TY - JOUR
T1 - The Impact of Extreme Rainstorms on Escarpment Morphology in Arid Areas
T2 - Insights From the Central Negev Desert
AU - Shmilovitz, Yuval
AU - Marra, Francesco
AU - Enzel, Yehouda
AU - Morin, Efrat
AU - Armon, Moshe
AU - Matmon, Ari
AU - Mushkin, Amit
AU - Levi, Yoav
AU - Khain, Pavel
AU - Rossi, Matthew W.
AU - Tucker, Greg
AU - Pederson, Joel
AU - Haviv, Itai
N1 - Publisher Copyright:
© 2023. The Authors.
PY - 2023/10
Y1 - 2023/10
N2 - The impact of climate on topography, which is a theme in landscape evolution studies, has been demonstrated, mostly, at mountain range scales and across climate zones. However, in drylands, spatiotemporal discontinuities of rainfall and the crucial role of extreme rainstorms raise questions and challenges in identifying climate properties that govern surface processes. Here, we combine methods to examine hyperarid escarpment sensitivity to storm-scale forcing. Using a high-resolution DEM and field measurements, we analyzed the topography of a 40-km-long escarpment in the Negev desert (Israel). We also used rainfall intensity data from a convection-permitting numerical weather model for storm-scale statistical analysis. We conducted hydrological simulations of synthetic rainstorms, revealing the frequency of sediment mobilization along the sub-cliff slopes. Results show that cliff gradients along the hyperarid escarpment increase systematically from the wetter (90 mm yr−1) southwestern to the drier (45 mm yr−1) northeastern sides. Also, sub-cliff slopes at the southwestern study site are longer and associated with milder gradients and coarser sediments. Storm-scale statistical analysis reveals a trend of increasing extreme (>10 years return-period) intensities toward the northeast site, opposite to the trend in mean annual rainfall. Hydrological simulations based on these statistics indicate a higher frequency of sediment mobilization in the northeast, which can explain the pronounced topographic differences between the sites. The variations in landscape and rainstorm properties across a relatively short distance highlight the sensitivity of arid landforms to extreme events.
AB - The impact of climate on topography, which is a theme in landscape evolution studies, has been demonstrated, mostly, at mountain range scales and across climate zones. However, in drylands, spatiotemporal discontinuities of rainfall and the crucial role of extreme rainstorms raise questions and challenges in identifying climate properties that govern surface processes. Here, we combine methods to examine hyperarid escarpment sensitivity to storm-scale forcing. Using a high-resolution DEM and field measurements, we analyzed the topography of a 40-km-long escarpment in the Negev desert (Israel). We also used rainfall intensity data from a convection-permitting numerical weather model for storm-scale statistical analysis. We conducted hydrological simulations of synthetic rainstorms, revealing the frequency of sediment mobilization along the sub-cliff slopes. Results show that cliff gradients along the hyperarid escarpment increase systematically from the wetter (90 mm yr−1) southwestern to the drier (45 mm yr−1) northeastern sides. Also, sub-cliff slopes at the southwestern study site are longer and associated with milder gradients and coarser sediments. Storm-scale statistical analysis reveals a trend of increasing extreme (>10 years return-period) intensities toward the northeast site, opposite to the trend in mean annual rainfall. Hydrological simulations based on these statistics indicate a higher frequency of sediment mobilization in the northeast, which can explain the pronounced topographic differences between the sites. The variations in landscape and rainstorm properties across a relatively short distance highlight the sensitivity of arid landforms to extreme events.
KW - cliff
KW - escarpment
KW - rainstorms
KW - runoff
KW - sheetwash
KW - topographic analysis
UR - http://www.scopus.com/inward/record.url?scp=85173754364&partnerID=8YFLogxK
U2 - 10.1029/2023JF007093
DO - 10.1029/2023JF007093
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AN - SCOPUS:85173754364
SN - 2169-9003
VL - 128
JO - Journal of Geophysical Research: Earth Surface
JF - Journal of Geophysical Research: Earth Surface
IS - 10
M1 - e2023JF007093
ER -