 |
| Titel |
The influence of tropical cyclones in gully formation: A case study from
Madagascar |
| VerfasserIn |
Andrea Raveloson, Amanda Szabó, Balázs Székely |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138542
|
| Publikation (Nr.) |
 EGU/EGU2017-1589.pdf |
|
|
|
|
|
| Zusammenfassung |
| Soil erosion has been recognized as the main cause of land degradation worldwide and gully
erosion is currently considered as one of the most striking erosion type. Madagascar is one of
the most affected country with special gullies called lavakas. Despite of the several decade
long research, the reasons and the mechanism of their formation are still unknown.
Anthropogenic factors, specific combination of lithology, weathering profile and
topography are most often stated but numerous publications mention climate as a
main factor. We studied the role of climatic conditions and tropical cyclones since
2014.
This study aims to analyze lavaka distribution with GIS methods and to find relation
between lavaka density, lavaka density change and climatic conditions. Lavakas have been
identified in 17 selected study sites by visual recognition using satellite images from years
2000-2009 and 2003-2008. A total of 1330 km2 has been processed at 1 km x 1 km grid cell
scale.
The total number of recognized lavakas was 1592 in the 17 sites that corresponds
to a varying lavaka density of 0 and 8.53 km−2. Data show that the appearance
of lavakas is related to the spatial distribution and the inter-annual variability of
precipitation and this connection is further strengthened by the tropical cyclones.
Furthermore, among our 17 study sites changes in lavaka density were observed between
2000-2009 and 2003-2008 only in areas frequently hit by cyclones in the last 20 years. |
|
|
|
|
|
|