TY - JOUR
T1 - Landscape reorganization under changing climatic forcing
T2 - Results from an experimental landscape
AU - Singh, Arvind
AU - Reinhardt, Liam
AU - Foufoula-Georgiou, Efi
N1 - Publisher Copyright:
© 2015. American Geophysical Union. All Rights Reserved.© American Geophysical Union.All Rights Reserved.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - Understanding how landscapes respond to climate dynamics in terms of macroscale (average topographic features) and microscale (landform reorganization) is of interest both for deciphering past climates from today's landscapes and for predicting future landscapes in view of recent climatic trends. Although several studies have addressed macro-scale response, only a few have focused on quantifying smaller-scale basin reorganization. To that goal, a series of controlled laboratory experiments were conducted where a self-organized complete drainage network emerged under constant precipitation and uplift dynamics. Once steady state was achieved, the landscape was subjected to a fivefold increase in precipitation (transient state). Throughout the evolution, high-resolution spatiotemporal topographic data in the form of digital elevation models were collected. The steady state landscape was shown to possess three distinct geomorphic regimes (unchannelized hillslopes, debris-dominated channels, and fluvially dominated channels). During transient state, landscape reorganization was observed to be driven by hillslopes via accelerated erosion, ridge lowering, channel widening, and reduction of basin relief as opposed to channel base-level reduction. Quantitative metrics on which these conclusions were based included slope-area curve, correlation analysis of spatial and temporal elevation increments, and wavelet spectral analysis of the evolving landscapes. Our results highlight that landscape reorganization in response to increased precipitation seems to follow "an arrow of scale": major elevation change initiates at the hillslope scale driving erosional regime change at intermediate scales and further cascading to geomorphic changes at the channel scale as time evolves. Key Points: Climate shifts reorganize landscapes at all scales Fluvial regime expands to smaller scales under increased precipitation Landscape reorganization mainly driven by hillslope erosion
AB - Understanding how landscapes respond to climate dynamics in terms of macroscale (average topographic features) and microscale (landform reorganization) is of interest both for deciphering past climates from today's landscapes and for predicting future landscapes in view of recent climatic trends. Although several studies have addressed macro-scale response, only a few have focused on quantifying smaller-scale basin reorganization. To that goal, a series of controlled laboratory experiments were conducted where a self-organized complete drainage network emerged under constant precipitation and uplift dynamics. Once steady state was achieved, the landscape was subjected to a fivefold increase in precipitation (transient state). Throughout the evolution, high-resolution spatiotemporal topographic data in the form of digital elevation models were collected. The steady state landscape was shown to possess three distinct geomorphic regimes (unchannelized hillslopes, debris-dominated channels, and fluvially dominated channels). During transient state, landscape reorganization was observed to be driven by hillslopes via accelerated erosion, ridge lowering, channel widening, and reduction of basin relief as opposed to channel base-level reduction. Quantitative metrics on which these conclusions were based included slope-area curve, correlation analysis of spatial and temporal elevation increments, and wavelet spectral analysis of the evolving landscapes. Our results highlight that landscape reorganization in response to increased precipitation seems to follow "an arrow of scale": major elevation change initiates at the hillslope scale driving erosional regime change at intermediate scales and further cascading to geomorphic changes at the channel scale as time evolves. Key Points: Climate shifts reorganize landscapes at all scales Fluvial regime expands to smaller scales under increased precipitation Landscape reorganization mainly driven by hillslope erosion
KW - climate change
KW - landscape evolution
KW - power spectral density
KW - river network
KW - slope-area
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U2 - 10.1002/2015WR017161
DO - 10.1002/2015WR017161
M3 - Article
AN - SCOPUS:84937514117
VL - 51
SP - 4320
EP - 4337
JO - Water Resources Research
JF - Water Resources Research
SN - 0043-1397
IS - 6
ER -