Search
Now showing items 1-8 of 8
Mixed-Resolution Ensemble Data Assimilation
Publisher: American Meteorological Society
Abstract: nsemble Kalman filters perform data assimilation by forming a background covariance matrix from an ensemble forecast. Most of the literature on ensemble Kalman filters assumes that all ensemble members come from the same ...
Handling Nonlinearity in an Ensemble Kalman Filter: Experiments with the Three-Variable Lorenz Model
Publisher: American Meteorological Society
Abstract: n ensemble Kalman filter (EnKF) is optimal only for linear models because it assumes Gaussian distributions. A new type of outer loop, different from the one used in 3D and 4D variational data assimilation (Var), is proposed ...
Identifying Low-Dimensional Nonlinear Behavior in Atmospheric Data
Publisher: American Meteorological Society
Abstract: Computational modeling is playing an increasingly vital role in the study of atmospheric?oceanic systems. Given the complexity of the models a fundamental question to ask is, How well does the output of one model agree ...
Extracting Envelopes of Nonzonally Propagating Rossby Wave Packets
Publisher: American Meteorological Society
Abstract: Previously developed techniques that have been used to extract envelopes of Rossby wave packets are based on the assumption of zonally propagating waves. In this note a method that does not require such an assumption is ...
Correcting for Surface Pressure Background Bias in Ensemble-Based Analyses
Publisher: American Meteorological Society
Abstract: Model error is the component of the forecast error that is due to the difference between the dynamics of the atmosphere and the dynamics of the numerical prediction model. The systematic, slowly varying part of the model ...
Extracting Envelopes of Rossby Wave Packets
Publisher: American Meteorological Society
Abstract: Packets of Rossby waves play an important role in the transfer of kinetic energy in the extratropics. The ability to locate, track, and detect changes in the envelope of these wave packets is vital to detecting baroclinic ...
Balance and Ensemble Kalman Filter Localization Techniques
Publisher: American Meteorological Society
Abstract: In ensemble Kalman filter (EnKF) data assimilation, localization modifies the error covariance matrices to suppress the influence of distant observations, removing spurious long-distance correlations. In addition to allowing ...
Assessing Predictability with a Local Ensemble Kalman Filter
Publisher: American Meteorological Society
Abstract: In this paper, the spatiotemporally changing nature of predictability is studied in a reduced-resolution version of the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS), a state-of-the-art ...