On the importance of subsurface heat flux for estimating the mass balance of alpine glaciers

In this study, energy and mass balance is quantified using an energy balance model to represent the glacier melt of Urumqi Glacier No. 1, Chinese Tian Shan. Based on data from an Automatic Weather Station (4025 m a.s.l) and the mass balance field survey data nearby on the East Branch of the glacier, the “COupled Snowpack and Ice surface energy and Mass balance model” (COSIMA) was used to derive energy and mass balance simulations during the ablation season of 2018. Results show that the modeled cumulative mass balance (−0.67 ± 0.03 m w.e.) agrees well with the in-situ measurements (−0.64 ± 0.16 m w.e.) (r2 = 0.96) with the relative difference within 5% during the study period. The correlation coefficient between modeled and observed surface temperatures is 0.88 for daily means. The main source of melt energy at the glacier surface is net shortwave radiation (84%) and sensible heat flux (16%). The energy expenditures are from net longwave radiation (55%), heat flux for snow/ice melting (32%), latent heat flux of sublimation and evaporation (7%), and subsurface heat flux (6%). The sensitivity testing of mass balance shows that mass balance is more sensitive to temperature increase and precipitation decrease than temperature decrease and precipitation increase.

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Modeling Mass-Balance Changes During a Glaciation Cycle

Annals of Glaciology ◽

10.1017/s0260305500008661 ◽

1990 ◽

Vol 14 ◽

pp. 238-241 ◽

Cited By ~ 24

Author(s):

M.S. Pelto ◽

S.M. Higgins ◽

T.J. Hughes ◽

J.L. Fastook

Keyword(s):

Mass Balance ◽

Ice Sheets ◽

Climatic Conditions ◽

Alpine Glacier ◽

Alpine Glaciers

Identification of present-day climate setting and alpine glacier-balance gradients indicates that the balance gradient of alpine glaciers is primarily determined by climatic conditions. Determination of balance gradients for specific climatic settings on present-day ice sheets provides an analog for determining the mass balance on paleo and future ice sheets.

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Thin ice, deep snow and surface flooding in Kotzebue Sound: landfast ice mass balance during two anomalously warm winters and implications for marine mammals and subsistence hunting

Journal of Glaciology ◽

10.1017/jog.2021.49 ◽

2021 ◽

pp. 1-15

Author(s):

Andrew R. Mahoney ◽

Kate E. Turner ◽

Donna D. W. Hauser ◽

Nathan J. M. Laxague ◽

Jessica M. Lindsay ◽

...

Keyword(s):

Heat Flux ◽

Sea Ice ◽

Mass Balance ◽

Marine Mammals ◽

Advisory Council ◽

Subsistence Hunting ◽

Ice Growth ◽

Landfast Ice ◽

Ice Mass Balance ◽

Kotzebue Sound

Abstract The inaugural data from the first systematic program of sea-ice observations in Kotzebue Sound, Alaska, in 2018 coincided with the first winter in living memory when the Sound was not choked with ice. The following winter of 2018–19 was even warmer and characterized by even less ice. Here we discuss the mass balance of landfast ice near Kotzebue (Qikiqtaġruk) during these two anomalously warm winters. We use in situ observations and a 1-D thermodynamic model to address three research questions developed in partnership with an Indigenous Advisory Council. In doing so, we improve our understanding of connections between landfast ice mass balance, marine mammals and subsistence hunting. Specifically, we show: (i) ice growth stopped unusually early due to strong vertical ocean heat flux, which also likely contributed to early start to bearded seal hunting; (ii) unusually thin ice contributed to widespread surface flooding. The associated snow ice formation partly offset the reduced ice growth, but the flooding likely had a negative impact on ringed seal habitat; (iii) sea ice near Kotzebue during the winters of 2017–18 and 2018–19 was likely the thinnest since at least 1945, driven by a combination of warm air temperatures and a persistent ocean heat flux.

