Rainfall Components: Variability and Spatial Distribution in a Mediterranean Area (Valencia Region)

Abstract

In the last half of the twentieth century, the precipitation regime on the Spanish east coast showed an overall pattern of reduction in precipitation totals. This work presents the results from a novel procedure to disaggregate the precipitation series in the Valencia region on the basis of their meteorological origin. Important differences are found between specific trends and changes in the contributions from 1) Atlantic frontal systems, 2) convective–orographic storms, and 3) easterly advections over the Mediterranean Sea (backdoor cold fronts). The series for the three components are then used to analyze the evolution, variability, and spatial distribution of the region’s rainfall and to determine the correlations with the North Atlantic Oscillation (NAO) index. The results establish significant differences between inland areas, with a trend toward decreasing precipitation and thus increasing aridity, and coastal areas, with increasing precipitation that tends to be progressively more torrential in nature. Likewise, the correlations with the NAO index also change and show opposite signs for the different components.

Daily precipitation observations over Emilia‐Romagna: mean values and extremes

“…effect and leads also to an increase in the number of cdd. Similar results have also been documented over the Valencia region, in Spain, by Millán et al (2005).…”

Trend analysis of annual and seasonal rainfall time series in the Mediterranean area

“…In addition, it has to be noted that meteorological events relevant to the studied region have different geographical origins and, in some cases, are not affected by the presence of orographic barriers. From this point of view, precipitation variability over the studied area also has to be read in a context of synoptic type events assessment, as illustrated in some recent studies concerning the Mediterranean basin (Millán et al, 2005), through the identification of the geographical origin and of the relative importance of different meteorological events. To this aim, the database should be extended both in space and time, that is, the temporal variability (time series) of a number of additional meteorological stations have to be collected.…”

“…With regard to the European context, negative trend areas are more pronounced in the central and southern regions, corresponding to the Mediterranean basins, whose most relevant characteristic is extreme rainfall variability, both in space and time (Piervitali et al, 1997;Schonwiese and Rapp, 1997;Romero et al, 1998;Millán et al, 2005;Mehta and Yang, 2008). The implications of these changes are particularly significant for these areas, stressed by the combination of a dry climate and an excessive water demand.…”

Characterization of typical coastal circulations with high‐resolution measurements in the Gulf of Valencia

“…The mountains in the north have higher elevations than the mountains in the west and south of the basin. Millán et al (2004) and Estrela et al (2008) provide more detailed descriptions on the topographic feature of the Valencia region. The inland stations Turis and Pedralba are located at the mouth of two valleys, which have different orientations (Figure 1(a)).…”