Observing short timescale cloud development to constrain aerosol-cloud interactions
File(s)
Published version
Author(s)
Gryspeerdt, Edward
Glassmeier, Franziska
Feingold, Graham
Hoffmann, Fabian
Murray-Watson, Rebecca
Type
Journal Article
Abstract
The aerosol impact on liquid water path (LWP) is a key uncertainty in the overall climate impact of aerosol. However, despite a significant effort in this area, the size of the effect remains poorly constrained, and even the sign is unclear. Recent studies have shown that the relationship between droplet number concentration (Nd ) and LWP is an unreliable measure of the
impact of Nd variations on LWP due to the difficulty in establishing causality. In this work, we use satellite observations of the short-term development of clouds to examine the role of Nd perturbations in LWP variations.
Similar to previous studies, an increase followed by a general decrease in LWP with increasing Nd is observed, suggesting an overall negative LWP response to Nd and a warming LWP adjustment to aerosol. However, the Nd also responds to the local environment, with aerosol production, entrainment from the free troposphere and wet scavenging all acting to modify the Nd . Many of these effects act to further steepen the Nd -LWP relationship and obscure the causal Nd impact on LWP.
Using the temporal development of clouds to account for these feedbacks in the Nd -LWP system, a weaker negative Nd -LWP relationship is observed over most of the globe. This relationship is highly sensitive to the initial cloud state, illuminating the roles of different processes in shaping the Nd -LWP relationship. The nature of the current observing system limits this work to
a single time period for observations, highlighting the need for more frequent observations of key cloud properties to constrain cloud behaviour at process timescales.
impact of Nd variations on LWP due to the difficulty in establishing causality. In this work, we use satellite observations of the short-term development of clouds to examine the role of Nd perturbations in LWP variations.
Similar to previous studies, an increase followed by a general decrease in LWP with increasing Nd is observed, suggesting an overall negative LWP response to Nd and a warming LWP adjustment to aerosol. However, the Nd also responds to the local environment, with aerosol production, entrainment from the free troposphere and wet scavenging all acting to modify the Nd . Many of these effects act to further steepen the Nd -LWP relationship and obscure the causal Nd impact on LWP.
Using the temporal development of clouds to account for these feedbacks in the Nd -LWP system, a weaker negative Nd -LWP relationship is observed over most of the globe. This relationship is highly sensitive to the initial cloud state, illuminating the roles of different processes in shaping the Nd -LWP relationship. The nature of the current observing system limits this work to
a single time period for observations, highlighting the need for more frequent observations of key cloud properties to constrain cloud behaviour at process timescales.
Date Issued
2022-09-09
Date Acceptance
2022-08-11
Citation
Atmospheric Chemistry and Physics, 2022, 22, pp.11727-11738
ISSN
1680-7316
Publisher
Copernicus Publications
Start Page
11727
End Page
11738
Journal / Book Title
Atmospheric Chemistry and Physics
Volume
22
Copyright Statement
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
License URL
Sponsor
Royal Society
Identifier
https://acp.copernicus.org/articles/22/11727/2022/
Grant Number
URF\R1\191602
Subjects
Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Environmental Sciences
Meteorology & Atmospheric Sciences
Environmental Sciences & Ecology
LIQUID WATER PATH
SATELLITE-OBSERVATIONS
DROPLET NUMBER
STRATOCUMULUS
PARAMETERIZATION
CONDENSATION
SIMULATIONS
DEPTH
MODEL
TERRA
Meteorology & Atmospheric Sciences
0201 Astronomical and Space Sciences
0401 Atmospheric Sciences
Publication Status
Published
Date Publish Online
2022-09-09