Albedo of coastal landfast sea ice in Prydz Bay, Antarctica: Observations and parameterization

Abstract

The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica (off Zhongshan Station) during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters (e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed, which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo.

Measurements of turbulence transfer in the near-surface layer over the Antarctic sea-ice surface from April through November in 2016

“…From Figure 5f, the highest monthly mean albedo, being 0.93, occurred in July. The albedo gradually decreased from July to October, reflecting the freezing process of accumulated snow (Yang and others, 2016). While melting process changed the properties of ice surface, making the monthly mean albedo in November much smaller (0.69) than that in other months (>0.8).…”

Spectral albedo of coastal landfast sea ice in Prydz Bay, Antarctica

“…The fast-ice observation site is located in the coastal area off Zhongshan Station (69°22 ′ S, 76°22 ′ E), Prydz Bay, East Antarctica (Yang and others, 2016;Zhao and others, 2019). Prydz Bay is mostly covered by seasonal sea ice.…”

“…Snowfall and drifting snow cause large spatial and temporal changes in the surface albedo (Laine, 2008). The ice albedo can increase from 0.54 to 0.89 after the occurrence of snowfall (Pirazzini, 2004), and snow thickness is an important factor influencing Antarctic landfast sea-ice albedo (Yang and others, 2016). The albedo of snow and ice is also strongly influenced by the solar elevation angle, and has significant daily cycles under clear skies (Pirazzini, 2004).…”

Atmospheric Dynamics Footprint on the January 2016 Ice Sheet Melting in West Antarctica

“…Unlike the melting of the fringing ice shelves from below, which is dominated by nonradiative processes, both radiative and nonradiative processes are important for the melting of surface snow. From the long-term change perspective, radiative processes include external forcings, such as CO 2 (Marshall & Thompson, 2016), and internal feedback processes, such as ice-albedo feedback (Yang et al, 2016), water vapor feedback, cloud feedback (Bony et al, 2006), cloud ice feedback in nonsummer months (Kay & Gettelman, 2009), and cloud optical depth feedback (Zelinka et al, 2012). Atmospheric nonradiative processes, which include changes in atmospheric large-scale circulations, regulate Antarctic ice sheet via causing air temperature and wind stress changes (Holland & Kwok, 2012).…”