author_facet Koller, J.
Chen, Y.
Reeves, G. D.
Friedel, R. H. W.
Cayton, T. E.
Vrugt, J. A.
Koller, J.
Chen, Y.
Reeves, G. D.
Friedel, R. H. W.
Cayton, T. E.
Vrugt, J. A.
author Koller, J.
Chen, Y.
Reeves, G. D.
Friedel, R. H. W.
Cayton, T. E.
Vrugt, J. A.
spellingShingle Koller, J.
Chen, Y.
Reeves, G. D.
Friedel, R. H. W.
Cayton, T. E.
Vrugt, J. A.
Journal of Geophysical Research: Space Physics
Identifying the radiation belt source region by data assimilation
Paleontology
Space and Planetary Science
Earth and Planetary Sciences (miscellaneous)
Atmospheric Science
Earth-Surface Processes
Geochemistry and Petrology
Soil Science
Water Science and Technology
Ecology
Aquatic Science
Forestry
Oceanography
Geophysics
author_sort koller, j.
spelling Koller, J. Chen, Y. Reeves, G. D. Friedel, R. H. W. Cayton, T. E. Vrugt, J. A. 0148-0227 American Geophysical Union (AGU) Paleontology Space and Planetary Science Earth and Planetary Sciences (miscellaneous) Atmospheric Science Earth-Surface Processes Geochemistry and Petrology Soil Science Water Science and Technology Ecology Aquatic Science Forestry Oceanography Geophysics http://dx.doi.org/10.1029/2006ja012196 <jats:p>We describe how assimilation of radiation belt data with a simple radial diffusion code can be used to identify and adjust for unknown physics in the model. We study the dropout and the following enhancement of relativistic electrons during a moderate storm on 25 October 2002. We introduce a technique that uses an ensemble Kalman filter and the probability distribution of the forecast ensemble to identify if the model is drifting away from the observations and to find inconsistencies between model forecast and observations. We use the method to pinpoint the time periods and locations where most of the disagreement occurs and how much the Kalman filter has to adjust the model state to match the observations. Although the model does not contain explicit source or loss terms, the Kalman filter algorithm can implicitly add very localized sources or losses in order to reduce the discrepancy between model and observations. We use this technique with multisatellite observations to determine when simple radial diffusion is inconsistent with the observed phase space densities indicating where additional source (acceleration) or loss (precipitation) processes must be active. We find that the outer boundary estimated by the ensemble Kalman filter is consistent with negative phase space density gradients in the outer electron radiation belt. We also identify specific regions in the radiation belts (<jats:italic>L</jats:italic>* ≈ 5–6 and to a minor extend also <jats:italic>L</jats:italic>* ≈ 4) where simple radial diffusion fails to adequately capture the variability of the observations, suggesting local acceleration/loss mechanisms.</jats:p> Identifying the radiation belt source region by data assimilation Journal of Geophysical Research: Space Physics
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series Journal of Geophysical Research: Space Physics
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title Identifying the radiation belt source region by data assimilation
title_unstemmed Identifying the radiation belt source region by data assimilation
title_full Identifying the radiation belt source region by data assimilation
title_fullStr Identifying the radiation belt source region by data assimilation
title_full_unstemmed Identifying the radiation belt source region by data assimilation
title_short Identifying the radiation belt source region by data assimilation
title_sort identifying the radiation belt source region by data assimilation
topic Paleontology
Space and Planetary Science
Earth and Planetary Sciences (miscellaneous)
Atmospheric Science
Earth-Surface Processes
Geochemistry and Petrology
Soil Science
Water Science and Technology
Ecology
Aquatic Science
Forestry
Oceanography
Geophysics
url http://dx.doi.org/10.1029/2006ja012196
publishDate 2007
physical
description <jats:p>We describe how assimilation of radiation belt data with a simple radial diffusion code can be used to identify and adjust for unknown physics in the model. We study the dropout and the following enhancement of relativistic electrons during a moderate storm on 25 October 2002. We introduce a technique that uses an ensemble Kalman filter and the probability distribution of the forecast ensemble to identify if the model is drifting away from the observations and to find inconsistencies between model forecast and observations. We use the method to pinpoint the time periods and locations where most of the disagreement occurs and how much the Kalman filter has to adjust the model state to match the observations. Although the model does not contain explicit source or loss terms, the Kalman filter algorithm can implicitly add very localized sources or losses in order to reduce the discrepancy between model and observations. We use this technique with multisatellite observations to determine when simple radial diffusion is inconsistent with the observed phase space densities indicating where additional source (acceleration) or loss (precipitation) processes must be active. We find that the outer boundary estimated by the ensemble Kalman filter is consistent with negative phase space density gradients in the outer electron radiation belt. We also identify specific regions in the radiation belts (<jats:italic>L</jats:italic>* ≈ 5–6 and to a minor extend also <jats:italic>L</jats:italic>* ≈ 4) where simple radial diffusion fails to adequately capture the variability of the observations, suggesting local acceleration/loss mechanisms.</jats:p>
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author Koller, J., Chen, Y., Reeves, G. D., Friedel, R. H. W., Cayton, T. E., Vrugt, J. A.
