6-8 April 2018
Tech Gate Vienna
Europe/Berlin timezone
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Displaying 104 contributions out of 104
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The TraCE-21000 Project, a collaboration among the National Center for Atmospheric Research, the University of Wisconsin, and Oregon State University, explored the transient evolution of the climate system, especially the time-evolving nature of the atmosphere, ocean, sea ice, and land surface and their interactions, from 22,000 years before present to today. The transient simulations with the Com ... More
Presented by Dr. Bette OTTO-BLIESNER on 7 Apr 2018 at 15:00
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Some of the least well-constrained aspects of the last deglaciation are the changes to atmospheric dynamics, and yet they facilitate the redistribution of atmospheric moisture and heat and changes to surface ocean currents and sea ice distributions. Due to the fast response times of the atmosphere and relatively slow rates of change of ice sheet boundary conditions and orbital forcing, changes to ... More
Presented by Heather ANDRES on 7 Apr 2018 at 14:15
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
The paleoclimate record allows to establish the role of natural forcing in generating climate variability in states that are very different from today, such as at the last Glacial Maximum 21 000 years ago. Here we present the results from an ensemble of idealized 1000-year-long simulations for the Last Glacial Maximum (n=5) and the Preindustrial (n=5), performed with the isotope-enabled version ... More
Presented by Dr. Kira REHFELD on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Overall, the PalMod project goal is to provide the best answers to overarching questions as, for example, What are the processes that govern the built-up and termination of ice sheets, or What is the best methodology to optimize comprehensive Earth system models. The data assimilation work in PalMod Working Group (WG) 3 “Proxy data synthesis” can be thought of as a direct contribution towar ... More
Presented by Dr. Javier GARCIA-PINTADO on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
We present a new ocean climatology of the sea surface during the Last Glacial Maximum (LGM, 23,000–19,000 years before present) mapped on a global 1° × 1° grid (GLOMAP, glacial ocean map of gridded climatological surface data). This is an extension of the Glacial Atlantic Ocean Mapping (GLAMAP) sea-surface temperature (SST) reconstruction of the Atlantic SST, which is based on results of the ... More
Presented by Dr. André PAUL on 8 Apr 2018 at 09:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Combining ocean general circulation models with proxy data via data assimilation (DA) is a powerful means to obtain more reliable estimates of the past ocean's state. The Last Glacial Maximum (19-23 ka BP, LGM) was a climatic state substantially different from today and the large-scale ocean circulation patterns during this time remain uncertain. At present, only a few attempts on using data assim ... More
Presented by Ms. Charlotte BREITKREUZ on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Our knowledge about past climates depends on information from paleo-observations, i.e. proxies, and climate simulations. Comparing simulations and proxies requires approaches to bridge the gap between both and address their specific uncertainties. One way are so called pseudo-proxies. These in turn depend on an understanding of the uncertainties of the real proxies, i.e. the noise-characteristics ... More
Presented by Dr. Oliver BOTHE on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
We present a software tool that allows the efficient homogenization of large paleoclimatic data sets into consistent compilations and data products. The software combines a graphical user interface with a simple document-based database and functionality for documentation, stratigraphy, age modelling and semi-automatic data processing and extraction. Data can be imported from Excel or text files, a ... More
Presented by Dr. Stefan MULITZA, Dr. Michael LANGNER on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
We investigate glacial–interglacial variations in the marine stable carbon-isotope record applying the marine ecosystem and biogeochemistry model RECOM, which is forced with model output from fully coupled climate simulations. Different to most other marine biogeochemistry models, RECOM does not rely on fixed stoichiometric ratios of phytoplankton organic matter. Instead, the composition of phyt ... More
Presented by Dr. Martin BUTZIN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Nitrogen is a key limiting nutrient that influences marine productivity and carbon sequestration in the ocean via the biological pump. In this study, we present the first estimates of nitrogen cycling in a coupled 3D ocean-biogeochemistry-isotope model forced with realistic boundary conditions from the Last Glacial Maximum (LGM) ~21,000 years before present constrained by nitrogen isotopes. The mo ... More
Presented by Dr. Christopher SOMES on 7 Apr 2018 at 16:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
We present the latest results from a fully transient simulation of the early last deglaciation (21-15 ka) using the Hadley Centre Climate model, HadCM3. In line with the Palaeoclimate Model Intercomparison Project Phase 4 (PMIP4) core experiment design, this simulation uses the ICE-6G_C ice sheet reconstruction with the land-sea mask and bathymetry updating every 500 years, and the height of the i ... More
Presented by Dr. Ruza IVANOVIC on 7 Apr 2018 at 12:00
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
Paleo ice sheet reconstructions without confident uncertainty bounds have limited value. For approaches based on glaciological models, such bounds require a model that adequately probes uncertainties in both climate and ice processes along with a methodology for using paleo-observations to constrain this probe. To date, paleo glaciological models of the Greenland ice sheet (GrIS) either do no ... More
Presented by Prof. Lev TARASOV on 8 Apr 2018 at 10:00
