M.L. Van Woert
156
Time (Days)
Fig. 5. Same as Fig. 4 except that net heat flux is assumed to be the sum of the sensible,
latent, and longwave heat fluxes
tions occurring -40% of the time for the months May through August; partial
cloudy conditions were noted only occasionally in their diaries. The observed
U-shaped cloud cover distribution is consistent with cloud cover distributions
from recent observations in the Arctic and the Weddell Sea (Andréas, pers. comm.).
Because high-quality, time-coincident, fractional cloud cover data were not
available for this study, a baseline of C=0.5 was chosen. To examine the potential
impact of cloud cover fluctuations on polynya extent, the polynya model was once
again forced with the bulk sensible and latent heat fluxes [39] and the Maykut and
Church [40] longwave flux parameterization using 0, 50, and 100% cloud fractions. The time sériés of open water fraction was first regressed against the modeled polynya extent based on 50% cloud fraction to obtain an initial régression
line. A new time sériés of modeled polynya extent was then generated by select-