North America: Assessing the Use of Regional Models in a Storyline Framework for Understanding Climate Hazards

The logo of CORDEX flagship Pilot Studies

Physical storylines are a physically self-consistent unfolding of past events or of plausible future events and pathways (Shepherd et al. 2018).  They generally consist of both a recreation of a past event or period and an exploration of future analogue events that may arise under different future climate change scenarios. In short, storylines are a way to frame a problem in terms of 1) a geographic region, 2) an event, and 3) a set of process drivers for that event.  Extreme events and/or climate hazards, particularly those that have had a resounding effect on stakeholder and policymaker decisions, are natural candidates for examination using physical storylines.

We propose to leverage the storyline framework for understanding model performance and future projected changes across multiple extreme weather and climate events or periods of interest to our project stakeholders.

Eight different types of weather/climate extremes that took place over the contiguous U.S. (CONUS) will be examined.  The 2018 California wildfire season, atmospheric river events on the West Coast, the 2015 spring season of repeated mesoscale convective system (MCS) occurrence in the southern U.S. Plains that led to widespread flooding, Hurricane Irma, the 1996 rain-on-snow flooding event in the Susquehanna River basin, strong Northeast U.S. windstorms caused by both extratropical cyclones and derechos, and Northeast U.S. droughts.

These eight different physical storylines will be drawn on as test cases for assessing if regional models can reproduce these rare events at high to very high resolution in a manner that is consistent with observations, allow us to better understand the processes behind the events, and assess how these extreme events may look in the future. Two different methods for producing projections will be applied here, depending on the hazard in question.  A pseudo-global warming approach will be applied in most, but for some, e.g. the atmospheric rivers, future analogs will be identified via the mining of simulation ensembles.  This provides us with an opportunity to examine two different methods for generating event projections.

For this FPS, we will distill the information gained from the use of these storylines into actionable information for the international regional modeling community and potential interested stakeholders.

Contact person:
Stefan Rahimi-Esfarjani

Annual Report 2022 
Annual Report 2023

John Cassano