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Your search keyword '"University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)"' showing total 3 results
Start Over Author "University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)" Publisher american geophysical union (agu)
3 results on '"University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)"'

1. Variations in Atlantic surface ocean paleoceanography, 50°-80°N: A time-slice record of the last 30,000 years

Author

Sarnthein, Michael, Jansen, Eystein, Weinelt, Mara, Arnold, Maurice, Duplessy, Jean Claude, Erlenkeuser, Helmut, Flatøy, Astrid, Johannessen, Gro, Johannessen, Truls, Jung, Simon, Koc, Nalan, Labeyrie, Laurent, Maslin, Mark, Pflaumann, Uwe, Schulz, Hartmut, Samthein, Michael, Duplessy, Jean, Flat0y, Astrid, Kiel University, Geological Institute [Bergen], University of Bergen (UiB), Centre des Faibles Radioactivités, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Institut für Geologie [Hannover], and Leibniz Universität Hannover=Leibniz University Hannover

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Paleontology, Last Glacial Maximum, Oceanography, Paleoceanography, Interglacial, Glacial period, Younger Dryas, Ice sheet, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Quaternary, Meltwater, Geology
Abstract

International audience; Eight time slices of surface-water paleoceanography were reconstructed from stable isotope and paleotemperature data to evaluate late Quaternary changes in density, current directions, and sea-ice cover in the Nordic Seas and NE Atlantic. We used isotopic records from 110 deep-sea cores, 20 of which are accelerator mass spectrometry (AMS)-14C dated and 30 of which have high (>8 cm/kyr) sedimentation rates, enabling a resolution of about 120 years. Paleotemperature estimates are based on species counts of planktonic foraminifera in 18 cores. The •5180 and •513C distributions depict three main modes of surface circulation: (1) The Holocene-style interglacial mode which largely persisted over the last 12.8 •4C ka, and probably during large parts of stage 3. (2) The peak glacial mode showing a cyclonic gyre in the, at least, seasonally ice-free Nordic Seas and a meltwater lens west of Ireland. Based on geostrophic forcing, it possibly turned clockwise, blocked the S-N flow across the eastern Iceland-Shetland ridge, and enhanced the Irminger current around west Iceland. It remains unclear whether surface-water density was sufficient for deepwater formation west of Norway. (3) A meltwater regime culminating during early glacial Termination I, when a great meltwater lens off northern Norway probably induced a clockwise circulation reaching south up to Faeroe, the northward inflow of Irminger Current water dominated the Icelandic Sea, and deepwater convection was stopped. In contrast to circulation modes two and three, the Holocene-style circulation mode appears most stable, even unaffected by major meltwater pools originating from the Scandinavian ice sheet, such as during •80 event 3.1 and the B611ing. Meltwater phases markedly influenced the European continental climate by suppressing the "heat pump" of the Atlantic salinity conveyor belt. During the peak glacial, melting icebergs blocked the eastward advection of warm surface water toward Great Britain, thus accelerating buildup of the great European ice sheets; in the early deglacial, meltwater probably induced a southward flow of cold water along Norway, which led to the Oldest Dryas cold spell.

Published
1995

2. Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model

Author

Nicolas Bellouin, Peter Braesicke, Jim Haywood, Paul Agnew, John E. Barnes, Cathy Clerbaux, Pierre-François Coheur, D. A. Degenstein, Paul Telford, Olivier Boucher, Lieven Clarisse, Andrew Jones, Adam Bourassa, College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université libre de Bruxelles (ULB), University of Saskatchewan [Saskatoon] (U of S), Mauna Loa Observatory (MLO), ESRL Global Monitoring Laboratory [Boulder] (GML), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA)-NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), NCAS-Climate [Cambridge], Department of Chemistry [Cambridge, UK], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), UK’s National Centre for Atmospheric Science (NCAS)., EU FP6 Integrated Programme, and CNES

Subjects
Earth's energy budget, Atmospheric Science, 010504 meteorology & atmospheric sciences, Climate, [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, Aquatic Science, 010502 geochemistry & geophysics, Oceanography, Atmospheric sciences, 01 natural sciences, chemistry.chemical_compound, Geochemistry and Petrology, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Earth and Planetary Sciences (miscellaneous), Sulfate aerosol, Sarychev, Volcano, Aerosol, Stratosphere, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Sulphuric acid, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], geography, Vulcanian eruption, geography.geographical_feature_category, Ecology, Paleontology, Forestry, Radiative forcing, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, Eruption, Climatology, Environmental science, Climate model
Abstract

