Successive warm-wet and warm-dry events in the Great Lakes Basin : future projections using CMIP6 models

Abstract

Successive warm/wet – warm/dry (SWWWD) events and successive warm/dry – warm/wet (SWDWW) events can substantially impact water availability, vegetational growth and agricultural productivity, undermine the performance of infrastructure and exacerbate natural hazards, including wildfires and flooding. In this study, we characterize and assess the projected changes in concurrent warm-dry, concurrent warm-wet, SWWWD and SWDWW events based on 1-, 1.5-, 2-, 3-, and 4- degree global warming above the pre-industrial level. This analysis is conducted using an ensemble of eight GCMs participating in the Coupled Model Intercomparison Phase (CMIP6) over the Great Lakes basin, with five variables of interest (maximum and minimum temperature, precipitation, U – and V – components of the wind) bias-corrected using the Multivariate Bias Correction algorithm (MBCn). The monthly varying 80th percentile of temperature and precipitation is used to identify warm and wet events, respectively, while the monthly varying 20th percentile of precipitation is used to calculate the dry events. The results show that as the warming level increases, the frequency of concurrent warm-wet and warm-dry events rises, with a projected prevalence of more concurrent warm-wet events in the GL basin compared to concurrent warm-dry events. Furthermore, our analysis indicates that with an increase in the warming level, the frequency of SWWWD and SWDWW events is projected to rise, with the five major lake shorelines and surrounding areas identified as hotspots for these successive events. Overall, this study underscores the projected increases and potential impact of SWWWD and SWDWW events on the Great Lakes (GL) basin and provides valuable information for future planning and adaptation strategies.