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Energy and mass balance of Zhadang glacier surface, central Tibetan Plateau

Journal of Glaciology ◽

10.3189/2013jog12j152 ◽

2013 ◽

Vol 59 (213) ◽

pp. 137-148 ◽

Cited By ~ 68

Author(s):

Guoshuai Zhang ◽

Shichang Kang ◽

Koji Fujita ◽

Eva Huintjes ◽

Jianqing Xu ◽

...

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Tibetan Plateau ◽

Surface Energy ◽

Mass Balance ◽

Longwave Radiation ◽

Specific Mass ◽

Glacier Surface ◽

Central Tibetan Plateau ◽

Precipitation Seasonality

AbstractClimate variables that control the annual cycle of the surface energy and mass balance on Zhadang glacier in the central Tibetan Plateau were examined over a 2 year period using a physically based energy-balance model forced by routine meteorological data. The modelled results agree with measured values of albedo, incoming longwave radiation, surface temperature and surface level of the glacier. For the whole observation period, the radiation component dominated (82%) the total surface energy heat fluxes. This was followed by turbulent sensible (10%) and latent heat (6%) fluxes. Subsurface heat flux represented a very minor proportion (2%) of the total heat flux. The sensitivity of specific mass balance was examined by perturbations of temperature (±1 K), relative humidity (±20%) and precipitation (±20%). The results indicate that the specific mass balance is more sensitive to changes in precipitation than to other variables. The main seasonal variations in the energy balance were in the two radiation components (net shortwave radiation and net longwave radiation) and these controlled whether surface melting occurred. A dramatic difference in summer mass balance between 2010 and 2011 indicates that the glacier surface mass balance was closely related to precipitation seasonality and form (proportion of snowfall and rainfall).

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Representing moisture fluxes and phase changes in glacier debris cover using a reservoir approach

The Cryosphere ◽

10.5194/tc-8-1429-2014 ◽

2014 ◽

Vol 8 (4) ◽

pp. 1429-1444 ◽

Cited By ~ 31

Author(s):

E. Collier ◽

L. I. Nicholson ◽

B. W. Brock ◽

F. Maussion ◽

R. Essery ◽

...

Keyword(s):

Heat Flux ◽

Surface Energy ◽

Mass Balance ◽

Latent Heat ◽

Latent Heat Flux ◽

Phase Changes ◽

Heat Extraction ◽

Future Research ◽

Effective Thermal Diffusivity ◽

Ice Melt

Abstract. Due to the complexity of treating moisture in supraglacial debris, surface energy balance models to date have neglected moisture infiltration and phase changes in the debris layer. The latent heat flux (QL) is also often excluded due to the uncertainty in determining the surface vapour pressure. To quantify the importance of moisture on the surface energy and climatic mass balance (CMB) of debris-covered glaciers, we developed a simple reservoir parameterization for the debris ice and water content, as well as an estimation of the latent heat flux. The parameterization was incorporated into a CMB model adapted for debris-covered glaciers. We present the results of two point simulations, using both our new "moist" and the conventional "dry" approaches, on the Miage Glacier, Italy, during summer 2008 and fall 2011. The former year coincides with available in situ glaciological and meteorological measurements, including the first eddy-covariance measurements of the turbulent fluxes over supraglacial debris, while the latter contains two refreeze events that permit evaluation of the influence of phase changes. The simulations demonstrate a clear influence of moisture on the glacier energy and mass-balance dynamics. When water and ice are considered, heat transmission to the underlying glacier ice is lower, as the effective thermal diffusivity of the saturated debris layers is reduced by increases in both the density and the specific heat capacity of the layers. In combination with surface heat extraction by QL, subdebris ice melt is reduced by 3.1% in 2008 and by 7.0% in 2011 when moisture effects are included. However, the influence of the parameterization on the total accumulated mass balance varies seasonally. In summer 2008, mass loss due to surface vapour fluxes more than compensates for the reduction in ice melt, such that the total ablation increases by 4.0%. Conversely, in fall 2011, the modulation of basal debris temperature by debris ice results in a decrease in total ablation of 2.1%. Although the parameterization is a simplified representation of the moist physics of glacier debris, it is a novel attempt at including moisture in a numerical model of debris-covered glaciers and one that opens up additional avenues for future research.