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Ice sheets constitute the largest and most uncertain potential source of future sea-level rise. The quality of predicted future sea-level contributions from ice sheets based on flow modelling strongly depends on how well the models are able to represent the present-day state of the ice sheets. Previous and ongoing model intercomparison efforts (e.g. SeaRISE and ISMIP6) have identified large uncert ... More
Presented by Dr. Thomas KLEINER on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Iceberg studies are of great interest for understanding how fresh water is transported and distributed in the ocean, as water release plays an important role in ocean heat transfer and Atlantic meridional overturning circulation (AMOC). Main processes after the calving of an iceberg are the drift and change in size due to deterioration. The classical way of implementing icebergs is based on Lagran ... More
Presented by Olga EROKHINA on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 1)
Track: Novel methodological aspects of long-term simulations and reconstructions
Climate variations at decadal to centennial timescales are not well understood in the Southern Ocean and Antarctica because of the lack of data and the systematic biases of climate models. Nevertheless, by combining both sources of information using data assimilation, we can reduce the uncertainties during some periods, test hypotheses about the mechanisms ruling past changes and highlight some fu ... More
Presented by Prof. Hugues GOOSSE on 7 Apr 2018 at 15:45
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Observations of sea-level variations allow the validation of numerical models used to reconstruct past and predict future sea-level change. Sea-level indicators (SLIs) are used as the main source for deriving relative sea level (RSL) variations during previous epochs for which tide-gauge and satellite measurements were yet not available. However, the levelling of an SLI relative to present sea lev ... More
Presented by Ms. Milena LATINOVIć on 7 Apr 2018 at 16:30
Type: oral presentation Session: Cryosphere-climate interactions
Track: Cryosphere-climate interactions
During the past two decades, several atmospheric and oceanic general circulation models (GCMs) have been enhanced by the capability to explicitly simulate the hydrological cycle of the two stable water isotopes H218O and HDO. They have provided a wealth of understanding regarding changes of the water isotope signals in various archives under different past climate conditions. Fully coupled atmosph ... More
Presented by Dr. Martin WERNER on 8 Apr 2018 at 12:00
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Some values of parameters (constants) of global oceanic biogeochemical models are highly uncertain, yet their specification may affect simulation results on long time scales and / or under transient forcing. For example, the sinking speed of particulate organic matter and phytoplankton growth rate can determine the partitioning of nutrients, and hence oxygen and carbon dioxide, among different wat ... More
Presented by Dr. Iris KRIEST on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The assimilation of palaeoclimate proxy records into climate modelling frameworks allows for the reconstruction of past climatic fields. By combining the real-world information recorded by the proxies with the dynamical information encoded within the models, data assimilation (DA) represents an integrated approach whereby climate modelling becomes part of the process of palaeoclimate reconstructio ... More
Presented by Dr. Steven PHIPPS on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
We present CLIMBER-X, a newly developed comprehensive Earth System model of intermediate complexity designed to explore and understand climate-cryosphere-carbon cycle interactions on temporal scales ranging from centuries to glacial-interglacial cycles. CLIMBER-X includes a frictional-geostrophic 3D ocean model (GOLDSTEIN), a sea ice model, a semi-empirical statistical-dynamical atmosphere model ... More
Presented by Matteo WILLEIT on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Sea level changes may have an important effect on climate. In Earth-system models the land-sea mask is usually fixed. The time-dependent ocean boundaries and bottom topography need to be considered for simulations of the last deglaciation, where the global sea level increased by about 120m. The aim of this project is to make the ocean component POP (Parallel Ocean Program) of the CESM (Community E ... More
Presented by Dr. Anna MATULKA on 7 Apr 2018 at 16:30
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Over the past million years, marine, polar ice core and terrestrial records all highlight the sudden and dramatic nature of glacial terminations, the shifts in global climate that occurred as the world passed from dominantly glacial to interglacial conditions. These climate transitions provide the most compelling evidence available in the climate record for the role of greenhouse gases and feedbac ... More
Presented by Prof. Gerrit LOHMANN on 8 Apr 2018 at 15:15
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Spatial reconstructions of past climate are important to compare the state of the climate under different forcing conditions. Pollen records can be used for local climate reconstructions, while equilibrium global climate simulations contain information about possible large scale structures given a set of external forcings. We present spatial reconstructions of Asian climate for the Mid Holocene (M ... More
Presented by Mr. Nils WEITZEL on 7 Apr 2018 at 16:30
Session: PalMod Overview
Presented by Dr. Andreas SCHMITTNER
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
In paleoclimate simulations, glacial runoff is usually injected as freshwater in large bands across the North Atlantic. However, results from Condron and Winsor (2012) demonstrate that the distribution of glacial runoff in the open ocean (ie. beyond the Western Boundary Current) disagrees with the commonly used hosing regions. Furthermore, using realistic glacial discharge routing for injecting gl ... More
Presented by Mr. Ryan LOVE on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The scalability of the atmospheric model ECHAM6 at low resolution as used in paleo climate simulations suffers from the limited number of gridpoints. As a consequence, the potential of current HPC architectures cannot be used at full scale for such experiments, particularly within the available domain-decomposition approach. Therefore, we propose to extend concurrency further by running the radia ... More
Presented by Mohammad Reza HEIDARI on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Spatio-temporally resolved reconstructions of past climate are important to understand the large scale behavior of the climate system and the response to changes in forcings. Unfortunately, they are subject to large uncertainties, have to deal with a complex proxy-climate structure, and a physically reasonable interpolation between the sparse proxy observations is difficult. In theory, Bayesian hi ... More
Presented by Mr. Nils WEITZEL on 7 Apr 2018 at 16:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
During the last termination of ice age cycle (deglaciation), Heinrich event 1 as well as B/A, Antarctic Cold Reversal (ACR) and Younger Dryas occurred as millennial scale climate changes. Here we ran several deglaciation experiments as well as sensitivity experiments using a coupled atmosphere and ocean GCM (MIROC4m AOGCM) developed in Japan and analyzed the stability of AMOC and climate. The mod ... More
Presented by Prof. Ayako ABE-OUCHI on 7 Apr 2018 at 13:45
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The reconstruction of reliable paleo-climatic signals from terrestrial records is crucial for robust model-data comparisons of past climates on the continents. Lake sediments are ideal archives of continuous paleoclimatic information, due to their wide geographical distribution and good chronological control. However, lake sediments enclose paleoenvironmental information that originates from multi ... More
Presented by Dr. Arne RAMISCH on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The millennial-scale history of CO2 releases during the last deglaciation from either Northern or Southern Pacific abyssal waters remains enigmatic. This is due to conflicting indications about subarctic Pacific physical ventilation changes based on various marine proxies, especially for the cold Heinrich Stadial 1 (HS-1). Here, we use a complex Earth System Model to discuss deglacial North Pacifi ... More
Presented by Dr. Xun GONG on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
A simulation of the history of the atmospheric carbon dioxide concentration (pCO2) during the last glacial cycle is one of the crucial tasks of the PalMod project. Since the marine carbon cycle plays a key role for the pCO2 variations at the glacial-interglacial time scale, we aim at coupling a sediment diagenesis model, which treats the dissolution/preservation of particulate matter formed by mar ... More
Presented by Dr. Takasumi KURAHASHI-NAKAMURA on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The organic carbon content in a lake sediment core from the dry maar of Auel (Eifel Germany) reveals the identical succession of warm MIS3 interstadials as known from the North Atlantic and Greenland temperature time series. Each cold stadial of MIS3 was characterized by dust activity, which was inactive during the interstadial phases. This patterns indicates a primary influence from the North Atl ... More
Presented by Prof. Frank SIROCKO on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The continually evolving large ice sheets present in the Northern Hemisphere during the last glacial cycle caused significant changes to river pathways both through directly blocking rivers and through glacial isostatic adjustment. These river pathway changes are believed to of had a significant impact on the evolution of ocean circulation through changing the pattern of fresh water discharge into ... More
Presented by Dr. Thomas RIDDICK on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Proxy measurements of ocean tracers at the Last Glacial Maximum (LGM, ca. 23-19 ka) suggest that the western Atlantic Ocean was filled dominantly by Antarctic Bottom Water (AABW), with a lesser role for North Atlantic Deep Water (NADW) relative to the modern. Proposed explanations for a shoaled NADW-AABW boundary (NAB) include changes in the strength and/or structure of the Atlantic meridional ove ... More
Presented by Dan AMRHEIN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Marine Isotope Stage 3 (MIS3; ~ 60 ka to 30 ka BP) was punctuated by abrupt climate transitions between colder stadial and warmer interstadial climate conditions. The fluctuations are known as Dansgaard–Oeschger (D-O) events which are featured by a rapid warming from stadial to interstadial in a few decades as recorded by the Greenland ice cores. In this work, using a state-of-the-art climate ... More
Presented by Dr. Chuncheng GUO on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
The El Niño–Southern Oscillation (ENSO) is the largest source of interannual climate variability on our planet. ENSO has undergone substantial changes throughout the Holocene with periods of weak and strong activity alternating on multidecadal to centennial timescales. There is also mounting evidence from paleo-proxy reconstructions of ENSO for a period of reduced ENSO variance about 3,000 – ... More
Presented by Dr. Sun-Seon LEE, Prof. Axel TIMMERMANN on 7 Apr 2018 at 16:30
Type: oral presentation Session: Cryosphere-climate interactions
Track: Cryosphere-climate interactions
Throughout the last glacial cycle natural millennial scale variations in atmospheric CO2 have occurred in response to abrupt changes in deep ocean circulation, which themselves are reflected by observable changes in surface conditions across the North Atlantic region; CO2 tends to increase while the surface North Atlantic is anomalously cold and covered in rafted ice (conditions typically associat ... More
Presented by Prof. Stephen BARKER on 8 Apr 2018 at 11:15
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Running coupled climate models through a whole deglaciation is essential to understand the strong climate fluctuations occurring during that period of time. Here, we present results of the first set of Earth System Model (ESM) simulations of the last deglaciation with continuously evolving topography, coastlines and bathymetry. Because ESMs are generally not constructed to deal with time varyin ... More
Presented by Uwe MIKOLAJEWICZ on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Paleo-climate simulations as carried out in the German PalMod project allow for relatively low resolution due to computational restrictions. Often this resolution is unable to represent important transport processes with sufficient accuracy. Since many of these processes (examples include dust transport, volcanic ash dispersion, etc.) are local in nature, local adaptive mesh refinement (AMR) can a ... More
