Examinando por Autor "Gil, M."

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Acceso Abierto
Mid-winter lower stratosphere temperatures in the Antarctic vortex: comparison between observations and ECMWF and NCEP operational models
(EGU European Geosciences Union, 2007-01-24) Parrondo, María Concepción; Yela González, Margarita; Gil, M.; Von der Gathen, P.; Ochoa, H.
Radiosonde temperature profiles from Belgrano (78° S) and other Antarctic stations have been compared with European Centre for Medium-Range Weather Forecasting (ECMWF) and National Centers for Environmental Prediction (NCEP) operational analyses during the winter of 2003. Results show good agreement between radiosondes and NCEP and a bias in the ECMWF model which is height and temperature dependent, being up to 3°C too cold at 80 and 25–30 hPa, and hence resulting in an overestimation of the predicted potential PSC areas. Here we show the results of the comparison and discuss the potential implications that this bias might have on the ozone depletion computed by Chemical Transport Models based on ECMWF temperature fields, after rejecting the possibility of a bias in the sondes at extreme low temperatures.
Restringido
OClO, NO2 and O3 total column observations over Iceland during the winter 1993/94
(AGU Publishing, 1996-11-15) Gil, M.; Puentedura, O.; Yela González, Margarita; Parrondo, María Concepción; Jadhav, D. B.; Thorkelsson, B.
Ground-based observation of OClO, NO2, and O3 columns by differential UV-Visible spectroscopy at twilight during the fall winter of 1993/94 at the sub-Arctic station of Reykjavik (64°N, 23°W) are presented. Results show no direct evidence of ozone depletion during the period but significant amounts of OClO were observed in December and January when NO2 abundances were at the annual minimum. NO2 columns are found to be controlled by the hours of light available but highly modulated by the lower stratosphere temperature. OClO was observed outside the vortex as well, but only at times when NO2 was low.