TY  - JOUR
A1  - Wendi, Dadiyorto
A1  - Liong, Shie-Yui
A1  - Sun, Yabin
A1  - Doan, Chi Dung
T1  - An innovative approach to improve SRTM DEM using multispectral imagery and artificial neural network
JF  - Journal of advances in modeling earth systems
N2  - Although the Shuttle Radar Topography Mission [SRTM) data are a publicly accessible Digital Elevation Model [DEM) provided at no cost, its accuracy especially at forested area is known to be limited with root mean square error (RMSE) of approx. 14 m in Singapore's forested area. Such inaccuracy is attributed to the 5.6 cm wavelength used by SRTM that does not penetrate vegetation well. This paper considers forested areas of central catchment of Singapore as a proof of concept of an approach to improve the SRTM data set. The approach makes full use of (1) the introduction of multispectral imagery (Landsat 8), of 30 m resolution, into SRTM data; (2) the Artificial Neural Network (ANN) to flex its known strengths in pattern recognition and; (3) a reference DEM of high accuracy (1 m) derived through the integration of stereo imaging of worldview-1 and extensive ground survey points. The study shows a series of significant improvements of the SRTM when assessed with the reference DEM of 2 different areas, with RMSE reduction of ∼68% (from 13.9 m to 4.4 m) and ∼52% (from 14.2 m to 6.7 m). In addition, the assessment of the resulting DEM also includes comparisons with simple denoising methodology (Low Pass Filter) and commercially available product called NEXTMap® World 30™.
KW  - SRTM improvements
KW  - Landsat 8
KW  - ANN
Y1  - 2016
U6  - https://doi.org/10.1002/2015MS000536
SN  - 1942-2466
VL  - 8
SP  - 691
EP  - 702
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - RPRT
A1  - Agarwal, Ankit
A1  - Boessenkool, Berry
A1  - Fischer, Madlen
A1  - Hahn, Irene
A1  - Köhn, Lisei
A1  - Laudan, Jonas
A1  - Moran, Thomas
A1  - Öztürk, Ugur
A1  - Riemer, Adrian
A1  - Rözer, Viktor
A1  - Sieg, Tobias
A1  - Vogel, Kristin
A1  - Wendi, Dadiyorto
A1  - Bronstert, Axel
A1  - Thieken, Annegret
T1  - Die Sturzflut in Braunsbach, Mai 2016
T1  - The flash flood of Braunsbach, May 2006
BT  - eine Bestandsaufnahme und Ereignisbeschreibung
BT  - a hydrological survey and event analysis
N2  - Im Graduiertenkolleg NatRiskChange der Universität Potsdam und anderen Forschungseinrichtungen werden beobachtete sowie zukünftig mögliche Veränderungen von Naturgefahren untersucht. Teil des strukturierten Doktorandenprogramms sind sogenannte Task-Force-Einsätze, bei denen die Promovierende zeitlich begrenzt ein aktuelles Ereignis auswerten. Im Zuge dieser Aktivität wurde die Sturzflut vom 29.05.2016 in Braunsbach (Baden-Württemberg) untersucht.
In diesem Bericht werden erste Auswertungen zur Einordnung der Niederschläge, zu den hydrologischen und geomorphologischen Prozessen im Einzugsgebiet des Orlacher Bachs sowie zu den verursachten Schäden beleuchtet.

Die Region war Zentrum extremer Regenfälle in der Größenordnung von 100 mm innerhalb von 2 Stunden. Das 6 km² kleine Einzugsgebiet hat eine sehr schnelle Reaktionszeit, zumal bei vorgesättigtem Boden. Im steilen Bachtal haben mehrere kleinere und größere Hangrutschungen über 8000 m³ Geröll, Schutt und Schwemmholz in das Gewässer eingetragen und möglicherweise kurzzeitige Aufstauungen und Durchbrüche verursacht. Neben den großen Wassermengen mit einer Abflussspitze in einer Größenordnung von 100 m³/s hat gerade die Geschiebefracht zu großen Schäden an den Gebäuden entlang des Bachlaufs in Braunsbach geführt.
N2  - The DFG graduate school “Natural Hazards and Risks in a Changing World” (NatRiskChange), which is located at the University of Potsdam and its partner institutions, studies previous as well as ongoing and potential future changes in the risk posed by natural hazards. The education program includes so-called task force activities, where the PhD students conduct a rapid event assessment directly after the occurrence of a hazardous natural event. Within this context the flash flood that hit the village Braunsbach (Baden-Württemberg, Germany) at May 29th, 2016 was investigated.
This report summarizes first results describing the rainfall amount and intensities as well as hydrological and geomorphological processes in the corresponding catchment area of the Orlacher Bach. Further, the damages caused in Braunsbach are investigated.

Rainfall intensity measures documented extreme precipitation in the area of Braunsbach with a cumulative amount of about 100 mm within 2 hours. The small catchment area, with a size of 6 km², has a small response time, especially under pre-saturated soil conditions. Several landslides, that occurred at the steep slopes of the river valley, transported more than 8000 m³ of gravel, debris and organic material into the water runoff. They may have caused temporal blockades, that collapsed after a certain amount of water accumulated. In addition to the high discharge, with peak values in the order of 100 m³/s, the high sediment content of the flash flood is mainly responsible for the large damages caused to the buildings in Braunsbach.
KW  - Sturzflut
KW  - Naturgefahren
KW  - Extremniederschlag
KW  - Schadensabschätzung
KW  - Hangrutschungen
KW  - flash flood
KW  - natural hazards
KW  - extreme precipitation
KW  - damage assessment
KW  - landslides
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394881
ER  -