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  • Articles  (69)
  • Data  (14)
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  • Articles  (69)
  • Data  (14)
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  • Other types  (4)
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  • 1
    Publication Date: 2023-11-24
    Description: The Middle Miocene (15.99–11.65 Ma) of Europe witnessed major climatic, environmental, and vegetational change, yet we are lacking detailed reconstructions of Middle Miocene temperature and precipitation patterns over Europe. Here, we use a high‐resolution (∼0.75°) isotope‐enabled general circulation model (ECHAM5‐wiso) with time‐specific boundary conditions to investigate changes in temperature, precipitation, and δ〈sup〉18〈/sup〉O in precipitation (δ〈sup〉18〈/sup〉O〈sub〉p〈/sub〉). Experiments were designed with variable elevation configurations of the European Alps and different atmospheric CO〈sub〉2〈/sub〉 levels to examine the influence of Alpine elevation and global climate forcing on regional climate and δ〈sup〉18〈/sup〉Op patterns. Modeling results are in agreement with available paleobotanical temperature data and with low‐resolution Middle Miocene experiments of the Miocene Model Intercomparison Project (MioMIP1). However, simulated precipitation rates are 300–500 mm/yr lower in the Middle Miocene than for pre‐industrial times for central Europe. This result is consistent with precipitation estimates from herpetological fossil assemblages, but contradicts precipitation estimates from paleobotanical data. We attribute the Middle Miocene precipitation change in Europe to shifts in large‐scale pressure patterns in the North Atlantic and over Europe and associated changes in wind direction and humidity. We suggest that global climate forcing contributed to a maximum δ〈sup〉18〈/sup〉O〈sub〉p〈/sub〉 change of ∼2‰ over high elevation (Alps) and ∼1‰ over low elevation regions. In contrast, we observe a maximum modeled δ〈sup〉18〈/sup〉O〈sub〉p〈/sub〉 decrease of 8‰ across the Alpine orogen due to Alpine topography. However, the elevation‐δ〈sup〉18〈/sup〉O〈sub〉p〈/sub〉 lapse rate shallows in the Middle Miocene, leading to a possible underestimation of paleotopography when using present‐day δ〈sup〉18〈/sup〉O〈sub〉p〈/sub〉—elevation relationships data for stable isotope paleoaltimetry studies.
    Description: Key Points: A high‐resolution isotope‐enabled general circulation model is used to explore Middle Miocene climate and precipitation δ〈sup〉18〈/sup〉O across Europe. Middle Miocene bi‐directional precipitation change consistent with herpetological fossils and account for precipitation δ〈sup〉18〈/sup〉O variations. Global Miocene climate forcing contributed a max δ〈sup〉18〈/sup〉O change of ∼2‰ over the high Alpine elevation and to ∼1‰ over low elevation.
    Description: German research fondation
    Description: Alexander‐von‐Humboldt foundation, Feodor‐Lynen‐Fellowship
    Description: Alexander‐von‐Humboldt foundation, Humboldt Research Fellowship
    Description: Scientific Steering Committee
    Description: https://mpimet.mpg.de/fileadmin/projekte/ICON-ESM/mpi-m_sla_201202.pdf
    Description: https://gitlab.awi.de/mwerner/mpi-esm-wiso
    Description: https://zenodo.org/record/6308475#.Y0gmDSFS-2w
    Keywords: ddc:550.724 ; Europe ; Middle Miocene ; climate modeling ; stable water isotopes ; temperature ; precipitation ; paleoclimate ; paleoelevation ; Alps
    Language: English
    Type: doc-type:article
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  • 2
    Publication Date: 2023-11-23
    Description: Based on inferences from proxy records the Miocene (23.03–5.33 Ma) was a time of amplified polar warmth compared to today. However, it remains a challenge to simulate a warm Miocene climate and pronounced polar warmth at reconstructed Miocene CO〈sub〉2〈/sub〉 concentrations. Using a state‐of‐the‐art Earth‐System‐Model, we implement a high‐resolution paleobathymetry and simulate Miocene climate at different atmospheric CO〈sub〉2〈/sub〉 concentrations. We estimate global mean surface warming of +3.1°C relative to the preindustrial at a CO〈sub〉2〈/sub〉 level of 450 ppm. An increase of atmospheric CO〈sub〉2〈/sub〉 from 280 to 450 ppm provides an individual warming of ∼1.4°C, which is as strong as all other Miocene forcing contributions combined. Substantial changes in surface albedo are vital to explain Miocene surface warming. Simulated surface temperatures fit well with proxy reconstructions at low‐ to mid‐latitudes. The high latitude cooling bias becomes less pronounced for higher atmospheric CO〈sub〉2〈/sub〉 concentrations. At such CO〈sub〉2〈/sub〉 levels simulated Miocene climate shows a reduced polar amplification, linked to a breakdown of seasonality in the Arctic Ocean. A pronounced warming in boreal fall is detected for a CO〈sub〉2〈/sub〉 increase from 280 to 450 ppm, in comparison to weaker warming for CO〈sub〉2〈/sub〉 changes from 450 to 720 ppm. Moreover, a pronounced warming in winter is detected for a CO〈sub〉2〈/sub〉 increase from 450 to 720 ppm, in contrast to a moderate summer temperature increase, which is accompanied by a strong sea‐ice concentration decline that promotes cloud formation in summer via enhanced moisture availability. As a consequence planetary albedo increases and dampens the temperature response to CO〈sub〉2〈/sub〉 forcing at a warmer Miocene background climate.
