Ice floe pattern

Ice floes in the marginal sea ice zone of the Southern Ocean seen from a helicopter. The picture was taken during a flight with an airborne DOAS (Differential Optical Absorption Spectroscopy) remote sensing instrument measuring the vertical distribution of bromine monoxide (BrO) in the atmosphere. Despite mixing ratios in the order of only a few parts per trillion, BrO dramatically changes the chemistry of the boundary layer over areas of many square kilometers during springtime in Polar regions. It can completely deplete tropospheric ozone or oxidize gaseous elemental mercury leading to its deposition to the biosphere.