LIVIVO - Search results -

Search results

Result 1 - 10 of total 10

Search options

Book ; Online: Uncertainty in aerosol–cloud radiative forcing is driven by clean conditions

Gryspeerdt, Edward / Povey, Adam C. / Grainger, Roy G. / Hasekamp, Otto / Hsu, N. Christina / Mulcahy, Jane P. / Sayer, Andrew M. / Sorooshian, Armin

eISSN: 1680-7324

2023

Abstract: Atmospheric aerosols and their impact on cloud properties remain the largest uncertainty in the human forcing of the climate system. By increasing the concentration of cloud droplets ( N d ), aerosols reduce droplet size and increase the reflectivity of ... ...

Abstract	Atmospheric aerosols and their impact on cloud properties remain the largest uncertainty in the human forcing of the climate system. By increasing the concentration of cloud droplets ( N d ), aerosols reduce droplet size and increase the reflectivity of clouds (a negative radiative forcing). Central to this climate impact is the susceptibility of cloud droplet number to aerosol ( β ), the diversity of which explains much of the variation in the radiative forcing from aerosol–cloud interactions (RFaci) in global climate models. This has made measuring β a key target for developing observational constraints of the aerosol forcing. While the aerosol burden of the clean, pre-industrial atmosphere has been demonstrated as a key uncertainty for the aerosol forcing, here we show that the behaviour of clouds under these clean conditions is of equal importance for understanding the spread in radiative forcing estimates between models and observations. This means that the uncertainty in the aerosol impact on clouds is, counterintuitively, driven by situations with little aerosol. Discarding clean conditions produces a close agreement between different model and observational estimates of the cloud response to aerosol but does not provide a strong constraint on the RFaci. This makes constraining aerosol behaviour in clean conditions an important goal for future observational studies.
Subject code	520 ; 551
Language	English
Publishing date	2023-04-05
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online: Global analysis of the controls on seawater dimethylsulfide spatial variability

Manville, George / Bell, Thomas G. / Mulcahy, Jane P. / Simó, Rafel / Galí, Martí / Mahajan, Anoop S. / Hulswar, Shrivardhan / Halloran, Paul R.

eISSN: 1726-4189

2023

Abstract: Dimethylsulfide (DMS) emitted from the ocean makes a significant global contribution to natural marine aerosol and cloud condensation nuclei, and therefore our planet’s climate. Oceanic DMS concentrations show large spatiotemporal variability, but ... ...

Abstract	Dimethylsulfide (DMS) emitted from the ocean makes a significant global contribution to natural marine aerosol and cloud condensation nuclei, and therefore our planet’s climate. Oceanic DMS concentrations show large spatiotemporal variability, but observations are sparse, so products describing global DMS distribution rely on interpolation or modelling. Understanding the mechanisms driving DMS variability, especially at local scales, is required to reduce uncertainty in large scale DMS estimates. We present a study of mesoscale and sub-mesoscale (<100 km) seawater DMS variability that takes advantage of the recent expansion in high frequency seawater DMS observations and uses all available data to investigate the typical distances over which DMS varies in all major ocean basins. These DMS spatial variability lengthscales (VLS) are uncorrelated with DMS concentrations. DMS concentrations and VLS can therefore be used separately to help identify mechanisms underpinning DMS variability. When data are grouped by sampling campaigns, almost 80 % of the DMS VLS can be explained using the VLS of sea surface height anomalies, density, and chlorophyll- a . Our global analysis suggests that both physical and biogeochemical processes play an equally important role in controlling DMS variability, in contrast with previous results based on data from the low–mid latitudes. The explanatory power of sea surface height anomalies indicates the importance of mesoscale eddies in driving DMS variability, previously unrecognised at a global scale and in agreement with recent regional studies. DMS VLS differs regionally, including surprisingly high frequency variability in low latitude waters. Our results independently confirm that relationships used in the literature to parameterise DMS at large scales appear to be considering the right variables. However, contrasts in regional DMS VLS highlight that important driving mechanisms remain elusive. The role of sub-mesoscale features should be resolved or accounted for in DMS process ...
Subject code	551
Language	English
Publishing date	2023-01-17
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online: Evaluation of SO2, SO42− and an updated SO2 dry deposition parameterization in UKESM1

Hardacre, Catherine / Mulcahy, Jane P. / Pope, Richard / Jones, Colin G. / Rumbold, Steven R. / Li, Can / Turnock, Steven T.

eISSN: 1680-7324

2021

Abstract: In this study we evaluate simulated surface SO 2 and sulphate (SO 4 2− ) concentrations from the United Kingdom Earth System Model (UKESM1) against observations from ground based measurement networks in the USA and Europe for the period 1987 to 2014. We ... ...