    Description: Key Points: At a CO〈sub〉2〈/sub〉 level of 450 ppm, a Miocene simulation shows a global mean surface warming of +3.1°C relative to the preindustrial state. Atmospheric CO〈sub〉2〈/sub〉 increase from 280 to 450 ppm causes a warming of ∼1.4°C, which is as strong as all other forcing factors combined. At higher atmospheric CO〈sub〉2〈/sub〉 levels, the Miocene climate shows a reduced polar amplification linked to a breakdown of seasonality in the Arctic.
    Description: Alfred Wegener Institute
    Description: Helmholtz Centre for Polar and Marine Research
    Description: https://doi.org/10.1594/PANGAEA.943430
    Description: https://github.com/FESOM/fesom2/
    Description: https://mpimet.mpg.de/en/science/modeling-with-icon/code-avilability
    Keywords: atmospheric CO2 ; Miocene ; Miocene temperature change ; polar amplification ; climate modeling ; Miocene bathymetry
    Language: English
    Type: doc-type:article
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  • 3
    Publication Date: 2023-11-13
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Owing to the complicated spatial–temporal characteristics of East Asian precipitation (EAP), climate models have limited skills in simulating the modern Asian climate. This consequently leads to large uncertainties in simulations of the past EAP variation and future projections. Here, we explore the performance of the newly developed Alfred Wegener Institute Climate Model, version 3 (AWI‐CM3) in simulating the climatological summer EAP. To test whether the model's skill depends on its atmosphere resolution, we design two AWI‐CM3 simulations with different horizontal resolutions. The result shows that both simulations have acceptable performance in simulating the summer mean EAP, generally better than the majority of individual models participating in the Coupled Model Intercomparison Project (CMIP6). However, for the monthly EAP from June to August, AWI‐CM3 exhibits a decayed skill, which is due to the subseasonal movement of the western Pacific subtropical high bias. The higher‐resolution AWI‐CM3 simulation shows an overall improvement relative to the one performed at a relatively lower resolution in all aspects taken into account regarding the EAP. We conclude that AWI‐CM3 is a suitable tool for exploring the EAP for the observational period. Having verified the model's skill for modern climate, we suggest employing the AWI‐CM3, especially with high atmosphere resolution, both for applications in paleoclimate studies and future projections.〈/p〉
    Description: 〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉This figure shows the skill scores of AWI‐CM3 and CMIP6 models in simulating the climatological summer East Asian precipitation (EAP), which indicates that AWI‐CM3 simulations perform better than most CMIP6 individual models for the summer mean EAP, while AWI‐CM3's skills decay from June to August.〈boxed-text position="anchor" content-type="graphic" id="joc8075-blkfxd-0001" xml:lang="en"〉 〈graphic position="anchor" id="jats-graphic-1" xlink:href="urn:x-wiley:08998418:media:joc8075:joc8075-toc-0001"〉 〈alt-text〉image〈/alt-text〉 〈/graphic〉 〈/boxed-text〉〈/p〉
    Description: National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Helmholtz Climate Initiative REKLIM
    Description: Helmholtz Program
    Description: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347
    Description: China Scholarship Council http://dx.doi.org/10.13039/501100004543
    Description: https://opendata.dwd.de/climate_environment/GPCC/html/fulldata-monthly_v2022_doi_download.html
    Description: https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_4.05
    Description: http://aphrodite.st.hirosaki-u.ac.jp/products.html
    Description: https://jra.kishou.go.jp/JRA-55/index_en.html
