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Article: An underestimated negative cloud feedback from cloud lifetime changes. N&V p468

Mülmenstädt, Johannes

2021 Volume 11, Issue 6, Page(s) 508

Language	English
Document type	Article
ZDB-ID	2614383-5
ISSN	1758-678x
Database	Current Contents Nutrition, Environment, Agriculture

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Article: The Radiative Forcing of Aerosol–Cloud Interactions in Liquid Clouds: Wrestling and Embracing Uncertainty

Mülmenstädt, Johannes / Graham Feingold

Current climate change reports. 2018 Mar., v. 4, no. 1

2018

Abstract: This article discusses some of the challenges that have limited progress in quantifying the radiative forcing associated with aerosol–cloud interactions (ACI) in warm (liquid-water) clouds. It reviews recent progress and suggests new ways of viewing the ... ...

Abstract	This article discusses some of the challenges that have limited progress in quantifying the radiative forcing associated with aerosol–cloud interactions (ACI) in warm (liquid-water) clouds. It reviews recent progress and suggests new ways of viewing the problem that might accelerate progress. It calls for much greater attention to the scale problem, both in terms of aerosol–cloud process representation in models and comparison with observations. It suggests careful consideration of the balance in detail with which processes are represented, and proposes a merging of detailed process understanding and system-wide behavior. In this spirit, it advocates tackling the problem with models of varying complexity that consider both the depth and breadth of the complex dynamical system. Finally, it considers shifting attention from untangling aerosol and meteorological effects on cloud systems towards understanding the co-variability of key aerosol and meteorological drivers of cloud systems.
Keywords	aerosols ; climate change ; liquids ; models ; radiative forcing ; uncertainty
Language	English
Dates of publication	2018-03
Size	p. 23-40.
Publishing place	Springer International Publishing
Document type	Article
Note	Review
ISSN	2198-6061
DOI	10.1007/s40641-018-0089-y
Database	NAL-Catalogue (AGRICOLA)

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Book ; Online: Evaluation of aerosol–cloud interactions in E3SM using a Lagrangian framework

Christensen, Matthew W. / Ma, Po-Lun / Wu, Peng / Varble, Adam C. / Mülmenstädt, Johannes / Fast, Jerome D.

eISSN: 1680-7324

2023

Abstract: A Lagrangian framework is used to evaluate aerosol–cloud interactions in the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) version 1 (E3SMv1) for measurements taken at Graciosa Island in the Azores where a U.S. Department of ... ...

Abstract	A Lagrangian framework is used to evaluate aerosol–cloud interactions in the U.S. Department of Energy's Energy Exascale Earth System Model (E3SM) version 1 (E3SMv1) for measurements taken at Graciosa Island in the Azores where a U.S. Department of Energy Atmosphere Radiation Measurement (ARM) site is located. This framework uses direct measurements of cloud condensation nuclei (CCN) concentration (instead of relying on satellite retrievals of aerosol optical depth) and incorporates a suite of ground-based ARM measurements, satellite retrievals, and meteorological reanalysis products that when applied to over a 1500 trajectories provides key insights into the evolution of low-level clouds and aerosol radiative forcing that is not feasible from a traditional Eulerian analysis framework. Significantly lower concentrations (40 %) of surface CCN concentration are measured when precipitation rates in 48 h back trajectories average above 1.2 mm d −1 in the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) product. The depletion of CCN concentration when precipitation rates are elevated is nearly twice as large in the ARM observations compared to E3SMv1 simulations. The model CCN concentration bias remains significant despite modifying the autoconversion and accretion rates in warm clouds. As the clouds in trajectories associated with larger surface-based CCN concentration advect away from Graciosa Island, they maintain higher values of droplet number concentrations ( N d ) over multiple days in observations and E3SM simulations compared to trajectories that start with lower CCN concentrations. The response remains robust even after controlling for meteorological factors such as lower troposphere stability, the degree of cloud coupling with the surface, and island wake effects. E3SMv1 simulates a multi-day aerosol effect on clouds and a Twomey radiative effect that is within 30 % of the ARM and satellite observations. However, the mean cloud droplet concentration is more than 2–3 times ...
Subject code	551
Language	English
Publishing date	2023-03-02
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: The Global Atmosphere-aerosol Model ICON-A-HAM2.3-Initial Model Evaluation and Effects of Radiation Balance Tuning on Aerosol Optical Thickness.

