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Does increasing model stratospheric resolution improve extended‐range forecast skill?
Author(s) -
Roff Greg,
Thompson David W. J.,
Hendon Harry
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl046515
Subject(s) - stratosphere , extratropical cyclone , troposphere , forecast skill , climatology , environmental science , northern hemisphere , initialization , geopotential height , latitude , atmospheric sciences , range (aeronautics) , middle latitudes , meteorology , atmospheric model , geology , geography , computer science , precipitation , materials science , geodesy , composite material , programming language
The effect of stratospheric resolution on extended‐range forecast skill at high Southern latitudes is explored. Ensemble forecasts are made for two model configurations that differ only in vertical resolution above 100 hPa. An ensemble of twelve 30‐day forecasts is made from mid‐November for years 1979 to 2008. November is when the Southern Hemisphere stratosphere is most variable, and so this is when impacts on the Southern extratropical troposphere are expected to be greatest. As expected, the high resolution model is associated with better forecast skill in the stratosphere throughout the 30 day integration. Surprisingly, the high resolution model is also associated with significant forecast skill improvement (∼5%) in the troposphere ∼3–4 weeks after the initialization date. The results suggest extended‐range forecast skill can be improved in current forecast schemes by increasing model stratospheric resolution, improving representation of stratospheric dynamics and thermodynamics, and improving stratospheric initial conditions.