By its temperature, the sea water close to the continent (Morocco) can decrease or increase the rain efficiency of the disturbances coming from elsewhere and also modify the pressure field. The ...distant thermal anomalies appear through their effects on the amplitude and the localisation of the tropospheric waves: - from an example one can see how an unusual position of the Gulf Stream can influence the distribution of the coastal rainfall. - the winter thermal anomalies in the North Pacific linked with the extreme monthly rainfall on the coast of Morocco, which is significantly higher or lower. - the spring rains, particularly at the south of Casablanca, seem to be related to the fluctuations of the Southern Oscillation and to the temperature of the Pacific equatorial waters during the previous winter term.
The seasonal precipitations of the cisatlasic Morocco are correlated to the indexes of diverse teleconnection pattern. In winter, the main correlations are established with the North Atlantic ...Oscillation. The spring and autumn precipitations are correlate with the Southern Oscillation. strong and positive in spring with the index both contemporaneous and lagged from a season to another, negative and more modest in autumn with the field of variation of 700 hPa height.
La fréquence, la durée et l'occurrence horaire du brouillard dans quelques stations côtieres atlantiques du Maroc sont précisées. La combinaison de processus radiatifs et advectifs conditionne ...l'installation des brouillards selon des modalités qui sont déterminées par la température des eaux côtieres, l'altitude de la surface d'inversion et le type de situation atmosphérique.
The frequency, the duration and the horary occurrence of fog upon several coast stations of Morocco are precised. Combination of radiative and advective processes commands the instalment of the fog, according to the different modes which are conditionned by the temperature of the coast waters, the altitude of the inversion surface and the type of the atmospheric situation.
Résumé. - Les précipitations saisonnières (été exclu) du Maroc cisatlasique (1953-1982) sont corrélées avec des indices de différentes téléconnexions. En hiver, les corrélations principales ...s'établissent avec l'Oscillation nord-atlantique, aux saisons intermédiaires avec l'Oscillation australe : fortes et positives au printemps avec l'indice contemporain ou décalé d'une à deux saisons, négatives et plus modestes en automne, avec un indice décalé d'une ou deux saisons. Les principales corrélations sont cohérentes avec les champs de variation de géopotentiels à 700 hPa correspondants.
Abstract. - The seasonal precipitations (summer excluded) of the cisatlasic Morocco (1953-1982) are correlated to the indexes of diverse teleconnection pattern. In winter the main correlations are established with the North Atlantic Oscillation. The spring and autumn precipitations are correlate with the Southern Oscillation : strong and positive in spring with the index both contemporaneous and lagged from a season to another, negative and more modest in autumn with an index either lagging one or two seasons. The main correlations are coherent with the field of variation of 700 hPa height.
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