Constraints on southern hemisphere tropical climate change during the Little Ice Age and Younger Dryas based on glacier modeling of the Quelccaya Ice Cap, Peru

Malone, A.; Pierrehumbert, Raymond T.; Lowell, Thomas V.; Kelly, M. A.; Stroup, Justin S.

doi:10.1016/j.quascirev.2015.08.001

Cited by 20 publications

(14 citation statements)

References 65 publications

(134 reference statements)

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“…One method is to drive a glacier model with a range of climate conditions to determine the ones that are compatible with the glacier length records (Allison and Kruss, 1977;Oerlemans, 1986;Jomelli et al, 2011;Luthi, 2014;Malone et al, 2015;Sagredo et al, 2017;Zechetto et al, 2017;Doughty et al, 2017). The temperature and precipitation reconstructions deduced from glacier length fluctuations can also be compared to estimates obtained from other records and climate model results to test the compatibility between the different sources of information.…”

Section: Introductionmentioning

confidence: 99%

Testing the consistency between changes in simulated climate and Alpine glacier length over the past millennium

et al. 2018

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Abstract.It is standard to compare climate model results covering the past millennium and reconstructions based on various archives in order to test the ability of models to reproduce the observed climate variability. Up to now, glacier length fluctuations have not been used systematically in this framework even though they offer information on multidecadal to centennial variations complementary to other records. One reason is that glacier length depends on several complex factors and so cannot be directly linked to the simulated climate. However, climate model skill can be measured by comparing the glacier length computed by a glacier model driven by simulated temperature and precipitation to observed glacier length variations. This is done here using the version 1.0 of the Open Global Glacier Model (OGGM) forced by fields derived from a range of simulations performed with global climate models over the past millennium. The glacier model is applied to a set of Alpine glaciers for which observations cover at least the 20th century. The observed glacier length fluctuations are generally well within the range of the simulations driven by the various climate model results, showing a general consistency with this ensemble of simulations. Sensitivity experiments indicate that the results are much more sensitive to the simulated climate than to OGGM parameters. This confirms that the simulations of glacier length can be used to evaluate the climate model performance, in particular the simulated summer temperatures that largely control the glacier changes in our region of interest. Simulated glacier length is strongly influenced by the internal variability in the system, putting limitations on the model-data comparison for some variables like the trends over the 20th century in the Alps. Nevertheless, comparison of glacier length fluctuations on longer timescales, for instance between the 18th century and the late 20th century, appear less influenced by the natural variability and indicate clear differences in the behaviour of the various climate models.

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Section: Introductionmentioning

confidence: 99%

Testing the consistency between changes in simulated climate and Alpine glacier length over the past millennium

et al. 2018

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“…Precipitation events can also affect ablation through the ways in which cloud cover influences surface energy budgets, in particular, longwave radiation (Hock, 2005), which could introduce additional nonlinear mass-balance responses to climate variability. Previous studies using higher complexity mass-balance models, however, suggest that changing the magnitude of short-term precipitation variability does not affect the average glacier length (Farinotti, 2013; Malone and others, 2015). Many non-linearities are inherent in glacier mass balance, although not all non-linearities produce asymmetries that can affect the mean state.…”

Section: Discussionmentioning

confidence: 95%

“…Changes in average glacier length, however, are usually associated with changes in the mean climate, but a portion of average length changes could also be due to changes in interannual climate variability. Farinotti (2013) and Malone and others (2015), using different numerical modeling techniques, find that the mean length of a glacier retreats upslope as the magnitude of interannual climate variability increases. Thus, the role of interannual climate variability on the average length and mass balance of glaciers warrants further investigation.…”

Section: Introductionmentioning

confidence: 99%

Interannual climate variability helps define the mean state of glaciers

2019

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Changes in glacier length and extent are indicators of contemporary and archives of past climate changes, but this common climate proxy presents a challenge for inferring a climate signal. Modeling studies suggest that length fluctuations can occur due to interannual climate variability within an unchanging mean climate and that changes in interannual climate variability can also drive changes in average length. This paper quantifies the impacts of interannual climate variability on average glacier length and mass balance, using a flowline model coupled to a simplified mass-balance model. Results illustrate that changes in the magnitude of interannual temperature variability can non-linearly affect the mean glacier length through a mass-balance asymmetry between warm and cold years. This asymmetry is present in models where melt only initiates after a temperature threshold is crossed. Glaciers susceptible to this asymmetry can be identified based on the shape of their mass-balance profiles. The presence of mass-balance asymmetries in glaciological databases is evaluated, but current records are too short for high statistical resolving power. While the asymmetry in this study can affect the average length and mass-balance, its impacts are small, and paleoclimate interpretations from glacier-length changes are likely not notably influenced by this process.