Abstract	In this study we evaluate simulated surface SO 2 and sulphate (SO 4 2− ) concentrations from the United Kingdom Earth System Model (UKESM1) against observations from ground based measurement networks in the USA and Europe for the period 1987 to 2014. We find that UKESM1 captures the historical trend for decreasing concentrations of atmospheric SO 2 and SO 4 2− in both Europe and the USA over the period 1987 to 2014. However, in the polluted regions of the eastern USA and Europe, UKESM1 over-predicts surface SO 2 concentrations by a factor of 3, while under-predicting surface SO 4 2− concentrations by 25–35 %. In the cleaner western USA, the model over-predicts both surface SO 2 and SO 4 2− concentrations by a factor of 12 and 1.5 respectively. We find that UKESM1’s bias in surface SO 2 and SO 4 2− concentrations is variable according to region and season. We also evaluate UKESM1 against total column SO 2 from the Ozone Monitoring Instrument (OMI) using an updated data product. This comparison provides information about the model’s global performance, finding that UKESM1 over predicts total column SO 2 over much of the globe, including the large source regions of India, China, the USA and Europe as well as over outflow regions. Finally, we assess the impact of a more realistic treatment of the model’s SO 2 dry deposition parameterization. This change increases SO 2 dry deposition to the land and ocean surfaces, thus reducing the atmospheric loading of SO 2 and SO 4 2− . In comparison with the ground-based and satellite observations, we find that the modified parameterization reduces the model’s over prediction of surface SO 2 concentrations and total column SO 2 . Relative to the ground-based observations the simulated surface SO 4 2− concentrations are also reduced, while the simulated SO 2 dry deposition fluxes increase.
Subject code	290 ; 333
Language	English
Publishing date	2021-04-28
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online: Identifying climate model structural inconsistencies allows for tight constraint of aerosol radiative forcing

Regayre, Leighton A. / Deaconu, Lucia / Grosvenor, Daniel P. / Sexton, David M. H. / Symonds, Christopher / Langton, Tom / Watson-Paris, Duncan / Mulcahy, Jane P. / Pringle, Kirsty J. / Richardson, Mark / Johnson, Jill S. / Rostron, John W. / Gordon, Hamish / Lister, Grenville / Stier, Philip / Carslaw, Ken S.

eISSN:

2023

Abstract: Aerosol radiative forcing uncertainty affects estimates of climate sensitivity and limits model skill at making climate projections. Efforts to improve the representations of physical processes in climate models, including extensive comparisons with ... ...

Abstract	Aerosol radiative forcing uncertainty affects estimates of climate sensitivity and limits model skill at making climate projections. Efforts to improve the representations of physical processes in climate models, including extensive comparisons with observations, have not significantly constrained the range of possible aerosol forcing values. A far stronger constraint, in particular for the lower (most-negative) bound, can be achieved using global mean energy-balance arguments based on observed changes in historical temperature. Here, we show that structural deficiencies in a climate model, revealed as inconsistencies among observationally constrained cloud properties in the model, limit the effectiveness of observational constraint of the uncertain physical processes. We sample uncertainty in 37 model parameters related to aerosols, clouds and radiation in a perturbed parameter ensemble of the UK Earth System Model and evaluate 1 million model variants (different parameter settings from Gaussian Process emulators) against satellite-derived observations over several cloudy regions. We show that it is possible to reduce the parametric uncertainty in global mean aerosol forcing by more than 50 %, constraining it to a range in close agreement with energy-balance constraints (around −1.3 to −0.1 W m −2 ). However, our analysis of a very large set of model variants exposes model internal inconsistencies that would not be apparent in a small set of model simulations. Incorporating observations associated with these inconsistencies weakens the forcing constraint because they require a wider range of parameter values to accommodate conflicting information. Our estimated aerosol forcing range is the maximum feasible constraint using our structurally imperfect model and the chosen observations. Structural model developments targeted at the identified inconsistencies would enable a larger set of observations to be used for constraint, which would then narrow the uncertainty further. Such an approach provides a rigorous ...
Subject code	551
Language	English
Publishing date	2023-02-16
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article: U.K. Community Earth System Modeling for CMIP6.

