Masa de agua precipitable, índices de inestabilidad e isocero en el Mediterráneo Occidental durante el Periodo de Observación Especial HyMeX-SOP1 (otoño de 2012)

Abstract

The first Special Observation Period (SOP1) of the HyMeX research program was carried out during autumn 2012 in the Western Mediterranean basin. It considered several target areas where moisture flows and precipitation events were studied in detail. Four radiosonde stations were used to derive Total amount of Precipitable Water (TPW), atmospheric instability indices, and freezing level during SOP1. Average TPW was 0.5-1.5 standard deviations higher than last decade's average value. This positive anomaly was greater in mid-tropospheric levels than in the lower troposphere. Heavy precipitation events were observed in the presence of significantly high TPW content; however, high humidity and instability values did not always involve convective precipitation, since additional factors are needed in order to trigger convection. Freezing level presented significant fluctuations due to the intrusions of cold air masses, which became more and more frequent throughout the autumn.