Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model
Snow initialisation has been previously investigated as a potential source of predictability at the subseasonal-to-seasonal (S2S) timescales in winter and spring, through its local radiative, thermodynamical and hydrological feedbacks. However, previous studies were conducted with low-top models ove...
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ftzenodo:oai:zenodo.org:3249056 2023-06-06T11:51:24+02:00 Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model Li Fei Orsolini Yvan Keenlyside Noel Shen Mao-Lin Counillon Francois Wang Yiguo 2019-06-18 https://zenodo.org/record/3249056 https://doi.org/10.5281/zenodo.3249056 unknown info:eu-repo/grantAgreement/EC/H2020/727852/ info:eu-repo/grantAgreement/EC/H2020/641727/ info:eu-repo/grantAgreement/EC/H2020/641816/ info:eu-repo/grantAgreement/EC/H2020/727862/ info:eu-repo/grantAgreement/EC/H2020/776613/ doi:10.5281/zenodo.3249055 https://zenodo.org/communities/blue-actionh2020 https://zenodo.org/record/3249056 https://doi.org/10.5281/zenodo.3249056 oai:zenodo.org:3249056 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode info:eu-repo/semantics/conferencePoster poster 2019 ftzenodo https://doi.org/10.5281/zenodo.324905610.5281/zenodo.3249055 2023-04-13T21:07:24Z Snow initialisation has been previously investigated as a potential source of predictability at the subseasonal-to-seasonal (S2S) timescales in winter and spring, through its local radiative, thermodynamical and hydrological feedbacks. However, previous studies were conducted with low-top models over short periods only. Furthermore, the potential role of the land surface–stratosphere connection upon the S2S predictability had remained unclear. To this end, we have carried out twin 30-member ensembles of 2-month (November–January) retrospective forecasts over the period 1985–2016, with either realistic or degraded snow initialisation. A high-top version of the Norwegian Climate Prediction Model is used, based on the Whole Atmosphere Community Climate Model, to insure improved coupling with the stratosphere. In a composite difference of high versus low initial Eurasian snow, the surface temperature is strongly impacted by the presence of snow, and wave activity fluxes into the stratosphere are enhanced at a 1-month lag, leading to a weakened polar vortex. Focusing further on 7 years characterized by a strongly negative phase of the Arctic Oscillation (AO), we find a weak snow feedback contributing to the maintenance of the negative AO. By comparing the twin forecasts, we extracted the predictive skill increment due to realistic snow initialisation. The prediction of snow itself is greatly improved and there is increased skill in surface temperature over snow-covered land at the 0-day lead time, and localized skill increment in the transition regions at the southern edge of the snow-covered land areas, over parts of midlatitude continents, at lead times longer than 30 days. This work has not been published yet. Conference Object Arctic Zenodo Arctic |
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Snow initialisation has been previously investigated as a potential source of predictability at the subseasonal-to-seasonal (S2S) timescales in winter and spring, through its local radiative, thermodynamical and hydrological feedbacks. However, previous studies were conducted with low-top models over short periods only. Furthermore, the potential role of the land surface–stratosphere connection upon the S2S predictability had remained unclear. To this end, we have carried out twin 30-member ensembles of 2-month (November–January) retrospective forecasts over the period 1985–2016, with either realistic or degraded snow initialisation. A high-top version of the Norwegian Climate Prediction Model is used, based on the Whole Atmosphere Community Climate Model, to insure improved coupling with the stratosphere. In a composite difference of high versus low initial Eurasian snow, the surface temperature is strongly impacted by the presence of snow, and wave activity fluxes into the stratosphere are enhanced at a 1-month lag, leading to a weakened polar vortex. Focusing further on 7 years characterized by a strongly negative phase of the Arctic Oscillation (AO), we find a weak snow feedback contributing to the maintenance of the negative AO. By comparing the twin forecasts, we extracted the predictive skill increment due to realistic snow initialisation. The prediction of snow itself is greatly improved and there is increased skill in surface temperature over snow-covered land at the 0-day lead time, and localized skill increment in the transition regions at the southern edge of the snow-covered land areas, over parts of midlatitude continents, at lead times longer than 30 days. This work has not been published yet. |
format |
Conference Object |
author |
Li Fei Orsolini Yvan Keenlyside Noel Shen Mao-Lin Counillon Francois Wang Yiguo |
spellingShingle |
Li Fei Orsolini Yvan Keenlyside Noel Shen Mao-Lin Counillon Francois Wang Yiguo Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
author_facet |
Li Fei Orsolini Yvan Keenlyside Noel Shen Mao-Lin Counillon Francois Wang Yiguo |
author_sort |
Li Fei |
title |
Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
title_short |
Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
title_full |
Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
title_fullStr |
Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
title_full_unstemmed |
Impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the Norwegian Climate Prediction Model |
title_sort |
impact of snow initialisation in subseasonal-to-seasonal winter forecasts with the norwegian climate prediction model |
publishDate |
2019 |
url |
https://zenodo.org/record/3249056 https://doi.org/10.5281/zenodo.3249056 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
info:eu-repo/grantAgreement/EC/H2020/727852/ info:eu-repo/grantAgreement/EC/H2020/641727/ info:eu-repo/grantAgreement/EC/H2020/641816/ info:eu-repo/grantAgreement/EC/H2020/727862/ info:eu-repo/grantAgreement/EC/H2020/776613/ doi:10.5281/zenodo.3249055 https://zenodo.org/communities/blue-actionh2020 https://zenodo.org/record/3249056 https://doi.org/10.5281/zenodo.3249056 oai:zenodo.org:3249056 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode |
op_doi |
https://doi.org/10.5281/zenodo.324905610.5281/zenodo.3249055 |
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1767957099803836416 |