Senior, Catherine A / Jones, Colin G / Wood, Richard A / Sellar, Alistair / Belcher, Stephen / Klein-Tank, Albert / Sutton, Rowan / Walton, Jeremy / Lawrence, Bryan / Andrews, Timothy / Mulcahy, Jane P

Journal of advances in modeling earth systems

2020 Volume 12, Issue 9, Page(s) e2019MS002004

Abstract: We describe the approach taken to develop the United Kingdom's first community Earth system model, UKESM1. This is a joint effort involving the Met Office and the Natural Environment Research Council (NERC), representing the U.K. academic community. We ... ...

Abstract	We describe the approach taken to develop the United Kingdom's first community Earth system model, UKESM1. This is a joint effort involving the Met Office and the Natural Environment Research Council (NERC), representing the U.K. academic community. We document our model development procedure and the subsequent U.K. submission to CMIP6, based on a traceable hierarchy of coupled physical and Earth system models. UKESM1 builds on the well-established, world-leading HadGEM models of the physical climate system and incorporates cutting-edge new representations of aerosols, atmospheric chemistry, terrestrial carbon, and nitrogen cycles and an advanced model of ocean biogeochemistry. A high-level metric of overall performance shows that both models, HadGEM3-GC3.1 and UKESM1, perform better than most other CMIP6 models so far submitted for a broad range of variables. We point to much more extensive evaluation performed in other papers in this special issue. The merits of not using any forced climate change simulations within our model development process are discussed. First results from HadGEM3-GC3.1 and UKESM1 include the emergent climate sensitivity (5.5 and 5.4 K, respectively) which is high relative to the current range of CMIP5 models. The role of cloud microphysics and cloud-aerosol interactions in driving the climate sensitivity, and the systematic approach taken to understand this role, is highlighted in other papers in this special issue. We place our findings within the broader modeling landscape indicating how our understanding of key processes driving higher sensitivity in the two U.K. models seems to align with results from a number of other CMIP6 models.
Language	English
Publishing date	2020-09-21
Publishing country	United States
Document type	Journal Article
ZDB-ID	2462132-8
ISSN	1942-2466
ISSN	1942-2466
DOI	10.1029/2019MS002004
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Article ; Online: The hemispheric contrast in cloud microphysical properties constrains aerosol forcing.

McCoy, Isabel L / McCoy, Daniel T / Wood, Robert / Regayre, Leighton / Watson-Parris, Duncan / Grosvenor, Daniel P / Mulcahy, Jane P / Hu, Yongxiang / Bender, Frida A-M / Field, Paul R / Carslaw, Kenneth S / Gordon, Hamish

Proceedings of the National Academy of Sciences of the United States of America

2020 Volume 117, Issue 32, Page(s) 18998–19006

Abstract: The change in planetary albedo due to aerosol-cloud interactions during the industrial era is the leading source of uncertainty in inferring Earth's climate sensitivity to increased greenhouse gases from the historical record. The variable that controls ... ...

Abstract	The change in planetary albedo due to aerosol-cloud interactions during the industrial era is the leading source of uncertainty in inferring Earth's climate sensitivity to increased greenhouse gases from the historical record. The variable that controls aerosol-cloud interactions in warm clouds is droplet number concentration. Global climate models demonstrate that the present-day hemispheric contrast in cloud droplet number concentration between the pristine Southern Hemisphere and the polluted Northern Hemisphere oceans can be used as a proxy for anthropogenically driven change in cloud droplet number concentration. Remotely sensed estimates constrain this change in droplet number concentration to be between 8 cm
Keywords	covid19
Language	English
Publishing date	2020-07-27
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	209104-5
ISSN	1091-6490 ; 0027-8424
ISSN (online)	1091-6490
ISSN	0027-8424
DOI	10.1073/pnas.1922502117
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Cologne/Königswinter

Zs.A 1148: Show issues

Location:
Je nach Verfügbarkeit (siehe Angabe bei Bestand)
bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
Jg. 1995 - 2021: Lesesall (1.OG)
ab Jg. 2022: Lesesaal (EG)

Order via subito

Details ▾
- See ZB MED holdings
- Order with fees

Book ; Online: Identifying climate model structural inconsistencies allows for tight constraint of aerosol radiative forcing