Salzmann, M / Ferrachat, S / Tully, C / Münch, S / Watson-Parris, D / Neubauer, D / Siegenthaler-Le Drian, C / Rast, S / Heinold, B / Crueger, T / Brokopf, R / Mülmenstädt, J / Quaas, J / Wan, H / Zhang, K / Lohmann, U / Stier, P / Tegen, I

Journal of advances in modeling earth systems

2022 Volume 14, Issue 4, Page(s) e2021MS002699

Abstract: The Hamburg Aerosol Module version 2.3 (HAM2.3) from the ECHAM6.3-HAM2.3 global atmosphere-aerosol model is coupled to the recently developed icosahedral nonhydrostatic ICON-A (icon-aes-1.3.00) global atmosphere model to yield the new ICON-A-HAM2.3 ... ...

Abstract	The Hamburg Aerosol Module version 2.3 (HAM2.3) from the ECHAM6.3-HAM2.3 global atmosphere-aerosol model is coupled to the recently developed icosahedral nonhydrostatic ICON-A (icon-aes-1.3.00) global atmosphere model to yield the new ICON-A-HAM2.3 atmosphere-aerosol model. The ICON-A and ECHAM6.3 host models use different dynamical cores, parameterizations of vertical mixing due to sub-grid scale turbulence, and parameter settings for radiation balance tuning. Here, we study the role of the different host models for simulated aerosol optical thickness (AOT) and evaluate impacts of using HAM2.3 and the ECHAM6-HAM2.3 two-moment cloud microphysics scheme on several meteorological variables. Sensitivity runs show that a positive AOT bias over the subtropical oceans is remedied in ICON-A-HAM2.3 because of a different default setting of a parameter in the moist convection parameterization of the host models. The global mean AOT is biased low compared to MODIS satellite instrument retrievals in ICON-A-HAM2.3 and ECHAM6.3-HAM2.3, but the bias is larger in ICON-A-HAM2.3 because negative AOT biases over the Amazon, the African rain forest, and the northern Indian Ocean are no longer compensated by high biases over the sub-tropical oceans. ICON-A-HAM2.3 shows a moderate improvement with respect to AOT observations at AERONET sites. A multivariable bias score combining biases of several meteorological variables into a single number is larger in ICON-A-HAM2.3 compared to standard ICON-A and standard ECHAM6.3. In the tropics, this multivariable bias is of similar magnitude in ICON-A-HAM2.3 and in ECHAM6.3-HAM2.3. In the extra-tropics, a smaller multivariable bias is found for ICON-A-HAM2.3 than for ECHAM6.3-HAM2.3.
Language	English
Publishing date	2022-04-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	2462132-8
ISSN	1942-2466
ISSN	1942-2466
DOI	10.1029/2021MS002699
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online: Observed Process-level Constraints of Cloud and Precipitation Properties over the Southern Ocean for Earth System Model Evaluation

Stanford, McKenna Wallace / Fridlind, Ann / Silber, Israel / Ackerman, Andrew / Cesana, Greg / Mülmenstädt, Johannes / Protat, Alain / Alexander, Simon / McDonald, Adrian

eISSN:

2023

Abstract: Over the remote Southern Ocean, cloud feedbacks contribute substantially to Earth system model (ESM) radiative biases. The evolution of low Southern Ocean clouds (cloud top heights < ~ 3 km) is strongly modulated by precipitation and/or evaporation, ... ...

Abstract	Over the remote Southern Ocean, cloud feedbacks contribute substantially to Earth system model (ESM) radiative biases. The evolution of low Southern Ocean clouds (cloud top heights < ~ 3 km) is strongly modulated by precipitation and/or evaporation, which act as the primary sink of cloud condensate. Constraining precipitation processes in ESMs requires robust observations suitable for process-level evaluations. A year-long subset (April 2016 – March 2017) of ground-based profiling instrumentation deployed during the Macquarie Island Cloud and Radiation Experiment (MICRE) field campaign (54.5° S, 158.9° E) combines a 95 GHz (W-band) Doppler cloud radar, two lidar ceilometers, and balloon-borne soundings to quantify the occurrence frequency of precipitation from liquid-phase cloud base. Liquid-based clouds at Macquarie Island precipitate ~ 70 % of the time, with deeper and colder clouds precipitating more frequently and at a higher intensity compared to thinner and warmer clouds. Supercooled cloud layers precipitate more readily than layers with cloud top temperatures > 0 °C, regardless of the geometric thickness of the layer, and also evaporate more frequently. We further demonstrate an approach to employ these observational constraints for evaluation of a 9-year GISS-ModelE3 ESM simulation. Model output is processed through the Earth Model Column Collaboratory (EMC 2 ) radar and lidar instrument simulator with the same instrument specifications as those deployed during MICRE, therefore accounting for instrument sensitivities and ensuring a coherent comparison. Relative to MICRE observations, the ESM produces a smaller cloud occurrence frequency, smaller precipitation occurrence frequency, and greater sub-cloud evaporation. The lower precipitation occurrence frequency by the ESM relative to MICRE contrasts with numerous studies that suggest a ubiquitous bias by ESMs to precipitate too frequently over the SO when compared with satellite-based observations, likely owing to sensitivity limitations of ...
Subject code	551
Language	English
Publishing date	2023-02-10
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Substantial Climate Response outside the Target Area in an Idealized Experiment of Regional Radiation Management

