Increasing Frequency of Flood Events across the Central United States: A Hierarchy of Whys
The frequency of flood events has been increasing across large areas of the central United States since the second half of the 20th century. Little is known about what is driving these changes, and the fundamental question we ask ourselves is: why? Using an observation-driven approach, we develop a statistical framework to attribute the changes in the frequency of flood peak events to changes in the climate system and to land use / land cover. We focus on 287 U.S. Geological Survey sites with at least 50 years of daily discharge measurements between the second half of the 20th century and the present. Our analyses are performed at the seasonal level and consider five predictors (i.e., precipitation, temperature, antecedent wetness conditions, agriculture, and population density). Results indicate that precipitation and antecedent wetness conditions are the strongest predictors, with the role of the latter that increases as we lower the threshold for the event identification. Furthermore, we highlight the role of weather types in explaining the observed changes in precipitation and, consequently, in the frequency of flood events.
The aim of this presentation is to provide insights into the possible reasons responsible for the changes in the frequency of flood events across the central United States, providing basic information that may enhance our capability of predicting and projecting these changes.
Date:
7 February 2020, 11:00 (Friday, 3rd week, Hilary 2020)
Venue:
Dyson Perrins Building, off South Parks Road OX1 3QY
Venue Details:
Herbertson Room
Speaker:
Dr Gabriele Villarini (Director, IIHR – Hydroscience & Engineering)
Organising department:
School of Geography and the Environment
Organiser:
Marcus Buechel (NERC DTP Student, University of Oxford)
Organiser contact email address:
marcus.buechel@chch.ox.ac.uk
Part of:
Oxford Hydrology Group
Topics:
Booking required?:
Not required
Audience:
Members of the University only
Editor:
Marcus Buechel
