21 research outputs found
The Spatial Scaling Behaviour of Extreme Precipitation in an Atmospheric General Circulation Model and in Observational Data
Cambio en las emisiones de compuestos orgánicos volátiles en ambientes urbanos: múltiples vías para obtener un aire más limpio
Extreme Precipitation in an Atmosphere General Circulation Model: Impact of Horizontal and Vertical Model Resolution
To investigate the influence of atmospheric model resolution on the representation of daily precipitation extremes, ensemble simulations with the atmospheric general circulation model ECHAM5 at different horizontal (T213 to T31) and vertical (L31 to L19) resolutions and forced with observed sea surface temperatures and sea ice concentrations have been carried out for 01/1982 - 09/2010. All results have been compared with the highest resolution, which has been validated against observations.
Resolution affects both the representation of physical processes and the averaging of precipitation across grid boxes. The latter, in particular, smoothes out localized extreme events. These effects have been disentangled by averaging precipitation simulated at the highest resolution to the corresponding coarser grid. Extremes are represented by seasonal maxima, modeled by the generalized extreme value distribution.
Effects of averaging and representation of physical processes vary with region and season. In the tropical summer hemisphere, extreme precipitation is reduced by up to 30% due to the averaging effect, and a further 65% owing to a coarser representation of physical processes. Towards mid- to high latitudes, the latter effect reduces to 20%; in the winter hemisphere it vanishes towards the poles. A strong drop is found between T106 and T63 in the convection dominated tropics. At the lowest resolution, northern hemisphere winter precipitation extremes, mainly caused by large scale weather systems, are in general represented reasonably well. Coarser vertical resolution causes an equatorward shift of maximum extreme precipitation in the tropics. The impact of vertical resolution on mean precipitation is less pronounced; for horizontal resolution it is negligible
Fusión de datos de modelos numéricos y mediciones de campo de deposición atmosférica total a escala global: una iniciativa de la OMM
Beneficios del monitoreo de la composición atmosférica y del intercambio internacional de datos
De las observaciones atmosféricas y el análisis de los gases de efecto invernadero a la estimación de emisiones: una aventura científica
Respuesta del dióxido de carbono y de la calidad del aire a la reducción de emisiones fruto de las restricciones vinculadas a la COVID-19
Rising Mediterranean Sea Surface Temperatures Amplify Extreme Summer Precipitation in Central Europe
The beginning of the 21st century was marked by a number of severe summer floods in Central Europe associated with extreme precipitation (e.g., Elbe 2002, Oder 2010 and Danube 2013). Extratropical storms, known as Vb-cyclones, cause summer extreme precipitation events over Central Europe and can thus lead to such floodings. Vb-cyclones develop over the Mediterranean Sea, which itself strongly warmed during recent decades. Here we investigate the influence of increased Mediterranean Sea surface temperature (SST) on extreme precipitation events in Central Europe. To this end, we carry out atmosphere model simulations forced by average Mediterranean SSTs during 1970–1999 and 2000–2012. Extreme precipitation events occurring on average every 20 summers in the warmer-SST-simulation (2000–2012) amplify along the Vb-cyclone track compared to those in the colder-SST-simulation (1970–1999), on average by 17% in Central Europe. The largest increase is located southeast of maximum precipitation for both simulated heavy events and historical Vb-events. The responsible physical mechanism is increased evaporation from and enhanced atmospheric moisture content over the Mediterranean Sea. The excess in precipitable water is transported from the Mediterranean Sea to Central Europe causing stronger precipitation extremes over that region. Our findings suggest that Mediterranean Sea surface warming amplifies Central European precipitation extremes