A5067235605- Climate variability and models
- Oceanographic and Atmospheric Processes
- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- Marine and coastal ecosystems
- Methane Hydrates and Related Phenomena
- Epistemology, Ethics, and Metaphysics
- Atmospheric chemistry and aerosols
- Arctic and Antarctic ice dynamics
- Philosophical Ethics and Theory
- Geophysics and Gravity Measurements
- Philosophy and Theoretical Science
- Hydrocarbon exploration and reservoir analysis
- Marine and environmental studies
- Tropical and Extratropical Cyclones Research
- Geological and Geophysical Studies
- Nuclear Physics and Applications
- Geological Studies and Exploration
- Geological formations and processes
- Psychology of Moral and Emotional Judgment
- Cinema and Media Studies
- Infrared Target Detection Methodologies
- Atmospheric Ozone and Climate
- Plant Water Relations and Carbon Dynamics
University of Reading
2016-2025
National Centre for Atmospheric Science
2016-2025
National Institute of Meteorology
2021-2023
Bjerknes Centre for Climate Research
2022
University of Bergen
2022
National Oceanography Centre
2020
University of Southampton
2020
Abstract Identifying the prime drivers of twentieth-century multidecadal variability in Atlantic Ocean is crucial for predicting how will evolve coming decades and resulting broad impacts on weather precipitation patterns around globe. Recently, Booth et al. showed that Hadley Centre Global Environmental Model, version 2, Earth system configuration (HadGEM2-ES) closely reproduces observed variations area-averaged North sea surface temperature twentieth century. The simulated HadGEM2-ES are...
Abstract In the mid-1990s, subpolar gyre of North Atlantic underwent a remarkable rapid warming, with sea surface temperatures increasing by around 1°C in just 2 yr. This warming followed prolonged positive phase Oscillation (NAO) but also coincided an unusually negative NAO index winter 1995/96. By comparing ocean analyses and carefully designed model experiments, it is shown that this can be understood as delayed response to not simply instantaneous Furthermore, inferred was partly caused...
Abstract We describe and evaluate historical simulations which use the third Hadley Centre Global Environment Model in Coupled configuration 3.1 (HadGEM3‐GC3.1) form part of UK's contribution to sixth Intercomparison Project, CMIP6. These simulations, run at two resolutions, respond historically evolving forcings such as greenhouse gases, aerosols, solar irradiance, volcanic land use, ozone concentrations. assess response these compare against observational record. This includes evolution...
Abstract The Atlantic Meridional Overturning Circulation (AMOC) has been, and will continue to be, a key factor in the modulation of climate change both locally globally. However, there remains considerable uncertainty recent AMOC evolution. Here, we show that multimodel mean strengthened by approximately 10% from 1850–1985 new simulations 6th Coupled Model Intercomparison Project (CMIP6), larger than was seen CMIP5. Across models, strength trend up 1985 is related proxy for aerosol forcing....
Abstract Preindustrial control simulations with the third Hadley Centre Global Environmental Model, run in Coupled configuration 3.1 of Met Office Unified Model (HadGEM3‐GC3.1) are presented at two resolutions. These N216ORCA025, which has a horizontal resolution 60 km atmosphere and 0.25° ocean, N96ORCA1, 130 1° ocean. The aim this study is to document climate variability these simulations, make comparisons against present‐day observations (albeit under different forcing), discuss...
In the mid 1990s North Atlantic subpolar gyre (SPG) warmed rapidly, with sea surface temperatures (SST) increasing by 1°C in just a few years. By examining initialized hindcasts made UK Met Office Decadal Prediction System (DePreSys), it is shown that warming could have been predicted. Conversely, only consider changes radiative forcings are not able to capture rapid warming. Heat budget analysis shows success of DePreSys due initialization anomalously strong northward ocean heat transport....
Abstract Instrumental observations, paleoproxies, and climate models suggest significant decadal variability within the North Atlantic subpolar gyre (NASPG). However, a poorly sampled observational record diversity of model behaviors mean that precise nature mechanisms this are unclear. Here we analyze an exceptionally large multimodel ensemble 42 present‐generation to test whether NASPG state biases systematically affect representation variability. Temperature salinity in Labrador Sea...
