Sensitivity of a Coupled Ocean-atmosphere Model to Improved Sea-ice Parameterizations PDF Download
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Author: Stephen J. Vavrus
Publisher:
ISBN:
Category :
Languages : en
Pages : 220
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Book Description
Author: Stephen J. Vavrus
Publisher:
ISBN:
Category :
Languages : en
Pages : 220
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Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309265266
Category : Science
Languages : en
Pages : 93
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Book Description
Recent well documented reductions in the thickness and extent of Arctic sea ice cover, which can be linked to the warming climate, are affecting the global climate system and are also affecting the global economic system as marine access to the Arctic region and natural resource development increase. Satellite data show that during each of the past six summers, sea ice cover has shrunk to its smallest in three decades. The composition of the ice is also changing, now containing a higher fraction of thin first-year ice instead of thicker multi-year ice. Understanding and projecting future sea ice conditions is important to a growing number of stakeholders, including local populations, natural resource industries, fishing communities, commercial shippers, marine tourism operators, national security organizations, regulatory agencies, and the scientific research community. However, gaps in understanding the interactions between Arctic sea ice, oceans, and the atmosphere, along with an increasing rate of change in the nature and quantity of sea ice, is hampering accurate predictions. Although modeling has steadily improved, projections by every major modeling group failed to predict the record breaking drop in summer sea ice extent in September 2012. Establishing sustained communication between the user, modeling, and observation communities could help reveal gaps in understanding, help balance the needs and expectations of different stakeholders, and ensure that resources are allocated to address the most pressing sea ice data needs. Seasonal-to-Decadal Predictions of Arctic Sea Ice: Challenges and Strategies explores these topics.
Author:
Publisher:
ISBN: 9781109386943
Category : Sea ice
Languages : en
Pages :
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Book Description
The response of a simulated sea-ice distribution to different numerical approximations of atmospheric state variables is investigated with respect to the improvement of sea-ice model physics within coupled climate system models (CSM). Model representation of the Antarctic sea-ice environment within CSM's has been limited by poor model physics and a lack of continental-scale, sea-ice thickness observations for model evaluation. The availability of continental-scale thickness observations was addressed using sea-ice thickness estimates derived from weekly, National Ice Center (NIC) operation sea-ice charts for the Southern Ocean from 1995 to 1998. Previous studies reported a good agreement between Antarctic seaice thickness estimates derived from NIC observations and in situ sea-ice thickness observations within the Ross Sea. Prediction errors determined for sea-ice thickness estimates derived from the NIC dataset indicate a mean absolute error (MAE) less than "10 cm, an index of agreement (d 1) of 0.94, and resolution errors 20 cm for commonly used model resolutions. The response of the sea-ice distribution produced by the National Center for Atmospheric Research (NCAR) Community Sea Ice Model, Version 5 (CSIM5) to atmospheric energy fluxes is evaluated using NIC observations. The simulated sea-ice environment responded strongly to the value of atmospheric specific humidity due to the parameterized numerical approximation of the latent heat flux used by the CSIM5. The CSIM5 produced a thinner ice pack with a lesser extent in response high atmospheric moisture, as indicated by extensive areas of large ( 50 cm), negative model prediction errors. The model produced a thicker, more extensive ice pack in response to low atmospheric moisture as indicated by even larger (> 200 cm), positive model prediction errors.
Author: J.C.J. Nihoul
Publisher: Elsevier
ISBN: 0080870783
Category : Science
Languages : en
Pages : 793
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Book Description
The exchange of momentum, heat, moisture, gases (such as CO2 and O2) and salt between the atmosphere and the ocean is a phenomenon of paramount importance for the dynamics of the atmosphere and the ocean. With the pressing need for reliable climate forecast (e.g. to deal with severe food and energy problems) interactive ocean-atmosphere models have become one of the main objectives of geophysical fluid dynamics. This volume provides the first state-of-the-art review of interactive ocean-atmosphere modelling and its application to climates. The papers are by active and eminent scientists from different countries and different disciplines. They provide a up-to-date survey of major recent discoveries and valuable recommendations for future research.