Presented by Mr. Yumeng CHEN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Enhanced melting of the Greenland ice sheet during warm phases (interstadials) of the last glacial cycle is generally considered to have reduced the formation rate of deep water in the subpolar North Atlantic. The consequent and potentially strong weakening of the Atlantic meridional overturning circulation may explain the inevitable return to a cooler climate (stadial). The particular role of mes ... More
Presented by Torge MARTIN on 7 Apr 2018 at 16:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The sign and magnitude of deglacial changes in the land biosphere carbon stock (Δland) are uncertain. Estimates range from releases of 200-400 GtC (Zimov et al., 2006, Science; Zech et al., 2011, Climate of the Past) to uptakes as high as 1300 GtC over the deglacial period (Adams et al., 1990, Global and Planetary Change). Recent estimates locate Δland around an uptake of 300-400 GtC (Ciais et a ... More
Presented by Aurich JELTSCH-THöMMES on 7 Apr 2018 at 14:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
In-depth interpretation of atmospheric methane (CH4) paleo records requires comprehensive estimates of the climate-driven variations of its sources and sinks. The former, being difficult to estimate even for the present day conditions, are by large of biogenic origin and typically require rather complex parameterisations in modelling approaches. The latter, in contrast, can be reckoned with somewh ... More
Presented by Dr. Sergey GROMOV on 7 Apr 2018 at 14:45
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
Simulation over a long time scale in climate sciences as done, e.g., in paleo climate simulations require coarse grids due to computational constraints. Coarse grids, however, leave important smaller scales unresolved. Thus small scale processes that significantly influence the resolved scales can either be neglected (which is not desired) or their influence has to be taken care of by different me ... More
Presented by Dr. Konrad SIMON on 8 Apr 2018 at 10:15
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Particle ballasting refers to the acceleration of sinking organic soft tissue in the ocean by aggregation with denser particles such as calcite shells, opal shells, or mineral dust. The acceleration of organic soft tissue due to, for example, higher aeolian dust deposition rates, may have led to a more effective biological carbon pump during glacial periods compared to interglacial periods. Partic ... More
Presented by Dr. Malte HEINEMANN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Loess sediments, defined as aeolian silt deposits, cover today about 3.3% of global land surface and are globally widely distributed, although more abundant at higher latitudes (around 70°N-30°N, 25°S-40°S). Generally, loess deposits present high weathering fluxes because of their grain size distribution and mineralogical composition. Due to their significant area coverage and relatively high ... More
Presented by Janine BöRKER on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Glacial isostatic adjustment (GIA) plays an important role for the reconstruction of relative sea level and paleo topography/bathymetry during the last glacial cycle. Regions temporarily covered by ice-sheets (e.g. Laurentide ice sheet, Fennoscandian ice sheet) adjust to the loading by vertical depression and corresponding sea-level change of several hundred meters. In the far-field, relative sea ... More
Presented by Dr. Meike BAGGE on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Ocean circulation plays an essential role in Earth’s climate and the global carbon cycle. A prerequisite for improving confidence in future climate projections is the accurate numerical modeling of past deep ocean circulation changes. Unfortunately our understanding of such changes in terms of transport pathways and transit times is impeded by ambiguities in data-based reconstructions which heav ... More
Presented by Anne MOUCHET on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
We have implemented an optimality-based NPZD model with Nutrients (nitrogen, phosphorus), ordinary Phytoplankton and diazotrophs, Zooplankton, and Detritus into the UVic Earth System Climate Model. The new model decouples C, N and P in the optimality-based plankton compartments, which allows phytoplankton to utilize ambient nutrients in different N:P ratios and thus allows for dynamic stoichiometr ... More
Presented by Dr. Chia-Te CHIEN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Feedbacks between the cryosphere and the overall climate system are the strongest internal regulating mechanisms of Earth’s climate during the last deglaciation. In order to evaluate the relative influence of bi-directional feedbacks between the cryosphere and the climate, we employ a coupled ice-sheet climate simulation of a limited time period within the last deglaciation. By isolating each fe ... More
Presented by Dr. Paul GIERZ on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
The initialization of ice sheet models at the last glacial maximum (LGM) plays an important role for simulating the last deglaciation using state-of-the-art Earth system models (ESMs), which consist of general circulation models of the atmosphere and the ocean (AOGCMs) coupled to ice sheet models. As AOGCMs are computational rather expensive, the question appears how initialization of ice sheet mo ... More
Presented by Dr. Reinhard CALOV on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
As ice sheets melt or grow, the flux of freshwater into the ocean changes and the bedrock adjusts due to isostatic adjustments, leading to variations in the bottom topography and the oceanic boundaries. For long-term integrations with large changes in the ice volume, it is therefore necessary to consider transient ocean bathymetry and coastlines. However, in most standard ESMs they are fixed throu ... More
Presented by Virna Loana MECCIA on 8 Apr 2018 at 09:15
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Although methane is an important greenhouse gas, the CH4 budget and the attribution of relative emissions to specific sources is still poorly constrained. Emissions from wetlands contribute most to natural CH4 emissions and to its uncertainty. In bottom up model estimates, that prescribe wetlands using various wetland mapping datasets, uncertainties result mostly from the uncertain spatial distrib ... More
