Barella-Ortiz et al. (2019) Evaluation of drought representation and propagation in regional climate model simulations across Spain

Identification

• Journal: Hydrology and earth system sciences
• Year: 2019
• Authors: Anaïs Barella-Ortiz, Pere Quintana Seguí
• DOI: 10.5194/hess-23-5111-2019

Research Groups

• Observatori de l'Ebre, Universitat Ramon Llull – CSIC, Roquetes, Spain
• Centre National de Recherche Météorologique (CNRM) (Developer of CNRM-RCSM4/ISBA)
• Goethe Universität Frankfurt (GUF) (Developer of COSMO-CLM)
• Universidad Complutense de Madrid (UCM) and Universidad de Castilla-La Mancha (UCLM) (Developers of PROMES)
• Spanish Centre for Studies and Experimentation on Public Works (CEDEX) (Developer of SIMPA)

Short Summary

This study evaluates the representation and propagation of meteorological, soil moisture, and hydrological droughts in three Regional Climate Models (RCMs) across Spain using standardized indices. RCMs successfully simulate meteorological drought but exhibit significant uncertainties in non-meteorological drought types and propagation dynamics, primarily due to differences in Land Surface Model (LSM) structure.

Objective

• To analyze how Regional Climate Models (RCMs) characterize meteorological, soil moisture, and hydrological drought across Spain.
• To analyze how RCMs represent the propagation from precipitation anomalies to soil moisture and streamflow anomalies.

Study Configuration

• Spatial Scale: Mainland Spain (Iberian Peninsula). Analysis focused on large river basins (area greater than 10,000 square kilometers).
• Temporal Scale: 1989 to 2008 (Meteorological and Soil Moisture drought analysis); 1989 to 2005 (Hydrological drought analysis). Analysis performed using monthly data.

Methodology and Data

• Models used: CNRM-RCSM4 (RS4, uses ISBA-3L), COSMO-CLM (CL4), PROMES (PMS, uses ORCHIDEE), ISBA-3L (ISB, offline), ORCHIDEE (ORC, offline), SIMPA (SMP, hydrological model).
• Data sources: Med-CORDEX database (RCM simulations), ERA-Interim (atmospheric forcing), SAFRAN (SLR, meteorological reference), Observed streamflow (OBS), AEMET network (observations).
• Indices: Standardized Precipitation Index (SPI), Standardized Soil Moisture Index (SSMI), Standardized Runoff Index (SRI), Standardized Streamflow Index (SSI).
• Techniques: Nonparametric standardization methodology for indices; Drought propagation analysis by maximizing Pearson correlation between SPI-n (accumulated precipitation) and SSMI/SRI/SSI-1 (1-month scale); Kling–Gupta efficiency (KGE) used for streamflow validation.

Main Results

• RCMs provide a good representation of meteorological drought, successfully reproducing the timing of major drought spells and improving spatial drought structures over certain regions (e.g., Ebro Basin) compared to the ERA-Interim driving data.
• Significant uncertainties are identified in soil moisture and hydrological drought representation; the Root-Mean-Square Difference (RMSD) of standardized indices often exceeds 0.5 compared to reference data, suggesting a change in drought category.
• Model structure (Land Surface Model physics) is the dominant factor determining drought propagation dynamics, prevailing over the driving atmospheric data.
• For meteorological-to-soil moisture drought propagation, RS4 (coupled to ISBA) shows a very fast response time (1 to 4 months), while CL4 shows slower dynamics (up to 20 months).
• For meteorological-to-hydrological drought propagation, RS4 and PMS show quick responses (1 to 3 months) in the Ebro Basin, while CL4 is in better agreement with reference data (SMP/OBS) over the Duero Basin, showing larger scales (9 to 13 months).

Contributions

• Provided a comprehensive evaluation of RCM performance across meteorological, soil moisture, and hydrological drought types in Spain using standardized indices.
• Quantified the added value of RCMs in meteorological drought representation by demonstrating their capacity to filter out spurious trends present in the global driving data (ERA-Interim).
• Assessed drought propagation dynamics within RCMs, revealing that the choice of Land Surface Model (LSM) structure critically influences the temporal scale at which precipitation anomalies propagate to soil moisture and streamflow.

Funding

• Ministerio de Ciencia, Innovación y Universidades (grant nos. CGL2013-47261-R and CGL2017-85687-R).
• European Regional Development Fund (grant no. EFA210/16/PIRAGUA) in the framework of the INTERREG V-A España-Francia-Andorra programme (HyMeX program contribution).

Citation

@article{BarellaOrtiz2019Evaluation,
  author = {Barella-Ortiz, Anaïs and Quintana‐Seguí, Pere},
  title = {Evaluation of drought representation and propagation in regional climate model simulations across Spain},
  journal = {Hydrology and earth system sciences},
  year = {2019},
  doi = {10.5194/hess-23-5111-2019},
  url = {https://doi.org/10.5194/hess-23-5111-2019}
}

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