Preprints
https://doi.org/10.5194/tc-2021-134
https://doi.org/10.5194/tc-2021-134

  17 Jun 2021

17 Jun 2021

Review status: this preprint is currently under review for the journal TC.

The sensitivity of landfast sea ice to atmospheric forcing in single-column model simulations: a case study at Zhongshan Station, Antarctica

Fengguan Gu1, Qinghua Yang1, Frank Kauker2,3, Changwei Liu1, Guanghua Hao4, Chaoyuan Yang1, Jiping Liu5, Petra Heil6, Xuewei Li1, and Bo Han1 Fengguan Gu et al.
  • 1School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
  • 2Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
  • 3Ocean Atmosphere Systems, Tewesstseg 4, 20249 Hamburg, Germany
  • 4Key Laboratory of Marine Hazards Forecasting, National Marine Environmental Forecasting Center, Ministry of Natural Resources, Beijing 100081, China
  • 5Department of Atmospheric and Environmental Sciences, State University of New York at Albany, Albany, NY, USA
  • 6Australian Antarctic Division and Australian Antarctic Program Partnership, Private Bag 80, Hobart, Tas 7001, Australia

Abstract. Single-column sea ice models are used to focus on the thermodynamic evolution of the ice. Generally these models are forced by atmospheric reanalysis in absence of atmospheric in situ observations. Here we assess the sea ice thickness (SIT) simulated by a single-column model (ICEPACK) with in situ observations obtained off Zhongshan Station for the austral winter of 2016. In the reanalysis the surface air temperature is about 1 °C lower, the total precipitation is about 2 mm day−1 larger, and the surface wind speed is about 2 m s−1 higher compared to the in situ observations, respectively. Using sensitivity experiments we evaluate the simulation bias in sea ice thickness due to the uncertainty in the individual atmospheric forcing variables. We show that the unrealistic precipitation in the reanalysis leads to a bias of 14.5 cm in sea ice thickness and of 17.3 cm in snow depth. In addition, our data show that increasing snow depth works to gradually inhibits the growth of sea ice associated with thermal blanketing by the snow due to changing the vertical heat flux. Conversely, given suitable conditions, the sea ice thickness may grow suddenly when the snow load gives rise to flooding and leads to snow-ice formation. A potential mechanism to explain the different characteristics of the precipitation bias on snow and sea ice is discussed. The flooding process for landfast sea ice might cause different effect compared to pack ice, thus need to be reconsidered in ICEPACK. Meanwhile, the overestimation in surface wind speed in reanalysis is likely responsible for the underestimation in simulated snow depth, however this had little influence on the modelled ice thickness.

Fengguan Gu et al.

Status: open (until 18 Aug 2021)

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Fengguan Gu et al.

Fengguan Gu et al.

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Short summary
The sea ice thickness was simulated by a single-column model and compared with in situ observations obtained off Antarctic Zhongshan Station. It is shown that the unrealistic precipitation in the atmospheric forcing data leads to the largest bias in sea ice thickness and snow depth modelling. In addition, the increasing snow depth gradually inhibits the growth of sea ice associated with thermal blanketing by the snow.