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- Author or Editor: ANDRÉ J. ROBERT x
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Abstract
This project used a series of 500-mb. charts prepared originally for the study of planetary waves. These charts, covering both hemispheres, provided the initial conditions for a spectral barotropic model. In this model, the calculations proceeded from functions equivalent to spherical harmonics with the stream field represented by 153 degrees of freedom. A set of five integrations carried to 72 hr. produced reasonably good forecasts that did not appear to be affected seriously by the deficiencies of the observational network.
Abstract
This project used a series of 500-mb. charts prepared originally for the study of planetary waves. These charts, covering both hemispheres, provided the initial conditions for a spectral barotropic model. In this model, the calculations proceeded from functions equivalent to spherical harmonics with the stream field represented by 153 degrees of freedom. A set of five integrations carried to 72 hr. produced reasonably good forecasts that did not appear to be affected seriously by the deficiencies of the observational network.
Abstract
A semi-implicit time integration scheme tested earlier with a spectral model is now adapted to a grid point model of the primitive equations. Predictions prepared by the implicit method compare quite favorably with the forecasts produced by an explicit technique. The implicit model runs about four times faster; and after 5 days of integration, the forecasts differ by less than 20 m.
Abstract
A semi-implicit time integration scheme tested earlier with a spectral model is now adapted to a grid point model of the primitive equations. Predictions prepared by the implicit method compare quite favorably with the forecasts produced by an explicit technique. The implicit model runs about four times faster; and after 5 days of integration, the forecasts differ by less than 20 m.
Abstract
A rather general theory of nonlinear computational stability is reported. Instability is caused by both spatial and temporal high frequencies that, if not present initially, will appear from nonlinear interactions. It appears that through simple remedies relative stability, if not perfect stability, can be achieved.
Abstract
A rather general theory of nonlinear computational stability is reported. Instability is caused by both spatial and temporal high frequencies that, if not present initially, will appear from nonlinear interactions. It appears that through simple remedies relative stability, if not perfect stability, can be achieved.
Abstract
The International Climate Assessment & Dataset (ICA&D) concept provides climate services on a regional scale for users in participating countries and the broader scientific community. It builds on the expertise gained in Europe, where national meteorological services collaborate by sharing climate data in order to produce regional climate assessments. Universities and data-rescue initiatives have joined this collaboration. The result is a web-based information system that combines quality-controlled daily station data with derived climate indices. Indices are provided for mean and extreme climate conditions including droughts, heat waves, and heavy rainfall events. ICA&D systems currently exist in Europe and in three regions of the world vulnerable to climate change: Southeast Asia, Latin America, and West Africa. Historical perspectives on climate variability and change are integrated with the monitoring of current climate evolution through regular updates of the data series obtained from meteorological observing stations. Web users have access to plots and maps of climate indices, showing time series, trends, or deviations from climatology. All information can be downloaded for noncommercial research and educational purposes, except for a part of the daily data that the data provider does not want to share.
Abstract
The International Climate Assessment & Dataset (ICA&D) concept provides climate services on a regional scale for users in participating countries and the broader scientific community. It builds on the expertise gained in Europe, where national meteorological services collaborate by sharing climate data in order to produce regional climate assessments. Universities and data-rescue initiatives have joined this collaboration. The result is a web-based information system that combines quality-controlled daily station data with derived climate indices. Indices are provided for mean and extreme climate conditions including droughts, heat waves, and heavy rainfall events. ICA&D systems currently exist in Europe and in three regions of the world vulnerable to climate change: Southeast Asia, Latin America, and West Africa. Historical perspectives on climate variability and change are integrated with the monitoring of current climate evolution through regular updates of the data series obtained from meteorological observing stations. Web users have access to plots and maps of climate indices, showing time series, trends, or deviations from climatology. All information can be downloaded for noncommercial research and educational purposes, except for a part of the daily data that the data provider does not want to share.
