A study of the influence of thin ice thickness in the calculation of sea ice concentration from satellite passive microwave data

• Published in: Journal of the Japan society of photogrammetry and remote sensing Vol. 40; no. 5; pp. 39 - 51
• Main Authors: Nakayama, Masashige, Cho, Kohei, Shimoda, Haruhisa, Sakata, Toshibumi, Tanikawa, Tomonori, Nishio, Fumihiko
• Format: Journal Article
• Language: English
• Published: Japan Society of Photogrammetry and Remote Sensing 2001
• ISSN: 0285-5844; 1883-9061
• DOI: 10.4287/jsprs.40.5_39

Ice concentration derived from satellite passive microwave sensor data is a key parameter for monitoring the global sea ice cover areas. Since the sea surface heat flux is quite sensitive to the existence of thin ice, accurate calculation of ice concentration within thin ice area is very important for heat exchange between ocean and atmosphere. In this study, two sea ice concentration algorithms, namely NASA Team algorithm and Bootstrap algorithm, were compared for the thin sea ice area of the Okhotsk Sea to evaluate the effect of sea ice thickness to the calculation of ice concentration from SSM/I data. Firstly, 100% sea ice concentration areas were extracted by using simultaneously collected NOAA/AVHRR/2 data. Then the ice concentrations of those areas were calculated with using SSM/I. The result shows that the NASA Team algorithm was likely to underestimate the ice concentration within the 100% thin ice area. The ice thickness of those areas was estimated with using AVHRR/ 2 data, and they were compared with the measured brightness temperatures of each SSM/I channels. It has become clear that the wavebands of 19GHz and 37GHz at horizontal polarization were sensitive to the thickness of thin ice. This explains why ice concentrations of thin ice area were underestimated with the NASA Team algorithm.