Diverging future surface mass balance between the Antarctic ice shelves and grounded ice sheet

Kittel, Christoph; Amory, Charles; Agosta, Cécile; Jourdain, Nicolas C.; Höfer, Stefan; Delhasse, Alison; Doutreloup, Sébastien; Huot, Pierre-Vincent; Lang, Charlotte; Fichefet, Thierry; Fettweis, Xavier

doi:10.5194/tc-15-1215-2021

Cited by 107 publications

(138 citation statements)

References 99 publications

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“…The largest increases are found at the sixth and seventh vertical levels (38 and 67 m), near the level experiencing maximum sublimation (fourth vertical model level, 12 m). As already suggested (e.g., Kodama et al, 1985), wind speed can increase during drifting snow events because of increased density of the air-snow mixture and an increased stable thermal stratification (Fig. 6a) caused by the atmospheric sublimation-induced cooling, which is a positive feedback on a sloping surface due to the gravitational nature of katabatic winds (Bintanja, 2000).…”

Section: Impact On the Boundary Layersupporting

confidence: 56%

“…MAR is a hydrostatic regional climate model solving primitive equations as originally described in Gallée and Schayes (1994) and has been extensively used for decade-long climate simulations over high-latitude regions (e.g., Agosta et al, 2019;Fettweis et al, 2017Fettweis et al, , 2020Mottram et al, 2020;Kittel et al, 2021). Five atmospheric water species are represented in the model: specific humidity, cloud droplets, rain drops, cloud ice crystals, and snow particles (Gallée and Schayes, 1994).…”

Section: Model Descriptionmentioning

confidence: 99%

“…Firstly, the increase in air density due to the weight of suspended snow, which is accounted for in the model by including the contribution of suspended snow in the computation of the potential virtual temperature (Gallée et al, 2001), is inherently amplified when eroded particles contribute to the airborne snow mass. Secondly, driftingsnow sublimation and subsequent cooling of the atmosphere is computed at each model vertical level and contributes to increasing air density and atmospheric stability, which enhances the along-slope pressure gradient force and is a positive feedback in katabatic flows (Kodama et al, 1985;Gallée, 1998). Finally, the aerodynamic roughness length z 0 is computed following a relationship previously fitted on observed z 0 values in order to take into account the seasonality of surface roughness in a drifting-snow climate as observed in Adelie Land (Amory et al, 2021).…”

Section: Model Descriptionmentioning

confidence: 99%

“…In this paper we use the regional climate model MAR to quantify the influence of drifting snow on the nearsurface climate and SEB in Adelie Land, a coastal region of East Antarctica particularly prone to erosive winds and where drifting-snow equipment deployed over the past few years provide observational support for model evaluation near the surface (Trouvilliez et al, 2014;Amory et al, 2021). MAR has been widely used to simulate the climate and surface mass balance of polar ice sheets (e.g., Fettweis et al, 2017Fettweis et al, , 2020Hofer et al, 2017Hofer et al, , 2019Kittel et al, 2018Kittel et al, , 2021Mottram et al, 2020) and includes a detailed representation of drifting-snow processes already applied to study snow mass transport and wind-driven ablation in coastal East Antarctica (Gallée et al, 2005(Gallée et al, , 2013Amory et al, 2015Amory et al, , 2021. The explicit coupling of the drifting-snow scheme with the atmospheric component of the model enables a vertical discretization of drifting-snow profiles and related sublimation within the atmospheric boundary layer and takes into account the radiative contribution of driftingsnow particles.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica

Toumelin

Amory

Favier³

et al. 2021

The Cryosphere

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Abstract. In order to understand the evolution of the climate of Antarctica, dominant processes that control surface and low-atmosphere meteorology need to be accurately captured in climate models. We used the regional climate model MAR (v3.11) at 10 km horizontal resolution, forced by ERA5 reanalysis over a 9-year period (2010–2018) to study the impact of drifting snow (designating here the wind-driven transport of snow particles below and above 2 m) on the near-surface atmosphere and surface in Adelie Land, East Antarctica. Two model runs were performed, one with and one without drifting snow, and compared to half-hourly in situ observations at D17, a coastal and windy location of Adelie Land. We show that sublimation of drifting-snow particles in the atmosphere drives the difference between model runs and is responsible for significant impacts on the near-surface atmosphere. By cooling the low atmosphere and increasing its relative humidity, drifting snow also reduces sensible and latent heat exchanges at the surface (−5.7 W m−2 on average). Moreover, large and dense drifting-snow layers act as near-surface cloud by interacting with incoming radiative fluxes, enhancing incoming longwave radiation and reducing incoming shortwave radiation in summer (net radiative forcing: 5.7 W m−2). Even if drifting snow modifies these processes involved in surface–atmosphere interactions, the total surface energy budget is only slightly modified by introducing drifting snow because of compensating effects in surface energy fluxes. The drifting-snow driven effects are not prominent near the surface but peak higher in the boundary layer (fourth vertical level, 12 m) where drifting-snow sublimation is the most pronounced. Accounting for drifting snow in MAR generally improves the comparison at D17, especially for the representation of relative humidity (mean bias reduced from −14.0 % to −0.7 %) and incoming longwave radiation (mean bias reduced from −20.4 W m−2 to −14.9 W m−2). Consequently, our results suggest that a detailed representation of drifting-snow processes is required in climate models to better capture the near-surface meteorology and surface–atmosphere interactions in coastal Adelie Land.

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Section: Impact On the Boundary Layersupporting

confidence: 56%

Section: Model Descriptionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica

Toumelin

Amory

Favier³

et al. 2021

The Cryosphere

Self Cite

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“…The time-dependent, multilayer, single-column snow model is based on a firn densification model and relates the firn density, temperature and liquid water content to the surface temperature, accumulation and wind speed. The regional climate model MAR version 3.11, henceforth termed MAR, has been developed independently from RACMO (Kittel et al, 2021). It covers the AIS with a horizontal resolution of 35 km and is forced by the ERA5 reanalysis data (Hersbach et al, 2020) over the period January 1979 through December 2019.…”

Section: Introductionmentioning

confidence: 99%

Surface Mass Balance Models Vs. Stake Observations: A Comparison in the Lake Vostok Region, Central East Antarctica

et al. 2021

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The surface mass balance (SMB) is very low over the vast East Antarctic Plateau, for example in the Vostok region, where the mean SMB is on the order of 20–35 kg m-2 a-1. The observation and modeling of spatio-temporal SMB variations are equally challenging in this environment. Stake measurements carried out in the Vostok region provide SMB observations over half a century (1970–2019). This unique data set is compared with SMB estimations of the regional climate models RACMO2.3p2 (RACMO) and MAR3.11 (MAR). We focus on the SMB variations over time scales from months to decades. The comparison requires a rigorous assessment of the uncertainty in the stake observations and the spatial scale dependence of the temporal SMB variations. Our results show that RACMO estimates of annual and multi-year SMB agree well with the observations. The regression slope between modelled and observed temporal variations is close to 1.0 for this model. SMB simulations by MAR are affected by a positive bias which amounts to 6 kg m-2 a-1 at Vostok station and 2 kg m-2 a-1 along two stake profiles between Lake Vostok and Ridge B. None of the models is capable to reproduce the seasonal distributions of SMB and precipitation. Model SMB estimates are used in assessing the ice-mass balance and sea-level contribution of the Antarctic Ice Sheet by the input-output method. Our results provide insights into the uncertainty contribution of the SMB models to such assessments.

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The Transient Sea Level response to external forcing in CMIP6 models

Grinsted

Bamber

Bingham

et al. 2022

Preprint

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 The rate of ice sheet mass loss and ocean expansion has a near linear relationship to global mean surface warming in both models and data.  The modeled transient sensitivity of the sea level budget to warming is compatible with historical behavior except for Antarctic mass loss.  Models of Antarctic mass loss may be biased as data shows increasing losses with warming in contrast to models.

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Diverging future surface mass balance between the Antarctic ice shelves and grounded ice sheet

Cited by 107 publications

References 99 publications

Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica

Sensitivity of the surface energy budget to drifting snow as simulated by MAR in coastal Adelie Land, Antarctica

Surface Mass Balance Models Vs. Stake Observations: A Comparison in the Lake Vostok Region, Central East Antarctica

The Transient Sea Level response to external forcing in CMIP6 models

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