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3. HARMONIE-AROME 4DVar [Presentación]

Author

Sánchez Arriola, Jana, Barkmeijer, Jan, Lindskog, Magnus, Gustafsson, Nils, Bojarova, Jelena, Azad, Roohollah, Monteiro, Isabel, Escribá, Pau, Whelan, Eoin, Ridal, Martin, Vignes, Ole, Stappers, Roel, and Randriamampianina, Roger

Subjects
HARMONIE–AROME, Data assimilation project, Numerical weather prediction
Abstract

Presentación realizada en: 2nd ACCORD ASW celebrado del 4 al 8 de abril de 2022 en Ljubljana, Eslovenia.

Published
2022

5. HARMONIE-AROME 4D-Var

Author

Barkmeijer, Jan, Lindskog, Magnus, Gustafsson, Nils, Bojarova, Jelena, Azad, Roohollah, Monteiro, Isabel, Secriba, Pau, Whelan, Eoin, Ridal, Martin, Sánchez Arriola, Jana, Vignes, Ole, Stappers, Roel, and Randriamampianina, Roger

Subjects
HARMONIE–AROME, Data assimilation project, Numerical weather prediction
Abstract

The status of CY43 HARMONIE-AROME 4D-Var is presented. Central to the HARMONIE-AROME 4D-Var implementation is the multi-incremental approach and the current setup comprises two outer loops at six and three times the main forecast grid resolution of 2.5 km. This setup is flexible though, as is the length of the observation window. Results will be given for 4D-Var in comparison to 3D-Var for three domains, centered around Scandinavia, the Iberian Peninsula and the Netherlands. The starting point here is that both 3D-Var and 4D-Var are using identical observations types. Generally speaking it can be concluded that 4DVar forecasts are superior. The paper also gives an extensive list of opportunities from which particularly HARMONIE-AROME 4D-Var can benefit. For example, increasing the observation set, improving the treatment of observations during the observation window and new algorithmic avenues.

Published
2021

9. Evaluating the use of Aeolus satellite observations in the regional NWP model Harmonie-Arome.

Author

Hagelin, Susanna, Azad, Roohollah, Lindskog, Magnus, Schyberg, Harald, and Körnich, Heiner

Subjects
*NUMERICAL weather forecasting, *WIND speed, *ELECTRONIC data processing
Abstract

The impact of using wind speed data from the Aeolus satellite in a limited area Numerical Weather Prediction (NWP) system is being investigated using the limited area NWP model Harmonie-Arome over the Nordic region. We assimilate the Horizontal Line of Sight (HLOS) winds observed by Aeolus using 3D-Var data assimilation for two different periods, one in Sept-Oct 2018 when the satellite was recently launched, and a later period in Apr-May 2020 to investigate the updated data processing of the HLOS winds. We find that the quality of the Aeolus observations have degraded between the first and second experiment period over our domain. However observations from Aeolus, in particular the Mie winds, have a clear impact on the analysis of the NWP model for both periods whereas the forecast impact is neutral when compared against radiosondes. Results from evaluation of observation minus background and observation minus analysis departures based on Desroziers diagnostics show that the observation error should be increased for Aeolus data in our experiments, but the impact of doing so is small. We also see that there is potential improvement in using 4D-Var data assimilation, which generate flow-dependent analysis increments, with the Aeolus data. [ABSTRACT FROM AUTHOR]

Published
2021
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