Spatial and Temporal Changes in Compound Extremes in a Tropical Region: Links to Climate Variability and Change.

Compound hydroclimatic extremes, characterized by the simultaneous or sequential occurrence of multiple essential climate variables (ECVs), have significant implications for both water resources management and human health. Climate change is increasingly linked to a rise in the frequency and intensity of extreme temperature and precipitation events worldwide. As such, understanding the interplay between these variables is critical for improving forecasting and formulating effective adaptation strategies. This study investigates the joint occurrences of temperature and precipitation at 78 stations and of temperature and relative humidity extremes at 31 sites, assessing the spatial and temporal variability of these extreme events in Florida’s tropical and subtropical low-lying regions. Influences of climate variability attributed to the El Niño Southern Oscillation (ENSO) on compound extremes are also evaluated using temporal windows that coincide with its two main phases (i.e., warm and cool).  Preliminary findings indicate an increase in mean joint occurrences across several sites, suggesting an emerging trend that warrants further investigation. Nonparametric statistical tests confirm significant changes across two distinct temporal windows. The analysis reveals non-uniform patterns in compound extremes, influenced by both climate change and regional factors, such as the presence of large water bodies and wetlands. Notably, increases in the Heat Index (HI) highlight the growing risks to human health and the rising energy demand in the region. These findings underscore the need for further research to fully understand the spatial and temporal dynamics of compound extremes amid ongoing climate change.