Thickness and production of sea ice in the Okhotsk Sea coastal polynyas from AMSR-E

• Published in: Journal of Geophysical Research
• Main Authors: Nihashi, Sohey, Ohshima, Kay I., Tamura, Takeshi, Fukamachi, Yasushi, Saitoh, Sei-ichi
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union
• Subjects: 452; Okhotsk; okhotsk sea; Sea ice
• Online Access: http://hdl.handle.net/2115/39843; https://doi.org/10.1029/2008JC005222

From comparisons with thickness of sea ice from AVHRR and ice-profiling sonar data, we have developed an AMSR-E thin ice thickness algorithm for the Sea of Okhotsk. This algorithm can estimate ice thickness of ≤0.2 m without snow using the polarization ratio of AMSR-E brightness temperature at a 36.5 GHz channel from a linear relationship with AVHRR ice thickness. When a snow cover exists on the thin ice surface, as occurred a few times in each winter, it is shown that the algorithm cannot detect the thin ice. Sea-ice and dense shelf water (DSW) production in coastal polynya are estimated based on heat flux calculation with the daily AMSR-E ice thickness for 3 winters (December-March) of 2002/2003 - 2004/2005. The ice production is largest in the northwest shelf (NWS) polynya which accounts for ～45% of the sum of ice production in major coastal polynyas. The ice production in major coastal polynyas would cover the maximum ice area of the Okhotsk Sea if the average ice thickness is assumed to be 1 m. Variability of the ice production is mainly modulated by air temperature. In the NWS polynya, which is the main DSW production area, the annual DSW formation rate is estimated to be ～0.36 Sv.