IUGG 2003 Abstract

JSP09 Physical Aspects of Air-Sea Interaction (IAPSO, IAMAS)  Thursday, July 10 PM Location: Site B, Room 20 Presiding Chair:S. Gulev

TIME [ 1645 ] [ JSP09/10P/B20-010 ]

AIRCRAFT OBSERVATIONS OF AIR MASS MODIFICATION OVER ADVANCING ICE COVERIN THE SEA OF OKHOTSK

Jun INOUE(Institute of Low Temperature Science, Hokkaido University, Japan)

Masayuki KAWASHIMA(Institute of Low Temperature Science, Hokkaido University, Japan) Yasushi FUJIYOSHI ( Institute of Low Temperature Science, Hokkaido University, Japan ) Masaaki WAKATSUCHI ( Institute of Low Temperature Science, Hokkaido University, Japan )

In order to investigate a role of leads in advancing of ice cover,turbulent heat transport processes over the ice-covered Sea of Okhotskwas studied by use of aircraft observations during two cold-air outbreakevents. One case is characterized by a heterogeneous ice concentrationcontaining numerous wide open leads, and the other one occurred overrelatively narrow leads. By using the technique of joint frequencydistribution, it is found that the buoyancy flux is mainly generated bythe rising thermals over the upwind leads for each case. The sensibleheat flux by these thermals abruptly decreases from 600 W/m^2 to 100W/m^2 with increase of accumulated fetch-width of upstream leads up to 5km within the ice cover. These results suggest that the role of theaccumulated open water is as important as that of coastal polynyas forthe new-ice formation and resultant advance of sea-ice extent in theseasonal ice zone during cold-air outbreaks.