    Description: https://esgf-node.llnl.gov/search/cmip6
    Keywords: ddc:551.6 ; AWI‐CM3 ; CMIP6 ; East Asia ; summer precipitation
    Language: English
    Type: doc-type:article
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  • 4
    Publication Date: 2023-04-12
    Description: We provide global fields of simulated ocean velocity in zonal (netCDF variable UKO) and meridional (netCDF variable VKE) direction at a depth of 420 m. Six climate states are covered in the data set: 1. data set PI_mpiom_UKO_VKE_timmean_420m.nc: pre-industrial (PI) control state (representative for 1850 AD) as used in the publications by Stepanek and Lohmann (2012) and Zhang et al. (2013). The respective data is courtesy of Zhang et al. (2013) 2. data set LGM_mpiom_UKO_VKE_timmean_420m.nc: a climate state of the Last Glacial Maximum (simulation LGM-W by Zhang et al., 2013), representative for 21 kiloyears (ka) before present (BP) 3. data set Plio_mpiom_UKO_VKE_timmean_420m.nc: a climate state of the Mid-Pliocene Warm Period (simulation experiment 2 by Stepanek and Lohmann, 2012), that covers the time from 3.29 - 2.97 million years (Ma) BP 4. data set MIO_mpiom_UKO_VKE_timmean_420m.nc: a climate state representing conditions of the early to middle Miocene (23 to 15 Ma BP) including a regional bathymetry reconstruction (15 Ma) of the North Atlantic / Arctic Ocean by Ehlers and Jokat (2013) and considering 450 ppm of carbon dioxide (simulation EO450 by Stärz et al., 2017) 5. data set MioW_mpiom_UKO_VKE_timmean_420m.nc: a climate state representing conditions of the early to middle Miocene (23 to 15 Ma BP) including a regional bathymetry reconstruction (15 Ma) of the Weddell Sea (Huang et al., 2014) and considering 450 ppm of carbon dioxide in the atmosphere (simulation MIOW_450 by Huang et al., 2017) 6. data set MioW_PIS_mpiom_UKO_VKE_timmean_420m.nc: a climate state similar to 5. but with PI (278 ppm) carbon dioxide concentration and prescribed modern ice sheets (simulation MIOW_PIS by Huang et al., 2017) All data sets represent climatological annual averages over a time period of 100 years. The oceanography is based on climate simulations performed with the Community Earth System Models (COSMOS) that consist of the atmosphere general circulation model ECHAM5 (Roeckner et al., 2003), internally coupled to the land surface and terrestrial carbon cycle model JSBACH (Raddatz et al., 2007) in T31 resolution (3.75°x3.75°) with 19 vertical levels on a hybrid sigma-pressure coordinate, and the ocean general circulation model MPIOM (Marsland et al., 2003) on a bipolar curvilinear GR30 grid with a formal resolution of 3.0°x1.8° and 40 z-coordinate levels. Exchange of momentum, mass, and energy between the atmosphere and ocean domain is enabled via the OASIS3 coupler (Valcke et al., 2003). For all simulations, ocean characteristics (including sea ice) and properties of atmosphere and land (including the land carbon cycle and dynamic vegetation) are computed based on the prescribed climate forcing (concentration of atmospheric trace gases, configuration of the Earth's orbit) and boundary conditions (land surface elevation, ice sheets, ocean bathymetry, and land sea mask). For details of the utilized boundary conditions and climate forcing refer to the original publications describing the data (Stepanek and Lohmann, 2012; Zhang et al., 2013; Huang et al., 2017; Stärz et al., 2017). In case of analyzing velocities of the Arctic Ocean, note that for few grid cells in the northernmost data row (89.5°N), between 280°E and 293°E, there is a data artifact in variable VKE. This artifact is a side effect of rotating and interpolatiing velocities from the curvilinear model grid to a standard NSWE coordinate system; this artifact has not been removed from the data sets.
