Quantifying the snowmelt-albedo feedback at Neumayer Station, East Antarctica

Jakobs, Constantijn L.; Reijmer, C. H.; Munneke, Peter Kuipers; König-Langlo, Gert; Broeke, Michiel van den

doi:10.5194/tc-2018-221

Cited by 10 publications

(22 citation statements)

References 46 publications

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“…The choice of fresh snow grain size is limited by the availability of look‐up tables for the dry snow metamorphism d r e,dry (see also Jakobs et al. (2019)); the refrozen snow grain size provided the best comparison with observations (Van Wessem et al., 2018). Furthermore, f o , f n , and f r are the fractions of old, fresh and refrozen snow.…”

Section: Methodsmentioning

confidence: 99%

“…(2011) and Jakobs et al. (2019), who used more than two layers to calculate the surface albedo. Equations for d α u , d α τ , d r e,dry , d r e,wet and A can be found in Gardner and Sharp (2010).…”

Section: Methodsmentioning

confidence: 99%

“…In a previous study, we used high‐quality meteorological observations from Neumayer Station, located on Ekström ice shelf in East Antarctica, to quantify the effect of SMAF on surface melt rates (Jakobs et al., 2019). We used a surface energy balance (SEB) model that includes a grain‐size‐dependent albedo parameterization, and found that on average, SMAF enhanced surface melt (1992–2016) at Neumayer Station by a factor of 2.5, but with significant inter‐annual variability.…”

Section: Introductionmentioning

confidence: 99%

“…Only one component of SMAF, the “real” melt, can be compared to observations, which has been done in Jakobs et al. (2019).…”

Section: Introductionmentioning

confidence: 99%

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Spatial Variability of the Snowmelt‐Albedo Feedback in Antarctica

et al. 2021

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Surface melt is an important process for the stability of ice shelves, and therewith the Antarctic ice sheet. In Antarctica, absorption of solar radiation is mostly the largest energy source for surface melt, which is further enhanced by the snowmelt‐albedo feedback (SMAF): Refrozen snow has a lower albedo than new snow, which causes it to absorb more solar radiation, further increasing the energy available for surface melt. This feedback has previously been shown to increase surface melt by approximately a factor of 2.5 at Neumayer Station in East Antarctica. In this study, we use a regional climate model to quantify SMAF for the entire Antarctic ice sheet. We find that it is most effective on ice shelves in East Antarctica, and is less important in the Antarctic Peninsula and on the Ross and Filchner‐Ronne ice shelves. We identify a relationship between SMAF and average summer 2 m air temperatures, and find that SMAF is most important around 265 ± 2 K. On a subseasonal scale, we identify several parameters that contribute to SMAF: the length of dry periods, the time between significant snowfall events and snowmelt events, and prevailing temperatures. We then apply the same temperature dependency of SMAF to the Greenland ice sheet and find that it is potentially active in a narrow band around the ice sheet, and finally discuss how the importance of SMAF could change in a warming climate.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Only one component of SMAF, the “real” melt, can be compared to observations, which has been done in Jakobs et al. (2019).…”

Section: Introductionmentioning

confidence: 99%

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Spatial Variability of the Snowmelt‐Albedo Feedback in Antarctica

et al. 2021

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“…On the other hand, Holland et al (2011) and Kuipers Munneke et al (2014b) suggested that modelled firn air content on large parts of Larsen C ice shelf is too low, caused by either meltrates that are overestimated, or accumulation rates that are too low, or both. This can also be related to how deep the meltwater penetrates into the firn and how important the sensitive melt-albedo feedbacks (Jakobs et al, 2018) is. Obviously, to tackle these problems, more observational constraints are needed.…”

Section: Firn Air Content Lateral Meltwater and Superimposed Icementioning

confidence: 99%

Modelling perennial firn aquifers in the Antarctic Peninsula (1979–2016)

Wessem¹,

Steger²,

Wever³

et al. 2020

Preprint

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Abstract. We use two snow models, the IMAU Firn Densification Model (IMAU-FDM) and SNOWPACK, to model firn characteristics in the Antarctic Peninsula (AP). We force these models with mass and energy fluxes from the Regional Atmospheric Climate MOdel (RACMO2.3p2) to construct a 1979–2016 climatology of AP firn density, temperature and liquid water content. A comparison with 75 snow temperature observations at 10 m depth and with density from 11 firn cores, suggests that both snow models perform adequately. In this study, we focus on the detection of so-called perennial firn aquifers (PFAs), that are formed when surface meltwater percolates into the firnpack in summer, is then buried by snowfall, and does not refreeze during the following winter. In 941 model grid points, covering ~ 28,000 km2, PFAs existed for at least one year in the simulated period, most notably in the western AP. At these locations, surface meltwater production exceeds 150 to 300 mm w.e. yr−1, with accumulation at least an order of magnitude larger. Most pronounced and widespread are PFAs modelled on and around Wilkins ice shelf. Here, both meltwater production and accumulation rates are sufficiently high to cause PFA formation in most years in the 1979–2016 period, covering a large part of the ice shelf. Other notable PFA locations are Wordie ice shelf, an ice shelf that has almost completely disappeared in recent decades, and the relatively warm northwestern mountain ranges of Palmer Land, where accumulations rates can be extremely large and PFAs are formed frequently. We find that not only the magnitude of melt and accumulation is important, but also the timing. If large accumulation events occur in the months following an above average summer melt event, this favours PFA formation in that year. Finally, we find that most PFAs are predicted near the grounding lines of the (former) Prince Gustav, Wilkins and Wordie ice shelves. This highlights the need to further investigate how PFAs may impact ice shelf disintegration events, in a similar way as supraglacial lakes do.

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Greenland Ice Sheet Daily Surface Melt Flux Observed From Space

Zheng

Cheng

Shang

et al. 2022

Geophysical Research Letters

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Greenland Ice Sheet (GrIS) surface melt has contributed to the global sea‐level rise and the ongoing warming is expected to promote this process. This study provides a new strategy for the quantitative estimate of GrIS daily surface melt at enhanced resolution (3.125 km) from a remote sensing perspective beyond traditional regional climate models (RCMs). Daily melt flux is estimated from spaceborne radiometer observations with a back‐propagation neural network model. The network is trained with melt fluxes that are calculated using detailed in‐situ atmospheric and snow observations and a surface energy balance model. Our results provide details about the extreme melt in mid‐July 2012 when surface melt occurred at Summit and the meltwater volume exceeded 20 Gt as a result of anomalous warming. Meltwater volume from the satellite is very close to that from RCMs.

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Quantifying the snowmelt-albedo feedback at Neumayer Station, East Antarctica

Cited by 10 publications

References 46 publications

Spatial Variability of the Snowmelt‐Albedo Feedback in Antarctica

Spatial Variability of the Snowmelt‐Albedo Feedback in Antarctica

Modelling perennial firn aquifers in the Antarctic Peninsula (1979–2016)

Greenland Ice Sheet Daily Surface Melt Flux Observed From Space

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