1,722,040 research outputs found
Progress in Earth System Science: What Does It Take to Make Our Ideas Clear?
No full textTo describe the progress in Earth System Science, a conceptual framework is proposed which includes hypothesis testing, the formulation of models with different complexity as well as expressing discoveries in terms of metaphors. The later approach is demonstrated by the conveyor belt concept in oceanography which influenced the discussion about abrupt climate changes where the ocean circulation may be involved. It is argued that the combination of different methodologies/complexities and independent results is necessary to prevent over-simplistic views in each discipline of Earth System Science. Emphasis is given on typical steps to obtain new ideas for a new discovery. Examples for over-simplistic views are mentioned for past climate information from proxy data. The recorder system of the proxy has to be taken into account, otherwise the climate information can be misinterpreted. It is concluded that in the field of Earth System Science, basic knowledge and true collaborative problem solving is necessary to make scientists aware of the underlying principles, the limitations and open questions. This is furthermore necessary to develop and sharpen our ideas about the complex Earth System
Climate model (Consortium for Small-scale Modeling, COSMOS) results of different Laurentide Ice Sheet reconstructions during the Last Glacial Maximum in NetCDF format
No full textHerein, we publish the simulated global annual mean sea surface temperature (THO), surface air temperature (SAT) over a time period of 100 years retrieved from equilibrium climate simulations for the Last Glacial Maximum (~21 ka BP). We investigate the range of temperature variability that occurs in response to uncertainties in the boundary conditions of Laurentide ice sheet (LIS). We performed LGM simulations, applying six different LIS reconstructions (ICE-6g, GLAC-1a, ANU, Gowan, Licciardi and PMIP3) in a fully coupled atmosphere-ocean-sea-ice model. The model data has been used in the publication by Hossain et al., 2021. The climate data has been produced with Consortium for Small-scale Modeling (COSMOS; ECHAM5/JSBACH/MPIOM/OASIS3), utilized at a resolution of T31 in the atmosphere with 19 vertical layers and a resolution of GR30 (~3.0°x1.8°) in the ocean with 40 vertical layers. The model setup refers to boundary conditions (terrestrial topography, ocean bathymetry), greenhouse gas concentrations (CO2 = 185 ppm; CH4 = 350 ppb; N2O = 200 ppb) and orbital forcing representative for the LGM and are imposed in accordance with the PMIP3 protocol. We also run COSMOS using PI boundary conditions (ice-sheet topography, orbital forcing, greenhouse gas concentrations and ocean bathymetry). Details on setup and identifiers of LGM model simulations can be found in Table S1 of Hossain et al., 2021
Orbitally forced simulated surface air temperature of the last 1,000,000 years
No full textWe 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)
Marine radiocarbon reservoir ages simulated for IntCal20, link to model results in NetCDF format
No full textBeyond ~13.9 cal kBP, the IntCal19 radiocarbon calibration curve is based upon combining data across a range of different archives including corals and planktic foraminifera. In order to reliably incorporate such marine data into an atmospheric curve, we need to resolve these records into their constituent atmospheric signal and marine reservoir age. This dataset includes results of marine reservoir age simulations enabling this resolution, applying the LSG ocean general circulation model forced with various climatic background conditions and with atmospheric radiocarbon changes according to the Hulu Cave speleothem record. Simulation period is 54,000-10,700 cal BP, depth range is 0-50 m. Land values are flagged with -100. This dataset is an update of PANGAEA datasets doi:10.1594/PANGAEA.876733 and doi:10.1594/PANGAEA.775379
Historical and projected (RCP8.5) temperatures and ice depths simulated with the Alfred Wegener Institute Earth System Model (AWI-ESM)
No full textThis dataset contains the results of a simulation using the global climate model AWI-ESM coupled with the interactive ice sheet model PISM. The simulation consists of a historical run (1850-2014) and a future scenario using the Representative Concentration Pathways scenarios RCP8.5. This scenario spans the years 2006-2100 and was prolonged to the year 2299 with fixed greenhouse gas concentrations. The variables provided are temperature at 2 meters above surface and ice depth. The data are used for a mathematical model to describe long-term changes in extreme temperatures (Contzen, Dickhaus and Lohmann, 2023). This dataset contains spatial data on a regular lon lat grid (0.5°x0.5° horizontal resolution) using monthly time steps. All files are in the NetCDF format
Integration of Passive Tracers in a Three-Dimensional Ice Sheet Model
No full textComponents of the climate system, such as ice sheets and marine sediments serve as invaluable archives, which can be tapped into, to reconstruct paleoclimate conditions. The relative abundance of hydrogen and oxygen isotopes in ice cores is a proxy for past local temperature evolution. However the translation of these proxies into temperature is not straightforward. Complex interdependencies in the climate system can hide or override the local climate signal at which the ice core was drilled. Using 3D ice sheet modelling in concert with passive tracer advection one can simulate the isotopic distribution in ice sheets and compare them to ice core data. Combining this method in a coupled climate model environment, containing atmosphere and ocean components, one can theoretically simulate the isotopic cycle from the source to the actual ice record. Such an approach would greatly support the interpretation of proxy data whilst constraining the output of 3D ice sheet models (ISMs). We present the implementation of passive tracer advection in our 3D ISM RIMBAY (Thoma et al. in Geosci Model Dev 1:1–21, 2014, Goeller et al. in Cryosphere 7:1095–1106, 2014) and asses the potential of the method to reproduce chronologies of the polar ice sheet
Climate model output illustrating effects of carbon dioxide and ocean mixing on Miocene and Pliocene climate
No full textWe 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
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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