Presented by Jurek MüLLER on 7 Apr 2018 at 16:30
Type: oral presentation Session: Cryosphere-climate interactions
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Understanding the thermal structure of the Atlantic Ocean during major climate changes is of crucial importance to constrain the flow of energy from the surface into the oceans interior. Within the ocean, the effect of anthropogenic global warming is mostly traceable in the upper 700m of the water column and leads to a deepening of the thermocline. In this depth range cold-water corals represent a ... More
Presented by Prof. Norbert FRANK on 8 Apr 2018 at 11:45
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
The Holocene is characterized by long term changes in seasonality induced by insolation that has altered monsoon and ENSO characteristics. How different feedbacks from the surface hydrology, vegetation or dust have shaped these tropical climate characteristics is not well understood. We consider a multi-complexity ensemble of mid to late Holocene simulations with the IPSL Earth System model that a ... More
Presented by Dr. Pascale BRACONNOT on 8 Apr 2018 at 14:30
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
There are indications from ice cores that the deposition of mineral dust was twice as strong or even stronger at the Last Glacial Maximum (LGM) than at present. This is assumed to be due to a combination of changes in the vegetation cover and an altered atmospheric circulation with impacts on the wet deposition. Dust has several important effects in the Earth system. For example, airborne dust can ... More
Presented by Anne KUBIN on 7 Apr 2018 at 16:30
Type: oral presentation Session: Cryosphere-climate interactions
Track: Cryosphere-climate interactions
We study the interactions of ice sheets with the other components of the climate system in a new modeling system that encompasses a wide range of interactions between ice sheets, their mass balance, the solid Earth and the climate. Forcing the model with increasing greenhouse gas concentrations allows us to study the full interactions of the different climate system components and thus deepen our ... More
Presented by Florian ZIEMEN on 8 Apr 2018 at 11:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The hydrological cycle is a fundamental component of the Earth’s climate system. Modeling the time response of this cycle and the implied physical processes challenges the general circulation models (GCM) used to study the climate system and to project future climate. Water stable isotopes (H216O, H218O and HD16O) are integrated tracers of climate processes occurring in various branches of the h ... More
Presented by Dr. Alexandre CAUQUOIN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Elevated Si:N drawdown and export ratios in the present-day Southern Ocean lead to a low Si:N ratio in the unused nutrients from the Southern Ocean that are transported to low latitudes via mode and intermediate waters. It has been hypothesised that iron fertilisation of the Southern Ocean in the last glacial has led to a lower Si:N drawdown ratio there and hence changed stoichiometry of nutrients ... More
Presented by Dr. Christoph VOELKER on 7 Apr 2018 at 16:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Performing a fully transient simulation of the last glacial cycle and particularly the last deglaciation is a phenomenal challenge for our understanding and ability to model climate change. As a precursor for such an endeavour, we present results from a large series of "snapshot" simulations. Implicit within such simulations is the assumption that climate is in equilibrium with its forcing. We wil ... More
Presented by Prof. Paul VALDES on 7 Apr 2018 at 11:45
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
The pattern and timing of retreat of the last British Irish Ice Sheet has been constrained in more detail than any other palaeo ice sheet, thanks to the efforts of the ongoing BRITICE-CHRONO project. We are modelling the climate-ice sheet interaction in two contrasting catchments of the British Irish Ice Sheet. By combining the glacial geomorphology and Quaternary geology data with numerical model ... More
Presented by Mr. Niall GANDY on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Episodes of massive freshwater discharge to the North Atlantic (NA) are related to cold conditions in the NA realm, so-called Heinrich stadials (HSs). In contrast, the meltwater history of the North Pacific (NP) realm remains unclear, leading to persistent debates on inter-basin responses of millennial-scale climate variability between the NP and NA during HSs. Here we show evidence regarding fres ... More
Presented by Dr. Xu ZHANG on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Pollen data from North America (1064 sites), Europe (1384 sites) and Siberia (402) were extracted from available data bases. Pollen names were homogenized and assigned to plant functional types and then to biomes respectively, following the standard biome reconstruction procedure. The mean value of pollen taxa from all available pollen assemblages within a time window is selected as the “poll ... More
Presented by Prof. Ulrike HERZSCHUH on 7 Apr 2018 at 16:30
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Modern El Niño-Southern Oscillation (ENSO) events are characterized by their phase locking of variability to the seasonal cycle and tend to peak at the end of calendar year. However, in an idealized NCAR-CCSM3 simulation of the climate of the last 300 thousand years, ENSO seasonal phase locking is shifted periodically following the precessional forcing: ENSO tends to peak in boreal winter when pe ... More
Presented by Dr. Zhengyao LU on 8 Apr 2018 at 15:30
Session: PalMod Overview
Presented by Marie-Luise KAPSCH on 7 Apr 2018 at 09:15
Session: PalMod Overview
Presented by Dr. Tatiana ILYINA on 7 Apr 2018 at 09:30
Session: PalMod Overview
Presented by Prof. Ulrike HERZSCHUH on 7 Apr 2018 at 09:45
Session: PalMod Overview
Presented by Prof. Thomas SLAWIG on 7 Apr 2018 at 10:00
