Abstract. Convective rainfall is often focalized in areas of moisture convergence. A close relationship between precipitation and fast variations of vertically-integrated water vapour (IWV) has been found in numerous cases. Therefore, continuous monitoring of atmospheric humidity and its spatial distribution is crucial to the operational forecaster for a proper nowcasting of heavy rainfall events. The microwave signals continuously broadcasted by the Global Navigation Satellite Systems (GNSS) satellites are influenced by the water vapour as they travel through the atmosphere. Estimates of IWV retrieved from ground-based GNSS observations may, then, constitute a source of information on the horizontal distribution and the time evolution of atmospheric humidity. At the Spanish Meteorological Agency (AEMET), a near-real-time map of IWV estimates retrieved from ground GNSS measurements in the Iberian Peninsula and West Mediterranean region is operationally built and presented to the forecaster. The maps are generated every 15 minutes following a one-dimensional variational assimilation scheme with the previous map as the background state. A case study is presented in order to illustrate some strengths and weaknesses of the product, to assess the potential benefit of using GNSS products in nowcasting and to define the steps to be done in order to make use of the full potential of the method.
Abstract. The climatic reference values for monthly and annual average air temperature and total precipitation in Catalonia -northeast of Spain -are calculated using a combination of statistical methods and geostatistical techniques of interpolation. In order to estimate the uncertainty of the method, the initial dataset is split into two parts that are, respectively, used for estimation and validation. The resulting maps are then used in the automatic outlier detection in meteorological datasets.
En este trabajo se analizan los parámetros de la función de distribución de probabilidad (FDP) de las anomalías de las temperaturas máximas y mínimas en Cataluña durante el periodo 1951-2017, así como su tendencia. Para ello, se utilizan series diarias de anomalías de temperaturas promediadas para Cataluña. Se concluye que el aumento en la temperatura media ha sido de 0,23 ºC por década. El incremento ha sido mayor en las temperaturas máximas que en las mínimas y el verano ha sido la estación que más ha contribuido a este incremento. De los resultados obtenidos del análisis de las FDP de las series de anomalías de temperatura destaca que la dispersión de las anomalías de las máximas es mayor que la de las mínimas y que el sesgo de ambas distribuciones es negativo. Respecto a la evolución interdecadal de las FDP de las series, resalta el aumento de la varianza en las anomalías de las temperaturas máximas, especialmente en verano y en primavera. El efecto combinado del aumento del valor medio y de la varianza ha conducido a un incremento de la severidad y la frecuencia de los episodios extremadamente cálidos.
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