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The role of soil states in medium-range weather predictability
soil states medium-range weather predictability
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2009/11/12
Current day operational ensemble weather prediction systems generally rely upon perturbed atmospheric initial states, thereby neglecting the eventual effect on the atmospheric evolution that uncertain...
Operational forecasting is hampered both by the rapid divergence of nearby initial conditions and by error in the underlying model. Interest in chaos has fuelled much work on the first of these two is...
Climate model attractors:chaos,quasi-regularity and sensitivity to small perturbations of external forcing
Climate model attractors chaos quasi-regularity sensitivity small perturbations external forcing
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2009/11/12
In this paper we discuss some theoretical results obtained for climate models (theorems for the existence of global attractors and inertial manifolds, estimates of attractor dimension and Lyapunov exp...
土壤理化参数的反射光谱分析
高光谱遥感 土壤 反射光谱 土壤生态地球化学参数
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2009/11/12
土壤可见光和近红外波段(400~2 500 nm)反射光谱信息包含了大量土壤物理化学参数,土壤反射光谱测量简单、快速,无需破坏样品,而且还可以通过高光谱遥感方法制图。文中使用江苏国土生态地球化学调查中获取的大量土壤样品,研究了土壤阳离子交换量(CEC)、有机质含量、pH值、铁氧化物类型、铁铝硅等常量元素含量等重要土壤生态地球化学参数的光谱反应。结果显示,土壤CEC是进行光谱预测非常成功的参数,1 ...
Conditional nonlinear optimal perturbation and its applications
Conditional nonlinear optimal perturbation applications
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2009/11/12
Conditional nonlinear optimal perturbation (CNOP) is proposed to study the predictability of numerical weather and climate prediction. A simple coupled ocean-atmosphere model for ENSO is adopted as an...
Can an ensemble give anything more than Gaussian probabilities?
ensemble anything more Gaussian probabilities
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2009/11/12
Can a relatively small numerical weather prediction ensemble produce any more forecast information than can be reproduced by a Gaussian probability density function (PDF)? This question is examined us...
Increasing the horizontal resolution of ensemble forecasts at CMC
horizontal resolution ensemble forecasts CMC
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2009/11/12
Ensemble forecasts are run operationally since February 1998 at the Canadian Meteorological Centre, with outputs up to ten days. The ensemble size was increased from eight to sixteen members in August...
A quasi-analytical ice-sheet model for climate studies
quasi-analytical ice-sheet model climate studies
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2009/11/12
A simple quasi-analytical model is developed to study the response of ice-sheets to climate change. The model is axisymmetrical and rests on a bed with a constant slope. The mechanics are highly param...
Linear and nonlinear post-processing of numerically forecasted surface temperature
Linear and nonlinear post-processing numerically forecasted surface temperature
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2009/11/12
In this paper we test different approaches to the statistical post-processing of gridded numerical surface air temperatures (provided by the European Centre for Medium-Range Weather Forecasts) onto th...
Enhanced Monte Carlo Singular System Analysis and detection of period 7.8 years oscillatory modes in the monthly NAO index and temperature records
Monte Carlo Singular System Analysis oscillatory modes NAO index and temperature records
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2009/11/11
An extension of the Monte Carlo Singular System Analysis (MC SSA) is described, based on evaluating and testing regularity of dynamics of the SSA modes against the colored noise null hypothesis, in ad...
Detecting nonlinearity in time series driven by non-Gaussian noise:the case of river flows
nonlinearity time series non-Gaussian noise case of river flows
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2009/11/11
Several methods exist for the detection of nonlinearity in univariate time series. In the present work we consider riverflow time series to infer the dynamical characteristics of the rainfall-runoff t...
Nonlinear dimensionality reduction in climate data
Nonlinear dimensionality reduction climate data
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2009/11/11
Linear methods of dimensionality reduction are useful tools for handling and interpreting high dimensional data. However, the cumulative variance explained by each of the subspaces in which the data s...
A comparison of predictors of the error of weather forecasts
comparison predictors error of weather forecasts
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2009/11/11
Three different potential predictors of forecast error - ensemble spread, mean errors of recent forecasts and the local gradient of the predicted field - were compared. The comparison was performed us...
Testing the performance of three nonlinear methods of time seriesanalysis for prediction and downscaling of European daily temperatures
nonlinear methods time seriesanalysis European daily temperatures
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2009/11/11
We investigated the usability of the method of local linear models (LLM), multilayer perceptron neural network (MLP NN) and radial basis function neural network (RBF NN) for the construction of tempor...