@article{vanderMeijTemmeWallingaetal.2017, author = {van der Meij, Marijn W. and Temme, Arnaud J. A. M. and Wallinga, J. and Hierold, W. and Sommer, Michael}, title = {Topography reconstruction of eroding landscapes - A case study from a hummocky ground moraine (CarboZALF-D)}, series = {Geomorphology : an international journal on pure and applied geomorphology}, volume = {295}, journal = {Geomorphology : an international journal on pure and applied geomorphology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2017.08.015}, pages = {758 -- 772}, year = {2017}, abstract = {Erosion processes, aggravated by human activity, have a large impact on the spatial variation of soil and topographic properties. Knowledge of the topography prior to human-induced erosion (paleotopography) in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises. However, developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists. Here, we present a set of paleotopographies for a closed kettle hole catchment in north-east Germany (4 ha), obtained through different reconstruction approaches. Current soil and colluvium thickness, estimated from a dataset of 264 soil descriptions using Ordinary Kriging, were used as input for a mass balance, or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion. The performance of the different approaches was assessed with cross-validation and the count of mispredicted eroded, depositional or stable landscape positions. The paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance. This thickness (1.00 m) is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial CaCO3 content. The performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth. To conclude, we mention several methodological and practical points of attention for future topography reconstruction studies, concerning data quality and availability, spatial configuration of data and other processes affecting topography. (C) 2017 Elsevier B.V. All rights reserved.}, language = {en} } @article{VogelOzturkRiemeretal.2017, author = {Vogel, Kristin and Ozturk, Ugur and Riemer, Adrian and Laudan, Jonas and Sieg, Tobias and Wendi, Dadiyorto and Agarwal, Ankit and Roezer, Viktor and Korup, Oliver and Thieken, Annegret}, title = {Die Sturzflut von Braunsbach am 29. Mai 2016 - Entstehung, Ablauf und Sch{\"a}den eines „Jahrhundertereignisses"}, series = {Hydrologie und Wasserbewirtschaftung}, volume = {61}, journal = {Hydrologie und Wasserbewirtschaftung}, number = {3}, publisher = {Bundesanst. f{\"u}r Gew{\"a}sserkunde}, address = {Koblenz}, issn = {1439-1783}, doi = {10.5675/HyWa_2017,3_2}, pages = {163 -- 175}, year = {2017}, abstract = {Am Abend des 29. Mai 2016 wurde der Ort Braunsbach im Landkreis Schw{\"a}bisch-Hall (Baden-W{\"u}rttemberg) von einer Sturzflut getroffen, bei der mehrere H{\"a}user stark besch{\"a}digt oder zerst{\"o}rt wurden. Die Sturzflut war eine der Unwetterfolgen, die im Fr{\"u}hsommer 2016 vom Tiefdruckgebiet Elvira ausgel{\"o}st wurden. Der vorliegende Bericht ist der zweite Teil einer Doppelver{\"o}ffentlichung, welche die Ergebnisse zur Untersuchung des Sturzflutereignisses im Rahmen des DFG-Graduiertenkollegs "Naturgefahren und Risiken in einer sich ver{\"a}ndernden Welt" (NatRiskChange, GRK 2043/1) der Universit{\"a}t Potsdam pr{\"a}sentiert. W{\"a}hrend Teil 1 die meteorologischen und hydrologischen Ereignisse analysiert, fokussiert Teil 2 auf die geomorphologischen Prozesse und die verursachten Geb{\"a}udesch{\"a}den. Dazu wurden Ursprung und Ausmaß des w{\"a}hrend des Sturzflutereignisses mobilisierten und in den Ort getragenen Materials untersucht. Des Weiteren wurden zu 96 betroffenen Geb{\"a}uden Daten zum Schadensgrad sowie Prozess- und Geb{\"a}udecharakteristika aufgenommen und ausgewertet. Die Untersuchungen zeigen, dass bei der Betrachtung von Hochwassergef{\"a}hrdung die Ber{\"u}cksichtigung von Sturzfluten und ihrer speziellen Charakteristika, wie hoher Feststofftransport und sprunghaftes Verhalten insbesondere in bebautem Gel{\"a}nde, wesentlich ist, um effektive Schutzmaßnahmen ergreifen zu k{\"o}nnen.