TY - JOUR A1 - Apaestegui, James A1 - Cruz, Francisco William A1 - Vuille, Mathias A1 - Fohlmeister, Jens Bernd A1 - Carlo Espinoza, Jhan A1 - Sifeddine, Abdelfettah A1 - Strikis, Nicolas A1 - Guyot, Jean Loup A1 - Ventura, Roberto A1 - Cheng, Hai A1 - Edwards, R. Lawrence T1 - Precipitation changes over the eastern Bolivian Andes inferred from speleothem (delta O-18) records for the last 1400 years JF - Earth & planetary science letters N2 - Here we present high-resolution delta O-18 records obtained from speleothems collected in the eastern Bolivian Andes. The stable isotope records are related to the regional- to large-scale atmospheric circulation over South America and allow interpreting changes in delta O-18 during the last 1400 yr as a function of changes in precipitation regimes over the southern tropical Andes. Two distinct phases with more negative delta O-18 values, interpreted as periods of increased convective activity over the eastern Andean Cordillera in Bolivia are observed concomitantly with periods of global climate anomalies during the last millennium, such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) respectively. Changes in the Bolivian delta O-18 record during the LIA are apparently related to a southward displacement of the Intertropical Convergence Zone (ITCZ), which acts as a main moisture driver to intensify convection over the tropical continent. During the MCA, however, the increased convective activity observed in the Bolivian record is likely the result of a different mechanism, which implies moisture sourced mainly from the southern tropical Atlantic. This interpretation is consistent with paleoclimate records further to the north in the tropical Andes that show progressively drier conditions during this time period, indicating a more northerly position of the ITCZ. The transition period between the MCA and the LIA shows a slight tendency toward increased delta O-18 values, indicating weakened convective activity. Our results also reveal a non-stationary anti-phased behavior between the delta O-18 reconstructions from Bolivia and northeastern Brazil that confirms a continental-scale east-west teleconnection across South America during the LIA. KW - speleothems KW - stable isotopes KW - MCA KW - LIA KW - Bolivia KW - South American Monsoon Y1 - 2018 U6 - https://doi.org/10.1016/j.epsl.2018.04.048 SN - 0012-821X SN - 1385-013X VL - 494 SP - 124 EP - 134 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Huss, Matthias A1 - Bookhagen, Bodo A1 - Huggel, C. A1 - Jacobsen, Dean A1 - Bradley, Raymond S. A1 - Clague, J. J. A1 - Vuille, Mathias A1 - Buytaert, Wouter A1 - Cayan, D. R. A1 - Greenwood, G. A1 - Mark, B. G. A1 - Milner, A. M. A1 - Weingartner, Rolf A1 - Winder, M. T1 - Toward mountains without permanent snow and ice JF - Earths future N2 - The cryosphere in mountain regions is rapidly declining, a trend that is expected to accelerate over the next several decades due to anthropogenic climate change. A cascade of effects will result, extending from mountains to lowlands with associated impacts on human livelihood, economy, and ecosystems. With rising air temperatures and increased radiative forcing, glaciers will become smaller and, in some cases, disappear, the area of frozen ground will diminish, the ratio of snow to rainfall will decrease, and the timing and magnitude of both maximum and minimum streamflow will change. These changes will affect erosion rates, sediment, and nutrient flux, and the biogeochemistry of rivers and proglacial lakes, all of which influence water quality, aquatic habitat, and biotic communities. Changes in the length of the growing season will allow low-elevation plants and animals to expand their ranges upward. Slope failures due to thawing alpine permafrost, and outburst floods from glacier-and moraine-dammed lakes will threaten downstream populations.Societies even well beyond the mountains depend on meltwater from glaciers and snow for drinking water supplies, irrigation, mining, hydropower, agriculture, and recreation. Here, we review and, where possible, quantify the impacts of anticipated climate change on the alpine cryosphere, hydrosphere, and biosphere, and consider the implications for adaptation to a future of mountains without permanent snow and ice. Y1 - 2017 U6 - https://doi.org/10.1002/2016EF000514 SN - 2328-4277 VL - 5 SP - 418 EP - 435 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Marwan, Norbert A1 - Trauth, Martin H. A1 - Vuille, Mathias A1 - Kurths, Jürgen T1 - Comparing modern and Pleistocene ENSO-like influences in NW Argentina using nonlinear time series analysis methods N2 - Higher variability in rainfall and river discharge could be of major importance in landslide generation in the north-western Argentine Andes. Annual layered (varved) deposits of a landslide dammed lake in the Santa Maria Basin (26°S, 66°W) with an age of 30,000 14C years provide an archive of precipitation variability during this time. The comparison of these data with present-day rainfall observations tests the hypothesis that increased rainfall variability played a major role in landslide generation. A potential cause of such variability is the El Niño/ Southern Oscillation (ENSO). The causal link between ENSO and local rainfall is quantified by using a new method of nonlinear data analysis, the quantitative analysis of cross recurrence plots (CRP). This method seeks similarities in the dynamics of two different processes, such as an ocean-atmosphere oscillation and local rainfall. Our analysis reveals significant similarities in the statistics of both modern and palaeo-precipitation data. The similarities in the data suggest that an ENSO-like influence on local rainfall was present at around 30,000 14C years ago. Increased rainfall, which was inferred from a lake balance modeling in a previous study, together with ENSO-like cyclicities could help to explain the clustering of landslides at around 30,000 14C years ago. Y1 - 2003 UR - http://arxiv.org/abs/nlin.CD/0303056 ER -