Surface mass balance, ice velocity and near-surface ice temperature on Qaanaaq Ice Cap, northwestern Greenland, from 2012 to 2016

Tsutaki, Shun; Sugiyama, Shin; Sakakibara, Daiki; Aoki, Teruo; Niwano, Michio

doi:10.1017/aog.2017.7

Cited by 26 publications

(21 citation statements)

References 64 publications

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“…The site is located near the equilibrium line of the glacier, which was 1001 m a.s.l. in 2014, as determined by a mass balance study (Tsutaki et al, 2017). As reported previously, snow algae visibly bloomed on the snowpack at the study site from late July to August in 2014.…”

Section: Study Sites and Observation Methodssupporting

confidence: 66%

Temporal changes in snow albedo, including the possible effects of red algal growth, in northwest Greenland, simulated with a physically based snow albedo model

Onuma

Takeuchi

Tanaka

et al. 2019

Preprint

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Abstract. Surface albedo of snow and ice is substantially reduced by inorganic impurities, such as aeolian mineral dust (MD) and black carbon (BC), and also by organic impurities, such as microbes that live in the snow. In this paper, we present the temporal changes of surface albedo, snow grain size, MD, BC, and snow algal cell concentration observed on a snowpack in northwest Greenland during the ablation season of 2014 and our attempt to reproduce the changes in albedo with a physically based snow albedo model. We also attempt to reproduce the effects of inorganic impurities and the red snow algae (Chlamydomonas nivalis) on albedo. Concentrations of MD and red snow algae in the surface snow were found to increase in early August, while snow grain size and BC were found to not significantly change throughout the ablation season. Surface albedo was found to have decreased by 0.08 from late July to early August. The albedo simulated by the model agreed with the albedo observed during the study period. However, red snow algae exerted little effect on surface albedo in early August. This is probably owing to the abundance of smaller cells (4.9 × 104 cells L^-1) when compared with the cell abundance of typical red algal snow (~ 108 cells L−1). The simulation of snow albedo until the end of the melting season, with an algal growth model, revealed that the reduction in albedo attribute to red algae could equal 0.004, out of a total reduction of 0.102 arising from the three impurities on a snowpack in northwest Greenland. Finally, we conducted scenario simulations using the snow albedo model, coupled with the algal growth model, in order to simulate the possible effects of red algal blooming on snow albedo under warm conditions in northwest Greenland. The result suggests that albedo reduction by red snow algal growth under warm conditions (surface snow temperature of +1.5 °C) reached 0.04, equivalent to a radiative forcing of 7.5 W m−2 during the ablation season of 2014. This coupled albedo model has the potential to dynamically simulate snow albedo, including the effect of organic and inorganic impurities, leading to proper estimates of the surface albedo of snow cover in Greenland.

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Section: Study Sites and Observation Methodssupporting

confidence: 66%

Temporal changes in snow albedo, including the possible effects of red algal growth, in northwest Greenland, simulated with a physically based snow albedo model

Onuma

Takeuchi

Tanaka

et al. 2019

Preprint

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“…Nevertheless, the main annual air temperature at Qaanaaq airport, ca. 30 km south-west and seawards from the drilling sites, from 2005 to 2015, is −8.5 • C (Sugiyama et al, 2014;Tsutaki et al, 2017). The ice temperatures of −3.74 (BH2) and −1.35 • C measured in Bowdoin Glacier below the penetration depth of seasonal variations (Figure 4a) are significantly higher than this value.…”

Section: Latent Heatmentioning

confidence: 84%

Englacial Warming Indicates Deep Crevassing in Bowdoin Glacier, Greenland

et al. 2020

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All around the margins of the Greenland Ice Sheet, marine-terminating glaciers have recently thinned and accelerated. The reduced basal friction has yielded increased flow velocity, while the rate of longitudinal stretching has been limited by ice viscosity, which itself critically depends on temperature. However, ice temperature has rarely been measured on such fast-flowing and heavily crevassed glaciers. Here, we present a 3-year record of englacial temperatures obtained 2 (in 2014) to 1 km (in 2017) from the calving front of Bowdoin Glacier (Kangerluarsuup Sermia), a tidewater glacier in northwestern Greenland. Two boreholes separated by 165 (2014) to 197 m (2017) show significant temperature differences averaging 2.07 • C on their entire depth. Englacial warming of up to 0.39 • C a −1 , an order of magnitude above the theoretical rate of heat diffusion and viscous dissipation, indicates a deep and local heat source within the tidewater glacier. We interpret the heat source as latent heat from meltwater refreezing in crevasses reaching to, or near to, the bed of the glacier, whose localization may be controlled by preferential meltwater infiltration in topographic dips between ogives.

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“…Since the depth of the snowpack was deeper than that of surrounding areas, the snow persisted through much of the melt season. Site B is located at 944 m a.s.l., and was close to the equilibrium line of the glacier (Tsutaki et al, 2017). Meteorological data used in the study were collected with an auto-matic weather station (AWS), which was installed at Site B in 2012 by the Snow Impurity and Glacier Microbe effects on abrupt warming in the Arctic project (SIGMA) (Aoki et al, 2014).…”

Section: Study Sites and Methodsmentioning

confidence: 99%

Observations and modelling of algal growth on a snowpack in north-western Greenland

Onuma¹,

Takeuchi²,

Tanaka³

et al. 2018

The Cryosphere

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Abstract. Snow algal bloom is a common phenomenon on melting snowpacks in polar and alpine regions and can substantially increase snow melt rates due to the effect of albedo reduction on the snow surface. In order to reproduce algal growth on the snow surface using a numerical model, temporal changes in snow algal abundance were investigated on the Qaanaaq Glacier in north-western Greenland from June to August 2014. Snow algae first appeared at the study sites in late June, which was approximately 94 h after air temperatures exceeded the melting point. Algal abundance increased exponentially after this appearance, but the increasing rate became slow after late July, and finally reached 3.5 × 10 7 cells m −2 in early August. We applied a logistic model to the algal growth curve and found that the algae could be reproduced with an initial cell concentration of 6.9 × 10 2 cells m −2 , a growth rate of 0.42 d −1 , and a carrying capacity of 3.5 × 10 7 cells m −2 on this glacier. This model has the potential to simulate algal blooms from meteorological data sets and to evaluate their impact on the melting of seasonal snowpacks and glaciers.

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Surface mass balance, ice velocity and near-surface ice temperature on Qaanaaq Ice Cap, northwestern Greenland, from 2012 to 2016

Cited by 26 publications

References 64 publications

Temporal changes in snow albedo, including the possible effects of red algal growth, in northwest Greenland, simulated with a physically based snow albedo model

Temporal changes in snow albedo, including the possible effects of red algal growth, in northwest Greenland, simulated with a physically based snow albedo model

Englacial Warming Indicates Deep Crevassing in Bowdoin Glacier, Greenland

Observations and modelling of algal growth on a snowpack in north-western Greenland

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