    Keywords: AWI_PaleoClimate; File format; File name; File size; Paleo-climate Dynamics @ AWI; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 24 data points
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  • 5
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    PANGAEA
    In:  Supplement to: Stepanek, Christian; Lohmann, Gerrit (2012): Modelling mid-Pliocene climate with COSMOS. Geoscientific Model Development, 5(5), 1221-1243, https://doi.org/10.5194/gmd-5-1221-2012
    Publication Date: 2023-06-24
    Description: In this manuscript we describe the experimental procedure employed at the Alfred Wegener Institute in Germany in the preparation of the simulations for the Pliocene Model Intercomparison Project (PlioMIP). We present a description of the utilized Community Earth System Models (COSMOS, version: COSMOS-landveg r2413, 2009) and document the procedures that we applied to transfer the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project mid-Pliocene reconstruction into model forcing fields. The model setup and spin-up procedure are described for both the paleo- and preindustrial (PI) time slices of PlioMIP experiments 1 and 2, and general results that depict the performance of our model setup for mid-Pliocene conditions are presented. The mid-Pliocene, as simulated with our COSMOS setup and PRISM boundary conditions, is both warmer and wetter in the global mean than the PI. The globally averaged annual mean surface air temperature in the mid-Pliocene standalone atmosphere (fully coupled atmosphere-ocean) simulation is 17.35 °C (17.82 °C), which implies a warming of 2.23 °C (3.40 °C) relative to the respective PI control simulation.
    Type: Dataset
    Format: application/zip, 189.9 kBytes
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  • 6
    Publication Date: 2023-12-07
    Description: We provide a climatic data set of the history of annual mean surface air temperature (SAT) over the last 1,000,000 years. The SAT (i.e. the temperature at 2 meter height above the ground) has been simulated by means of the Community Earth System Models (COSMOS, consisting of ECHAM5, JSBACH, MPIOM). These have been exposed to the solution of elements of the Earth's orbit around the sun (eccentricity, obliquity, longitude of the perihelion) by Laskar et al. (2004) for the last 1,000,000 years. Towards practical feasibility of the climate simulation, the orbital forcing has been accelerated by a factor of 100 based on the method described by Lorenz and Lohmann (2004). A detailed description of the COSMOS' application in the framework of paleoclimate can be found, for example, in the publication by Stepanek and Lohmann (2012).
    Keywords: climate simulation; last 1 000 000 years; Orbital forcing; Paleoclimate; Paleo Modelling; PalMod
    Type: Dataset
    Format: application/x-netcdf, 176 MBytes
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  • 7
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    Unknown
    PANGAEA
    In:  Supplement to: Guagnin, Maria; Jennings, Richard; Eager, Heidi; Parton, Ash; Stimpson, Christopher; Stepanek, Christian; Pfeiffer, Madlene; Groucutt, Huw S; Drake, Nick A; Alsharekh, Abdullah; Petraglia, Michael D (2016): Rock art imagery as a proxy for Holocene environmental change: A view from Shuwaymis, NW Saudi Arabia. The Holocene, 26(11), 1822-1834, https://doi.org/10.1177/0959683616645949
    Publication Date: 2023-12-09
    Description: In this data set we publish the simulated global annual mean precipitation over a time period of 50 years retrieved from equilibrium climate simulations for Pre-Industrial (PI) and 8 ka BP (HOL6) and utilized in the publication by Guagnin et al. (2016). The climate data has been produced with COSMOS (ECHAM5/JSBACH/MPIOM/OASIS3), utilized at a resolution of T31 in the atmosphere (19 hybrid sigma-pressure levels) and a resolution of GR30 (bipolar orthogonal curvilinear grid, formal resolution of ~3.0°x1.8°) in the ocean (40 z-coordinate levels). The only differences between the model setups of simulations PI and HOL6 are the settings of the Earth's orbital parameters and the atmosphere's constituents of trace gases, that have been set to the values representative for the respective time slice (see Table 1 of Guagnin et al. (2016) for details).
    Type: Dataset
    Format: application/zip, 1.6 MBytes
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  • 8
    Publication Date: 2024-04-20
    Description: We present basal melt rates for the ice shelves in equilibrium simulations of the Antarctic ice sheet (AIS), using the 3D thermodynamical Parallel Ice Sheet Model (PISM) version 1.1 with PICO as ocean component. The applied climate forcing consists of yearly mean present-day temperature and precipitation fields from RACMO2.3 (RACMO2 ANT27), and 400-800 m depth average ocean temperature and salinity, obtained from simulations using the atmosphere-ocean general circulation model COSMOS (ocean model MPIOM). COSMOS was run using pre-industrial settings (PID; 278 ppm CO2), settings from 40 kyr ago (40ka; 195 ppm CO2), and Last Glacial Maximum settings (LGM; 185 ppm CO2). All simulations are started with present-day bedrock conditions, and a present-day AIS size (Bedmap2). The steady state simulations are conducted by applying the same climate forcing over 200 kyr, after a thermodynamical spin-up (no mass changes) of 200,100 yr.
