Serrano‐Notivoli et al. (2017) SPREAD: a high-resolution daily gridded precipitation dataset for Spain – an extreme events frequency and intensity overview

Identification

• Journal: Earth system science data
• Year: 2017
• Date: 2017-09-14
• Authors: Roberto Serrano‐Notivoli, Santiago Beguerı́a, Miguel Ángel Saz, Luis Alberto Longares Aladrén, Martín de Luis
• DOI: 10.5194/essd-9-721-2017

Research Groups

• Department of Geography and Regional Planning, University of Zaragoza, Zaragoza, 50009, Spain
• Environmental Sciences Institute (IUCA), University of Zaragoza, Zaragoza, 50009, Spain
• Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (EEAD-CSIC), Zaragoza, 50059, Spain

Short Summary

This study developed SPREAD, a high-resolution (5 km) daily gridded precipitation dataset for Spain (1950-2012), revealing distinct regional patterns in daily and extreme precipitation events, with the Mediterranean coast and Central Range experiencing the highest frequency and intensity of extremes.

Objective

• To develop SPREAD, a high-resolution (5 km) daily gridded precipitation dataset for Spain, and to characterize the spatial distribution of daily and extreme precipitation events across the region using 13 derived indices.

Study Configuration

• Spatial Scale: Peninsular Spain (492 175 km²), Balearic Islands (4992 km²), and Canary Islands (7493 km²) at a 5 × 5 km spatial resolution.
• Temporal Scale: 1950–2012 for peninsular Spain, and 1971–2012 for Balearic and Canary Islands.

Methodology and Data

• Models used: Generalized Linear Models (GLMs) for calculating Reference Values (RVs) and the R package reddPrec for reconstruction and gridding.
• Data sources: Raw data from 12,858 observatories across Spain, primarily from the Spanish Meteorological Agency (AEMET) (83.1%), Ministry of Agriculture and Environment (MAGRAMA) (4.2%), and various regional hydrological and meteorological services.

Main Results

• A high-resolution (5 × 5 km) daily gridded precipitation dataset (SPREAD) was successfully created for Spain.
• Quality control removed an annual average of 2.4% of data in peninsular Spain, 1.7% in the Balearic Islands, and 1.8% in the Canary Islands.
• The method demonstrated high accuracy in wet/dry day prediction (true negative rate > 94%, true positive rate > 79% for most regions).
• Magnitude estimation showed high correlation (Pearson's r > 0.93) between observed and estimated daily precipitation, daily medians in wet days, and the 95th percentile of wet days.
• Daily mean precipitation intensity (PMED) was highest (> 8 mm) in the Central Range, Pyrenees, Baetic Range, and south-western/north-western peninsular Spain.
• The number of wet days (NWD) showed a strong north-west (> 100 days) to south-east (< 30 days) gradient in peninsular Spain.
• The mean length of dry spells (CDDm) followed a similar north-west (< 5 days) to south-east (> 30 days) gradient.
• Extreme precipitation indices indicated that the Mediterranean coast and the Central Range experienced the highest frequency and intensity of extreme events, with the Central Range reaching maximum 1-day precipitation (RX1) values over 200 mm.
• The percentage of precipitation over the 95th percentile (R95rel) exceeded 30% along the Mediterranean coast, highlighting the extreme character of daily precipitation in these areas.
• Uncertainty in estimates generally increased from north-west to south-east in peninsular Spain for daily precipitation indices and was higher along the Mediterranean coast for extreme precipitation indices.

Contributions

• Development of SPREAD, a novel high-resolution (5x5 km) daily gridded precipitation dataset covering all of Spain (peninsular, Balearic, and Canary Islands) for an extended period (1950-2012).
• Utilizes the most comprehensive raw data available (12,858 observatories), including short series, for a robust reconstruction.
• Employs a unique local, independent estimation methodology for each day and grid point, effectively capturing local and day-to-day precipitation variability without excessive smoothing.
• Provides a quantitative measure of uncertainty (standard error) for each daily precipitation estimation, enhancing the reliability assessment of the dataset.
• Offers a more detailed and precise spatial and temporal characterization of daily and extreme precipitation patterns in Spain compared to existing global or regional datasets.
• Identifies specific regions (e.g., Central Range, Mediterranean coast) with maximum extreme precipitation values that were not fully resolved in previous studies.

Funding

• Research projects CGL2015-69985-R and CGL2014-52135-C3-1-R, financed by the Spanish Ministerio de Economía y Competitividad (MINECO) and FEDER-ERDF funds.
• Government of Aragón through the “Programme of research groups” (groups H38, “Clima, Cambio Global y Sistemas Naturales” and “E68, Geomorfología y Cambio Global”).

Citation

@article{SerranoNotivoli2017SPREAD,
  author = {Serrano‐Notivoli, Roberto and Beguerı́a, Santiago and Saz, Miguel Ángel and Aladrén, Luis Alberto Longares and Luis, Martín de},
  title = {SPREAD: a high-resolution daily gridded precipitation dataset for Spain – an extreme events frequency and intensity overview},
  journal = {Earth system science data},
  year = {2017},
  doi = {10.5194/essd-9-721-2017},
  url = {https://doi.org/10.5194/essd-9-721-2017}
}