Dipu, Sudhakar / Quaas, Johannes / Quaas, Martin / Rickels, Wilfried / Mülmenstädt, Johannes / Boucher, Olivier

2021

Abstract: Radiation management (RM) has been proposed as a conceivable climate engineering (CE) intervention to mitigate global warming. In this study, we used a coupled climate model (MPI-ESM) with a very idealized setup to investigate the efficacy and risks of ... ...

Abstract	Radiation management (RM) has been proposed as a conceivable climate engineering (CE) intervention to mitigate global warming. In this study, we used a coupled climate model (MPI-ESM) with a very idealized setup to investigate the efficacy and risks of CE at a local scale in space and time (regional radiation management, RRM) assuming that cloud modification is technically possible. RM is implemented in the climate model by the brightening of low-level clouds (solar radiation management, SRM) and thinning of cirrus (terrestrial radiation management, TRM). The region chosen is North America, and we simulated a period of 30 years. The implemented sustained RM resulted in a net local radiative forcing of −9.8 Wm−2 and a local cooling of −0.8 K. Surface temperature (SAT) extremes (90th and 10th percentiles) show negative anomalies in the target region. However, substantial climate impacts were also simulated outside the target area, with warming in the Arctic and pronounced precipitation change in the eastern Pacific. As a variant of RRM, a targeted intervention to suppress heat waves (HW) was investigated in further simulations by implementing intermittent cloud modification locally, prior to the simulated HW situations. In most cases, the intermittent RRM results in a successful reduction of temperatures locally, with substantially smaller impacts outside the target area compared to the sustained RRM.
Keywords	ddc:330 ; regional radiation management ; climate engineering ; radiative forcing
Subject code	550 ; 551
Language	English
Publisher	Basel: MDPI
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Cloud base height retrieval from multi-angle satellite data

Böhm, Christoph / Sourdeval, Odran / Mülmenstädt, Johannes / Quaas, Johannes / Crewell, Susanne

eISSN: 1867-8548

2019

Abstract: Clouds are a key modulator of the Earth energy budget at the top of the atmosphere and at the surface. While the cloud top height is operationally retrieved with global coverage, only few methods have been proposed to determine cloud base height ( z base ...

Abstract	Clouds are a key modulator of the Earth energy budget at the top of the atmosphere and at the surface. While the cloud top height is operationally retrieved with global coverage, only few methods have been proposed to determine cloud base height ( z base ) from satellite measurements. This study presents a new approach to retrieve cloud base heights using the Multi-angle Imaging SpectroRadiometer (MISR) on the Terra satellite. It can be applied if some cloud gaps occur within the chosen distance of typically 10 km. The MISR cloud base height (MIBase) algorithm then determines z base from the ensemble of all MISR cloud top heights retrieved at a 1.1 km horizontal resolution in this area. MIBase is first calibrated using 1 year of ceilometer data from more than 1500 sites within the continental United States of America. The 15th percentile of the cloud top height distribution within a circular area of 10 km radius provides the best agreement with the ground-based data. The thorough evaluation of the MIBase product z base with further ceilometer data yields a correlation coefficient of about 0.66 , demonstrating the feasibility of this approach to retrieve z base . The impacts of the cloud scene structure and macrophysical cloud properties are discussed. For a 3-year period, the median z base is generated globally on a 0.25 ∘ × 0.25 ∘ grid. Even though overcast cloud scenes and high clouds are excluded from the statistics, the median z base retrievals yield plausible results, in particular over ocean as well as for seasonal differences. The potential of the full 16 years of MISR data is demonstrated for the southeast Pacific, revealing interannual variability in z base in accordance with reanalysis data. The global cloud base data for the 3-year period (2007–2009) are available at https://doi.org/10.5880/CRC1211DB.19 .
Subject code	333
Language	English
Publishing date	2019-03-20
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Physical science research needed to evaluate the viability and risks of marine cloud brightening.

