Changes in compound drought-heat events over Brazil’s Pantanal wetland: an assessment using remote sensing data and multiple drought indicators

• Published in: Climate dynamics 2024, Vol.62 (1), p.739-757
• Main Authors: Cunha, Ana Paula M. A., Buermann, Wolfgang, Marengo, José A.
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Climate change; Climatology; Disaster management; Disaster risk; Drought; Dry season; Earth and Environmental Science; Earth Sciences; Emergency preparedness; Environmental assessment; Environmental protection; Environmental risk; Evapotranspiration; Evapotranspiration-precipitation relationships; Geophysics/Geodesy; Global warming; Heat; Monthly precipitation; Oceanography; Precipitation; Probability density function; Probability density functions; Probability theory; Remote sensing; Risk management; Risk reduction; Standardized precipitation index; Temperature data; Temperature index; Vegetation; Wetlands
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-023-06937-x

Brazil’s Pantanal wetland is one of the most threatened Brazilian ecosystems from direct anthropogenic pressures and climate change. In this study, the overarching research question is to explore whether compound drought-heat events (CDHEs) have become more recurrent, intense, and widespread over Brazil’s Pantanal wetland in recent decades. For this, we purpose and tested two different approaches using validated long-term time series of monthly precipitation, temperature, and the satellite-based Vegetation Health Index (VHI) to characterize the spatiotemporal pattern of CDHEs over Pantanal. Firstly, we assessed global gridded precipitation and temperature data sets against ground measurements to choose an appropriate dataset for this study. Then, we calculated the Standardized Precipitation Index (SPI), Standardized Temperature Index (STI), and Standardized Precipitation Evapotranspiration Index (SPEI) from 1981 to 2021. The results showed that using both approaches (CDHE-M1 and CDHE-M2), the frequency of events is higher considering the moderate category, which is expected since the criteria are less restrictive. In addition, the highest frequency of CDHE events occurs between September and November (the end of the dry season). The results also indicated that CDHE events have been more recurrent and widespread since 2000 in Pantanal. Besides, considering all methods for identifying the CDHEs, the probability density function indicates a shift pattern to warmer and drier conditions in the last 40 years. The Mann–Kendall tests also confirmed the assumption that there is a significantly increasing trend in the compound drought-heat events in the Pantanal. Developing methodologies for monitoring compound climate events is crucial for assessing climate risks in a warming climate. Besides, it is expected that our results contribute to the convincing of the urgent need for environmental protection strategies and disaster risk reduction plans for the Pantanal.