Recent developments in remotely operated and autonomous technology for interdisciplinary sea ice observations
The Arctic sea ice is a hostile environment, in which year-round human presence is a challenge for equipment and logistics. Most current knowledge about processes at the atmosphere-ice-ocean boundary is thus derived from either icebreaker cruises (mostly during summer) or few manned drifting stations. Data covering a wider extent both in the spatial and temporal dimension is still sparse. Until recently, autonomous year-round observations by drifting sea ice buoys have mostly focused on the physical properties of the sea ice system. Ice-mass balance buoys are a common tool for monitoring of sea ice growth and melt, ice-tethered upper ocean profilers significantly improved our understanding of Arctic circulation patterns, and polar atmospheric weather stations and other buoys are contributing to the global weather forecasts and sea ice drift analyses. In the last years, we extended the capabilities of autonomous sea ice observatories e.g. by the development of the affordable Snow Buoys, which measures snow height at four locations using acoustic pingers. For extending the knowledge about the seasonal development of the sea ice ecosystem, an ice-tethered ocean profiler was upgraded with bio-optical sensors to follow the development of algal blooms throughout the year. To bridge the data gap left by the ocean profiling system in the top five meters of the water column, we developed an extension of an ice mass balance buoy upgraded with bio-optical sensors in the uppermost water column and solar radiation sensors. To better address the spatial variability of the sea-ice system, a new remotely operated vehicle (ROV) for under-ice research was commissioned by the Alfred Wegener Institute. Apart from the basic capabilities of observation and manipulation the ice-launched vehicle comprises a comprehensive interdisciplinary sensor suite: A high definition zoom main video camera in conjunction with two navigation cameras and an upward-looking photographic still camera are used to observe and document the ice underside. Acoustic instruments include a scanning sonar, an altimeter measuring the distance to the ice, as well as a multibeam sonar for mapping of the under-ice topography. Spectral irradiance and radiance sensors are used to measure radiative fluxes under the ice in conjunction with the determination of bio-optical properties of the water. A CTD package extended with sensors for dissolved oxygen, pH and Nitrate complements the interdisciplinary sensor suite. Here we present the operational concept unifying temporal observations by drifting buoys with spatial observations using the new underwater vehicle. Ensuring comparability between both datasets by sensible sensor choices allows for new insights into the spatio-temporal evolution of the changing Arctic sea ice ecosystem.
AWI Organizations > Climate Sciences > Sea Ice Physics
AWI Organizations > Biosciences > Deep Sea Ecology and Technology