Luis et al. (2011) Precipitation concentration changes in Spain 1946–2005

Identification

• Journal: Natural hazards and earth system sciences
• Year: 2011
• Date: 2011-05-09
• Authors: Martín de Luis, José Carlos González Hidalgo, Michele Brunetti, Luis Alberto Longares Aladrén
• DOI: 10.5194/nhess-11-1259-2011

Research Groups

• Department of Geography, University of Zaragoza, Zaragoza, Spain
• Instituto Universitario de Ciencias Ambientales, Zaragoza, Spain
• Istituto di Scienze dell’Atmosfera e del Clima ISAC-CNR, Bologna, Italy

Short Summary

This study analyzed changes in precipitation concentration across conterminous Spain from 1946 to 2005 using the MOPREDAS database, revealing a general increase in precipitation concentration, particularly during the wet season and autumn, with significant spatial variability.

Objective

• To analyze the mean values and temporal changes of the Precipitation Concentration Index (PCI) at annual, seasonal (winter, spring, summer, autumn), and supra-seasonal (wet and dry periods) scales across conterminous Spain for the period 1946–2005, comparing two 30-year sub-periods (1946–1975 and 1976–2005).

Study Configuration

• Spatial Scale: Conterminous Spain (Iberian Peninsula), represented by a gridded dataset of 5334 cells with a 10 km resolution.
• Temporal Scale: 60 years (December 1945 to November 2005), analyzed at monthly, seasonal, and supra-seasonal scales, and compared between two 30-year sub-periods (1946–1975 and 1976–2005).

Methodology and Data

• Models used: Precipitation Concentration Index (PCI) (Oliver, 1980) calculated for annual, seasonal, and supra-seasonal periods. Statistical t-test used to assess the significance of differences between the two 30-year periods.
• Data sources: MOPREDAS (Monthly Precipitation Database of Spain), compiled from 2670 complete and homogeneous monthly precipitation series from the Spanish Meteorological Agency (AEMet) archives.

Main Results

• Annual PCI values range from less than 10 (uniform distribution, e.g., central Pyrenees) to greater than 20 (strong irregularity, e.g., southeast Spain), showing a general SW-NE gradient.
• A general increase in annual PCI values was observed across most of the Iberian Peninsula in the 1976–2005 period compared to 1946–1975, with significant increases in the central Pyrenees, Ebro basin, Iberian range, and southwest.
• The annual PCI increase is primarily attributed to an increase in precipitation concentration during the wet season (October to March).
• Seasonal changes include a significant decrease in winter PCI in the extreme northwest, a rise in spring PCI across most of the IP, a general decrease in summer PCI in western and southern areas (with increases in the northeast), and a general increase in autumn PCI over most of the IP (except for the Mediterranean coast).
• During the dry season (April to September), PCI shows a clear north (lower) to south (higher) gradient, with mostly non-significant changes between periods.
• During the wet season (October to March), PCI shows a clear west (lower) to east (higher) gradient, with highly significant increases in precipitation concentration in the central Pyrenees, central IP, and Southwest.
• Changes in PCI are complex and appear to be related to global atmospheric features and synoptic and local factors affecting precipitation trends, such as changes in storm tracks associated with the NAO and increased cyclone frequency in the western Mediterranean.

Contributions

• Presents the first detailed, high-resolution analysis of precipitation concentration across the entirety of conterminous Spain over a 60-year period, utilizing the dense MOPREDAS database.
• Provides a comprehensive understanding of the spatial and temporal variability and trends in precipitation concentration at multiple time scales (annual, seasonal, wet/dry periods).
• Identifies significant shifts in precipitation concentration patterns between two distinct 30-year periods, highlighting an overall trend towards increased concentration.
• Discusses the potential implications of these changes for water resource management, natural processes like soil erosion, fluvial regimes, groundwater recharge, water availability, and hydroelectric production.
• Emphasizes the critical role of precipitation concentration, beyond total precipitation, for effective water planning and erosion studies in the region.

Funding

• The Spanish Government, Contract Grant Sponsor CGL2008-05112-C02-01
• DGA (Aragón Regional Govt.), Consolidated Research Group “Clima. Agua, Cambio Global y Sistemas Naturales” (BOA 69, 11 June 2007)

Citation

@article{Luis2011Precipitation,
  author = {Luis, Martín de and Hidalgo, José Carlos González and Brunetti, Michele and Aladrén, Luis Alberto Longares},
  title = {Precipitation concentration changes in Spain 1946–2005},
  journal = {Natural hazards and earth system sciences},
  year = {2011},
  doi = {10.5194/nhess-11-1259-2011},
  url = {https://doi.org/10.5194/nhess-11-1259-2011}
}