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“…Palaeo-glacier records, particularly those from tropical latitudes,afford a unique opportunity to help address thesekey problems.Mountain glaciers are sensitive to small changes in temperature (Lowell, 2000;Favier et al, 2004;Oerlemans, 2005;Schaefer et al, 2006;Anderson and Mackintosh, 2012;Rupper and Roe, 2008;Rupper et al, 2012;Malone et al, 2015), as confirmed by their almost global response to modern warming (e.g., Dyurgerov and Meier, 2000), and leave a record of past fluctuations on the landscape in the form of moraines. Recent development of high-resolution glacier chronologies, fuelled by the refinement of cosmogenic surface-exposure dating, hasimproved our understanding of past climate behaviour and provided much-needed insight into the structure of key events including the last glacial maximum (LGM) and subsequent deglaciation.This time period, encompassing the last glacial-interglacial transition,is especiallypertinentasnot only doesit represent the highest-magnitude climate change of the last ~100 Ka, but many of the climatic transitions also were abrupt in nature (Denton et al, 2010).Studying the extant nature of glacier records from the LGM and termination enables comparison of past climate conditions and potential forcing mechanisms, such as greenhouse gases, Milankovitch cycles, and oceanatmosphere reorganisations.…”

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confidence: 94%

A cosmogenic 10Be chronology for the local last glacial maximum and termination in the Cordillera Oriental, southern Peruvian Andes: Implications for the tropical role in global climate

Bromley

Schaefer

Hall

et al. 2016

Quaternary Science Reviews

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Resolving patterns of tropical climate variability during and since the last glacial maximum (LGM) is fundamental to assessing the role of the tropics in global change, both on ice-age and sub-millennial timescales. Here, we present a 10 Be moraine chronology from the Cordillera Carabaya (14.3°S), a sub-range of the Cordillera Oriental in southern Peru, covering the LGM and the first half of the last glacial termination. Additionally, we recalculate existing 10 Be ages using a new tropical high-altitude production rate in order to put our record into broader spatial context. Our results indicate that glaciers deposited a series of moraines during marine isotope stage 2, broadly synchronous with global glacier maxima, but that maximum glacier extent may have occurred prior to stage 2. Thereafter, atmospheric warming drove widespread deglaciation of the Cordillera Carabaya. A subsequent glacier resurgence culminated at ~16,100 yrs, followed by a second period of glacier recession. Together, the observed deglaciation corresponds to Heinrich Stadial 1 (HS1: ~18,000-14,600 yrs), during which pluvial lakes on the adjacent Peruvian-Bolivian altiplano rose to their highest levels of the late Pleistocene as a consequence of southward displacement of the inter-tropical convergence zone and intensification of the South American summer monsoon. Deglaciation in the Cordillera Carabaya also coincided with the retreat of higher-latitude mountain glaciers in the SouthernHemisphere. Our findings suggest that HS1 was characterised by atmospheric warming and indicate that deglaciation of the southern Peruvian Andes was driven by rising temperatures, despite increased precipitation. Recalculated 10 Be data from other tropical Andean sites support this model. Finally, we suggest that the broadly uniform response during the LGM and termination of the glaciers examined here involved equatorial Pacific sea-surface temperature anomalies and propose a framework for testing the viability of this conceptual model. 1 Introduction As the energetic powerhouse of the globe, the tropics (23°N-23°S) are the principal source of heat energy and water vapour for the climate system andthus represent a fundamental and dynamic component of global climate (Cane, 1998; Pierrehumbert, 1999; Visser et al., 2003). Today, the tropical influence is exemplified by the El Niño

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Constraints on southern hemisphere tropical climate change during the Little Ice Age and Younger Dryas based on glacier modeling of the Quelccaya Ice Cap, Peru

Cited by 20 publications

References 65 publications

Testing the consistency between changes in simulated climate and Alpine glacier length over the past millennium

Testing the consistency between changes in simulated climate and Alpine glacier length over the past millennium

Interannual climate variability helps define the mean state of glaciers

A cosmogenic 10Be chronology for the local last glacial maximum and termination in the Cordillera Oriental, southern Peruvian Andes: Implications for the tropical role in global climate

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