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Paleo-ice sheet reconstructions are complicated by large uncertainties, particularly since it is usually only possible to infer thickness from indirect means such as the response of glacial isostatic adjustment (GIA). Recently, there has been increased attention to refining the chronology of ice sheet margins of paleo-ice sheets, and changes in relative sea level in formerly glaciated regions. Usi ... More
Presented by Dr. Evan GOWAN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
In trying to find algorithms to parallelize Cauchy problems in time very promising concepts and analysis were developed, especially in the recent 10 years [6]. It has been found that the straight forward implementation of the parareal algorithm in its native form [1] tends to lack the anticipated convergence and speed-up, especially when it comes to nonlinear hyperbolic PDE as the Shallow Water Eq ... More
Presented by Benedict PHILIPPI on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
The appropriateness of a deglacial simulation with a fully coupled ice sheet-climate model critically depends on the Last Glacial Maximum (LGM) state from which it is initialized. However, as the dynamics of ice sheet complexes operate over long time-scales (many thousands of years), obtaining such a state requires a computationally efficient spin-up strategy. Such a strategy has to carefully bal ... More
Presented by Dr. Irina ROGOZHINA on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
The wide range of response time scales of the atmosphere, ocean and ice sheets poses a major challenge for coupled ice sheet-climate simulations over a full glacial-interglacial cycle. Previous modeling studies of the climate states during the Last Glacial Maximum (LGM) and other periods of the last glacial cycle have demonstrated that even moderate changes in ice-sheet geometries may lead to stro ... More
Presented by Dr. Irina ROGOZHINA on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Couplers for large-scale simulations of climate systems have to satisfy a number of very stringent requirements in terms of flexibility (support of different grids/discretizations in each sub-model), accuracy (produce possibly few interpolation artifacts and guarantee the conservation of critical physical properties), and performance (be as light-weight as possible on shared and distributed memory ... More
Presented by Mr. Dragos B. CHIRILA on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Proxy-based reconstructions and modelling of Holocene spatio-temporal precipitation patterns for China and Mon- golia have hitherto yielded contradictory results, indicating that the basic mechanisms behind the East Asian Sum- mer Monsoon and, in particular, its interaction with the westerly jet stream, remain poorly understood. Here we present quantitative reconstructions of Holocene precipita ... More
Presented by Prof. Ulrike HERZSCHUH on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Climate reconstructions are usually performed using proxy data such as plant pollen that are only valid locally in space and time. However, the reconstructions exhibit errors that complicate spatial interpolation between locations. Using prior knowledge from a General Circulation Model (GCM) we define a dynamical stochastic process to estimate dominant spatial structures on global or regional scal ... More
Presented by Mr. Florian KAPP on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
Glacial-interglacial variations in atmospheric CO2 remain one of the great challenges in paleoclimate research. Improved understanding requires a quantification of the glacial ocean's carbon cycle. Here we present a decomposition of the modern and glacial ocean's carbon cycle using data-constrained models. Offline calculations using the Transport Matrix Method (TMM) are used to accurately quantify ... More
Presented by Dr. Andreas SCHMITTNER on 8 Apr 2018 at 09:00
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
We investigate the frequency and intensity of extreme weather events such as heavy precipitation or heat waves in a global atmosphere model run from 1982 to 2016 with observed surface conditions. Results from the simulations allow us to study how extreme weather events have changed due to recent decadal warming. We use a suite of model experiments with varying horizontal resolutions, which al ... More
Presented by Dr. Joakim KJELLSSON on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 1)
Track: Novel methodological aspects of long-term simulations and reconstructions
Much of the spatial and temporal variability in surface temperatures in the extra-tropical latitudes of the Northern Hemisphere is closely associated with the atmospheric circulation, which in turn is associated with specific teleconnection modes. Understanding changes in these modes is critical to understanding and forecasting much of regional climate change, particularly in the mid-latitudes whe ... More
Presented by Dr. Basil A.S. DAVIS on 7 Apr 2018 at 16:15
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Global climate simulations are not able to resolve the accumulation and ablation of ice sheets over steep topography gradients adequately. Within the PalMod project, we aim to develop parameterisations to account for the effects of such unresolved scales and to optimize existing parameterisations. Simulations with the non-hydrostatic regional climate model COSMO-CLM allow estimating mesoscale effe ... More
Presented by Melanie KARREMANN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
The concentration ratio of the stable water isotopes H218O and H216O (δ18O) closely reflects the phase change history of atmospheric water and condensation temperatures. For this reason, δ18O in ice cores can be used for quantitatively evaluating paleo climate simulations of isotope-enabled general circulation and regional models. To allow an optimal comparison between the δ18O in ice core samp ... More
Presented by Dr. Emanuel CHRISTNER on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Glacial cycles are accompanied by pronounced sea level changes between glacials and interglacials. In particular, during the warming phase of the last glacial cycle, sea level rose by ~80 m due to the melting of ice sheets. The concomitant flooding turned land areas – with nutrient and carbon stored in land vegetation and soils – into continental shelves, exposed to erosion in the ocean. At th ... More
Presented by Hanna PAULSEN on 7 Apr 2018 at 16:30
