Radiation observations on an ice floe on the Weddell Sea, 11/2004-01/2005

As a part of the international expedition Ice Station Polarstern (ISPOL), radiation measurements were carried out on ice floes on
the Weddell Sea (68 degrees S, 55 degrees W) in 28.11.2004 - 2.1.2005. Two sets
of radiation measurement equipment were used. Both sets measured downwelling
and upwelling shortwave radiation and downwelling and upwelling longwave
radiation. One set was equipped with pyranometers and pyrgeometers manufactured
by Kipp&Zonen, the other one with pyranometers and pyrgeometers by the Eppley
Laboratory.

The instruments were set up on two different locations on a single large ice
floe. For a short period, one of them was also set up on a separate floe. The
data have been processed at the Finnish Institute of Marine Research (FIMR).
The processed data set includes up- and downwelling components of short- and
longwave fluxes (W/m2) with a resolution of one minute. The longwave components
suffer from small dome heating effect, which has not been corrected.

Snow surface temperature and albedo were calculated from the radiation data.
The temperatures suffer from the dome heating effect. For comparison, a
corrected surface temperature was calculated from a weather mast air
temperature and eddy flux measured sensible heat flux, using the Monin-Obukhov
universal temperature profile. The albedo is generally around 0.7 - 0.9,
showing gradual decrease due to melting. There are some gaps of up to one day
in the measurement series.