    Keywords: 40ka; Antarctica; Antarctic Ice Sheet; Basal melt rates; Glacial climate; Last Glacial Maximum; pre-industrial
    Type: Dataset
    Format: application/zip, 164.5 kBytes
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  • 9
    Publication Date: 2024-04-20
    Description: We present climate model output for various atmosphere and ocean quantities that illustrate the impact of three different types of forcing on global climate characteristics during mid-Pliocene (~3.3 - 3.0 Million years before present, Ma BP) and early to Mid-Miocene (~23-15 Ma BP): -geography, including setups for modern, mid-Pliocene, and early to Mid-Miocene -carbon dioxide, ranging from Pre-Industrial (280 parts per million by volume, ppmv) to 840 ppmv -strength of ocean mixing via enhancement of respective mixing parameters, ranging from the unperturbed state to mild (five times), intermediate (ten times), and strong (twenty-fife times) enhancement of vertical mixing. The data provided with this data publication has been employed by the authors in the manuscript "Effects of CO2 and ocean mixing on Miocene and Pliocene temperature gradients" (revised for publication in the journal Paleoceanography and Paleoclimatology, special issue "The Miocene: The Future of the Past") for a comparative study of the effects of carbon dioxide and ocean mixing on various climate characteristics. Here we provide all climate output that has been employed towards creating analyses presented in that publication. Data is provided at the resolution employed for generating analyses for the manuscript. Atmosphere model output provided at native model resolution (T31, ~3.75°x3.75° horizontally). Ocean output provided at a regular grid (the native grid of the ocean model is curvilinear with a formal resolution of 3.0°x1.8° horizontally). Sea ice cover provided at a resolution of 1.0°x1.0°. Zonal mean of ocean potential temperature over all model levels provided at a latitudinal resolution of 1°, vertically discretized on native ocean model levels (40 pressure levels of non-linear spacing). Depth of the ocean mixed layer, sea surface temperature, and total heat flux across the atmosphere ocean interface given at resolutions of 0.5°x0.5° resolution. Data at higher resolutions is provided towards retaining more details of the coastlines and of ocean gateway regions.
    Keywords: Binary Object; Binary Object (File Size); carbon dioxide; climate model; climate patterns; Miocene; ocean mixing; Pliocene
    Type: Dataset
    Format: text/tab-separated-values, 133 data points
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  • 10
    Publication Date: 2024-06-21
    Description: The Pliocene Epoch (~2.6–5.3 million years ago, Ma) was characterized by a warmer than present climate with smaller Northern Hemisphere ice sheets, and therefore offers an example of a climate system in long-term equilibrium with current or predicted near-future carbon dioxide concentrations. The end of the Pliocene (~2.6 Ma) is marked by further ice-sheet expansion and intensification of glacial (cold) stages, referred to as the "intensification of Northern Hemisphere Glaciation" (iNHG). Here we present the data used to assess the spatial and temporal variability of ocean temperatures and ice-volume indicators through the late Pliocene and early Pleistocene (from 3.3 to 2.4 Ma) to determine the character of this climate transition. The data come from the Atlantic, Pacific, Indian and Southern Ocean, as well as some marginal seas. Here we present the synthesized alkenone sea-surface temperature, Mg/Ca sea-surface temperature, planktonic foraminifera d18O and benthic foraminifera d18O data which were used in our synthesis. Although the original data sets are largely published, here we present the alkenone SST records calculated using the BAYSPLINE calibration where these were not part of the original publication; the Mg/Ca-SST records where we revised the absolute SSTs; any data sets where we revised the age model.
    Keywords: alkenone SST; benthic and planktonic foraminifers; d18O of planktic foraminifera; foraminifera oxygen isotopes; Mg/Ca-based sea surface temperature; Northern Hemisphere glaciation; PAGES_PlioVAR; Pleistocene; Pliocene; PlioVAR - Pliocene climate variability over glacial-interglacial timescales
    Type: Dataset
    Format: application/zip, 7 datasets
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