The Semi-Direct Aerosol-Cloud Effects

This thesis is composed of two parts. In the first part we investigate the impact of Saharan dust on North Atlantic marine stratocumulus clouds (MSc) using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), Clouds and the Earth's Radiant Energy System (CERES), and Euro...

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Main Author: Amiri Farahani, Anahita
Other Authors: Allen, Robert James
Format: Other/Unknown Material
Language:English
Published: eScholarship, University of California 2018
Subjects:
Online Access:https://escholarship.org/uc/item/49d0x04k
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spelling ftcdlib:oai:escholarship.org/ark:/13030/qt49d0x04k 2023-05-15T17:30:33+02:00 The Semi-Direct Aerosol-Cloud Effects Amiri Farahani, Anahita Allen, Robert James 2018-01-01 application/pdf https://escholarship.org/uc/item/49d0x04k en eng eScholarship, University of California qt49d0x04k https://escholarship.org/uc/item/49d0x04k public Atmospheric sciences aerosol aerosol-cloud interactions cloud semi-direct effect etd 2018 ftcdlib 2021-02-18T15:14:24Z This thesis is composed of two parts. In the first part we investigate the impact of Saharan dust on North Atlantic marine stratocumulus clouds (MSc) using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), Clouds and the Earth's Radiant Energy System (CERES), and European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim). To calculate the aerosol- cloud radiative effect, we use two different methods These two methods yield similar results that Saharan dust modifies MSc in a way that acts to cool the planet. There is a strong seasonal variation, with the aerosol-cloud radiative effect switching from significantly negative during the boreal summer to weakly positive during boreal winter. When most dust resides above the clouds during summer, aerosol-cloud microphysical effects that involve the co-location of aerosol and cloud, such as the second aerosol indirect effect, would likely be muted relative to the SDE. Moreover, the positive value of the aerosol-cloud radiative effect during winter, when most dust resides within MSc, indicates that the semi-direct effect is dominant$-$ that is the only mechanism by a negative aerosol-cloud radiative effect can be obtained. We conclude that aerosol-cloud radiative effects associated with Saharan dust and North Atlantic MSc are dominated by the semi-direct effect. Other/Unknown Material North Atlantic University of California: eScholarship
institution Open Polar
collection University of California: eScholarship
op_collection_id ftcdlib
language English
topic Atmospheric sciences
aerosol
aerosol-cloud interactions
cloud
semi-direct effect
spellingShingle Atmospheric sciences
aerosol
aerosol-cloud interactions
cloud
semi-direct effect
Amiri Farahani, Anahita
The Semi-Direct Aerosol-Cloud Effects
topic_facet Atmospheric sciences
aerosol
aerosol-cloud interactions
cloud
semi-direct effect
description This thesis is composed of two parts. In the first part we investigate the impact of Saharan dust on North Atlantic marine stratocumulus clouds (MSc) using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), Clouds and the Earth's Radiant Energy System (CERES), and European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim). To calculate the aerosol- cloud radiative effect, we use two different methods These two methods yield similar results that Saharan dust modifies MSc in a way that acts to cool the planet. There is a strong seasonal variation, with the aerosol-cloud radiative effect switching from significantly negative during the boreal summer to weakly positive during boreal winter. When most dust resides above the clouds during summer, aerosol-cloud microphysical effects that involve the co-location of aerosol and cloud, such as the second aerosol indirect effect, would likely be muted relative to the SDE. Moreover, the positive value of the aerosol-cloud radiative effect during winter, when most dust resides within MSc, indicates that the semi-direct effect is dominant$-$ that is the only mechanism by a negative aerosol-cloud radiative effect can be obtained. We conclude that aerosol-cloud radiative effects associated with Saharan dust and North Atlantic MSc are dominated by the semi-direct effect.
author2 Allen, Robert James
format Other/Unknown Material
author Amiri Farahani, Anahita
author_facet Amiri Farahani, Anahita
author_sort Amiri Farahani, Anahita
title The Semi-Direct Aerosol-Cloud Effects
title_short The Semi-Direct Aerosol-Cloud Effects
title_full The Semi-Direct Aerosol-Cloud Effects
title_fullStr The Semi-Direct Aerosol-Cloud Effects
title_full_unstemmed The Semi-Direct Aerosol-Cloud Effects
title_sort semi-direct aerosol-cloud effects
publisher eScholarship, University of California
publishDate 2018
url https://escholarship.org/uc/item/49d0x04k
genre North Atlantic
genre_facet North Atlantic
op_relation qt49d0x04k
https://escholarship.org/uc/item/49d0x04k
op_rights public
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