[1] In June 2009 the Sarychev volcano located in the Kuril Islands to the northeast of Japan erupted explosively, injecting ash and an estimated 1.2 ± 0.2 Tg of sulfur dioxide into the upper troposphere and lower stratosphere, making it arguably one of the 10 largest stratospheric injections in the last 50 years. During the period immediately after the eruption, we show that the sulfur dioxide (SO2) cloud was clearly detected by retrievals developed for the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument and that the resultant stratospheric sulfate aerosol was detected by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and CALIPSO lidar. Additional surface-based instrumentation allows assessment of the impact of the eruption on the stratospheric aerosol optical depth. We use a nudged version of the HadGEM2 climate model to investigate how well this state-of-the-science climate model can replicate the distributions of SO2 and sulfate aerosol. The model simulations and OSIRIS measurements suggest that in the Northern Hemisphere the stratospheric aerosol optical depth was enhanced by around a factor of 3 (0.01 at 550 nm), with resultant impacts upon the radiation budget. The simulations indicate that, in the Northern Hemisphere for July 2009, the magnitude of the mean radiative impact from the volcanic aerosols is more than 60% of the direct radiative forcing of all anthropogenic aerosols put together. While the cooling induced by the eruption will likely not be detectable in the observational record, the combination of modeling and measurements would provide an ideal framework for simulating future larger volcanic eruptions.

Published
2010

3. Anthropogenic forcing of the Northern Annular Mode in CCMVal-2 models

Author

Dan Smale, W. Tian, Martyn P. Chipperfield, P. Braesicke, Steven C. Hardiman, Tetsu Nakamura, David Cugnet, Makoto Deushi, Sandip Dhomse, Kiyotaka Shibata, Slimane Bekki, Olaf Morgenstern, David Saint-Martin, John Scinocca, D. Olivié, Jean-Francois Lamarque, Julien Jumelet, N. Butchart, Eugene Rozanov, Martine Michou, Hideharu Akiyoshi, Aurore Voldoire, H. Teyssèdre, Marion Marchand, Nathan P. Gillett, Andrew Gettelman, Michael Sigmond, Yousuke Yamashita, Douglas E. Kinnison, David A. Plummer, John A. Pyle, François Lott, Rolando R. Garcia, Thomas Peter, National Institute of Water and Atmospheric Research [Lauder] (NIWA), National Institute for Environmental Studies (NIES), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), NCAS-Climate [Cambridge], Department of Chemistry [Cambridge, UK], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], School of Earth and Environment [Leeds] (SEE), University of Leeds, Meteorological Research Institute [Tsukuba] (MRI), Japan Meteorological Agency (JMA), National Center for Atmospheric Research [Boulder] (NCAR), Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), Centre for Atmospheric Science [Cambridge, UK], University of Cambridge [UK] (CAM), Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Physics [Toronto], University of Toronto, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Horizontal and vertical, Soil Science, Geopotential height, Forcing (mathematics), Aquatic Science, 010502 geochemistry & geophysics, Oceanography, Atmospheric sciences, 01 natural sciences, Model validation, Geochemistry and Petrology, Stratosphere-troposphere coupling, Earth and Planetary Sciences (miscellaneous), Climate change, Anthropogenic forcing, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecology, Paleontology, Forestry, Coherence (statistics), Ozone depletion, Geophysics, Arctic oscillation, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, 13. Climate action, Space and Planetary Science, Climatology, Greenhouse gas, Environmental science
Abstract

International audience; We address the question of how ozone and long-lived greenhouse gas changes impact the Northern Annular Mode (NAM). Using reanalyses and results from the Chemistry-Climate Model Validation 2 (CCMVal-2) initiative, we calculate seasonal NAM indices from geopotential height for winter and spring. From these, we determine the strength of stratosphere-troposphere coupling in the model simulations and the reanalyses. For both seasons, we find a large spread in the ability of models to represent the vertical coherence of the NAM, although most models are within the 95% confidence interval. In winter, many models underestimate the vertical coherence derived from the reanalyses. Some models exhibit substantial differences in vertical coherence between simulations driven with modeled and observed ocean conditions. In spring, in the simulations using modeled ocean conditions, models with poorer horizontal or vertical resolution tend to underestimate the vertical coupling, and vice versa for models with better resolution. Accounting for model deficits in producing an appropriate troposphere-stratosphere coupling, we show significant correlations of the NAM in winter with three indices representing the anthropogenic impact. Analysis of cross-correlations between these indices suggests that increasing CO2 is the main reason for these correlations in this season. In the CCMVal-2 simulations, CO2 increases are associated with a weakening of the NAM in winter. For spring, we show that the dominant effect is chemical ozone depletion leading to a transient strengthening of the NAM, with CO2 changes playing an insignificant role.

Published
2010

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