Heat Budget in the Ice Cover of the Southern Okhotsk Sea Derived from In-situ Observations

Abstract

From in-situ meteorological and ice observation in early February of 1996 and 1997, we estimate the heat budget in the ice cover of the southern Okhotsk Sea. Ice concentration and ice thickness distribution required for its calculation are obtained quantitatively from video analysis. One dimensionalthermodynamical model is used to calculate heat flux. The total heat flux is obtained by summing up the areally weighted heat flux on each ice thickness. As a result, the following characteristics are found in this region.(1) Due to relatively thin ice thickness, turbulent heat flux (sensible+latent) is upward, showing that the sea ice region gives turbulent heat to atmosphere. (2) Thin ice and open area contribute significantly to the total turbulent heat flux over the whole area. (3) Thermodynamical ice growth is limited to below 1 cm per day on average. The first and third results are the characteristics of this area located at a relatively low latitude, while the second one is generally observed for polar regions. The results also suggest that surface melting occur at daytime mainly due to solar radiation. The salinity of sea ice samples shows the values lower than that of the first-year ice in the polar regions and rather similar to that of the multi-year ice, which is lowered by surface melting during summer; this may support this suggestion.

Creation of a Heat and Salt Flux Dataset Associated with Sea Ice Production and Melting in the Sea of Okhotsk

“…In the Sea of Okhotsk, sea ice is mostly covered with snow, except for new (thin) ice (Toyota et al 2007). This ratio of one-fifth is based on in situ observations of Toyota et al (2000). This ratio of one-fifth is based on in situ observations of Toyota et al (2000).…”

Millennial-scale variations of sea-ice expansion in the southwestern part of the Okhotsk Sea during the past 120 kyr: Age model and ice-rafted debris in IMAGES Core MD01-2412

“…The southerly wind transports sea ice that formed in the northern part of the sea toward the south, creating a polynya along the coast that forms new sea ice. In the SW Okhotsk Sea, there is no net production of sea ice (Toyota et al, 2000).…”

“…As sea-ice drifts southward, the southerly wind creates a polynya along the coast resulting in the formation of new sea-ice. In the SW Okhotsk Sea, there is no net production of sea ice (Toyota et al, 2000); therefore, the source of sea-ice is only from the north, delivered by strong ESC during winter. During sea-ice formation and drifting, terrigenous clastic grains are incorporated into sea-ice mainly through coastal suspension freezing and when the sea-ice is grounded near coastline on continental shelf.…”

Aircraft Observations of Air-mass Modification Over the Sea of Okhotsk during Sea-ice Growth

“…Recently, the surface heat budget and turbulent heat fluxes in the southwestern region of the Sea of Okhotsk have been estimated using meteorological data and in-situ ice thickness data observed from an icebreaker, and/ or radiosonde data (e.g., Toyota et al, 2000;Inoue et al, 2001;Iwamoto et al, 2001;Ohshima et al, 2003). By treating the turbulent heat fluxes over the open water and sea-ice separately, Inoue et al (2003) pointed out that the ice concentration is a more important parameter for the estimation of turbulent heat flux than any other meteorological parameter under cold-air outbreak situations.…”