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Estimating Oceanic Heat Flux from Sea-Ice Thickness and Temperature Data

Annals of Glaciology ◽

10.3189/s026030550000882x ◽

1990 ◽

Vol 14 ◽

pp. 315-318 ◽

Cited By ~ 1

Author(s):

J.S. Wettlaufer ◽

N. Untersteiner ◽

R. Colony

Keyword(s):

Heat Flux ◽

Sea Ice ◽

Mass Balance ◽

Temperature Data ◽

Ice Thickness ◽

Sea Ice Thickness ◽

North East ◽

Oceanic Heat Flux ◽

Ocean Models

All studies and models of air—sea-ice interactions suffer from a paucity of information about the oceanic heat flux, which exerts a controlling influence on the sea-ice energy and mass balance. The role of the oceanic heat flux in the sea-ice energy and mass balance is discussed. The performance of ice-ocean models depends on a satisfactory specification of this rarely measured oceanic parameter. A method for determining the oceanic heat flux by measuring the temperatures and thickness of sea ice is described. The results obtained using this method and the data collected during the fall of 1988 in the eastern Arctic are presented. Values of the oceanic heat flux ranging from 0 to 37 W m−2 were estimated from observations taken in the region north-east of Fram Strait. The oceanic heat flux in this region varied in both time and space.

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Climatic Interpretation of Alpine Snowline Variations on Millennial Time Scales

Quaternary Research ◽

10.1006/qres.1994.1017 ◽

1994 ◽

Vol 41 (2) ◽

pp. 154-159 ◽

Cited By ~ 56

Author(s):

Geoffrey O. Seltzer

Keyword(s):

Mass Balance ◽

Time Scales ◽

Snow Accumulation ◽

Lapse Rate ◽

Glacier Mass Balance ◽

Glacier Surface ◽

Proxy Records ◽

Alpine Glaciers ◽

Number Of Factors ◽

Mass Balance Approach

AbstractThe depression of snowlines, or equilibrium-line altitudes, of alpine glaciers is often used by glacial geologists to infer variations in mass balance. The climatic interpretation of snowline depression, however, is complicated by the number of factors that control glacier mass balance. The simple lapse-rate method of temperature interpretation ignores the effects of changes in radiation and snow accumulation. The statistical approach to temperature interpretation, which regresses precipitation and temperature against snowline altitude, neglects the effect of radiation. The most comprehensive approach for the climatic interpretation of snowline depression couples the heat and mass balances of a glacier surface. A sensitivity analysis that utilizes the coupled heat- and mass-balance approach indicates that the ∼1000-m variation in snowline of alpine glaciers on glacial-to-interglacial time scales could be a result of significant changes in temperature, and to a lesser extent changes in insolation. Snowline variations are sensitive only to relatively large changes in annual accumulation, which should also be evident in other proxy records of moisture change. The approaches outlined here provide glacial geologists with a summary of how various climatic forcings associated with glaciation may be quantified from snowline data.

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Methodological approaches to infer end-of-winter snow distribution on alpine glaciers

Journal of Glaciology ◽

10.3189/2013jog13j015 ◽

2013 ◽

Vol 59 (218) ◽

pp. 1047-1059 ◽

Cited By ~ 46

Author(s):

Leo Sold ◽

Matthias Huss ◽

Martin Hoelzle ◽

Hubert Andereggen ◽

Philip C. Joerg ◽

...