Feingold, Graham / Ghate, Virendra P / Russell, Lynn M / Blossey, Peter / Cantrell, Will / Christensen, Matthew W / Diamond, Michael S / Gettelman, Andrew / Glassmeier, Franziska / Gryspeerdt, Edward / Haywood, James / Hoffmann, Fabian / Kaul, Colleen M / Lebsock, Matthew / McComiskey, Allison C / McCoy, Daniel T / Ming, Yi / Mülmenstädt, Johannes / Possner, Anna /

Prabhakaran, Prasanth / Quinn, Patricia K / Schmidt, K Sebastian / Shaw, Raymond A / Singer, Clare E / Sorooshian, Armin / Toll, Velle / Wan, Jessica S / Wood, Robert / Yang, Fan / Zhang, Jianhao / Zheng, Xue

Science advances

2024 Volume 10, Issue 12, Page(s) eadi8594

Abstract: Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science ... ...

Abstract	Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today's climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research-field and laboratory experiments, monitoring, and numerical modeling across a range of scales.
Language	English
Publishing date	2024-03-20
Publishing country	United States
Document type	Journal Article ; Review
ZDB-ID	2810933-8
ISSN	2375-2548 ; 2375-2548
ISSN (online)	2375-2548
ISSN	2375-2548
DOI	10.1126/sciadv.adi8594
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Global organic and inorganic aerosol hygroscopicity and its effect on radiative forcing.

Pöhlker, Mira L / Pöhlker, Christopher / Quaas, Johannes / Mülmenstädt, Johannes / Pozzer, Andrea / Andreae, Meinrat O / Artaxo, Paulo / Block, Karoline / Coe, Hugh / Ervens, Barbara / Gallimore, Peter / Gaston, Cassandra J / Gunthe, Sachin S / Henning, Silvia / Herrmann, Hartmut / Krüger, Ovid O / McFiggans, Gordon / Poulain, Laurent / Raj, Subha S /

Reyes-Villegas, Ernesto / Royer, Haley M / Walter, David / Wang, Yuan / Pöschl, Ulrich

Nature communications

2023 Volume 14, Issue 1, Page(s) 6139

Abstract: The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering ...

Abstract	The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering diverse environments from pristine to highly polluted conditions. We show that the effective aerosol hygroscopicity, κ, can be derived accurately from the fine aerosol mass fractions of organic particulate matter (ϵ
Language	English
Publishing date	2023-10-02
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-41695-8
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Article: Surprising similarities in model and observational aerosol radiative forcing estimates.

Gryspeerdt, Edward / Mülmenstädt, Johannes / Gettelman, Andrew / Malavelle, Florent F / Morrison, Hugh / Neubauer, David / Partridge, Daniel G / Stier, Philip / Takemura, Toshihiko / Wang, Hailong / Wang, Minghuai / Zhang, Kai

Atmospheric chemistry and physics

2020 Volume 20, Issue 1, Page(s) 613–623

Abstract: The radiative forcing from aerosols (particularly through their interaction with clouds) remains one of the most uncertain components of the human forcing of the climate. Observation-based studies have typically found a smaller aerosol effective ... ...

Abstract	The radiative forcing from aerosols (particularly through their interaction with clouds) remains one of the most uncertain components of the human forcing of the climate. Observation-based studies have typically found a smaller aerosol effective radiative forcing than in model simulations and were given preferential weighting in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). With their own sources of uncertainty, it is not clear that observation-based estimates are more reliable. Understanding the source of the model and observational differences is thus vital to reduce uncertainty in the impact of aerosols on the climate. These reported discrepancies arise from the different methods of separating the components of aerosol forcing used in model and observational studies. Applying the observational decomposition to global climate model (GCM) output, the two different lines of evidence are surprisingly similar, with a much better agreement on the magnitude of aerosol impacts on cloud properties. Cloud adjustments remain a significant source of uncertainty, particularly for ice clouds. However, they are consistent with the uncertainty from observation-based methods, with the liquid water path adjustment usually enhancing the Twomey effect by less than 50%. Depending on different sets of assumptions, this work suggests that model and observation-based estimates could be more equally weighted in future synthesis studies.
Language	English
Publishing date	2020-01-17
Publishing country	Germany
Document type	Journal Article
ISSN	1680-7316
ISSN	1680-7316
DOI	10.5194/acp-20-613-2020
Database	MEDical Literature Analysis and Retrieval System OnLINE

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