Stratospheric Polar Cap Mean Height and Temperature as Extended-Range Weather Predictors

• DOI: 10.1175/mwr2985.1
• Publication Date: 2005-08-19T21:32:47Z
• Authors: Peter Siegmund
• Keywords: Geopotential height; Geopotential; Atmospheric temperature

Abstract The skill of stratospheric and tropospheric predictors in predicting near-surface quantities at the extended range (∼10 days–2 months) has been investigated, using 40 yr reanalysis data from European Centre for Medium-Range Weather Forecasts. are 1) geopotential height (Z) various levels, 2) difference between Z 1000-hPa [Z − Z(1000)], 3) temperature levels. averages over area north 65°N. predictands Z(1000) averaged same geographical fields several quantities. predictive investigated different lead times predictor predictand averaging periods predictand. results show that troposphere is mainly due to sea level pressure, whereas stratosphere temperature. largest end December, 50 hPa 250 hPa. also significant upper summer. In winter, larger than 5 days a better daily itself. Whereas zero time, about 10 days, evidencing finite propagation time anomalies surface. wintertime monthly mean field limited region 60°N. zonal wind 850 particularly large around correlation pattern qualitatively similar corresponding Arctic Oscillation index, except middle latitudes Eurasia subtropical Pacific.