Light transmission and reflection in perennially ice‐covered Lake Hoare, Antarctica Journal Article uri icon



  • We have investigated the transmission and albedo of the perennial ice cover on Lake Hoare, Antarctica. Our database consists of year‐round measurements of the photosynthetically active radiation (400–700 nm) under the ice, measurements of the spatial variation of the under‐ice light in midsummer, and spectrally resolved measurements from 400 to 700 nm of the albedo and transmission of the ice cover in early (November) and in midsummer (January). Our results show that the transmission decreases in the first part of summer, dropping by a factor of ∼4 from November to January. We suggest that this is due to heating in the upper layers of the ice cover and the formation of Tyndall figures. Later in the summer when a significant liquid water fraction occurs within the ice cover, the transmission increases. In the fall when the ice cover freezes solid the transmission drops markedly. The spectrally resolved measurements from 400 to 700 nm show that ∼2–5% of the incident light in this spectral region penetrates the 3.5‐m thick ice cover. We have analyzed the spectral data using a two‐stream scattering solution to the radiative transfer equation with three vertical layers in the ice cover. A surficial glaze of scattering ice 1 cm thick overlies a layer of sandy, bubbly ice about a meter thick, and below this is a thick layer of sand‐free ice with bubbles. We find that the ice cover is virtually opaque at wavelengths longer than 800 nm. The net transmission of solar energy is ∼2%. Significant changes in the thickness of the ice cover have been reported at Lake Hoare. These are due primarily to changes in the thickness of the bottom layer only. Because this layer is relatively clear, the effect on the transmission through the ice cover from these changes is less than would be predicted assuming a homogeneous ice cover.

publication date

  • October 15, 1994

has restriction

  • closed

Date in CU Experts

  • January 25, 2017 1:10 AM

Full Author List

  • McKay CP; Clow GD; Andersen DT; Wharton RA

author count

  • 4

Other Profiles

International Standard Serial Number (ISSN)

  • 0148-0227

Additional Document Info

start page

  • 20427

end page

  • 20444


  • 99


  • C10