Direct observations of sea-ice thickness and brine rejection off Sakhalin in the Sea of Okhotsk

From December to June 2002-03, sea-ice and oceanic data were obtained from moorings near Sakhalin in the west central Okhotsk Sea. Ice draft measured by sonar reveals distinct periods of thin and thick ice. Thin-ice periods in January-March corresponded to offshore ice movement and increasing seawater salinity. The measured change in salinity corresponds well with that derived from heat-flux calculations using the observed ice thickness. Brine rejection from ice growing in a coastal polynya off northern Sakhalin is responsible for much of the observed salinity increase. The simultaneous observation of Dense shelf water (> 26.7σθ) suggests that this region is one possible source. The periods of thick-ice incursion are likely indicative of heavily deformed pack formed further north and drifting south with the current. The mean draft (1.95 m), thick-ice ratio, and keel frequency during these periods are close to values observed in the Beaufort Sea. Freshwater transport estimated from the observed ice thickness and velocity is larger than that of the Amur River discharge

Experimental demonstration of nonlinear waveform-dependent metasurface absorber with pulsed signals

The absorbing performance of a nonlinear waveform-dependent metasurface with pulsed signals is demonstrated. The metasurface is a periodic structure containing diodes, capacitors and resistors. These enable us to first rectify a high-power incoming signal to a static field, then store the energy during the illumination and dissipate it before the next pulse comes in. The incident pulses contain a finite width of spectrum of around 4.2 GHz. By using the nonlinear metasurface, absorption that depends on both the power and the duty cycle of the incoming signals is measured. These measurements demonstrate the first waveform-dependent absorbing metasurface. © The Institution of Engineering and Technology 2013

Experimental demonstration of nonlinear waveform-dependent metasurface absorber with pulsed signals

The absorbing performance of a nonlinear waveform-dependent metasurface with pulsed signals is demonstrated. The metasurface is a periodic structure containing diodes, capacitors and resistors. These enable us to first rectify a high-power incoming signal to a static field, then store the energy during the illumination and dissipate it before the next pulse comes in. The incident pulses contain a finite width of spectrum of around 4.2 GHz. By using the nonlinear metasurface, absorption that depends on both the power and the duty cycle of the incoming signals is measured. These measurements demonstrate the first waveform-dependent absorbing metasurface. © The Institution of Engineering and Technology 2013

(Table 1) Age control points and dating methods for sediment cores of the Sea of Okhotsk

Marine- and terrestrial-derived biomarkers (alkenones, brassicasterol, dinosterol, and long-chain n-alkanes), as well as carbonate, biogenic opal, and ice-rafted debris (IRD), were measured in two sediment cores in the Sea of Okhotsk, which is located in the northwestern Pacific rim and characterized by high primary productivity. Down-core profiles of phytoplankton markers suggest that primary productivity abruptly increased during the global Meltwater Pulse events 1A (about 14 ka) and 1B (about 11 ka) and stayed high in the Holocene. Spatial and temporal distributions of the phytoplankton productivity were found to be consistent with changes in the reconstructed sea ice distribution on the basis of the IRD. This demonstrates that the progress and retreat of sea ice regulated primary productivity in the Sea of Okhotsk with minimum productivity during the glacial period. The mass accumulation rates of alkenones, CaCO3, and biogenic opal indicate that the dominant phytoplankton species during deglaciation was the coccolithophorid, Emiliania huxleyi, which was replaced by diatoms in the late Holocene. Such a phytoplankton succession was probably caused by an increase in silicate supply to the euphotic layer, possibly associated with a change in surface hydrography and/or linked to enhanced upwelling of North Pacific Deep Water