Author: Alexander Mchedlishvili
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Over the last half a century, the Arctic sea ice extent and volume have been decreasing as a result of the amplified warming taking place in the Arctic. Similarly, the Antarctic summertime sea ice extent maximum has been the lowest in the satellite record for the last three years. As sea ice at both poles is changing in a warming climate, it is necessary to better understand the fundamental processes that determine sea ice properties such as extent, thickness, volume and drift. These processes, namely dynamic and thermodynamic ones, are triggered by the surrounding atmosphere and ocean. The overarching goal of this dissertation is to study dynamic processes while also considering thermodynamic aspects. Chapter 3 delves into the abovementioned dynamic and thermodynamic processes at mesoscale in the study of polynya events and thin sea ice anomalies above Maud Rise in the Antarctic. Chapter 4 looks at parameters that quantify dynamics, specifically at drag coefficients (Cd) that determine the momentum transfer between the atmosphere and sea ice, on a pan-Arctic scale. Finally, Chapter 5 implements the derived estimates of drag from observations into a coupled regional atmosphere-ocean-sea ice model in order to investigate the impact of variable drag on sea ice properties Arctic-wide. The Weddell Sea Polynya (occurring in 1974-1976 and 2016-2017) is an excellent case study in the impact of mesoscale as well as synoptic scale processes on sea ice. My analysis of the events corroborates past studies that identify the Weddell Sea polynya as one that is driven by dynamic as well as thermodynamic processes. In addition, using satellite-borne microwave imaging radiometers, large thin sea ice anomalies have been identified in polynya-free years (2010-2020). Given the reported links between the polynya and different dynamic and thermodynamic ocean and atmosphere processes, our results suggest that when an insufficient amount of these processes are active, a thin sea ice anomaly may emerge instead. The neutral sea ice-atmosphere Cd data-set is the first-ever assessment of drag on both pan- Arctic spatial and sub-yearly temporal scales. Leveraging the high resolution of Ice, Cloud and land Elevation Satellite 2 (IS2), as well as near-coincident Operation IceBridge (OIB) airborne surveys of sea ice topography, it was possible to observe the spatiotemporal evolution of drag from November 2018 to May 2022. My results showed the ice area directly north of the Canadian Archipelago and Greenland to have a Cd consistently above 2.0 × 10-3, while for most of the multiyear ice portion of the Arctic it is typically around ∼1.5 × 10-3. The first-year and young ice portion of the Arctic has a comparatively lower Cd (∼9 × 10-4) with an increase along the marginal ice zone that exceeds 1.5 × 10-3. This dataset was then used to derive a parameterization linking Cd to coincident IS2 sea ice thickness measurements, which was implemented into the regional atmosphere-ocean-sea ice model HIRHAM-NAOSIM. By running the model with and without the implementation, my results showed reasonable albeit small differences between the sea ice properties modelled by the two runs. Using sensitivity studies that varied the coefficients and integration of the Cd parameterization, I was then able to explain the differences observed. The main findings from the model study are that atmospheric and oceanic drag have the opposite effect on both sea ice drift and thickness on a pan-Arctic scale, and that over a period of three years, regardless of the range in drag variability, the impact of drag on sea ice in a coupled model is typically small in magnitude (
Author: Stephen J. Vavrus
Publisher:
ISBN:
Category :
Languages : en
Pages : 454
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Book Description
Author: Lakshmi H. Kantha
Publisher: Elsevier
ISBN: 0080512909
Category : Science
Languages : en
Pages : 981
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Book Description
Oceans play a pivotal role in our weather and climate. Ocean-borne commerce is vital to our increasingly close-knit global community. Yet we do not fully understand the intricate details of how they function, how they interact with the atmosphere, and what the limits are to their biological productivity and their tolerance to wastes. While satellites are helping us to fill in the gaps, numerical ocean models are playing an important role in increasing our ability to comprehend oceanic processes, monitor the current state of the oceans, and to a limited extent, even predict their future state.Numerical Models of Oceans and Oceanic Processes is a survey of the current state of knowledge in this field. It brings together a discussion of salient oceanic dynamics and processes, numerical solution methods, and ocean models to provide a comprehensive treatment of the topic. Starting with elementary concepts in ocean dynamics, it deals with equatorial, mid-latitude, high latitude, and coastal dynamics from the perspective of a modeler. A comprehensive and up-to-date chapter on tides is also included. This is followed by a discussion of different kinds of numerical ocean models and the pre- and post-processing