Influence of ENSO and PDO on mountain glaciers in the outer tropics: case studies in Bolivia

Veettil, Bijeesh Kozhikkodan; Bremer, Ulisses Franz; Souza, Sérgio Florêncio de; Maier, Éder Leandro Bayer; Simões, Jefferson Cárdia

doi:10.1007/s00704-015-1545-4

Cited by 23 publications

(20 citation statements)

References 44 publications

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“…The lower melt factor at this time dampens the intensity of melt, possibly because of the absence of heat transfer from rain (Francou, 2004), but it nonetheless simulates among the highest melt volumes of the simulation period ( Figure 5(a)), consistent with other studies showing increased melt in response to El Niño events in the Andes (Francou, 2004;Veettil et al, 2014a;Manciati et al, 2014;Maussion et al, 2015;Veettil et al, 2016). Huss et al (2009) …”

supporting

confidence: 77%

Multi-scale temporal variability in meltwater contributions in a tropical glacierized watershed

Saberi¹,

McLaughlin²,

Ng³

et al. 2018

Preprint

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Abstract. Climate models predict amplified warming at high elevations in low latitudes, making tropical glacierized regions some of the most vulnerable hydrological systems in the world. Observations reveal decreasing streamflow due to retreating glaciers in the Andes, which hold 99% of all tropical glaciers. However, the timescales over which meltwater contributes to streamflow and the pathways it takes -surface and subsurface -remain uncertain, hindering our ability to predict how shrinking glaciers will impact water resources. Two major contributors to this uncertainty are the sparsity of hydrologic mea-5 surements in tropical glacierized watersheds and the complication of hydrograph separation where there is year-round glacier melt. We address these challenges using a multi-method approach that employs repeat hydrochemical mixing model analysis, hydroclimatic time series analysis, and integrated watershed modeling. Each of these approaches interrogates distinct timescale relationships among meltwater, groundwater, and stream discharge. Our results challenge the commonly held conceptual model that glaciers buffer discharge variability. Instead, in a sub-humid watershed on Volcán Chimborazo, Ecuador, meltwater drives 10 nearly all the variability in discharge (Pearson correlation coefficient of 0.89 in simulations), with glaciers contributing a broad range of 20-60% or wider of discharge, mostly (86%) through surface runoff on hourly timescales, but also through infiltration that increases annual groundwater contributions by nearly 20%. We further found that rainfall may enhance melt contributions to discharge at timescales that complement melt generation, possibly explaining why minimum discharge occurred at the study site during warm but dry El Niño conditions, which typically heighten melt in the Andes. Our findings caution against extrap-15 olations from isolated measurements: stream discharge and meltwater contributions in tropical glacierized systems can change substantially at hourly to interannual timescales, due to climatic variability and surface to subsurface flow processes.

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supporting

confidence: 77%

Multi-scale temporal variability in meltwater contributions in a tropical glacierized watershed

Saberi¹,

McLaughlin²,

Ng³

et al. 2018

Preprint

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“…Total glacier coverage in the four considered cordilleras was reduced by 43.95% (from 152.65 to 85.56 km 2 ) between 1985 and 2015; reduction in glaciarized areas Palacios et al, 2014;Veettil et al, 2016aVeettil et al, , 2016cVeettil, 2017;Veettil and Souza, 2017). Overall glacial area reduction between 1985 and 2015 and the corresponding data are summarized in Table 1.…”

Section: Overall Glacier Area and Snowline Changesmentioning

confidence: 95%

Regional climate forcing and topographic influence on glacier shrinkage: eastern cordilleras of Peru

Veettil

Wang²,

Simões

et al. 2017

Intl Journal of Climatology

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This study assessed the influence of regional climate variability and topography on surface area changes at glacierized mountain peaks of four eastern tropical Andes cordilleras between 10.5 ∘ and 13.5 ∘ S, namely, Huaguruncho, Huaytapallana, Urubamba and Vilcabamba, during the period 1985-2015 using satellite data. Time series analysis of three key climate variables (temperature, precipitation and relative humidity) at 500 hPa level was also included. Decreasing trends in precipitation and increasing relative humidity trends were observed at the northern region. Further analysis on mean distribution of wind at 500 hPa level showed significant rising trend southwards during the austral winter. Glacierized surfaces at lower altitudes were shrinking faster than those at high altitudes as expected. However, spatial orientation of glacier retreat was not similar to nearby cordilleras such as Vilcanota and Carabaya excepting for Cordillera Urubamba. Despite the high rate of precipitation due to the humidity transport from the Amazon Basin on the eastern slopes, glaciers on the eastern and north-eastern slopes in the Cordillera Urubamba retreated at a higher rate compared with those glaciers on western and south-western sides. Whether higher retreat on the eastern sides towards the south is controlled by precipitation phase changes (rain or snow) or by increased humidity levels was discussed. Furthermore, there was a predominant snowline altitude (SLA) rising trend varying between 56 and 129 m for the studied glaciers. A sharp rise in SLAs for periods 1995-2000 and 2010-2015 was attested, coinciding with warming trends in the Pacific. The relative stability in observed SLAs between 2000 and 2010 also coincided with cooling trends in the Pacific.

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“…Numerous studies exist on the influence of El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on tropical glaciers in the Andes [23,[28][29][30][31][32][33][34], but are less frequent for Australasia [21]. During El Niño events, a rise in air temperature and reduction in precipitation have been observed throughout the tropics [35][36][37].…”

Section: Causes Of Glacier Recessionmentioning

confidence: 99%

Global Disappearance of Tropical Mountain Glaciers: Observations, Causes, and Challenges

Veettil

Kamp

2019

Geosciences

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This article reviews the current status of tropical glaciers in the South American Andes, East Africa, and Australasia by shedding light on past, present, and future glacier coverage in the tropics, the influence of global and regional climates on the tropical glaciers, the regional importance of these glaciers, and challenges of ongoing glacier recessions. While tropical glaciers have predominantly receded since the Little Ice Age, the rate of shrinkage has accelerated since the late 1970s as a result of climate changes. As a result, socio-ecological implications occur around ecosystem health, natural hazards, freshwater resources, agriculture, hydropower, mining, human and animal health, traditions and spirituality, and peace.

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Influence of ENSO and PDO on mountain glaciers in the outer tropics: case studies in Bolivia

Cited by 23 publications

References 44 publications

Multi-scale temporal variability in meltwater contributions in a tropical glacierized watershed

Multi-scale temporal variability in meltwater contributions in a tropical glacierized watershed

Regional climate forcing and topographic influence on glacier shrinkage: eastern cordilleras of Peru

Global Disappearance of Tropical Mountain Glaciers: Observations, Causes, and Challenges

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