Simulation of African Easterly Waves in the Community Climate System Model (CCSM)
Author : Evan M. Blaisdell
Publisher :
Page : 124 pages
File Size : 23,10 MB
Release : 2002
Category :
ISBN :
The Community Climate System Model
Author :
Publisher :
Page : 32 pages
File Size : 25,35 MB
Release : 2004
Category :
ISBN :
Book Description
A new version of the Community Climate System Model (CCSM) has been developed and released to the climate community. CCSM3 is a coupled climate model with components representing the atmosphere, ocean, sea ice, and land surface connected by a flux coupler. CCSM3 is designed to produce realistic simulations over a wide range of spatial resolutions, enabling inexpensive simulations lasting several millennia or detailed studies of continental-scale climate change. This paper will show results from the configuration used for climate-change simulations with a T85 grid for atmosphere and land and a 1-degree grid for ocean and sea-ice. The new system incorporates several significant improvements in the scientific formulation. The enhancements in the model physics are designed to reduce or eliminate several systematic biases in the mean climate produced by previous editions of CCSM. These include new treatments of cloud processes, aerosol radiative forcing, land-atmosphere fluxes, ocean mixed-layer processes, and sea-ice dynamics. There are significant improvements in the sea-ice thickness, polar radiation budgets, equatorial sea-surface temperatures, ocean currents, cloud radiative effects, and ENSO teleconnections. CCSM3 can produce stable climate simulations of millenial duration without ad hoc adjustments to the fluxes exchanged among the component models. Nonetheless, there are still systematic biases in the ocean-atmosphere fluxes in western coastal regions, the spectrum of ENSO variability, the spatial distribution of precipitation in the Pacific and Indian Oceans, and the continental precipitation and surface air temperatures. We conclude with the prospects for extending CCSM to a more comprehensive model of the Earth's climate system.
Uncertainties and Limitations in Simulating Tropical Cyclones
Author : Asuka Suzuki-Parker
Publisher : Springer Science & Business Media
Page : 89 pages
File Size : 19,38 MB
Release : 2012-01-05
Category : Science
ISBN : 3642250297
Book Description
The thesis work was in two major parts: development and testing of a new approach to detecting and tracking tropical cyclones in climate models; and application of an extreme value statistical approach to enable assessment of changes in weather extremes from climate models. The tracking algorithm applied a creative phase-space approach to differentiate between modeled tropical cyclones and their mid-latitude cousins. A feature here was the careful attention to sensitivity to choice of selection parameters, which is considerable. The major finding was that the changes over time were relatively insensitive to these details. This new approach will improve and add confidence to future assessments of climate impacts on hurricanes. The extremes approach utilized the Generalized Pareto Distribution (one of the standard approaches to statistics of extremes) applied to present and future hurricane distributions as modeled by a regional climate model, then applied the changes to current observations to extract the changes in the extremes. Since climate models cannot resolve these extremes directly, this provides an excellent method of determining weather extremes in general. This is of considerable societal importance as we are most vulnerable to such extremes and knowledge of their changes enables improved planning and adaptation strategies.
Community Climate System Model (CCSM)
Author : National Center for Atmospheric Research
Publisher :
Page : 512 pages
File Size : 12,45 MB
Release : 2006
Category : Climatology
ISBN :
Book Description
The Community Climate System Model Project from an Interagency Perspective
Author :
Publisher :
Page : 7 pages
File Size : 30,6 MB
Release : 2005
Category :
ISBN :
Book Description
In 2007, the Intergovernmental Panel on Climate Change (IPCC) will publish its Fourth Assessment Report of the Scientific Basis of Climate Change (AR4). A significant portion of the AR4 will be the analysis of coupled general circulation model (GCM) simulations of the climate of the past century as well as scenarios of future climates under prescribed emission scenarios. Modeling groups worldwide have contributed to AR4, including three from the U.S., the Community Climate System Model (CCSM) project, the National Aeronautics and Space Administration (NASA) Goddard Institute for Space Sciences, and the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL). This collection of model results is providing a wealth of new information that will be used to examine the state of climate science, the potential impacts from climate changes, and the policy consequences that they imply. Our focus here is on the CCSM project. Although it is centered at the National Center for Atmospheric Research (NCAR), the CCSM version 3 (CCSM3) was designed, developed, and applied in a uniquely distributed fashion with participation by many institutions. This model has produced some of the most scientifically complete and highest resolution simulations of climate change to date, thanks to the teamwork of many scientists and software engineers. Their contributions will become obvious as a steady stream of peer-reviewed publications appears in the scientific literature. Less obvious, however, is the largely hidden, unprecedented level of interagency cooperation and multi-institutional coordination that provided the direction and resources necessary to make the CCSM project successful. Contrary to the widely-held opinion that the US climate research effort in general, and the climate modeling effort in particular, is fragmented and disorganized (NRC 1998, 2001), the success of the CCSM project demonstrates that a uniquely US approach to model development can produce a world-class model.