Abstract Atlantic multidecadal variability (AMV) is the term used to describe pattern of in North sea surface temperatures (SSTs) that characterized by decades basinwide warm or cool anomalies, relative global mean. AMV has been associated with numerous climate impacts many regions world including decadal variations temperature and rainfall patterns, hurricane activity, level changes. Given its importance, understanding physical processes drive extent which evolution predictable a key...
Abstract The observational network around the North Atlantic has improved significantly over last few decades with subsurface profiling floats and satellite observations recent efforts to monitor Meridional Overturning Circulation (AMOC). These have shown decadal time scale changes across including in heat content, transport, circulation. However, there are still significant gaps coverage. Ocean reanalyses integrate a dynamically consistent ocean model can be used understand observed...
Abstract Previous work has shown that anthropogenic aerosol (AA) forcing drives a strengthening in the Atlantic meridional overturning circulation (AMOC) CMIP6 historical simulations over 1850–1985, but mechanisms have not been fully understood. Across models, it is there strong correlation between surface heat loss subpolar North (SPNA) and forced of AMOC. Despite link to AA forcing, AMOC response strongly related contribution anomalous downwelling shortwave radiation SPNA loss. Rather,...
Abstract We investigate how the ocean responds to 10-yr persistent surface heat flux forcing over subpolar North Atlantic (SPNA) associated with observed winter NAO in three CMIP6-class coupled models. The experiments reveal a broadly consistent response imposed forcing. Positive produces anomalously dense water masses SPNA, increasing southward lower (denser) limb of meridional overturning circulation (AMOC) density coordinates. propagation anomalous generates zonal pressure gradient...
© 2024 The Author(s). Published by the American Meteorological Society. This is an Author Accepted Manuscript distributed under terms of Creative Commons Attribution 4.0 International (CC BY 4.0) License . * Corresponding author, email: Antje.Weisheimer@physics.ox.ac.uk
Since the mid-1990s precipitation trends over eastern China display a dipole pattern, characterized by positive anomalies in south and negative north, named as Southern-Flood-Northern-Drought (SFND) pattern. This work investigates drivers of decadal changes East Asian summer monsoon (EASM), dynamical mechanisms involved, using coupled climate model (specifically an atmospheric general circulation to ocean mixed layer model) forced (1) anthropogenic greenhouse gases (GHG), (2) aerosol (AA)...
Abstract We assess the effect of Atlantic multidecadal variability (AMV) on global monsoon using idealized simulations. Warm AMV phases are associated with a significant strengthening precipitation over Northern Africa and India, anomalously weak South America. Changes in mediated by change atmospheric dynamics, primarily shift circulation related to both an enhanced interhemispheric thermal contrast remote impact Pacific Ocean, through changes Walker circulation. In contrast, thermodynamic...
Climate prediction skill on the interannual timescale, which sits between that of seasonal and decadal, is investigated using large ensembles from Met Office CESM initialised coupled systems. A key goal to determine what can be skillfully predicted about coming year when combining these two together. Annual surface temperature predictions show good at both global regional scales, but diminishes trend associated with warming removed. Skill for extended boreal summer (months 7–11) winter...
Abstract Atlantic multidecadal variability (AMV) has been linked to the observed slowdown of global warming over 1998–2012 through its impact on tropical Pacific. Given importance Pacific variability, better understanding this Atlantic–Pacific teleconnection is key for improving climate predictions, but robustness and strength link are uncertain. Analyzing a multi-model set sensitivity experiments, we find that models differ by factor 10 in simulating amplitude Equatorial cooling response...
Major changes are occurring across the North Atlantic climate system, including in atmosphere, ocean and cryosphere, many observed unprecedented instrumental records. As directly affect air quality of surrounding continents, it is important to fully understand how why taking place, not least predict region will change future. To this end, article characterizes recent region, especially period 2005–2016, different aspects system including: atmospheric circulation; composition; clouds...
Abstract It is widely thought that changes in both the surface buoyancy fluxes and wind stress drive variability Atlantic meridional overturning circulation (AMOC), but they on different time scales. For example, forcing dominates short-term through its effects Ekman currents coastal upwelling, whereas important for longer scales (multiannual decadal). However, role of multiannual to decadal less clear. Here authors present an analysis simulations with Nucleus European Modelling Ocean (NEMO)...