Vicente‐Serrano et al. (2010) Extreme winter precipitation in the Iberian Peninsula in 2010: anomalies, driving mechanisms and future projections

Identification

• Journal: Climate Research
• Year: 2010
• Date: 2010-12-06
• Authors: Sergio M. Vicente‐Serrano, Ricardo M. Trigo, Juan Ignacio López‐Moreno, Margarida L. R. Liberato, Jorge Lorenzo‐Lacruz, Santiago Beguerı́a, Enrique Morán‐Tejeda, Ahmed El Kenawy
• DOI: 10.3354/cr00977

Research Groups

• Departamento de Ciencias Históricas y Geográficas, Universidad de Tarapacá, Chile
• Group of Climatology, University of Barcelona, Spain
• Climatic Research Unit, School of Environmental Sciences, University of East Anglia, UK
• Department of Geography, University of Chile, Chile
• Center of Excellence for Climate Change Research, King Abdulaziz University, Saudi Arabia
• Interuniversitary Institute of Geography, University of Alicante, Spain
• Barcelona Supercomputing Center, Spain

Short Summary

This study defines a temporal distribution index (fractal dimension) for high-resolution precipitation data over Peninsular Spain and the Balearic Islands, revealing its synoptic implications and regional variations in rainfall behavior.

Objective

• To give a synoptic significance to the fractal dimension as an indicator of temporal variability in precipitation by determining the types of surface and mid-tropospheric (500 hPa) atmospheric situations associated with its extreme values.

Study Configuration

• Spatial Scale: Peninsular Spain and the Balearic Islands, using data from 48 observatories.
• Temporal Scale: Precipitation data from 1995 to 2010 at a 10-minute resolution. Synoptic data at 6-hour resolution (00:00, 06:00, 12:00, 18:00 UTC).

Methodology and Data

• Models used:
  • Fractal Dimension (FD) calculation: Box-counting method.
  • Synoptic classification: Jenkinson and Collison (J&C) methodology, adapted for both surface and 500 hPa geopotential elevation.
  • Statistical analysis: Proportions comparison test, cluster analysis, goodness-of-fit analysis using surrogate data (Mean Error, Mean Absolute Error, Root Mean Squared Error).
• Data sources:
  • Precipitation data: Spanish Meteorological Agency (AEMET) network of automatic stations.
  • Atmospheric pressure data (surface) and geopotential elevation (500 hPa): ERA Interim reanalysis project.

Main Results

• Fractal Dimension (FD) values for the 48 observatories ranged from 1.4499 (Ibiza Airport) to 1.6039 (Lugo Airport), with high coefficients of determination (R²) between 0.9853 and 0.9998.
• Goodness-of-fit analysis confirmed the robustness of the FD values, showing mean MAE of 0.045, mean RMSE of 0.056, and mean ME of -0.0017, indicating significant differences between observed FD values compared to simulated random series.
• Cluster analysis identified four distinct regions based on latitude, longitude, and FD values, demonstrating that the grouping is strongly influenced by FD values, not solely geography.
• The synoptic significance of extreme FD values varies regionally:
  • Northern/Atlantic region (e.g., A Coruña): Higher FD values are linked to a lower frequency of anticyclonic situations and a higher frequency of SW and W advective situations, with stronger flows at 500 hPa.
  • Central region (e.g., Castellón): Higher FD values are associated with a higher frequency of anticyclonic types and a lower frequency of advective types from the east.
  • Mediterranean region (e.g., Palma): Higher FD values are associated with a higher frequency of anticyclonic types and a lower frequency of advective types from the east.
  • Southern region (e.g., Jaén): Lower FD values occur with more frequent anticyclonic–easterly hybrid weather types and less frequent cyclonic types.
• Generally, higher FD values in the Atlantic half of the peninsula are associated with more frequent cyclonic and advective weather types, leading to more random precipitation behavior. In the Mediterranean, high FD values are linked to anticyclonic situations, suggesting the operation of local precipitation mechanisms.

Contributions

• Provides a novel synoptic interpretation of the fractal dimension as a temporal precipitation variability indicator, linking it to specific atmospheric circulation patterns at both surface and 500 hPa levels.
• Establishes a regionalization of Peninsular Spain and the Balearic Islands based on the fractal dimension of precipitation, demonstrating its dependence on local atmospheric mechanisms.
• Utilizes high-resolution (10-minute) precipitation data, which is critical for accurate fractal analysis and distinguishes this study from those using coarser temporal resolutions.
• Validates the methodology for calculating fractal dimensions using surrogate data, ensuring the reliability of the results.

Funding

• FONDECYT Project 11160059 (Chilean Government)
• UTA-Mayor Project 5755-17 (Universidad de Tarapacá)
• Convenio de Desempeño UTA-MINEDUC
• Climatology Group from the University of Barcelona investigation program (2014SGR300, Catalan Government)

Citation

@article{VicenteSerrano2010Extreme,
  author = {Vicente‐Serrano, Sergio M. and Trigo, Ricardo M. and López‐Moreno, Juan Ignacio and Liberato, Margarida L. R. and Lorenzo‐Lacruz, Jorge and Beguerı́a, Santiago and Morán‐Tejeda, Enrique and Kenawy, Ahmed El},
  title = {Extreme winter precipitation in the Iberian Peninsula in 2010: anomalies, driving mechanisms and future projections},
  journal = {Climate Research},
  year = {2010},
  doi = {10.3354/cr00977},
  url = {https://doi.org/10.3354/cr00977}
}