Natural Hazards and Risks in a Changing World
A graduate research school with the University of Potsdam, Potsdam Institute for Climate Impact Research (PIK), Helmholtz Centre Potsdam German Research Centre for Geosciences GFZ.
I1: Natural hazards in a changing climate – What causes the variability? (Thomas Moran, completed)
P3: Spatio-temporal response of extreme precipitation to climate change and decadal climate variability (Madlen Peter (geb. Fischer))
The aim of the project is to develop a statistical model of extreme precipitation to get return levels for different occurrence probabilities which are neccessary for many different stakeholders in risk assessment and the design of hydraulic structures. Therefor, the block-maxima approach of the extreme value theory is used to estimate a spatio-temporal variable Generalized Extreme Value (GEV) distribution. The Phd project is focused on the research area of Germany.
With respect to the conventionally calculated and used annual return levels, the monthly precipitation maxima are considered as well in this project to get additional monthly return levels. This information are of great interest for stakeholders, e.g. in agriculture and tourismn sector. Instead of considering each month separately, the smoothness in time is used by harmonic functions to capture the seasonality in one statistical model. It could be shown, that with this approach uncertainties of the monthly and even of the annual return levels can be reduced (Fischer et al. 2018).
In the statistical model can be included as well a spatial component by using orthogonal polynomials for longitude, latitude and altitude. Interactions between the months and the spatial coordinates makes the model very flexible and allows different seasonal cycles at different locations. With the spatial component the return levels of the statistical model can be improved even more and one can calculate values for un-gauged sites. This seasonal-spatial approach was applied for the smaller subregion of Berlin-Brandenburg and the results are published in Fischer et. al. 2019.
The recent investigations of this PhD project is focused on the transient changes of extreme precipitation. Similar to include the sesonal and the spatial variations, one can also capture the variations triggerd by climate change, either in form of using simply the time as proxy for climate change or an other meteorological parameter such as the global mean temperature.
Publications within this Project:
M. Fischer, H.W. Rust, U. Ulbrich; 2018: Seasonal Cycle in German Daily Precipitation Extremes, MetZet, 27(1): 3-13, https://doi.org/10.1127/metz/2017/0845.
M. Fischer, H.W. Rust, U. Ulbrich; 2019: A spatial and seasonal climatology of extreme precipitation return-levels – A case study, Spatial Statistics, https://doi.org/10.1016/j.spasta.2017.11.007.
I5: Changes in European windstorm characteristics (Christian Passow)
P6: Linking occurrence probabilities to large scale flow (Jana Ulrich)
Spatial modeling for rainfall extremes on different time scales (Oscar Jurado)
Droughts in a changing climate (Yan Li)