Joint Seminar: Increasing frequency, intensity, and areal extent of extreme precipitation events in Europe since 1950

Different spatial extents of heavy precipitation events can lead to either flash
flood or river flood that generally cause either greater loss of life or loss of property,
respectively. In the past, there are plenty of studies on physical mechanisms
leading to rainfall extremes and how climate change affect these events. Due to
more moisture available in a warmer climate, it is often assumed that the extreme
precipitation should increase in a similar manner if strong dynamical forcing
associated rainfall extremes remained the same. However, if the circulations and
dominant weather systems producing heavy rainfall changed in the warming
climate, there might be additional changing characteristics of extreme precipitation
events that required further studies. Using a long-term European high resolution
gridded precipitation observation based on gauged network data from 1950, we
investigate how the frequency, intensity, duration, areal extent, and the total
accumulated rainfall volume associated with the most intensive daily precipitation
events changes through time. We first identify all the heavy precipitation incidents
with an event tracking algorithm. Different thresholds are used to define the heavy
rainfall events and test the sensitivity of the result to the extreme event definition
and thresholds. After archiving all the extreme rainfall events, it is possible to make
ranking for all the historical events by total rainfall volume. From the event archive,
We also find that both the frequency and total volume of extreme rainfall events are
increase significantly in Europe since 1950. The main contribution to the volume
increase is from the larger spatial extent in more recent decades. We will discuss
the implication to the potential change in flash and river flood events as a function
of the warming. With the informations on the spatial and temporal evolution of
extreme events, We can further study the associated weather system and
environmental conditions that fueled the precipitation extremes.




15:15–14:15 h


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


Cheng-Ta Chen, National Taiwan Normal University


Leonard Borchert

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