author_facet Koller, J., Chen, Y., Reeves, G. D., Friedel, R. H. W., Cayton, T. E., Vrugt, J. A., Koller, J., Chen, Y., Reeves, G. D., Friedel, R. H. W., Cayton, T. E., Vrugt, J. A.
author_sort koller, j.
container_issue A6
container_start_page 0
container_title Journal of Geophysical Research: Space Physics
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description <jats:p>We describe how assimilation of radiation belt data with a simple radial diffusion code can be used to identify and adjust for unknown physics in the model. We study the dropout and the following enhancement of relativistic electrons during a moderate storm on 25 October 2002. We introduce a technique that uses an ensemble Kalman filter and the probability distribution of the forecast ensemble to identify if the model is drifting away from the observations and to find inconsistencies between model forecast and observations. We use the method to pinpoint the time periods and locations where most of the disagreement occurs and how much the Kalman filter has to adjust the model state to match the observations. Although the model does not contain explicit source or loss terms, the Kalman filter algorithm can implicitly add very localized sources or losses in order to reduce the discrepancy between model and observations. We use this technique with multisatellite observations to determine when simple radial diffusion is inconsistent with the observed phase space densities indicating where additional source (acceleration) or loss (precipitation) processes must be active. We find that the outer boundary estimated by the ensemble Kalman filter is consistent with negative phase space density gradients in the outer electron radiation belt. We also identify specific regions in the radiation belts (<jats:italic>L</jats:italic>* ≈ 5–6 and to a minor extend also <jats:italic>L</jats:italic>* ≈ 4) where simple radial diffusion fails to adequately capture the variability of the observations, suggesting local acceleration/loss mechanisms.</jats:p>
doi_str_mv 10.1029/2006ja012196
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spelling Koller, J. Chen, Y. Reeves, G. D. Friedel, R. H. W. Cayton, T. E. Vrugt, J. A. 0148-0227 American Geophysical Union (AGU) Paleontology Space and Planetary Science Earth and Planetary Sciences (miscellaneous) Atmospheric Science Earth-Surface Processes Geochemistry and Petrology Soil Science Water Science and Technology Ecology Aquatic Science Forestry Oceanography Geophysics http://dx.doi.org/10.1029/2006ja012196 <jats:p>We describe how assimilation of radiation belt data with a simple radial diffusion code can be used to identify and adjust for unknown physics in the model. We study the dropout and the following enhancement of relativistic electrons during a moderate storm on 25 October 2002. We introduce a technique that uses an ensemble Kalman filter and the probability distribution of the forecast ensemble to identify if the model is drifting away from the observations and to find inconsistencies between model forecast and observations. We use the method to pinpoint the time periods and locations where most of the disagreement occurs and how much the Kalman filter has to adjust the model state to match the observations. Although the model does not contain explicit source or loss terms, the Kalman filter algorithm can implicitly add very localized sources or losses in order to reduce the discrepancy between model and observations. We use this technique with multisatellite observations to determine when simple radial diffusion is inconsistent with the observed phase space densities indicating where additional source (acceleration) or loss (precipitation) processes must be active. We find that the outer boundary estimated by the ensemble Kalman filter is consistent with negative phase space density gradients in the outer electron radiation belt. We also identify specific regions in the radiation belts (<jats:italic>L</jats:italic>* ≈ 5–6 and to a minor extend also <jats:italic>L</jats:italic>* ≈ 4) where simple radial diffusion fails to adequately capture the variability of the observations, suggesting local acceleration/loss mechanisms.</jats:p> Identifying the radiation belt source region by data assimilation Journal of Geophysical Research: Space Physics
spellingShingle Koller, J., Chen, Y., Reeves, G. D., Friedel, R. H. W., Cayton, T. E., Vrugt, J. A., Journal of Geophysical Research: Space Physics, Identifying the radiation belt source region by data assimilation, Paleontology, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Atmospheric Science, Earth-Surface Processes, Geochemistry and Petrology, Soil Science, Water Science and Technology, Ecology, Aquatic Science, Forestry, Oceanography, Geophysics
title Identifying the radiation belt source region by data assimilation
title_full Identifying the radiation belt source region by data assimilation
title_fullStr Identifying the radiation belt source region by data assimilation
title_full_unstemmed Identifying the radiation belt source region by data assimilation
title_short Identifying the radiation belt source region by data assimilation
title_sort identifying the radiation belt source region by data assimilation
title_unstemmed Identifying the radiation belt source region by data assimilation
topic Paleontology, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Atmospheric Science, Earth-Surface Processes, Geochemistry and Petrology, Soil Science, Water Science and Technology, Ecology, Aquatic Science, Forestry, Oceanography, Geophysics
url http://dx.doi.org/10.1029/2006ja012196