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  • 1
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    Mathematical Model for Transitional Processes in Josephson Cryotrons Based on Tunnel Junctions (2010)
    Springer
    Details
    Publication Date: 2010-10-05
    Print ISSN: 1557-1939
    Electronic ISSN: 1557-1947
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by Springer
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  • 2
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    Evaluation of selected short-term predictions of UT1-UTC and LOD collected in the second earth orientation parameters prediction comparison campaign (2022)
    In:  Earth Planets and Space
    Details
    Publication Date: 2023-01-10
    Description: Advanced geodetic and astronomical tasks, such as precise positioning and navigation require forecasted Earth Orientation Parameters (EOP). The Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) aims to compare various EOP forecast methods implemented by different institutes from all over the world. Here we focus on universal time (UT1-UTC) and Length-of-Day (LOD) predictions received in the period between September 1st, 2021 and May 29th, 2022. The forecasts are preliminarily evaluated against the EOP 14 C04 solution delivered by the International Earth Rotation and Reference System Service (IERS) by using the mean absolute error (MAE) as the prediction quality measure. Exemplarily, we compare forecasts from IERS delivered by U.S. Naval Observatory (USNO) and a selected campaign participant to assess the impact of both input data and computation methodology on predictions. We show that improper treatment of long-periodic ocean tides has severely degraded LOD forecasting until this issue has been brought to the attention of the participant during a meeting of the 2nd EOP PCC. We consider this as a good example for the benefit of the campaign to the overall scientific community by providing specific feedback to individual processing centres on deficits in their products, which lead to quick and effective adaptations. The lessons learned from this analysis could be applied to other EOP forecasting methods based on Effective Angular Momentum (EAM) predictions.
    Language: English
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 3
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    Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC): Overview (2022)
    In:  Artificial Satellites
    Details
    Publication Date: 2023-01-16
    Description: Precise positioning and navigation on the Earth’s surface and in space require accurate earth orientation parameters (EOP) data and predictions. In the last few decades, EOP prediction has become a subject of increased attention within the international geodetic community, e.g., space agencies, satellite operators, researchers studying Earth rotation dynamics, and users of navigation systems. Due to this fact, many research centres from around the world have developed dedicated methods for the forecasting of EOP. An assessment of the various EOP prediction capabilities is currently being pursued in the frame of the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC), which began in September 2021 and will be continued until the end of the year 2022. The new campaign was prepared by the EOP PCC Office run by Centrum Badań Kosmicznych Polskiej Akademii Nauk (CBK PAN) in Warsaw, Poland, in cooperation with GeoForschungsZentrum (GFZ) and under the auspices of the International Earth Rotation and Reference Systems Service (IERS). In this paper, we provide an overview of the 2nd EOP PCC five months after its start. We discuss the technical aspects and present statistics about the participants and valid prediction files received so far. Additionally, we present the results of preliminary comparisons of different reference solutions with respect to the official IERS 14 C04 EOP series. Root mean square values for different solutions for polar motion, length of day, and precession-nutation components show discrepancies at the level from 0.04 to 0.36 mas, from 0.01 to 0.10 ms, and from 0.01 to 0.18 mas, respectively.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 4
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    Evaluation of the predictions submitted to the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-23
    Description: Real-time information on Earth Orientation Parameters (EOP) is needed for many advanced geodetic and astronomical tasks including positioning and navigation on Earth and in space. Therefore, EOP short-term prediction has become a subject of increased attention within the international geodetic community.Scientific progress in the prediction methods but also in the geodetic data processing, and modelling effective angular momentum functions raise the need to re-evaluate various EOP prediction approaches. This was the objective of the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC). The campaign lasted from September 1, 2021 to December 28, 2022. During this period, more than 7000 predictions were submitted by registered participants. Thanks to international cooperation, the campaign was a great success of the geodetic community.In this study, we provide a summary of the 2nd EOP PCC, focusing on the quality of EOP predictions. We present time evolution of the prediction accuracy obtained on the basis of the mean absolute error for the IERS 14 C04 solution as a reference. We also analyse the impact of filtering outlier predictions on the overall accuracy of the EOP forecasts. We end the presentation with initial conclusions on the most encouraging prediction methodologies together with plans for the possible continuation of the campaign involving new release of IERS 20 C04.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 5
