On the accuracy of analysed low temperatures in the stratosphereReport as inadecuate




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1 DMI - Danish Meteorological Institute

Abstract : The accuracy of ECMWF European Centre for Medium-Range Weather Forecasts temperatures has been investigated by comparison to radiosonde temperatures. Particularly, the extent of temperatures below which Polar Stratospheric Clouds PSCs consisting of nitric acid trihydrate can exist TNAT has been studied. In the 1999-2000 winter analyses and in the 40 year reanalyses ERA40 from the winter 1996-1997 the analysed extent agrees quite well with the radiosondes extent, whereas the 2002-2003 winter analyses considerably overestimate the extent from 40-11 hPa due to a general cold bias. Close to the frost point small-scale temperature variations, which ECMWF does not catch, substantially increase the extent of these low temperatures. Some of these small-scale variations are caused by lee-waves.





Author: B. M. Knudsen -

Source: https://hal.archives-ouvertes.fr/



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