Stratospheric Nudging And Predictable Surface Impacts (SNAPSI): a protocol for investigating the role of stratospheric polar vortex disturbances in subseasonal to seasonal forecasts

Hitchcock, P. ORCID: https://orcid.org/0000-0001-8993-3808, Butler, A. ORCID: https://orcid.org/0000-0002-3632-0925, Charlton-Perez, A. ORCID: https://orcid.org/0000-0001-8179-6220, Garfinkel, C. I. ORCID: https://orcid.org/0000-0001-7258-666X, Stockdale, T., Anstey, J., Mitchell, D. ORCID: https://orcid.org/0000-0002-0117-3486, Domeisen, D. I. V. ORCID: https://orcid.org/0000-0002-1463-929X, Wu, T. ORCID: https://orcid.org/0000-0001-5187-9121, Lu, Y. ORCID: https://orcid.org/0000-0001-9823-9367, Mastrangelo, D. ORCID: https://orcid.org/0000-0001-9438-5439, Malguzzi, P., Lin, H. ORCID: https://orcid.org/0000-0003-4353-0426, Muncaster, R., Merryfield, B. ORCID: https://orcid.org/0000-0003-4280-9724, Sigmond, M., Xiang, B., Jia, L., Hyun, Y.-K., Oh, J., Specq, D. ORCID: https://orcid.org/0000-0002-4572-0226, Simpson, I. R., Richter, J. H., Barton, C., Knight, J., Lim, E.-P. and Hendon, H. (2022) Stratospheric Nudging And Predictable Surface Impacts (SNAPSI): a protocol for investigating the role of stratospheric polar vortex disturbances in subseasonal to seasonal forecasts. Geoscientific Model Development, 15 (13). pp. 5073-5092. ISSN 1991-9603 doi: 10.5194/gmd-15-5073-2022

Abstract/Summary

Major disruptions of the winter season, high-latitude stratospheric polar vortices can result in stratospheric anomalies that persist for months. These sudden stratospheric warming events are recognized as an important potential source of forecast skill for surface climate on subseasonal to seasonal timescales. Realizing this skill in operational subseasonal forecast models remains a challenge, as models must capture both the evolution of the stratospheric polar vortices in addition to their coupling to the troposphere. The processes involved in this coupling remain a topic of open research. We present here the Stratospheric Nudging And Predictable Surface Impacts (SNAPSI) project. SNAPSI is a new model intercomparison protocol designed to study the role of the Arctic and Antarctic stratospheric polar vortex disturbances for surface predictability in subseasonal to seasonal forecast models. Based on a set of controlled, subseasonal ensemble forecasts of three recent events, the protocol aims to address four main scientific goals. First, to quantify the impact of improved stratospheric forecasts on near-surface forecast skill. Second, to attribute specific extreme events to stratospheric variability. Third, to assess the mechanisms by which the stratosphere influences the troposphere in the forecast models. Fourth, to investigate the wave processes that lead to the stratospheric anomalies themselves. Although not a primary focus, the experiments are furthermore expected to shed light on coupling between the tropical stratosphere and troposphere. The output requested will allow for a more detailed, process-based community analysis than has been possible with existing databases of subseasonal forecasts.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/106706
Identification Number/DOI	10.5194/gmd-15-5073-2022
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	European Geosciences Union
Download/View statistics	View download statistics for this item