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    Analysis of combined series of hydrological angular momentum developed on the basis of multiple climate models (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-22
    Description: Despite being important contributor to polar motion (PM) variation especially at seasonal time scales, hydrological angular momentum (HAM) is a main source of uncertainties in the estimation of PM excitation.With the growing scientific interest in climate change in recent years, works have intensified on the development of new climate models that simulate changes in the properties of the atmosphere, oceans and hydrosphere. One of the effects of these activities is latest implementation of the CMIP (Coupled Model Intercomparison Project) – CMIP6.In this study, we use various CMIP6 historical simulations to determine HAM series. We focus on the analysis of HAM calculated from clustered models determined on the basis of the mean of several models or on their combination with use of refined statistical algorithms. The obtained HAM series are analysed in different spectral bands and evaluated taking the hydrological signal in geodetically observed PM excitation as a reference. The results are also compared with those received for data from Gravity Recovery and Climate Experiment (GRACE) mission. Our research shows that despite the large differences between the HAM series obtained from single CMIP6 simulations, it is possible to choose the groups or combinations of models that allow for quite reliable determination of HAM, especially in seasonal spectral band. In terms of phase, the chosen models perform better than GRACE for annual prograde and semiannual retrograde term. In terms of amplitudes, the chosen models perform better than GRACE for annual prograde and annual retrograde term.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 6
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    Assessment of length-of-day and universal time predictions based on the results of the Second Earth Orientation Parameters Prediction Comparison Campaign (2024)
    In:  Journal of Geodesy
    Details
    Publication Date: 2024-04-22
    Description: Predicting Earth Orientation Parameters (EOP) is crucial for precise positioning and navigation both on the Earth’s surface and in space. In recent years, many approaches have been developed to forecast EOP, incorporating observed EOP as well as information on the effective angular momentum (EAM) derived from numerical models of the atmosphere, oceans, and land-surface dynamics. The Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) aimed to comprehensively evaluate EOP forecasts from many international participants and identify the most promising prediction methodologies. This paper presents the validation results of predictions for universal time and length-of-day variations submitted during the 2nd EOP PCC, providing an assessment of their accuracy and reliability. We conduct a detailed evaluation of all valid forecasts using the IERS 14 C04 solution provided by the International Earth Rotation and Reference Systems Service (IERS) as a reference and mean absolute error as the quality measure. Our analysis demonstrates that approaches based on machine learning or the combination of least squares and autoregression, with the use of EAM information as an additional input, provide the highest prediction accuracy for both investigated parameters. Utilizing precise EAM data and forecasts emerges as a pivotal factor in enhancing forecasting accuracy. Although several methods show some potential to outperform the IERS forecasts, the current standard predictions disseminated by IERS are highly reliable and can be fully recommended for operational purposes.
    Type: info:eu-repo/semantics/article
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  • 7
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    EOP predictions collected during the operational phase of the Second Earth Orientation Parameters Prediction Comparison Campaign (2023)
    GFZ Data Services
    Details
    Publication Date: 2024-01-08
    Description: This dataset contains predictions of Earth orientation parameters (EOP) submitted during the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC). The 2nd EOP PCC has been carried out by Centrum Badań Kosmicznych Polskiej Akademii Nauk CBK PAN in Warsaw in cooperation with the GFZ German Research Centre for Geosciences in Potsdam (Germany) and under the auspices of the International Earth Rotation and Reference Systems Service (IERS) within the IERS Working Group on the 2nd EOP PCC. The purpose of the campaign was to re-assess the current capabilities of EOP forecasting and to find most reliable prediction approaches. The operational part of the campaign lasted between September 1, 2021 and December 28, 2022. Throughout the duration of the 2nd EOP PCC, registered campaign participants submitted forecasts for all EOP parameters, including dX, dY, dPsi, dEps (components of celestial pole offsets), polar motion, differences between universal time and coordinated universal time, and its time-derivative length-of-day change. These submissions were made to the EOP PCC Office every Wednesday before the 20:00 UTC deadline. The predictions were then evaluated once the geodetic final EOP observations from the forecasted period became available. Each participant could register more than one method, and each registered method was assigned an individual ID, which was used, e.g., for file naming. The dataset contains text files with predicted parameters as submitted by campaign participants and MATLAB file which is a database with all correct predictions from each participant loaded into a structure.
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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