edu.ucar.opensky::articles:26054 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T19:39:26.843669 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d78919s4 https://doi.org/10.5281/zenodo.7576692 https Related Software #1 jlaucar/npg_gorokhovsky: Data and code used to generate figures in Gorokhovsky and Anderson 2023 Extending ensemble Kalman filter algorithms to assimilate observations with an unknown time offset 2023-02-07T00:00:00Z publication https://n2t.org/ark:/85065/d78919s4 https://doi.org/10.5194/npg-30-37-2023 Gorokhovsky, Elia author Anderson, Jeffrey L. author UCAR/NCAR - Library publisher Data assimilation (DA), the statistical combination ofcomputer models with measurements, is applied in a variety of scientificfields involving forecasting of dynamical systems, most prominently inatmospheric and ocean sciences. The existence of misreported or unknownobservation times (time error) poses a unique and interesting problem forDA. Mapping observations to incorrect times causes bias in the prior stateand affects assimilation. Algorithms that can improve the performance ofensemble Kalman filter DA in the presence of observing time error aredescribed. Algorithms that can estimate the distribution of time error arealso developed. These algorithms are then combined to produce extensions toensemble Kalman filters that can both estimate and correct for observationtime errors. A low-order dynamical system is used to evaluate theperformance of these methods for a range of magnitudes of observation timeerror. The most successful algorithms must explicitly account for thenonlinearity in the evolution of the prediction model. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation