Abstract
Compound weather and climate events are combinations of climate drivers
and/or hazards that contribute to societal or environmental risk.
Studying compound events often requires a multidisciplinary approach
combining domain knowledge of the underlying processes with, for
example, statistical methods and climate model outputs. Recently, to aid
the development of research on compound events, four compound event
types were introduced, namely (1) preconditioned, (2) multivariate, (3)
temporally compounding, and (4) spatially compounding events. However,
guidelines on how to study these types of events are still lacking.
Here, based on a bottom-up approach, we consider four case studies, each
associated with a specific event type and a research question, to
illustrate how the key elements of compound events (e.g., analytical
tools and relevant physical effects) can be identified. These case
studies show that (1) impacts on crops from hot and dry summers can be
exacerbated by preconditioning effects of dry and bright springs. (2)
Assessing compound coastal flooding in Perth (Australia) requires
considering the dynamics of a non-stationary multivariate process. For
instance, future mean sea-level rise will lead to the emergence of
concurrent coastal and fluvial extremes, enhancing compound flooding
risk. (3) In Portugal, deep-landslides are often caused by temporal
clusters of moderate precipitation events. Finally, (4) crop yield
failures in France and Germany are strongly correlated, threatening
European food security through spatially compounding effects. These
analyses allow for identifying general recommendations for studying
compound events. Overall, our insights can serve as a blueprint for
compound event analysis across disciplines and sectors.