Helicopter-Based High-Resolution C/STD Observations in the Marginal Ice Zone--Field Analysis and Results on the Ocean Data Equipment Model 302

The marginal ice zone, a transitional area between open and ice-covered ocean, provided a rigorous testing regime for the newer Ocean Data Equipment Model 302 C/STD, which is a major revision of its predecessor, the Model 202. It has increased resolution, stores all data in RAM for later transfer to cassette (via deck unit), can operate over extended time periods (8-10 hours) without recharging, is more compact and 51% lighter. Due to its size, a complete operational CTD system including winch, generator and survival gear was routinely fitted into a Bell 206B helicopter within 10 minutes. Upon landing at a site, the system would normally be in full operation within 5 minutes. Using a profile depth of 300 meters, sequential stations 6 nautical miles apart took 35 to 45 minutes. After each profile, data were transferred to cassette and briefly previewed. More detailed analysis of the calibrated data was completed onboard ship using digital output and analog traces. Dramatic views of mesoscale activity under the ice, such as eddies, interleaving, fronts and ice-edge jets were obtained from a total of 87 helicopter stations based on three different ships.