}, language = {de} } @phdthesis{Weege2017, author = {Weege, Stefanie}, title = {Climatic drivers of retrogressive thaw slump activity and resulting sediment and carbon release to the nearshore zone of Herschel Island, Yukon Territory, Canada}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-397947}, school = {Universit{\"a}t Potsdam}, pages = {163}, year = {2017}, abstract = {The Yukon Coast in Canada is an ice-rich permafrost coast and highly sensitive to changing environmental conditions. Retrogressive thaw slumps are a common thermoerosion feature along this coast, and develop through the thawing of exposed ice-rich permafrost on slopes and removal of accumulating debris. They contribute large amounts of sediment, including organic carbon and nitrogen, to the nearshore zone. The objective of this study was to 1) identify the climatic and geomorphological drivers of sediment-meltwater release, 2) quantify the amount of released meltwater, sediment, organic carbon and nitrogen, and 3) project the evolution of sediment-meltwater release of retrogressive thaw slumps in a changing future climate. The analysis is based on data collected over 18 days in July 2013 and 18 days in August 2012. A cut-throat flume was set up in the main sediment-meltwater channel of the largest retrogressive thaw slump on Herschel Island. In addition, two weather stations, one on top of the undisturbed tundra and one on the slump floor, measured incoming solar radiation, air temperature, wind speed and precipitation. The discharge volume eroding from the ice-rich permafrost and retreating snowbanks was measured and compared to the meteorological data collected in real time with a resolution of one minute. The results show that the release of sediment-meltwater from thawing of the ice-rich permafrost headwall is strongly related to snowmelt, incoming solar radiation and air temperature. Snowmelt led to seasonal differences, especially due to the additional contribution of water to the eroding sediment-meltwater from headwall ablation, lead to dilution of the sediment-meltwater composition. Incoming solar radiation and air temperature were the main drivers for diurnal and inter-diurnal fluctuations. In July (2013), the retrogressive thaw slump released about 25 000 m³ of sediment-meltwater, containing 225 kg dissolved organic carbon and 2050 t of sediment, which in turn included 33 t organic carbon, and 4 t total nitrogen. In August (2012), just 15 600 m³ of sediment-meltwater was released, since there was no additional contribution from snowmelt. However, even without the additional dilution, 281 kg dissolved organic carbon was released. The sediment concentration was twice as high as in July, with sediment contents of up to 457 g l-1 and 3058 t of sediment, including 53 t organic carbon and 5 t nitrogen, being released. In addition, the data from the 36 days of observations from Slump D were upscaled to cover the main summer season of 1 July to 31 August (62 days) and to include all 229 active retrogressive thaw slumps along the Yukon Coast. In total, all retrogressive thaw slumps along the Yukon Coast contribute a minimum of 1.4 Mio. m³ sediment-meltwater each thawing season, containing a minimum of 172 000 t sediment with 3119 t organic carbon, 327 t nitrogen and 17 t dissolved organic carbon. Therefore, in addition to the coastal erosion input to the Beaufort Sea, retrogressive thaw slumps additionally release 3 \% of sediment and 8 \% of organic carbon into the ocean. Finally, the future evolution of retrogressive thaw slumps under a warming scenario with summer air temperatures increasing by 2-3 °C by 2081-2100, would lead to an increase of 109-114\% in release of sediment-meltwater. It can be concluded that retrogressive thaw slumps are sensitive to climatic conditions and under projected future Arctic warming will contribute larger amounts of thawed permafrost material (including organic carbon and nitrogen) into the environment.}, language = {en} }