Interannual Dynamics of Ice Cliff Populations on Debris‐Covered Glaciers From Remote Sensing Observations and Stochastic Modeling

Kneib, Marin; Miles, Evan; Buri, Pascal; Molnár, Péter; McCarthy, Mike; Fugger, Stefan; Pellicciotti, Francesca

doi:10.1029/2021jf006179

Cited by 19 publications

(8 citation statements)

References 97 publications

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“…The analysis of high-resolution (<0.2 m) multitemporal UAV orthoimages and DEMs at five of the glaciers in this study shows that 79% of the newly formed cliff area from 202 cliff formation events is related to the presence of streams or ponds, which indicates that these hydrological features directly influence ice cliff formation (Text S1 and Figure S2 in Supporting Information S1). Such association is further confirmed by field observations (Figure 2g-2i) at numerous sites for both the formation and persistence of ice cliffs (Anderson, Armstrong, Anderson, Scherler, & Petersen, 2021;Brun et al, 2016;Kneib et al, 2021;Mölg et al, 2020;Sato et al, 2021). This association between streams and cliffs or ponds and cliffs, and the decreasing density of cliffs with distance from these features (Figure 2a) leads us to define a 40 m-buffer around ponds and streams within which we classify the cliff pixels as pond-influenced or stream-influenced (Figure 2).…”

Section: Influence Of Supraglacial Hydrology On Ice Cliff Distributionsupporting

confidence: 77%

“…While models accurately simulate the energy and mass balance contribution of individual ice cliffs (Buri et al., 2016; Kneib et al., 2022), their application at large spatial scales is limited by our understanding of the controls of ice cliff distribution. Indeed, estimates of ice cliff density are difficult to make (Anderson, Armstrong, Anderson, & Buri, 2021; Herreid & Pellicciotti, 2018; Kneib et al., 2020) and vary widely in time and space, between 1% and 15% of the debris‐covered area (e.g., Falaschi et al., 2021; Kneib et al., 2021; Loriaux & Ruiz, 2021; Sato et al., 2021; Steiner et al., 2019; Watson, Quincey, Smith, et al., 2017). Remote sensing studies have shown that cliffs are often associated with ponds (Steiner et al., 2019; Watson, Quincey, Carrivick, & Smith, 2017), hinting at a preferential location of ice cliffs where lower glacier longitudinal gradient and surface velocities promote surface ponding (Bolch et al., 2008; Quincey & Glasser, 2009; Quincey et al., 2007; Racoviteanu et al., 2021; Reynolds, 2000; Sakai & Fujita, 2010; Salerno et al., 2012).…”

Section: Introductionmentioning

confidence: 99%

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Controls on Ice Cliff Distribution and Characteristics on Debris‐Covered Glaciers

Kneib

Fyffe

Miles

et al. 2023

Geophysical Research Letters

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Ice cliff distribution plays a major role in determining the melt of debris‐covered glaciers but its controls are largely unknown. We assembled a data set of 37,537 ice cliffs and determined their characteristics across 86 debris‐covered glaciers within High Mountain Asia (HMA). We find that 38.9% of the cliffs are stream‐influenced, 19.5% pond‐influenced and 19.7% are crevasse‐originated. Surface velocity is the main predictor of cliff distribution at both local and glacier scale, indicating its dependence on the dynamic state and hence evolution stage of debris‐covered glacier tongues. Supraglacial ponds contribute to maintaining cliffs in areas of thicker debris, but this is only possible if water accumulates at the surface. Overall, total cliff density decreases exponentially with debris thickness as soon as the debris layer reaches a thickness of over 10 cm.

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Section: Influence Of Supraglacial Hydrology On Ice Cliff Distributionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Controls on Ice Cliff Distribution and Characteristics on Debris‐Covered Glaciers

Kneib

Fyffe

Miles

et al. 2023

Geophysical Research Letters

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“…CC BY 4.0 License. (Immerzeel et al, 2014;Brun et al, 2018;Mölg et al, 2019;Anderson et al, 2021a;Kneib et al, 2021Kneib et al, , 2022Mishra et al, 2021;Sato et al, 2021). These studies confirm the potential for investigating glacier-or sub-glacierscale domains based on high-resolution data, which can provide detailed observations of local processes (e.g., Westoby et al, 2020).…”

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confidence: 62%

Thinning and surface mass balance patterns of two neighboring debris-covered glaciers in southeastern Tibetan Plateau

