Local constraints reduce uncertainty in the projection of precipitation extremes from climate models

Date
Speaker
Francesco Marra

link webminar: https://global.gotomeeting.com/join/522822653

Abstract Understanding extreme precipitation under changing climatic conditions is crucial to manage weather- and flood-related hazards. However, the climate models commonly used to guide such assessments cannot resolve key processes related to extreme precipitation, and do not provide information at the scales relevant for practical applications. This limitation is critical when quantitative information on low yearly exceedance probabilities, such as the 100-year events, is required. Here it is shown that the interaction of precipitation systems with local features provides constraints on the statistical description of precipitation events that can then be used to narrow the uncertainty in future projections of extremes. Specifically, these local constraints facilitate projections for extreme events of low yearly exceedance probability based only on synoptic-scale information from climate models. We use historical data from >450 stations in Israel and Jordan to provide a climatology of extreme daily precipitation in the region and, using our approach, we are able to provide quantitative information on future extremes starting from literature studies based on climate model projections. Under our working hypotheses, we project a general decrease in extreme precipitation in the region, and an increase of the most severe events in the coastal area and in the southern deserts. The local constraints approach offers a path for improving the predictability of extreme events in a changing climate, despite the uncertainty associated with unresolved processes in climate models and with natural variability. 

Short bio go the Author: Dr Marra got his Msc in Physics from the University of Bologna and PhD in radar hydrology from the University of Padova. He is currently Research Associate at the Hebrew University of Jerusalem and will soon start his new Researcher position at the Institute of Atmospheric Sciences and Climate, National Research Council of Italy. His scientific research interests span different fields including atmospheric sciences (spatiotemporal precipitation patterns), remote sensing (weather radar and satellite based precipitation estimation), hydro-climatic extremes (extreme precipitation, frequency analyses from remote sensing data), hydrology (forecasting/monitoring of flash floods), geomorphology (landslide and debris flow triggering, flash floods geomorphic impact), and weather-related hazards in general. He loves climbing mountains.

Venue
Bologna (webinar)