Remote sensing of Arctic Fjords by Raman lidar: Heat transfer screening by layer of glacier’s relict water

West Spitsbergen fjords have been probed (on shipboard) by a compact Raman lidar (Wave Research Center, Prokhorov General Physics Institute, Russian Academy of Sciences), based on a pulsed diode-pumped Nd3+:YVO4 laser with frequency doubling, in August, 2011. The evolution of lidar signal spectra (Raman, fluorescence, and elastic scattering) when approaching the Paulabreen glacier of the Rinders Fjord has been measured. A new phenomenon was discovered: the formation of an immiscible layer of relict thaw water from the glacier on the sea surface. An increase in the layer thickness (to 5–10 cm near the glacier) was accompanied by a decrease in the layer temperature (which was determined by measuring the distortion of the OH Raman band) and the content of phytoplankton and dissolved organic matter to zero, with a simultaneous increase in the Rayleigh scattering amplitude and a change in the surface color from blue to gray. Smoothing of the rippled sea surface (covered by relict water) at the border of the wake trace (which it rolled down from) was observed for the first time, as far as we know. The mechanism of the formation of a supercooled (t ⩽ 0°C) layer and screening the heat diffusion, which reduces the contribution of the relatively warm sea water (≈3°C) to the thermal balance of Arctic and global climate, is discussed.