Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Interactions of Ice Sheets and Glaciers with the Ocean
Author: Air-Ice-Ocean Interaction
Author: Miles McPheePublisher: Springer
ISBN: 9780387783345
Category : Science
Languages : en
Pages : 0
Book Description
At a time when the polar regions are undergoing rapid and unprecedented change, understanding exchanges of momentum, heat and salt at the ice-ocean interface is critical for realistically predicting the future state of sea ice. By offering a measurement platform largely unaffected by surface waves, drifting sea ice provides a unique laboratory for studying aspects of geophysical boundary layer flows that are extremely difficult to measure elsewhere. This book draws on both extensive observations and theoretical principles to develop a concise description of the impact of stress, rotation, and buoyancy on the turbulence scales that control exchanges between the atmosphere and underlying ocean when sea ice is present. Several interesting and unique observational data sets are used to illustrate different aspects of ice-ocean interaction ranging from the impact of salt on melting in the Greenland Sea marginal ice zone, to how nonlinearities in the equation of state for seawater affect mixing in the Weddell Sea. The book’s content, developed from a series of lectures, may be appropriate additional material for upper-level undergraduates and first-year graduate students studying the geophysics of sea ice and planetary boundary layers.
Interactions Calotte Polaire/océan
Author: Nacho MerinoPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The next generation of climate models will include an ice-sheet model in order to improve the ice sheet mass balance projections by accounting for the ice dynamics and ice-oceans interactions. On the one hand, the Southern Ocean (SO) is indeed driving the acceleration of the Antarctic outlet glaciers via an increase in the basal melting of the ice shelves. On the other hand, the increasing ice discharge from Antarctic Ice Sheet (AIS) contributes to the current sea level rise and is likely to become the largest cryospheric contributor to sea level rise by the end of the current century. In addition, the related freshening may have significant implications on future sea-ice cover and on bottom water formation. However, it is not clear yet how the ocean and ice-sheet components of future coupled systems will account for the ice-ocean interactions, which are both causes and consequences of the AIS mass imbalance. Here in this work, different aspects of the standalone ocean and ice-sheet components have been investigated. A first step of this thesis has been focused in the representation of the glacial freshwater fluxes in current ocean models. Based on recent glaciological estimates, the ice shelf basal melting fluxes have been spatially distributed in an ORCA025 grid, and the calving rates have been applied into an improved version of the NEMO-ICB iceberg model. This preliminary study has been used to produce a monthly iceberg meltwater climatology, to be used to force current ocean models. This work shows the importance of representing the iceberg meltwater fluxes when modeling sea ice, which can be inexpensively achieve by using our climatology. The improvements in the representation of the glacial freshwater fluxes have been considered in the study of the ocean model response to the Antarctic mass imbalance. This study considers a realistic perturbation in the glacial freshwater forcing as close as possible as it will be represented in future ice-sheet/ocean models. According to our results, up to 50% of the recent Antarctic sea ice volume changes might be caused by the observed decadal AIS mass imbalance rate. Glacial freshwater forcing appears to be crucial to correctly represent the ice-ocean interactions and projecting sea ice cover of future coupled systems. However, the estimation of the glacial freshwater input in future climate models will be strongly dependent upon the capacity of ice-sheet models to reproduce the grounding line migrations of marine ice sheet glaciers. Current ice-sheet models present large uncertainties related to different parametrizations. In the context of the future climate models, we have studied the sensitivity of ocean-driven grounding line retreats to the application of two different friction laws and two different englacial stress approximations. The model responses almost indistinctively to either the SSA or the SSA* englacial stress approximations. However, differences in the contribution of the glacier to the sea level rise can be up to 50% depending on the friction law considered. The more physically constrained Schoof friction law is significantly more reactive to the ocean perturbations than Weertman law and should be considered in future coupled systems. This work underlines that uncertainties related to the ice sheet model estimates of grounding line migrations may not only contribute to uncertainties in sea level projections, but also the sea ice cover through the ice-ocean interaction in future ocean models.This conclusion suggests the need for improving the representation of both the ice shelf basal melting and the glacier interaction with the bedrock, in order to improve the climate projections of future climate models, in which the spatial and seasonal distribution of the glacial freshwater fluxes may play an important role in setting the sea ice cover.
Microwave Remote Sensing of Land Surfaces
Author: Nicolas BaghdadiPublisher: Elsevier
ISBN: 0081017685
Category : Technology & Engineering
Languages : en
Pages : 450
Book Description
Microwave Remote Sensing of Land Surface: Techniques and Methods brings essential coverage of the space techniques of observation on continental surfaces. The authors explore major applications and provide detailed chapters on physical principles, physics of measurement, and data processing for each technique, bringing readers up-to-date descriptions of techniques used by leading scientists in the field of remote sensing and Earth observation. - Presents clear-and-concise descriptions of modern methods - Explores current remote sensing techniques that include physical aspects of measurement (theory) and their applications - Provides physical principles, measurement, and data processing chapters that are included for each technique described
Meteorological and Geoastrophysical Abstracts
Author: Topex/Poseidon, mission franco-américaine
Author: Publisher:
ISBN:
Category : Artificial satellites in surveying
Languages : fr
Pages : 24
Book Description
Comptes rendus de l'Académie des sciences
Author: Current Research
Author: Advances in Ordovician Geology
Author: Christopher R. BarnesPublisher:
ISBN: 9780660139975
Category : Science
Languages : en
Pages : 364
Book Description
Selected papers from the August 1988 symposium on the Ordovician System. Authors from the U.K., Canada, Australia, and the U.S. contributed papers on a project to redefine regional chronostratigraphic subdivisions. Papers also cover Ordovician paleontology and biostratigraphy, emphasizing conodonts, graptolites and trilobites. The interrelationships of stratigraphy, eustasy, tectonics, and volcanisms are explored, with particular attention to the Appalachian Orogen. The final section of the volume documents some of the new data and interpretations of Ordovician paleo-oceanography, paleoclimatology, and paleogeography.
Author: