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Nombre de programmes trouvés : 5193
Conférences

le (17m29s)

Comparison of Simulated Tree-Ring Cellulose d180 at the European Scale

In order to investigate factors involved in the inter-annual variability of d180 in tree ring cellulose (d18OTRC), we simulated the d18OTRC from 1960 to 2001 over Europe. We used 1) simulated climate and water isotope fields of REMOiso, a meso-scale circulation model, 2) hypotheses of the distribution of roots and soil hydrology, and 3) a mechanistic model of oxygen-isotopes in tree ring cellulose (d18OTRC). Sensitivity tests show that relative humidity of the air and soil water d18O contribute differently to the d180 in tree ring cellulose according to regional climate. In the commonly observed hydrological situation, humidity of the air ...
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Conférences

le (11m49s)

Holocene Climatic Changes and Their Effect on Morphodynamics and Sedimentation in Campania

High-resolution paleoclimatic studies (e.g. 18O, 13C, CH4, MS, ect) provide 38 detailed reconstructions of the Holocene climatic variability, but they don’t are unable to provide direct informations about the effects of the climatic changes on landscape and human ecosystems. In order to assess the response of the subaerial geomorphologic/pedo-sedimentary systems to the climatic changes and their potential impact on the ancient human communities, detailed stratigraphical investigations in Campania (southern Italy) have been carried out. In addition to indications provided by litho-pedostratigraphical and geomorphological investigations, the study has recurred to historical, archaeological, and palaeobiological data. Some of the main global cyclical ...
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Conférences

le (31m27s)

From Climate Models to Earth System Models

Complex climate models that describe the evolution of the coupled ocean atmosphere cryosphere system are gradually extended to “non physical” components of the earth system, and account for land vegetation dynamics, ocean biology, global biogeochemistry and atmospheric chemistry. In the future, these models will have to better represent the potential feedbacks with society and therefore to couple the natural bio-physical components with the socio-economic system. The paper will review the present status of complex climate and Earth system models, report some preliminary attempts to include societal aspects, and highlight challenges for future research.
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Conférences

le (15m57s)

Cross-Disciplinary International Research on Land-Atmosphere Interactions

The presentation will focus on scientific issues of importance to global change and climate change research: interactions of reactive trace and greenhouse gases between the biosphere and atmosphere in combination with boundary layer processes, importance of land use and land cover for climate studies, and aerosol-cloud-precipitation-climate interactions. These issues are of vital importance and research is carried out under the auspices of the multi- and cross-disciplinary Integrated Land Ecosystem-Atmosphere 81 Processes Study (iLEAPS), a core project of the International Geosphere- Biosphere Programme (IGBP) in collaboration with other international research organizations. The interactions between the biosphere and the atmosphere mediated by ...
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Conférences

le (24m29s)

Detection and Attribution of Climate Change to Different Causes

According to the last IPCC report, the most part of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. This statement relies on a long process of demonstration that consisted in evaluating the ability of the successive generations of climate models to reproduce and interpret the climate variability of the last decades. The more and more numerous statistical analyses aiming at detecting and attributing climate change to natural and anthropogenic causes have reinforced the assessment of experts. The recent detection and attribution studies of observed ...
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Conférences

le (30m18s)

Borehole Climatology and Model Simulations: Steps to Integrated Assessment

Progress in understanding climate variability through the last millennium leans on simulation and reconstruction efforts. Exercises blending both approaches present a great potential for answering questions relevant both for the simulation and reconstruction of past climate, and depend on the specific peculiarities of proxies and methods involved in climate reconstructions, as well as the realism and limitations of model simulations. This talk addresses the use of millennial simulations with the ECHO-g model to explore three main issues that group most of the interaction between model and geothermal efforts: the use of models as a validation tool for borehole climate reconstructions; ...
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Conférences

le (15m24s)

The State of UK Climate Modelling

The UK recently invested £23 million (~US$40 million) in a program in Quantifying and Understanding the Earth SysTem (QUEST). The final product of this investment is the state-of-the-art QUEST Earth System Model (QUESM), which is comprised of the most comprehensive modeling and understanding of terrestrial, atmosphere, and marine processes ever built. QUESM is to be linked with the world-leading Hadley Centre’s GCM to assess and understand changes in the Earth system with respect to climate and global change. Here, I present the state of UK climate modeling, an overview of the QUEST Earth System Model, and detail the individual sub-models ...
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Conférences

le (10m13s)

Data-Model Fusion Approach in Global Change Research: Recent Development and Future Challenges

It is increasingly recognized that global change research requires methods and strategies for combing process models and data in systematic ways. This is leading to research towards the application of model-data fusion approach. The model-data fusion is a new quantitative approach to model analysis and data assimilation that provides a high level of empirical constraint over model predictions based on observations. Applications of model-data fusion require (a) a model that describes the underlying physical, chemical and biological processes, (b) experimental observations and (c) an optimization tool. The optimization tool is used to find optimal estimates of model parameters or states ...
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