This dataset contains model data for SNAPSI experiment 'control' produced by scientists at UKMO (UK Met Office, Exeter, UK). It is generated with the coupled climate ensemble prediction system GloSea6.

The SNAPSI project is a model intercomparison project to study the role of the stratosphere in subseasonal forecasts following stratospheric sudden warmings and the representation of stratosphere-troposphere coupling in subseasonal forecast models.

The control experiment is a set of retrospective, 45-day, 50-member ensemble forecasts. Following the initial date, the stratospheric zonal mean temperatures and zonal winds are nudged towards the time-evolving climatological state. The forecasts are initialized on the date indicated by the sub-experiment id; for instance, the sub-experiment 's20180125' is initialized on 25 January 2018. The ocean, sea-ice, land-surface and ozone are all initialized and run prognostically.

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Sources of additional information
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The following web links are provided in the Details/Docs section of this catalogue record:
- Stratospheric Nudging And Predictable Surface Impacts (SNAPSI): A Protocol for Investigating the Role of the Stratospheric Polar Vortex in Subseasonal to Seasonal Forecasts
- New set of controlled numerical experiments: Stratospheric Nudging And Predictable Surface Impacts (SNAPSI)
- MacLachlan, C., Arribas, A., Peterson, K. A., Maidens, A., Fereday, D., Scaife, A. A., Gordon, M., Vellinga, M., Williams, A., Comer, R. E., Camp, J., Xavier, P., and Madec, G.: Global Seasonal forecast system version 5 (GloSea5): a high-resolution seasonal forecast system, Q. 605 J. R. Meteorol. Soc., 141, 1072–1084, https://doi.org/10.1002/qj.2396, 2014