Open AccessImpact of ice temperature on microwave emissivity of thin newly formed sea ice
Author(s) -
Hwang Byong Jun,
Ehn Jens K.,
Barber David G.
Publication year - 2008
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jc003930
Subject(s) - emissivity , sea ice growth processes , sea ice thickness , sea ice , sea ice concentration , microwave , geology , atmospheric sciences , environmental science , arctic ice pack , materials science , climatology , optics , physics , quantum mechanics
This study examines the impact of ice temperature on microwave emissivity over thin, newly formed sea ice at 6, 19, and 37 GHz during October 2003 in the southern Beaufort Sea, where the physical properties of newly formed sea ice were coincidently measured with microwave emissions. Six ice stations with distinct properties were selected and divided according to ice surface temperature into warm (above –3°C) or cold (below –3°C) stations. The warm stations had a lower emissivity at the vertical polarization by 0.1 than the cold stations and a corresponding difference in brine volume and dielectric properties. Significant correlations were observed between brine volume and ice emissivity ( R 2 = 0.8, p value < 0.05). A sensitivity study showed that decreasing ice temperatures from −2.1° to −5.0°C explained the observed difference of 0.1 in ice emissivity between warm and cold stations. The results suggest that the temperature of thin bare ice could be the critical factor in determining ice emissivity near the melting point (about −2°C). Furthermore, a slight decrease in ice temperature (i.e., from −2° to −5°C) significantly reduces the brine volume, thus resulting in high ice emissivity. Finally, we demonstrate the potential of newly formed ice to cause errors in estimating sea ice concentrations using Advanced Microwave Scanning Radiometer–E data.