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Increasing Duration of Long Dry Periods in CMIP6 21st Century SSP5-8.5 Projections

Presentation Date
Wednesday, December 14, 2022 at 3:19pm - Wednesday, December 14, 2022 at 3:27pm
Location
McCormick Place - E253cd
Authors

Author

Abstract

Changes in the characteristics of precipitation have significant impacts on the frequency and duration of drought conditions. Globally, it is expected that the number of days without rainfall will increase with warming, in association with a smaller increase in average precipitation than the intensity of extreme rainfall events. In this study, these changes are assessed in the high emissions scenario projections for the 21st century (Shared Socioeconomic Pathway SSP5-8.5) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). A robust statistical approach is applied to assess changes across the full range of dry period duration. The CMIP6 multi-model mean reproduces the distribution of consecutive dry day duration reasonably well compared to gridded observations (GPCP 1DD and IMERG) on global scales, with some underestimation of moderate duration events (~10 to 30 days). Projections show a consistent decrease in the frequency of short events (< 10 days) and increase in longer events (> 10 days) across models, with greater than 10% increase in the frequency of very long events (100+ days). Regionally, these changes can be even larger, particular in historically dry regions. These findings indicate which regions may experience the largest and most consistent changes, with implications for future drought conditions.

Funding Program Area(s)