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Over the past few million years, the circulation of the deep ocean could have responded to changes in atmospheric CO2 concentrations, Earth’s orbital geometry and terrestrial ice sheet size through a daunting number of theoretical mechanisms. Here we assess many of these mechanisms according to the GFDL Earth system model, by applying forty different combinations of the three external forcings a ... More
Presented by Prof. Eric GALBRAITH on 8 Apr 2018 at 14:45
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
There are places on Earth that are so cold that water is frozen solid. These areas of snow or ice compose the cryosphere. The term “cryosphere” comes from the Greek word, “krios,” which means cold e.g. Greenland and Antarctica Lately (Feb’17), Researchers in University of Washington ,USA & University of Edinburgh found that the pools underneath the glacier, Thwaites, are draining out at ... More
Presented by Prof. Virendra GOSWAMI on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Paleo-climate records and geodynamic modelling indicate the existence of complex interactions between glacial sea level changes, volcanic degassing and atmospheric CO2, which may have modulated the climate system’s descent into the last ice age. Between B85 and 70 kyr ago, during an interval of decreasing axial tilt, the orbital component in global temperature records gradually declined, while a ... More
Presented by Dr. Gregor KNORR on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
Ice sheet models fail to reproduce reconstructed patterns of Northern Hemisphere ice sheet retreat through the last deglaciation (21,000-6,000 years ago) without tuning of the climate input. This is the main barrier to understanding the role of ice sheets in past abrupt climate and sea level changes. The primary reason for this failure is the large climatic uncertainty. We developed a statistical ... More
Presented by Dr. Lauren GREGOIRE on 8 Apr 2018 at 11:00
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
We present a set of simulations with the coupled climate model MPI-ESM, in which the Atlantic Meridional Overturning Circulation (AMOC) oscillates between a weak and a strong state on multi-centennial to millennial timescales. In each simulation, all respective forcings are held constant. The oscillations occur under medium to low CO2 concentrations (pCO2) of approximately 207 to 190 ppm in combin ... More
Presented by Marlene KLOCKMANN on 7 Apr 2018 at 14:00
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Mineral dust plays an important role in the Earth system both through direct and indirect effects, and changes in climate may also feed back onto the life cycle of mineral dust. Aerosol-cloud interactions and the role of aerosols in affecting the global biogeochemical and hydrological cycles are only partly understood, and additional challenges result from the ranges of spatial and temporal scales ... More
Presented by Dr. Ute MERKEL on 7 Apr 2018 at 16:30
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Further insight into ocean carbon cycle during the last glacial maximum (LGM), especially in terms of marine carbon sequestration and release, is crucial for understanding mechanisms that cause the large glacial-interglacial variations in atmospheric CO2 concentration. First model results from the Hamburg Ocean Carbon Cycle model (HAMOCC), which is a component of the Max Planck Institute Earth Sys ... More
Presented by Dr. Bo LIU on 8 Apr 2018 at 15:00
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Understanding how the Greenland Ice Sheet (GrIS) behaves in a warmer climate is of utmost importance in respect to improve future sea level rise projections. Many authors in the past did so by simulating the GrIS during the Eemian Interglacial, the most recent warmer-than-present period in Earth’s history, approximately 125,000 years ago. The idea behind it is that future Arctic temperature may ... More
Presented by Mr. Andreas PLACH on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
During the last deglaciation, a major global warming was punctuated by several abrupt climate changes, likely related to Atlantic Meridional Overturning Curculation (AMOC). A transient simulation from the Last Glacial Maximum (21,000 years ago) to Bolling-Allerod (BA, 14,000 years ago) is conducted using an atmosphere-ocean coupled general circulation model. Changing insolation, greenhouse gas con ... More
Presented by Mr. Takashi OBASE on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Climate—ice sheet coupling processes, such as meltwater discharge and sea-level rise, can substantially modulate the global ocean circulation and climate. Here, we explore the role of such coupling mechanisms and their impact on the Atlantic meridional overturning circulation (AMOC) in transient simulations of Termination 1. The simulations are performed with the 3-dimensional climate model of i ... More
Presented by Dr. Malte HEINEMANN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The "Green Sahara" is a term used to describe a period when today's Sahara desert was transformed into a region covered with vegetation and lakes by orbital modulation. In this study, the 2nd generation dynamic vegetation model LPJ-GUESS is driven by different atmospheric forcings from coupled EC-Earth model mid-Holocene time-slice simulations in which the vegetation is either prescribed to be mod ... More
Presented by Dr. Zhengyao LU on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
Studying glacial climate variability with complex Earth System Models (ESMs) remains a major challenge. Large part of the long-term variability throughout the glacial cycles is caused by interactions between the ice sheets and the climate (e.g. Heinrich Events starting in Dansgaard-Oeschger stadials). Modeling these interactions requires the coupling of interactive ice sheets into the model system ... More
Presented by Marie-Luise KAPSCH on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 3)
Track: Novel methodological aspects of long-term simulations and reconstructions
Published literature on the dust content in terrestrial and marine sediment cores is synchronized with terrestrial and marine pollen data and speleothem growth phases on a common time scale for eight selected key areas of the global climate system during the last 60 000 years. Records have different time resolution and are dated by different methods, but still are brought to a synthesis for each ... More