Yang

Miles

Westoby

et al. 2022

Preprint

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Abstract. Debris-covered glaciers are a common feature of the mountain cryosphere in the southeastern Tibetan Plateau. A better understanding of these glaciers change is necessary to reduce the uncertainties of the regional water resource variability, and to anticipate potential cryospheric risks. In this study, we quantify seasonal thinning (dh) and surface mass balance (SMB) patterns of two neighboring debris-covered glaciers (23 K Glacier and 24 K Glacier) in the southeastern Tibetan Plateau with repeated unpiloted aerial vehicle (UAV) surveys and in-situ measurements. We observe that the dh pattern of 23 K Glacier is distinct from that of 24 K Glacier, despite their proximity. The dh magnitude of the 23 K Glacier is ~1.4–3.0 times greater than that of the 24 K Glacier at all periods, which is mainly driven by the stronger dynamic state of 24 K Glacier. The contrasted behaviour between the two glaciers is also valid in the early twenty-first century. In contrast, the SMB patterns of the two glaciers are generally in agreement at different periods. The debris thickness distribution correlates with the SMB spatial distribution for both glaciers, while the supraglacial ice cliffs and ponds area density distribution is not correlated with SMB spatial distribution. This high-resolution comparison study of two neighboring glaciers confirms the significance of both glacier dynamic and debris thickness in controlling the thinning and melt for the different type debris-covered glaciers of the southeastern Tibetan Plateau in the context of climate change.

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“…Both the catchment‐scale and glacier‐scale comparisons show a discrepancy between remote sensing inferred and modeled ablation patterns in the debris‐covered ablation zone, where the model shows less annual ablation than is inferred from the satellite‐derived estimates. Like the other main glaciers in the valley, Langtang Glacier has a heavily debris‐covered tongue with supraglacial ice cliffs and ponds (Kneib, Miles, Buri, et al., 2021; Kneib, Miles, Jola, et al., 2021; E. S. Miles et al., 2017; Steiner et al., 2019) which locally enhance glacier melt (Buri et al., 2021; E. S. Miles et al., 2018) and lead to increased glacier thinning rates in areas of high density of these features (Ragettli, Bolch, et al., 2016). The mass loss effects of cliffs and ponds on the glacier surface are not included in the model and are also not represented in the debris thickness.…”

Section: Resultsmentioning

confidence: 99%

Land Surface Modeling in the Himalayas: On the Importance of Evaporative Fluxes for the Water Balance of a High‐Elevation Catchment

Buri,

Fatichi,

Shaw

et al. 2023

Water Resources Research

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High Mountain Asia (HMA) is among the most vulnerable water towers globally and yet future projections of water availability in and from its high‐mountain catchments remain uncertain, as their hydrologic response to ongoing environmental changes is complex. Mechanistic modeling approaches incorporating cryospheric, hydrological, and vegetation processes in high spatial, temporal, and physical detail have never been applied for high‐elevation catchments of HMA. We use a land surface model at high spatial and temporal resolution (100 m and hourly) to simulate the coupled dynamics of energy, water, and vegetation for the 350 km2 Langtang catchment (Nepal). We compare our model outputs for one hydrological year against a large set of observations to gain insight into the partitioning of the water balance at the subseasonal scale and across elevation bands. During the simulated hydrological year, we find that evapotranspiration is a key component of the total water balance, as it causes about the equivalent of 20% of all the available precipitation or 154% of the water production from glacier melt in the basin to return directly to the atmosphere. The depletion of the cryospheric water budget is dominated by snow melt, but at high elevations is primarily dictated by snow and ice sublimation. Snow sublimation is the dominant vapor flux (49%) at the catchment scale, accounting for the equivalent of 11% of snowfall, 17% of snowmelt, and 75% of ice melt, respectively. We conclude that simulations should consider sublimation and other evaporative fluxes explicitly, as otherwise water balance estimates can be ill‐quantified.

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Interannual Dynamics of Ice Cliff Populations on Debris‐Covered Glaciers From Remote Sensing Observations and Stochastic Modeling

Cited by 19 publications

References 97 publications

Controls on Ice Cliff Distribution and Characteristics on Debris‐Covered Glaciers

Controls on Ice Cliff Distribution and Characteristics on Debris‐Covered Glaciers

Thinning and surface mass balance patterns of two neighboring debris-covered glaciers in southeastern Tibetan Plateau

Land Surface Modeling in the Himalayas: On the Importance of Evaporative Fluxes for the Water Balance of a High‐Elevation Catchment

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