Keyword(s):

Mass Balance ◽

Snow Depth ◽

Multiple Linear Regression Model ◽

Field Measurements ◽

Liquid Water Content ◽

Snow Accumulation ◽

Small Scale ◽

Alpine Glaciers ◽

Mass Balance Models

AbstractSnow accumulation is an important component of the mass balance of alpine glaciers. To improve our understanding of the processes related to accumulation and their representation in state-of-the-art mass-balance models, extensive field measurements are required. We present measurements of snow accumulation distribution on Findelengletscher, Switzerland, for April 2010 using (1) in situ snow probings, (2) airborne ground-penetrating radar (GPR) and (3) differencing of two airborne light detection and ranging (lidar) digital elevation models (DEMs). Calculating high-resolution snow depth from DEM-differencing requires careful correction for vertical ice-flow velocity and densification in the accumulation area. All three methods reveal a general increase in snow depth with elevation, but also a significant small-scale spatial variability. Lidar-differencing and in situ snow probings show good agreement for the mean specific winter balance (0.72 and 0.78 m w.e., respectively). The lidar-derived distributed snow depth reveals significant zonal correlations with elevation, slope and curvature in a multiple linear regression model. Unlike lidar-differencing, GPR-derived snow depth is not affected by glacier dynamics or firn compaction, but to a smaller degree by snow density and liquid water content. It is thus a valuable independent data source for validation. The simultaneous availability of the three datasets facilitates the comparison of the methods and contributes to a better understanding of processes that govern winter accumulation distribution on alpine glaciers.

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Analytical Study of Critical Heat Flux in Two-Phase Thermosyphon: Relationship Between Maximum Falling Liquid Rate and Critical Heat Flux

Journal of Heat Transfer ◽

10.1115/1.2825861 ◽

1996 ◽

Vol 118 (2) ◽

pp. 422-428 ◽

Cited By ~ 13

Author(s):

M. Monde

Keyword(s):

Heat Flux ◽

Mass Balance ◽

Critical Heat Flux ◽

Partial Derivative ◽

Analytical Study ◽

Momentum Equation ◽

Vapor Flow ◽

Maximum Point ◽

Two Phase ◽

Good Agreement

An analytical study has been done on the critical heat flux of a two-phase thermosyphon, in which a liquid film and a vapor flow exist in a countercurrent annular flow. The CHF point on the thermosyphon is proved to correspond to a maximum falling liquid rate fed to the thermosyphon, which can be determined from three equations of momentum, its partial derivative with void fraction, and mass balance in the thermosyphon. This maximum point, furthermore, becomes identical to the point at which an envelope line generated from the momentum equation and its partial derivative intersects the mass balance line. The CHF calculated from the maximum liquid rate is found to be in fairly good agreement with the existing CHF data.

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Ablation modeling and surface energy budget in the ablation zone of Laohugou glacier No. 12, western Qilian mountains, China

Annals of Glaciology ◽

10.3189/2014aog66a902 ◽

2014 ◽

Vol 55 (66) ◽

pp. 111-120 ◽

Cited By ~ 24

Author(s):

Weijun Sun ◽

Xiang Qin ◽

Wentao Du ◽

Weigang Liu ◽

Yushuo Liu ◽

...

Keyword(s):

Heat Flux ◽

Energy Balance ◽

Surface Energy ◽

Mass Balance ◽

Latent Heat ◽

Energy Budget ◽

Sensible Heat Flux ◽

Qilian Mountains ◽

Surface Energy Budget ◽

Ablation Zone

AbstractGlacier surface melting can be described using energy-balance models. We conducted a surface energy budget experiment to quantify surface energy fluxes and to identify factors affecting glacial melt in the ablation zone of Laohugou glacier No. 12, western Qilian mountains. The surface energy budget was calculated based on data from an automatic weather station, and turbulent fluxes calculated using the bulk-aerodynamic approach were corrected using measurements from an eddy-covariance system. Simulated mass balances were validated by stake observations. Net shortwave radiation was the primary component of the surface energy balance (126Wm–2), followed by sensible heat flux. Net longwave radiation (–45Wm–2) and latent heat flux (–12.8 Wm–2) represented heat sinks. The bulk-aerodynamic method underestimated sensible and latent heat fluxes by 3.4 and 1.2 W m–2, respectively. The simulated total mass balance of –1703mmw.e. exceeded the observed total by 90 mm w.e. Daily positive accumulated temperature and low albedo were the main factors accelerating glacier melt. An uncertainty assessment showed that mass balance was very sensitive to albedo and varied by 36% when albedo changed by 0.1.

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