Regayre, Leighton A. / Deaconu, Lucia / Grosvenor, Daniel P. / Sexton, David / Symonds, Christopher C. / Langton, Tom / Watson-Paris, Duncan / Mulcahy, Jane P. / Pringle, Kirsty J. / Richardson, Mark / Johnson, Jill S. / Rostron, John / Gordon, Hamish / Lister, Grenville / Stier, Philip / Carslaw, Ken S.

eISSN:

2022

Abstract	Aerosol radiative forcing uncertainty affects estimates of climate sensitivity and limits model skill at making climate projections. Efforts to improve the representations of physical processes in climate models, including extensive comparisons with observations, have not significantly constrained the range of possible aerosol forcing values. A far stronger constraint, in particular for the lower (most-negative) bound, can be achieved using global mean energy-balance arguments based on observed changes in historical temperature. Here, we show that structural deficiencies in a climate model, revealed as inconsistencies among observationally constrained cloud properties, limit the effectiveness of observational constraint of the uncertain physical processes. We sample uncertainty in 37 model parameters related to aerosols, clouds and radiation in a perturbed parameter ensemble of the UK Earth System Model and evaluate one million model variants (different parameter settings from Gaussian Process emulators) against satellite-derived observations over several cloudy regions. We show it is possible to reduce the parametric uncertainty in global mean aerosol forcing by more than 50 % to a range in close agreement with energy-balance constraints (around -1.3 to -0.1 W m -2 ). However, incorporating observations associated with model inconsistencies weakens the constraint because the inconsistencies introduce conflicting information about relationships between model parameter values and aerosol forcing. Our estimated aerosol forcing range is the maximum feasible constraint using these observations and our structurally imperfect model. Structural model developments, targeted at the inconsistencies identified here, would enable a larger set of observations to be used for constraint, which would then narrow the uncertainty further.
Subject code	551
Language	English
Publishing date	2022-11-28
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online: The role of anthropogenic aerosols in the anomalous cooling from 1960 to 1990 in the CMIP6 Earth System Models

Zhang, Jie / Furtado, Kalli / Turnock, Steven T. / Mulcahy, Jane P. / Wilcox, Laura J. / Booth, Ben B. / Sexton, David / Wu, Tongwen / Zhang, Fang / Liu, Qianxia

eISSN: 1680-7324

2021

Abstract: The Earth System Models (ESMs) that participated in the 6th Coupled Model Intercomparison Project (CMIP6) tend to simulate excessive cooling in surface air temperature (TAS) between 1960 and 1990. The anomalous cooling is pronounced over the Northern ... ...

Abstract	The Earth System Models (ESMs) that participated in the 6th Coupled Model Intercomparison Project (CMIP6) tend to simulate excessive cooling in surface air temperature (TAS) between 1960 and 1990. The anomalous cooling is pronounced over the Northern Hemisphere (NH) midlatitudes, coinciding with the rapid growth of anthropogenic sulfur dioxide (SO 2 ) emissions, the primary precursor of atmospheric sulphate aerosols. Historical simulations with and without anthropogenic aerosol emissions indicate that the anomalous cooling within the ESMs is potentially due to in part from overestimated anthropogenic aerosols and the enhanced aerosol-forcing-sensitivity. Structural uncertainties between ESMs that contribute to these two factors have a larger impact on the anomalous cooling than internal variability. CMIP6 simulations can also help us to quantify the relative contributions of aerosol-forcing-sensitivity by aerosol-radiation interactions (ARI) and by aerosol-cloud interactions (ACI). However, even when the aerosol-forcing-sensitivity is similar between ESMs, the relative contributions of ARI and ACI may be substantially different. The ACI accounts for 64 to 87 % of the aerosol-forcing-sensitivity and is the main source of differences between the ESMs. The ACI can be further decomposed into a cloud-amount term (which depends linearly on cloud fraction) and a cloud-albedo term (which is independent of cloud fraction, to the first order). The large uncertainties of cloud-amount term are responsible for the aerosol-forcing-sensitivity differences and further the anomalous cooling differences among ESMs. The metrics used here therefore provide a simple way of assessing the physical mechanisms contributing to anomalous twentieth century cooling in any given ESM, which may benefit future model developments.
Subject code	551
Language	English
Publishing date	2021-07-15
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Book ; Online: Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models

