Geophysical Research Letters

Role of the stratosphere on the predictability of medium-range weather forecast: A case study of winter 2003–2004

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Abstract

[1] The role of the stratosphere on the predictability of medium-range weather forecast during the northern hemisphere winter is examined using numerical experiments with a middle atmosphere climate model of the Meteorological Research Institute. It is found that in the winter of 2003/04 when the stratosphere exhibited a large variability called the Polar-night Jet Oscillation (PJO), the predictability of the model tended to be very good for large-scale zonal variability if the prediction is performed just before the occurrence of stratospheric sudden warmings (SSWs). The role of the stratosphere is examined by comparing experiments for the 2002/03 year and using the model with and without the stratosphere included. The results of the study suggest that taking account of the role of stratospheric variability (PJO) is crucial for improving the predictability of medium-range weather forecast in certain winters.

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