Journal Article

Spatially Compounding Drought Events in Brazil

Gesualdo, Gabriela C., Mendiondo, Eduardo M., Brunner, Manuela I., Benso, Marcos R.

2024

Overview

Spatially compounding drought events affect multiple locations simultaneously, severely affecting food, water, energy, human health, and infrastructure sectors. Despite the cascading impacts and challenges compound droughts impose on society, we still lack an in‐depth understanding of spatially connected drought occurrences. Given the complexity and costs of droughts in Brazil, identifying regions prone to co‐experiencing droughts is critical for developing effective adaptation measures. Here, we develop a novel framework to assess the spatial co‐occurrence of hydrological drought events, which can be adapted for global applications to evaluate spatially compounding drought. This framework involves extracting drought data from individual catchments and calculating the co‐occurrence of droughts across all catchments. We apply this method to investigate the spatial connectedness of droughts in 511 Brazilian catchments over 39 years (1983–2022). Additionally, we classify catchments based on drought duration, intensity, deficit, number of events, and spatial connectedness to identify regions with similar drought behavior. Our findings reveal significant variability in drought characteristics and connectedness across Brazil, with the Central‐Northeast and Northwest Amazon regions being most affected by multiple and widespread droughts. We identify five distinct regions in Brazil that exhibit common drought behaviors, sharing attributes such as aridity, catchment area, and precipitation seasonality. These regions hold the potential to guide future adaptation plans for managing hydrological compound extremes at both the catchment and regional scales, including the development of risk pool networks. Our results underscore the importance of considering the interactions of spatially compounding hydrological droughts in risk assessments and adaptation strategies. Plain Language Summary Droughts are a serious problem in Brazil and can greatly impact food, water, energy, human health, and infrastructure. However, we do not yet understand where and how droughts occur in multiple locations at the same time. To address this issue, we propose a novel framework to study the relationship between droughts in 511 catchments across Brazil over 39 years. Our results show that drought severity and connectedness vary in different parts of the country, with the Central‐Northeast and Amazon's Northwest being the most affected. We divided the country into five regions with unique drought patterns to help us understand where these connected droughts might happen. This information can guide future plans for managing extreme droughts and risks. Our method can be used in other places too, helping us to understand drought connections globally. Key Points We developed a novel framework by extracting hydrological drought events from catchments and computing their co‐occurrence across all areas Brazil can be divided into five regions that share similar drought characteristics, connectedness, and also catchment features like aridity Understanding drought connectedness can inform risk pooling strategies and enhance resource allocation efficiency

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Adaptation / Aridity / Brazil / Catchment areas / Catchments / compound extremes / Compounding / Drought / drought adaptation measures / Drought characteristics / drought connectedness / Drought patterns / dry environmental conditions / energy / Extreme drought / Food / Foods / human health / Hydrologic drought / hydrological droughts / Hydrology / Information management / Infrastructure / Regional analysis / Regional development / Regional planning / Regions / risk / Risk assessment / Seasonal variations / Seasonality / society / spatial risk / water / Watersheds