Bock, Josué / Michou, Martine / Nabat, Pierre / Abe, Manabu / Mulcahy, Jane P. / Olivié, Dirk J. L. / Schwinger, Jörg / Suntharalingam, Parvadha / Tjiputra, Jerry / Hulten, Marco / Watanabe, Michio / Yool, Andrew / Séférian, Roland

eISSN: 1726-4189

2021

Abstract: Characteristics and trends of surface ocean dimethylsulfide (DMS) concentrations and fluxes into the atmosphere of four Earth system models (ESMs: CNRM-ESM2-1, MIROC-ES2L, NorESM2-LM, and UKESM1-0-LL) are analysed over the recent past (1980–2009) and ... ...

Abstract	Characteristics and trends of surface ocean dimethylsulfide (DMS) concentrations and fluxes into the atmosphere of four Earth system models (ESMs: CNRM-ESM2-1, MIROC-ES2L, NorESM2-LM, and UKESM1-0-LL) are analysed over the recent past (1980–2009) and into the future, using Coupled Model Intercomparison Project 6 (CMIP6) simulations. The DMS concentrations in historical simulations systematically underestimate the most widely used observed climatology but compare more favourably against two recent observation-based datasets. The models better reproduce observations in mid to high latitudes, as well as in polar and westerlies marine biomes. The resulting multi-model estimate of contemporary global ocean DMS emissions is 16–24 Tg S yr −1 , which is narrower than the observational-derived range of 16 to 28 Tg S yr −1 . The four models disagree on the sign of the trend of the global DMS flux from 1980 onwards, with two models showing an increase and two models a decrease. At the global scale, these trends are dominated by changes in surface DMS concentrations in all models, irrespective of the air–sea flux parameterisation used. In turn, three models consistently show that changes in DMS concentrations are correlated with changes in marine productivity; however, marine productivity is poorly constrained in the current generation of ESMs, thus limiting the predictive ability of this relationship. In contrast, a consensus is found among all models over polar latitudes where an increasing trend is predominantly driven by the retreating sea-ice extent. However, the magnitude of this trend between models differs by a factor of 3, from 2.9 to 9.2 Gg S decade −1 over the period 1980–2014, which is at the low end of a recent satellite-derived analysis. Similar increasing trends are found in climate projections over the 21st century.
Subject code	333 ; 551
Language	English
Publishing date	2021-06-29
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article: The hemispheric contrast in cloud microphysical properties constrains aerosol forcing

Proc. Natl. Acad. Sci. U. S. A

Abstract	The change in planetary albedo due to aerosol-cloud interactions during the industrial era is the leading source of uncertainty in inferring Earth's climate sensitivity to increased greenhouse gases from the historical record. The variable that controls aerosol-cloud interactions in warm clouds is droplet number concentration. Global climate models demonstrate that the present-day hemispheric contrast in cloud droplet number concentration between the pristine Southern Hemisphere and the polluted Northern Hemisphere oceans can be used as a proxy for anthropogenically driven change in cloud droplet number concentration. Remotely sensed estimates constrain this change in droplet number concentration to be between 8 cm-3 and 24 cm-3 By extension, the radiative forcing since 1850 from aerosol-cloud interactions is constrained to be -1.2 Wâ m-2 to -0.6 Wâ m-2 The robustness of this constraint depends upon the assumption that pristine Southern Ocean droplet number concentration is a suitable proxy for preindustrial concentrations. Droplet number concentrations calculated from satellite data over the Southern Ocean are high in austral summer. Near Antarctica, they reach values typical of Northern Hemisphere polluted outflows. These concentrations are found to agree with several in situ datasets. In contrast, climate models show systematic underpredictions of cloud droplet number concentration across the Southern Ocean. Near Antarctica, where precipitation sinks of aerosol are small, the underestimation by climate models is particularly large. This motivates the need for detailed process studies of aerosol production and aerosol-cloud interactions in pristine environments. The hemispheric difference in satellite estimated cloud droplet number concentration implies preindustrial aerosol concentrations were higher than estimated by most models.
Keywords	covid19
Publisher	WHO
Document type	Article
Note	WHO #Covidence: #32719114
Database	COVID19

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾

To top

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

More links

Kategorien

In stock of ZB MED Cologne/Königswinter

Order via subito

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Kategorien

Inter-library loan at ZB MED