Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers. / Gavin, D. G.; Colombaroli, D.; Morey, A. E.

In: American Geophysical Union, Fall Meeting 2015, Vol. 31, 12.2015.

Research output: Contribution to journalArticle

Published

Standard

Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers. / Gavin, D. G.; Colombaroli, D.; Morey, A. E.

In: American Geophysical Union, Fall Meeting 2015, Vol. 31, 12.2015.

Research output: Contribution to journalArticle

Harvard

APA

Vancouver

Author

BibTeX

@article{08230d0bd3c24362873ce50754592bd1,
title = "Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers",
abstract = "The inclusion of paleo-flood events greatly affects estimates of peak magnitudes (e.g., Q100) in flood-frequency analysis. Likewise, peak events also are associated with certain synoptic climatic patterns that vary on all time scales. Geologic records preserved in lake sediments have the potential to capture the non-stationarity in frequency-magnitude relationships, but few such records preserve a continuous history of event magnitudes. We present a 10-meter 2000-yr record from Upper Squaw Lake, Oregon, that contains finely laminated silt layers that reflect landscape erosion events from the 40 km2 watershed. CT-scans of the core (<1 mm resolution) and a 14C-dated chronology yielded a pseudo-annual time series of erosion magnitudes. The most recent 80 years of the record correlates strongly with annual peak stream discharge and road construction. We examined the frequency-magnitude relationship for the entire pre-road period and show that the seven largest events fall above a strongly linear relationship, suggesting a distinct process (e.g., severe fires or earthquakes) operating at low-frequency to generate large-magnitude events. Expressing the record as cumulative sediment accumulation anomalies showed the importance of the large events in {"}returning the system{"} to the long-term mean rate. Applying frequency-magnitude analysis in a moving window showed that the Q100 and Q10 of watershed erosion varied by 1.7 and 1.0 orders of magnitude, respectively. The variations in watershed erosion are weakly correlated with temperature and precipitation reconstructions at the decadal to centennial scale. This suggests that dynamics both internal (i.e., sediment production) and external (i.e., earthquakes) to the system, as well as more stochastic events (i.e., single severe wildfires) can at least partially over-ride external climate forcing of watershed erosion at decadal to centennial time scales.",
keywords = "1630 Impacts of global change, GLOBAL CHANGE, 4306 Multihazards, NATURAL HAZARDS, 4313 Extreme events, 4343 Preparedness and planning",
author = "Gavin, {D. G.} and D. Colombaroli and Morey, {A. E.}",
year = "2015",
month = dec,
language = "English",
volume = "31",
journal = "American Geophysical Union, Fall Meeting 2015",

}

RIS

TY - JOUR

T1 - Watershed erosion estimated from a high-resolution sediment core reveals a non-stationary frequency-magnitude relationship and importance of seasonal climate drivers

AU - Gavin, D. G.

AU - Colombaroli, D.

AU - Morey, A. E.

PY - 2015/12

Y1 - 2015/12

N2 - The inclusion of paleo-flood events greatly affects estimates of peak magnitudes (e.g., Q100) in flood-frequency analysis. Likewise, peak events also are associated with certain synoptic climatic patterns that vary on all time scales. Geologic records preserved in lake sediments have the potential to capture the non-stationarity in frequency-magnitude relationships, but few such records preserve a continuous history of event magnitudes. We present a 10-meter 2000-yr record from Upper Squaw Lake, Oregon, that contains finely laminated silt layers that reflect landscape erosion events from the 40 km2 watershed. CT-scans of the core (<1 mm resolution) and a 14C-dated chronology yielded a pseudo-annual time series of erosion magnitudes. The most recent 80 years of the record correlates strongly with annual peak stream discharge and road construction. We examined the frequency-magnitude relationship for the entire pre-road period and show that the seven largest events fall above a strongly linear relationship, suggesting a distinct process (e.g., severe fires or earthquakes) operating at low-frequency to generate large-magnitude events. Expressing the record as cumulative sediment accumulation anomalies showed the importance of the large events in "returning the system" to the long-term mean rate. Applying frequency-magnitude analysis in a moving window showed that the Q100 and Q10 of watershed erosion varied by 1.7 and 1.0 orders of magnitude, respectively. The variations in watershed erosion are weakly correlated with temperature and precipitation reconstructions at the decadal to centennial scale. This suggests that dynamics both internal (i.e., sediment production) and external (i.e., earthquakes) to the system, as well as more stochastic events (i.e., single severe wildfires) can at least partially over-ride external climate forcing of watershed erosion at decadal to centennial time scales.

AB - The inclusion of paleo-flood events greatly affects estimates of peak magnitudes (e.g., Q100) in flood-frequency analysis. Likewise, peak events also are associated with certain synoptic climatic patterns that vary on all time scales. Geologic records preserved in lake sediments have the potential to capture the non-stationarity in frequency-magnitude relationships, but few such records preserve a continuous history of event magnitudes. We present a 10-meter 2000-yr record from Upper Squaw Lake, Oregon, that contains finely laminated silt layers that reflect landscape erosion events from the 40 km2 watershed. CT-scans of the core (<1 mm resolution) and a 14C-dated chronology yielded a pseudo-annual time series of erosion magnitudes. The most recent 80 years of the record correlates strongly with annual peak stream discharge and road construction. We examined the frequency-magnitude relationship for the entire pre-road period and show that the seven largest events fall above a strongly linear relationship, suggesting a distinct process (e.g., severe fires or earthquakes) operating at low-frequency to generate large-magnitude events. Expressing the record as cumulative sediment accumulation anomalies showed the importance of the large events in "returning the system" to the long-term mean rate. Applying frequency-magnitude analysis in a moving window showed that the Q100 and Q10 of watershed erosion varied by 1.7 and 1.0 orders of magnitude, respectively. The variations in watershed erosion are weakly correlated with temperature and precipitation reconstructions at the decadal to centennial scale. This suggests that dynamics both internal (i.e., sediment production) and external (i.e., earthquakes) to the system, as well as more stochastic events (i.e., single severe wildfires) can at least partially over-ride external climate forcing of watershed erosion at decadal to centennial time scales.

KW - 1630 Impacts of global change

KW - GLOBAL CHANGE

KW - 4306 Multihazards

KW - NATURAL HAZARDS

KW - 4313 Extreme events

KW - 4343 Preparedness and planning

M3 - Article

VL - 31

JO - American Geophysical Union, Fall Meeting 2015

JF - American Geophysical Union, Fall Meeting 2015

ER -