between
water, salt, and organics in the atmosphere, with applications in ice nucleation and cloud
condensation nuclei (CCN) formation. This knowledge can be employed in the future for
atmospheric modeling. High in the clouds, water molecules transition into ice crystals
within particles composed of a mix of sea salt and organic materials. These crystals are
significant players in the generation of rain and snow, controlling the balance between
heating and cooling the planet by scattering the sunlight. The particles that seed ice
crystals are swirled into the atmosphere from both land and sea. But only a few particles
can act as a nucleus for forming ice crystals or condensation nuclei, making them more
effective ice/ cloud nucleators. This suggests that the few particles that do seed or nucleate
ice crystals have specific physical or chemical properties. Ice nucleation is a crucial step
in cloud formation and precipitation and plays an important role in the Earth's
hydrological cycle, energy balance, and radiative balance. Given its significance,
atmospheric ice/cloud nucleation on organic and salt aerosol particles is one of the
microscopic processes that are still poorly understood. Significant uncertainties exist in
the representation of nucleation processes in climate models. Therefore, probing aqueous
organic and salt aerosol particles is a challenge. This opens the door for computer
simulations and modeling of these intricate structures. The work presented herein probes
these processes by employing molecular dynamic simulations to understand the impacts
of aerosol-cloud interactions and atmospheric chemistry.
water, salt, and organics in the atmosphere, with applications in ice nucleation and cloud
condensation nuclei (CCN) formation. This knowledge can be employed in the future for
atmospheric modeling. High in the clouds, water molecules transition into ice crystals
within particles composed of a mix of sea salt and organic materials. These crystals are
significant players in the generation of rain and snow, controlling the balance between
heating and cooling the planet by scattering the sunlight. The particles that seed ice
crystals are swirled into the atmosphere from both land and sea. But only a few particles
can act as a nucleus for forming ice crystals or condensation nuclei, making them more
effective ice/ cloud nucleators. This suggests that the few particles that do seed or nucleate
ice crystals have specific physical or chemical properties. Ice nucleation is a crucial step
in cloud formation and precipitation and plays an important role in the Earth's
hydrological cycle, energy balance, and radiative balance. Given its significance,
atmospheric ice/cloud nucleation on organic and salt aerosol particles is one of the
microscopic processes that are still poorly understood. Significant uncertainties exist in
the representation of nucleation processes in climate models. Therefore, probing aqueous
organic and salt aerosol particles is a challenge. This opens the door for computer
simulations and modeling of these intricate structures. The work presented herein probes
these processes by employing molecular dynamic simulations to understand the impacts
of aerosol-cloud interactions and atmospheric chemistry.
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