requirements and techniques. Air-sea and ice-ocean coupled models are described, as well as data assimilation and nowcast/forecasts. Comprehensive appendices on wavelet transforms and empirical orthogonal functions are also included.This comprehensive and up-to-date survey of the field should be of interest to oceanographers, atmospheric scientists, and climatologists. While some prior knowledge of oceans and numerical modeling is helpful, the book includes an overview of enough elementary material so that along with its companion volume, Small Scale Processes in Geophysical Flows, it should be useful to both students new to the field and practicing professionals. * Comprehensive and up-to-date review* Useful for a two-semester (or one-semester on selected topics) graduate level course* Valuable reference on the topic* Essential for a better understanding of weather and climate
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309456002
Category : Science
Languages : en
Pages : 83
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Book Description
The sea ice surrounding Antarctica has increased in extent and concentration from the late 1970s, when satellite-based measurements began, until 2015. Although this increasing trend is modest, it is surprising given the overall warming of the global climate and the region. Indeed, climate models, which incorporate our best understanding of the processes affecting the region, generally simulate a decrease in sea ice. Moreover, sea ice in the Arctic has exhibited pronounced declines over the same period, consistent with global climate model simulations. For these reasons, the behavior of Antarctic sea ice has presented a conundrum for global climate change science. The National Academies of Sciences, Engineering, and Medicine held a workshop in January 2016, to bring together scientists with different sets of expertise and perspectives to further explore potential mechanisms driving the evolution of recent Antarctic sea ice variability and to discuss ways to advance understanding of Antarctic sea ice and its relationship to the broader ocean-climate system. This publication summarizes the presentations and discussions from the workshop.
Author: Tianjun Zhou
Publisher: Springer Science & Business Media
ISBN: 3642418015
Category : Science
Languages : en
Pages : 468
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Book Description
Coupled climate system models are of central importance for climate studies. A new model known as FGOALS ( the Flexible Global Ocean-Atmosphere-Land System model), has been developed by the Sate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP, CAS), a first-tier national geophysical laboratory. It serves as a powerful tool, both for deepening our understanding of fundamental mechanisms of the climate system and for making decadal prediction and scenario projections of future climate change. "Flexible Global Ocean-Atmosphere-Land System Model: A Modeling Tool for the Climate Change Research Community” is the first book to offer systematic evaluations of this model’s performance. It is comprehensive in scope, covering both developmental and application-oriented aspects of this climate system model. It also provides an outlook of future development of FGOALS and offers an overview of how to employ the model. It represents a valuable reference work for researchers and professionals working within the related areas of climate variability and change. Prof. Tianjun Zhou, Yongqiang Yu, Yimin Liu and Bin Wang work at LASG, the Institute of Atmospheric Physics, Chinese Academy of Sciences, China.
Author: David N. Thomas
Publisher: John Wiley & Sons
ISBN: 9781444317152
Category : Technology & Engineering
Languages : en
Pages : 641
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Book Description
As the Arctic perennial sea ice continues to disappear at an alarming rate, a full understanding of sea ice as a crucial global ecosystem, and the effects of its loss is vital for all those working with and studying global climate change. Building on the success of the previous edition, the second edition of Sea Ice, now much expanded and in full colour throughout, includes six completely new chapters with complete revisions of all the chapters included from the first edition. The Editors, Professor David Thomas and Dr Gerhard Dieckmann have once again drawn together an extremely impressive group of internationally respected contributing authors, ensuring a comprehensive worldwide coverage of this incredibly important topic. Sea Ice, second edition, is an essential purchase for oceanographers and marine scientists, environmental scientists, biologists, geochemists and geologists. All those involved in the study of global climate change will find this book to contain a wealth of important information. All libraries in universities and research establishments where these subjects are studied and taught will need multiple copies of this book on their shelves. truly multidisciplinary approach world leading authors and editors international in scope, covering both Arctic and Antarctic work of vital interest to all those involved in global warming and climate change research highly illustrated full colour book with colour images throughout
