TY  - JOUR
A1  - Schildgen, Taylor F.
A1  - Robinson, Ruth A. J.
A1  - Savi, Sara
A1  - Phillips, William M.
A1  - Spencer, Joel Q. G.
A1  - Bookhagen, Bodo
A1  - Scherler, Dirk
A1  - Tofelde, Stefanie
A1  - Alonso, Ricardo N.
A1  - Kubik, Peter W.
A1  - Binnie, Steven A.
A1  - Strecker, Manfred
T1  - Landscape response to late Pleistocene climate change in NW Argentina: Sediment flux modulated by basin geometry and connectivity
JF  - Journal of geophysical research : Earth surface
N2  - Fluvial fill terraces preserve sedimentary archives of landscape responses to climate change, typically over millennial timescales. In the Humahuaca Basin of NW Argentina (Eastern Cordillera, southern Central Andes), our 29 new optically stimulated luminescence ages of late Pleistocene fill terrace sediments demonstrate that the timing of past river aggradation occurred over different intervals on the western and eastern sides of the valley, despite their similar bedrock lithology, mean slopes, and precipitation. In the west, aggradation coincided with periods of increasing precipitation, while in the east, aggradation coincided with decreasing precipitation or more variable conditions. Erosion rates and grain size dependencies in our cosmogenic Be-10 analyses of modern and fill terrace sediments reveal an increased importance of landsliding compared to today on the west side during aggradation, but of similar importance during aggradation on the east side. Differences in the timing of aggradation and the Be-10 data likely result from differences in valley geometry, which causes sediment to be temporarily stored in perched basins on the east side. It appears as if periods of increasing precipitation triggered landslides throughout the region, which induced aggradation in the west, but blockage of the narrow bedrock gorges downstream from the perched basins in the east. As such, basin geometry and fluvial connectivity appear to strongly influence the timing of sediment movement through the system. For larger basins that integrate subbasins with differing geometries or degrees of connectivity (like Humahuaca), sedimentary responses to climate forcing are likely attenuated.
KW  - berylium-10
KW  - optically stimulated luminescence
KW  - Humahuaca Basin
KW  - South American Monsoon System
KW  - fluvial terraces
KW  - landscape connectivity
Y1  - 2016
U6  - https://doi.org/10.1002/2015JF003607
SN  - 2169-9003
SN  - 2169-9011
VL  - 121
SP  - 392
EP  - 414
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Castino, Fabiana
A1  - Bookhagen, Bodo
A1  - Strecker, Manfred
T1  - Rainfall variability and trends of the past six decades (1950-2014) in the subtropical NW Argentine Andes
JF  - Climate dynamics : observational, theoretical and computational research on the climate system
N2  - The eastern flanks of the Central Andes are characterized by deep convection, exposing them to hydrometeorological extreme events, often resulting in floods and a variety of mass movements. We assessed the spatiotemporal pattern of rainfall trends and the changes in the magnitude and frequency of extreme events (ae<yen>95th percentile) along an E-W traverse across the southern Central Andes using rain-gauge and high-resolution gridded datasets (CPC-uni and TRMM 3B42 V7). We generated different climate indices and made three key observations: (1) an increase of the annual rainfall has occurred at the transition between low (< 0.5 km) and intermediate (0.5-3 km) elevations between 1950 and 2014. Also, rainfall increases during the wet season and, to a lesser degree, decreases during the dry season. Increasing trends in annual total amounts characterize the period 1979-2014 in the arid, high-elevation southern Andean Plateau, whereas trend reversals with decreasing annual total amounts were found at low elevations. (2) For all analyzed periods, we observed small or no changes in the median values of the rainfall-frequency distribution, but significant trends with intensification or attenuation in the 95th percentile. (3) In the southern Andean Plateau, extreme rainfall events exhibit trends towards increasing magnitude and, to a lesser degree, frequency during the wet season, at least since 1979. Our analysis revealed that low (< 0.5 km), intermediate (0.5-3 km), and high-elevation (> 3 km) areas respond differently to changing climate conditions, and the transition zone between low and intermediate elevations is characterized by the most significant changes.
KW  - Extreme rainfall
KW  - South American Monsoon System
KW  - Central Andes
KW  - Quantile regression
KW  - Rain gauges
KW  - CPC-uni
KW  - TRMM
KW  - Orographic barrier
Y1  - 2017
U6  - https://doi.org/10.1007/s00382-016-3127-2
SN  - 0930-7575
SN  - 1432-0894
VL  - 48
SP  - 1049
EP  - 1067
PB  - Springer
CY  - New York
ER  -