Presented by Mr. Florian FUHRMANN on 8 Apr 2018 at 09:45
Type: poster Session: Poster Session
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The time between last glacial maximum (LGM) and preindustrial (PI) is a highly interesting time with regard to atmospheric methane concentrations. Between LGM and 10 ka BP atmospheric CH4, as reconstructed from ice cores, nearly doubled, with very rapid concentration changes of about 200 ppb occurring during the Younger Dryas and Bolling Allerod transitions. Although atmospheric CH4 is nearly iden ... More
Presented by Dr. Thomas KLEINEN on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Paleoclimate data provide a unique opportunity investigate climate dynamics on time scales beyond decadal. Despite the wealth of paleoclimate data that has been collected over the past decades, paleoclimate data is often archived in a fragmented and non-standardised way, hampering making full use of the data. To address this, we are building a multi-proxy marine paleoclimate data synthesis based o ... More
Presented by Lukas JONKERS on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
"GReenland ice sheet/OCEan Interaction (GROCE)"is a collaborative effort of several German universities and research institutions funded by the German Federal Ministry of Education and Research (BMBF) for the period 05/2017-04/2020. The project partners involves experts in oceanography, glaciology, geodesy and meteorology embarking on a holistic study of the melting rates and mass loss of the Nort ... More
Presented by Prof. Inga Monika KOSZALKA on 7 Apr 2018 at 16:30
Type: oral presentation Session: Cryosphere-climate interactions
Track: Cryosphere-climate interactions
Some studies suggest that specific equilibrium climate sensitivity S might be state-dependent. Reanalyzing existing paleodata of global mean surface temperature ∆Tg and radiative forcing ∆R of CO2 and land ice albedo for the last 800,000 years we show that this state-dependency of S is only found if ∆Tg is based on reconstructions, and not when ∆Tg is based on model simulations. Furthermor ... More
Presented by Dr. Peter KöHLER on 8 Apr 2018 at 12:15
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Automated calibration of marine biogeochemical models is a powerful tool for understanding their limitations. We present results from a 9-member test of the University of Victoria Earth System Climate Model in which identical biogeochemical parameter calibrations are conducted using varied physical model configurations. Vertical mixing coefficients of the 9 members are tuned to produce maximum nor ... More
Presented by Dr. Karin KVALE on 7 Apr 2018 at 16:30
Type: oral presentation Session: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
Track: Feedbacks, thresholds, and abrupt changes in the Earth System dynamics during the last deglaciation
The deglaciation over the Euro-Atlantic region is characterized by rapid climate shifts between warm/cold (inter-)stadials. Proxy- and modelling-evidence suggest a consistent link between cold annual/winter climates with cold ocean states of the Northern Atlantic. However, it remains unclear whether and (if so) how these cold ocean states during stadials should lead to cold European summers in the ... More
Presented by Dr. Frederik SCHENK on 7 Apr 2018 at 12:15
Type: poster Session: Poster Session
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Carbon storage in the terrestrial biosphere played an important role in the deglaciation phase from 21ka BP until present. During Last Glacial Maximum (LGM) atmospheric CO2 concentration was almost 100 ppm lower than the pre-industrial concentration. Ciais et al., 2012 suggest that the terrestrial carbon storage in LGM was 330 PgC lower but a 700 PgC larger permafrost carbon than under pre-industr ... More
Presented by Sibyll SCHAPHOFF on 7 Apr 2018 at 16:30
Type: oral presentation Session: Novel methodological aspects of long-term simulations and reconstructions (part 1)
Track: Novel methodological aspects of long-term simulations and reconstructions
Understanding the uncertainties associated with proxy-based reconstructions of past climate is critical if they are to be used to validate climate models and contribute to a comprehensive understanding of the climate system. Here we present two related and complementary approaches to quantifying proxy uncertainty. The proxy forward model (PFM) "sedproxy" bitbucket.org/ecus/sedproxy numerically ... More
Presented by Dr. Andrew DOLMAN, Mr. Torben KUNZ on 7 Apr 2018 at 16:00
Type: poster Session: Poster Session
Track: Novel methodological aspects of long-term simulations and reconstructions
Recent paleoclimate studies using data assimilation (DA) have mostly performed low or intermediate resolution global simulations. In an ``on-line'' paleo-data assimilation, the proxy time resolution is often too long for the dynamical models and the forecast state usually has no skill. For an ``off-line'' DA, the re-initialization cycle is completely removed after the assimilation step. We set-up ... More
Presented by Dr. Bijan FALLAH HASSANABADI on 7 Apr 2018 at 16:30
Type: poster Session: Poster Session
Track: Cryosphere-climate interactions
In earth system models (ESM) a number of sub-components, like atmosphere, ocean, terrestial and cryospheric systems are coupled with each other. Most often these sub-systems communicate with each other by exchanging boundary values or fluxes at their interfaces. In many cases the communication intervals are relatively large due to the different time scales of the corresponding sub-components or si ... More
Presented by Ms. Anusha SUNKISALA on 7 Apr 2018 at 16:30
Type: oral presentation Session: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Track: Spectrum of climate variability (governing processes, energy transfer across century-to-orbital timescales
Radiative forcing resulting from major explosive eruptions has been the dominant natural driver of past climate variability, at least over the past few hundred years. On glacial timescales, there is speculation that volcanic activity may play an important role in major climate transitions such as the last deglaciation and in Dansgaard-Oeschger and Heinrich events. Volcanic forcing has, however, la ... More
Presented by Matthew TOOHEY on 8 Apr 2018 at 15:45