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FloodAlp! Frequency and intensity of extreme floods in the Alps through the Holocene and implications for natural hazards in future climate scenarios

English title FloodAlp! Frequency and intensity of extreme floods in the Alps through the Holocene and implications for natural hazards in future climate scenarios
Applicant Anselmetti Flavio S.
Number 137930
Funding scheme Project funding (Div. I-III)
Research institution Institut für Geologie Universität Bern
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Geology
Start/End 01.12.2011 - 31.01.2013
Approved amount 126'922.00
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All Disciplines (2)

Discipline
Geology
Climatology. Atmospherical Chemistry, Aeronomy

Lay Summary (German)

Lead
Lay summary

Ziele des Forschungsprojekts:

Das FloodAlp! Projekt hat zum Ziel, die Häufigkeit und Intensität der Starkniederschläge im Alpenraum für die letzten ca. 10'000 Jahre zu rekonstruieren. Dabei soll gezeigt werden, ob es im Rahmen der vergangenen natürlichen Klimaschwankungen Perioden gab, während derer mehr oder weniger Flutereignisse auftraten. Im Weiteren wird untersucht, ob solche Ereignisse bevorzugt nördlich oder südlich der Alpen stattfanden, und ob während dieser Perioden bestimmte Wettersituationen und atmosphärische Zirkulationsmuster auftraten.

 

Kontext und Bedeutung des Projekts:

Angesichts der momentan stattfindenden Klimaveränderungen werden auch Prognosen gemacht, wie sich die Niederschlagsmuster je nach zukünftigen Szenarien verändern werden. Dabei ist einerseits die Entwicklung des Gesamtniederschlags wichtig, andererseits sind aber auch die Häufigkeit und Intensität der Extremereignisse von entscheidender Bedeutung, da diese grosse Naturgefahren darstellen (z. Bsp. Ereignisse August 2005). Um abschätzen zu können, ob sich die Häufigkeit und Intensität dieser Ereignisse verändern, soll zum ersten Mal die natürliche Variabilität dieser Flutereignisse im Alpenraum während der letzten ca. 10'000 Jahre rekonstruiert werden. Die Ergebnisse werden dann in den Zusammenhang der aktuellen, durch den Mensch beeinflussten Klimaveränderungen gestellt. Die erkannten Muster werden mit denen der zukünftigen Szenarien verglichen, die mittels verschiedener Klimamodelle erstellt wurden. Damit lässt sich evaluieren, ob diese Klimamodelle einmalige Abfolgen von Extremereignisse voraussagen, oder ob diese Muster auch mittels natürlicher Klimaschwankungen schon auftraten.

 

Wissenschaftlicher Rahmen und  Methodologie:

Um diese Ziele zu erreichen, werden die Schlammablagerungen zahlreicher Seen nördlich und südlich der Alpen untersucht. Jedes Starkniederschlagsereignis hinterlässt am Boden der Seen eine charakteristische Flutlage. Mittels geophysikalischer und geologischer Methoden wird die Schlammfüllung dieser Seebecken untersucht und beprobt, so dass die Abfolge dieser Flutlagen wie ein Geschichtsbuch gelesen werden kann. Diese einzelne Flutlagen können durch die Radiokarbon Altersbestimmung datiert werden, so dass für jeden See eine Chronologie der Flutereignisse aufgestellt werden kann. Ein Vergleich der Seen in den verschiedenen alpinen Zonen erlaubt somit eine regionale Analyse dieser Ereignisse, so das verschiedene Perioden mit unterschiedlichen Starkniederschlagsmustern ausgeschieden werden. Diese können wiederum in regionale Kilmamodelle integriert werden, so dass Rückschlüsse über die damaligen atmosphärischen Zirkulationsmuster gemacht werden können.

 

 


Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Frequency and intensity of palaeofloods at the interface of Atlantic and Mediterranean climate domains
Wilhelm B., Vogel H., Crouzet C., Etienne D., Anselmetti F. S. (2016), Frequency and intensity of palaeofloods at the interface of Atlantic and Mediterranean climate domains, in Climate of the Past, 12(2), 299-316.
Alpine lacustrine varved record reveals summer temperature as main control of glacier fluctuations over the past 2250 years
Glur L., Stalder N. F., Wirth S. B., Gilli A., Anselmetti F. S. (2014), Alpine lacustrine varved record reveals summer temperature as main control of glacier fluctuations over the past 2250 years, in The Holocene, 25(2), 280-287.
A 2000 year long seasonal record of floods in the southern European AlpsFLOOD SEASONALITY IN THE SOUTHERN ALPS
Wirth Stefanie B., Gilli Adrian, Simonneau Anaëlle, Ariztegui Daniel, Vannière Boris, Glur Lukas, Chapron Emmanuel, Magny Michel, Anselmetti Flavio S. (2013), A 2000 year long seasonal record of floods in the southern European AlpsFLOOD SEASONALITY IN THE SOUTHERN ALPS, in Geophysical Research Letters, 40(15), 4025-4029.
Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy)
Joannin S., Vannière B., Galop D., Peyron O., Haas J. N., Gilli A., Chapron E., Wirth S. B., Anselmetti F., Desmet M., Magny M. (2013), Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy), in Climate of the Past, 9(2), 913-933.
Combining sedimentological, trace metal (Mn, Mo) and molecular evidence for reconstructing past water-column redox conditions: The example of meromictic Lake Cadagno (Swiss Alps)
Wirth Stefanie B., Gilli Adrian, Niemann Helge, Dahl Tais W., Ravasi Damiana, Sax Nadja, Hamann Yvonne, Peduzzi Raffaele, Peduzzi Sandro, Tonolla Mauro, Lehmann Moritz F., Anselmetti Flavio S. (2013), Combining sedimentological, trace metal (Mn, Mo) and molecular evidence for reconstructing past water-column redox conditions: The example of meromictic Lake Cadagno (Swiss Alps), in Geochimica et Cosmochimica Acta, 120, 220-238.
Frequent floods in the European Alps coincide with cooler periods of the past 2500 years
Glur Lukas, Wirth Stefanie B., Büntgen Ulf, Gilli Adrian, Haug Gerald H., Schär Christoph, Beer Jürg, Anselmetti Flavio S. (2013), Frequent floods in the European Alps coincide with cooler periods of the past 2500 years, in Scientific Reports, 3, 1-5.
Holocene flood frequency across the Central Alps – solar forcing and evidence for variations in North Atlantic atmospheric circulation
Wirth Stefanie B., Glur Lukas, Gilli Adrian, Anselmetti Flavio S. (2013), Holocene flood frequency across the Central Alps – solar forcing and evidence for variations in North Atlantic atmospheric circulation, in Quaternary Science Reviews, 80, 112-128.
Lake sediments as archives of recur- rence rates and intensities of past flood events
Gilli A. Anselmetti F.S. Glur L. Wirth S. (2013), Lake sediments as archives of recur- rence rates and intensities of past flood events, in Springer Series Advances in Global Change Research, 225-242.
Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards
Simonneau A., Chapron E., Vannière B., Wirth S. B., Gilli A., Di Giovanni C., Anselmetti F. S., Desmet M., Magny M. (2013), Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards, in Climate of the Past, 9(2), 825-840.
Orbital changes, variation in solar activity and increased anthropogenic activities: controls on the Holocene flood frequency in the Lake Ledro area, Northern Italy
Vannière B., Magny M., Joannin S., Simonneau A., Wirth S. B., Hamann Y., Chapron E., Gilli A., Desmet M., Anselmetti F. S. (2013), Orbital changes, variation in solar activity and increased anthropogenic activities: controls on the Holocene flood frequency in the Lake Ledro area, Northern Italy, in Climate of the Past, 9(3), 1193-1209.
Bacterial GDGTs in Holocene sediments and catchment soils of a high Alpine lake: application of the MBT/CBT- paleothermometer
Niemann H. Stadnitskaia A. Wirth S.B. Gilli A. Anselmetti F.S. Sinninghe Damsté J.S. Schouten (2012), Bacterial GDGTs in Holocene sediments and catchment soils of a high Alpine lake: application of the MBT/CBT- paleothermometer, in Climate of the Past, 8, 889-906.
Development of a real-time PCR method for the detection of fossil 16S rDNA fragments of phototrophic sulfur bacteria in the sediments of Lake Cadagno
Ravasi D.F. Peduzzi S. Guidi V. Peduzzi R. Wirth S.B. Gilli A. & Tonolla M. (2012), Development of a real-time PCR method for the detection of fossil 16S rDNA fragments of phototrophic sulfur bacteria in the sediments of Lake Cadagno, in Geobiology, 10, 196-204.
Multidisciplinary distinction of mass-movement and flood-induced deposits in lacustrine environments: implications for Holocene palaeohydrology and natural hazards (Lake Ledro, Southern Alps, Italy)
Simonneau A. Chapron E. Vannière B. Wirth S.B. Gilli A. Di Giovanni C. Anselmetti F.S. Desmet (2012), Multidisciplinary distinction of mass-movement and flood-induced deposits in lacustrine environments: implications for Holocene palaeohydrology and natural hazards (Lake Ledro, Southern Alps, Italy), in Climate of the Past Discussions, 3205-3249.

