Alvarenga et al. (2025) Meteorological Droughts in the Paraopeba River Basin: Current Scenarios and Future Projections

Identification

• Journal: Land
• Year: 2025
• Date: 2025-10-21
• Authors: Claudiana Mesquita de Alvarenga, Lívia Alves Alvarenga, Pâmela Aparecida Melo, Javier Tomasella, Pâmela Rafanele França Pinto, Carlos Rogério de Mello
• DOI: 10.3390/land14102093

Research Groups

• Departamento de Recursos Hídricos, Universidade Federal de Lavras, Lavras 37203-202, Brazil
• Centro Nacional de Monitoramento e Alertas de Desastres Naturais (CEMADEN), São José dos Campos 12247-016, Brazil
• Centro de Ciência do Sistema Terrestre, Instituto Nacional de Pesquisas Espaciais (INPE), Cachoeira Paulista 12630-970, Brazil

Short Summary

This study evaluated the performance of CMIP6 climate models in projecting meteorological droughts in the Paraopeba River Basin using SPI and SPEI indices. The findings indicate a significant intensification of droughts throughout the 21st century, particularly under the pessimistic SSP585 scenario, highlighting the critical role of rising temperatures in exacerbating water deficits.

Objective

• To assess meteorological drought projections in the Paraopeba River Basin by evaluating the performance of CMIP6 models for current scenarios and then applying the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) for current and future (2040-2100) climate conditions under SSP245 and SSP585 emission scenarios at six- and twelve-month timescales.

Study Configuration

• Spatial Scale: Paraopeba River Basin, Minas Gerais state, Brazil, covering an area of 12,500 square kilometers.
• Temporal Scale:
  • Current Climate (Control Period): 1950 to 2014 (specifically 1992 to 2014 for model validation).
  • Future Projections: 2015 to 2100, subdivided into 2040–2060 (near future), 2061–2080 (mid-future), and 2081–2100 (end of the century).

Methodology and Data

• Models used:
  • Global Climate Models (GCMs): NASA-Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6) ensemble, specifically ACCESS-ESM1-5, TaiESM1, CMCC-ESM2, MPI-ESM1-2-LR-1, NorESM2-MM, MRI-ESM2, and CanESM5.
  • Drought Indices: Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI), calculated at six- and twelve-month timescales.
  • Emission Scenarios: Shared Socioeconomic Pathways (SSPs) SSP245 (intermediate) and SSP585 (pessimistic).
• Data sources:
  • Observed Precipitation Data: Brazilian Daily Weather Gridded Data (BR-DWGD).
  • Climate Model Outputs: Precipitation and temperature data from NEX-GDDP-CMIP6.

Main Results

• Seven selected CMIP6 models (ACCESS-ESM1-5, TaiESM1, CMCC-ESM2, MPI-ESM1-2-LR-1, NorESM2-MM, MRI-ESM2, and CanESM5) adequately represent current precipitation and drought patterns in the Paraopeba River Basin, showing a strong correlation (0.99) with observed data.
• Future projections indicate a significant intensification of droughts throughout the 21st century, with greater severity under the SSP585 scenario.
• By the end of the century (2081–2100), severe droughts are projected to increase:
  • SPI (six-month): 12.24% (SSP245) and 8.59% (SSP585).
  • SPEI (six-month): 22.8% (SSP245) and 17.97% (SSP585).
  • SPI (twelve-month): 17.14% (SSP245) and 17.12% (SSP585).
  • SPEI (twelve-month): 19.25% (SSP245) and 19.21% (SSP585).
• The SPEI, which accounts for increased evapotranspiration due to rising temperatures, consistently shows a stronger trend towards drier conditions and a greater magnitude of droughts compared to the SPI, especially under the SSP585 scenario and on the twelve-month timescale.
• The end-of-century projections (2081–2100) for SPEI-12 indicate persistent and prolonged water deficits, reflecting reduced interannual variability and a higher prevalence of dry conditions under the higher emission scenario.

Contributions

This study provides crucial insights into future meteorological drought conditions in the Paraopeba River Basin, a strategic region for water supply and hydroelectric generation in Brazil. By validating CMIP6 models and employing both SPI and SPEI, it offers a more comprehensive assessment of drought intensification under climate change, particularly highlighting the impact of rising temperatures on water deficits. The findings are valuable for informing public policies aimed at mitigation and adaptation strategies, strengthening the resilience of water systems, and ensuring the sustainable management of natural resources in the face of increasing extreme events.

Funding

• Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) [Grant number APQ-00709-21]
• Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [Grant number 305295/2021-7]
• Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [Grant number 305711/2024-5]

Citation

@article{Alvarenga2025Meteorological,
  author = {Alvarenga, Claudiana Mesquita de and Alvarenga, Lívia Alves and Melo, Pâmela Aparecida and Tomasella, Javier and Pinto, Pâmela Rafanele França and Mello, Carlos Rogério de},
  title = {Meteorological Droughts in the Paraopeba River Basin: Current Scenarios and Future Projections},
  journal = {Land},
  year = {2025},
  doi = {10.3390/land14102093},
  url = {https://doi.org/10.3390/land14102093}
}