Event Details

Event: Global Change Seminar
Date: 13:00, Wed 28 Jun, 2017
Speaker: Dr Markus Donat
Title: Understanding inter-annual variability and long-term changes in temperature and precipitation extremes
Venue: Crew Annexe, Teaching Lab 4
Host: Tim Cowan
Abstract: Given the potentially strong impacts of climate extremes on society, economy and environment, it is important to understand inter-annual variability and long-term changes in extremes to enable preparedness. High-quality observations of climate extremes are essential to study past changes and variability, to evaluate climate models, and to combine observations and models with the aim to understand processes and mechanisms that drive extremes. In the first part of my presentation I will talk about our recent efforts to develop global gridded datasets of observed climate extremes. These datasets have been enabling for a number of studies, as well as the assessment of past changes in temperature and precipitation extremes in the IPCC Fifth Assessment Report. In the second part, I will present examples of applying of these observational datasets in combination with climate model simulations to study variability and long-term changes in extremes. This includes a study of precipitation changes in the world’s dry and wet regions showing that, when aggregating over regions defined by their rainfall characteristics, models and observations show robust increases in precipitation totals and extremes in the dry regions and also intensification of extremes in the wet regions. Another example application investigates the environmental conditions on the exact date of extreme heat events globally. This study highlights the role of surface energy fluxes in amplifying heat extremes. In particular, I show that the global patterns of amplified warming of hot extremes relative to mean temperature warming can be explained by a repartitioning of surface energy fluxes, consistent with drying soils, on the days when the hot extremes occur.