Collaboration

Group / person Country
Types of collaboration
Univ. of Bern: Prof. Dr. Willy Tinner Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Univ. of Orleans: Dr. Emmanuel Chapron France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Univ. of Besancon: Prof. Michael Magny France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
University of Geneva: Dr. Stephanie Girardclos and Dr. Daniel Ariztegui Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
ETH Zürich: Prof. Christoph Schär, Institute for Atmospheric and Climate Science Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Communication with the public

Communication Title Media Place Year
Media relations: radio, television 10vor10 SRF 10vor10SRF German-speaking Switzerland 2013

Awards

Title Year
CHGEOL - Swiss Association of Geologists Award of the Swiss Association of Geologists (CHGEOL) for the best dissertation with high relevance for the applied geology sector. 2014

Associated projects

Number Title Start Funding scheme
146889 Quantifying human impact and recent climate change using clastic sediments from lacustrine records in Western Switzerland (Phase 2) 01.06.2013 Project funding (Div. I-III)
121909 FloodAlp! Frequency and intensity of extreme floods in the Alps through the Holocene and implications for natural hazards in future climate scenarios 01.12.2008 Project funding (Div. I-III)
144960 XRF Core Scanner and digital radiography 01.01.2013 R'EQUIP

Abstract

Summary of the research planFloods caused by extreme precipitation events represent one of the major natural hazards in the Alpine realm with several billions Swiss Francs of damage only in the last decade. New climate models point to the possibility that flood frequency and intensities increase as a result of the upcoming climate changes. To scale these predicted changes of extremes, knowledge of the natural variety is required, which is, however, currently limited to only the historic period. This relatively short time interval may not represent the full range of values. No systematic record of Holocene Alpine flood activities exists to date. The FloodAlp project aims to reconstruct the frequency and intensities of Holocene flood events in the Alps by using lake sediments as natural geologic archives acting as prehistoric recorders of extreme events. On the basis of the results acquired in over two years of the three-year SNF project, this proposal seeks funds for an additional fourth year to complete and expand the promising scientific achievements within the dissertations of PhD students Lukas Glur and Stefanie Wirth.The FloodAlp project started on 1.12.2008 with the employment of PhD student Stefanie Wirth (working place Geological Inst., ETHZ). The second PhD position was filled on 1.2.2009 with the hiring of Lukas Glur (working place Eawag, Dübendorf). Both PhD students focused in the first two years on their respective field areas N and S of the Alps. In this period, we investigated ~15 lakes in a north-south transect across the Alps, that cover also a range in altitude. These lake basins record extreme precipitation events with characteristic sediment layers, which contrast sharply to the regular background sediments. The large numbers of lakes is required to provide a meaningful statistical base of flood events, so that regional patterns can be recognized and local outlayers can be avoided. Applying sophisticated depth-to-age model for each lake, events will be dated and grouped in temporal intervals such as 100-year bins, so that all records can be compared on the same temporal scale. The north-south transect provides information on the regional pattern reflecting synchronous or asynchronous behavior north and south of the Alps. Such differences would represent contrasting circulation patterns that control distribution of moisture and precipitation. Differing patterns between high and low-altitude lakes may provide information on seasonal flood distribution, because high-altitude lakes are frozen half of the year and can record flood events only during summer.The requested fourth year of SNF support will allow the expansion of the already acquired lake records with five more lakes to provide a statistically more sound base of a central Alpine flood-event catalogue. The final flood chronologies will be evaluated in the context of climate significance, but they also will be compared to vegetation change and human impact caused by various forms of land use (in cooperation with Univ. Bern, Univ. Basel and Univ. Besancon). The observed climate pattern will be discussed with climate scientists from the Institute of Climate and Atmospheric Science at ETHZ. A special emphasis will be given on the periods during the Holocene that were characterized by warmer climate than today. These periods may act as analogs to compare the reconstructed natural extremes with the modeled future scenarios characterized by increased temperatures and an accelerated hydrologic cycle. The fourth year is furthermore needed to have sufficient time to prepare a series of publications as outcome of the two FloodAlp PhD theses.
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