Community Climate System Model (CCSM)
Author :
Publisher :
Page : 512 pages
File Size : 17,39 MB
Release : 2006
Category :
ISBN :
Book Description
Cloud-Resolving Modeling of Convective Processes
Author : Xiaofan Li
Publisher : Springer
Page : 364 pages
File Size : 45,65 MB
Release : 2016-05-17
Category : Science
ISBN : 3319263609
Book Description
This is an updated and revised second edition of the book presenting new developments in the field of cloud-resolving modeling. The first edition of the book introduces the framework of cloud-resolving model, methodologies for analysis of modeling outputs, and validation of simulations with observations. It details important scientific findings in the aspects of surface rainfall processes, precipitation efficiency, dynamic and thermodynamic processes associated with tropical convection, diurnal variations, radiative and cloud microphysical processes associated with development of cloud clusters, air-sea coupling on convective scales, climate equilibrium states, and remote sensing applications. In additional to the content from the first edition of the book, the second edition of the book contains the new scientific results in the development of convective-stratiform rainfall separation scheme, the analysis of structures of precipitation systems, the thermal effects of doubled carbon dioxide on rainfall, precipitation predictability, and modeling depositional growth of ice crystal. The book will be beneficial both to graduate students and to researchers who do cloud, mesoscale and global modeling.
Equatorial Waves Simulated by the NCAR Community Climate Model
Author : Xinhua Cheng
Publisher :
Page : 296 pages
File Size : 25,30 MB
Release : 1988
Category :
ISBN :
Book Description
Response of Regional Climate to Global Forcing
Author : Christopher Bryan Skinner
Publisher :
Page : pages
File Size : 25,61 MB
Release : 2014
Category :
ISBN :
Book Description
There is now unequivocal evidence that the Earth's climate is changing as a result of human activities. These changes pose a number of potential risks for human and natural systems. Within the Sahel, a semi-arid region of northern Africa that is home to over 50 million people, climate-related stresses on human systems are exacerbated by a limited capacity for climate adaptation and persistent uncertainty in projections of future climate. In this dissertation I utilize a suite of numerical modeling techniques in conjunction with observational data to study the multi-scale interactions that shape rainfall and atmospheric circulation in northern West Africa. This dissertation consists of three chapters. In the first chapter, I use an ensemble of general circulation model experiments to examine the relative roles of different global drivers in shaping projected changes in West African climate. Specifically, I assess the response of precipitation and atmospheric circulation in West Africa to the individual influences of direct atmospheric radiative forcing from projected increases in greenhouse gas concentrations and greenhouse gas-induced sea surface temperature forcing. In the second chapter, I evaluate the simulation of synoptic-scale weather disturbances, known as African easterly waves, in the latest generation of global climate models. African easterly waves serve as an important source of Sahel rainfall and play a critical role in Saharan dust transport and the initiation of the most intense Atlantic basin hurricanes. In this work I identify key reasons for biases in the simulation of African easterly waves, and offer several new insights for improved climate modeling efforts in West Africa. In the third chapter, I explore the response of atmospheric circulation in West Africa to projected increases in greenhouse gas concentrations. Models exhibit a robust increase in monsoon strength and African easterly wave activity in response to the pattern of future warming in West Africa. These results suggest the possibility of a number of future climate-related impacts on human and natural systems in West Africa and the greater Atlantic basin.
African Climate and Climate Change
Author : Charles J. R. Williams
Publisher : Springer Science & Business Media
Page : 204 pages
File Size : 15,78 MB
Release : 2011-02-11
Category : Science
ISBN : 9048138426
Book Description
Compared to many other regions of the world, Africa is particularly vulnerable to the effects of climate change and variability. Widespread poverty, an extensive disease burden and pockets of political instability across the continent has resulted in a low resilience and limited adaptative capacity of African society to climate related shocks and stresses. To compound this vulnerability, there remains large knowledge gaps on African climate, manifestations of future climate change and variability for the region and the associated problems of climate change impacts. Research on the subject of African climate change requires an interdisciplinary approach linking studies of environmental, political and socio-economic spheres. In this book we use different case studies on climate change and variability in Africa to illustrate different approaches to the study of climate change in Africa from across the spectrum of physical, social and political sciences. In doing so we attempt to highlight a toolbox of methodologies (along with their limitations and advantages) that may be used to further the understanding of the impacts of climate change in Africa and thus help form the basis for strategies to negate the negative implications of climate change on society.
