Diagnosis and modelling of a summer convective storm over Mediterranean Pyrenees

Abstract

Abstract. Over the Mediterranean Pyrenees and near coastal region there is a high frequency of convective storms during summertime. This fact determines a local maximum of precipitation at this season unlike the normal and general minimum over Mediterranean basin. The common synoptic and mesoscale patterns associated to convective phenomena are briefly analyzed and diagnosed with radar imagery, surface pressure and isobaric level fields and surface data. They usually involves a little distant through at medium levels, very weak pressure gradient at the surface and not significant instability, but a preferred Planetary Boundary Layer low-level convergence zones tied to the orography. As a result of this analysis two different kinds of circulations associated to recurrent convergence zones have been recognized: upvalley/upslope winds and sea breezes. High resolution simulations from a Numerical Weather Prediction model for a case study have carried out to analyze the role of the main key components, i.e. the orography, the sea and valley breeze and their influence to generate local convergence zones. Furthermore, the skills of the model to simulate the location and the intensity of the precipitation of these summer Mediterranean storms have been discussed.

Water discharge and sediment flux intermittency in the fluvial Escanilla Formation, Spain: Implications for changes in stratigraphic architecture

“…These new intermittency results indicate that sediments during the deposition of the HA intervals were on average transported within 4 ± 0.3 days most probably suggesting that the HA intervals were deposited under concentrated ‘bursts’ of sediment flux potentially under high‐frequency convective storms over the Pyrenees during summertime (Callado & Pascual, 2005; Llasat et al., 2021) while sediment transport in the LA intervals took on average 8 ± 0.65 days but represents a much larger spread in the number of days over which sediments were transported (Figure 5). While differences in intermittency, although small, are observed relative to the HA and LA intervals, they do not fully explain the differences in stratigraphy between these intervals.…”

Exhumation of the southern Pyrenean fold‐thrust belt (Spain) from orogenic growth to decay

“…At present, regional climate modeling shows that orography is the principal control on precipitation patterns in Spain that favor high-altitude precipitation and sheltered lowlands [Sotillo et al, 2003]. The eastern Pyrenees in particular are subjected to high-frequency, convective rainstorms during the summer unlike elsewhere in the Mediterranean basin because of the coupling of orographic cooling and wet air masses produced by the Mediterranean Sea [Callado and Pascual, 2005]. The presence of an evaporative lacustrine environment in the Ebro Basin through the Miocene [Garcia-Castellanos et al, 2003] may have also enhanced orographic precipitation and, thus, erosion along the southern range front.…”

Harmonic Analysis of the Spatiotemporal Pattern of Thunderstorms in Iran (1961–2010)

“…Also, some of them happened at midnights [10]. However, Callado and Pascual Berghaenel used different models to study the Mediterranean thunderstorms, and they argued that the high frequency of thunderstorms in Catalonia at the end of the spring and in summer can be attributed to local mountains and maritime influences [11]. Davolio et al simulated the intense convective precipitation event of September 8 th and 9 th , 2002, in the southeast of France, and they believed that the existence of a midsize convective system before the approaching of cold front was responsible for this event [12].…”