Precipitation concentration changes in Spain 1946–2005

Abstract

Abstract. An analysis was made of the Precipitation Concentration Index using the new MOPREDAS database of monthly precipitation in Spain (Monthly Precipitation Data base of Spain). The database was compiled after exhaustive quality control of the complete digitalized Spanish Meterological Agency (AEMet) archives and contains a total set of 2670 complete and homogeneous monthly precipitation series from 1946 to 2005. Thus, MOPREDAS currently holds the densest information available for the 1946-2005 period for Spain and ensures a high resolution of results. The Precipitation Concentration Index (PCI) is a powerful indicator of the temporal distribution of precipitation, traditionally applied at annual scales; as the value increases, the more concentrated the precipitation. Furthermore PCI is a part of the well-known Fournier index, with a long tradition on natural system analyses, as for example soil erosion. In this paper, the mean values of annual, seasonal and wet and dry periods of PCI in the conterminous Spain and for two normal periods (1946-1975 and 1976-2005) were studied.Precipitation in Spain follows a general NW-SE spatial pattern during the wet (months) period due to the Atlantic storm track, while during the dry (months) period, it follows a predominantly N-S spatial pattern. As a result, the annual values of PCI combine the two patterns and show a SW-NE PCI gradient.The analyses of the two sub-periods show significant changes in the precipitation occurred in conterminous Spain from 1946 to 2005, and precipitation concentration increased across most of the IP. At an annual scale, PCI increases mostly due to an increase in precipitation concentration during the wet season. At a seasonal scale significant changes were detected between 1945 -1975 and 1976, while changes in Correspondence to: J. C. González-Hidalgo (jcgh@posta.unizar.es) winter, spring and summer were mostly localized and not generalized (both increase and decrease). Changes in PCI seem to be complex and appear to be related to global atmospheric features and synoptic and local factors affecting precipitation trends. We discuss the possible explanation linked to the atmospheric pattern and monthly trends and their implications.

Variation of precipitation concentration from 1960 to 2014 in the Middle and Lower reaches of the Yangtze River Basin, China

“…However, other indices also have some shortcomings. Such as PCI (Oliver, 1980;Luis et al, 2011;, which just takes the total rainfall amount into consideration while ignores the timing, and CI (concentration index) based on the contribution of daily precipitation to the total rainfall amount (Martin-Vide, 2004). Hence, the improvement of indicator for reflecting the real concentration of precipitation needs further work.…”

Impact of the Darjeeling–Bhutan Himalayan front on rainfall hazard pattern

“…The PCI was estimated on an annual and seasonal scale: pre-monsoon, south-west monsoon and post-monsoon seasons. The number 100 in the formula for the annual PCI was replaced by the numbers 25 for monsoon and 33 for pre-and post-monsoon to represent the number of months in each season as a percentage of 12 months of the year (Luis et al 2011). …”

Spatial and Temporal Analysis of Rainfall Concentration Using the Gini Index and PCI

“…Similarly, a rainfall concentration study was developed in Mediterranean climates of Spain, using the PCI and considering a time period between 1946 and 2005 [29]. The authors concluded an annual increase of PCI values, a conclusion that was explained by an increase of winter precipitations.…”