This measurement of the Earth's total magnetic field is part of an interdisciplinary project examining the Aurora hydrothermal vent field in an attempt to understand its fluid circulation. The magnetic data was acquired with a PicoEnvirotec airborne system. An optical magnetometer was towed on a 30 m long rope beneath the helicopter to minimize any disturbances from the aircraft. The mean flight velocity was 80 kn (148 km/h), the mean flight level of the helicopter was 300 ft (91 m). In total, 1,391 nmi (2,573 km) of line data could be recorded. Around the Aurora vent field and in the northern Lena Trough 15 west-east trending lines of 40 nmi (74 km) each were acquired. The line spacing was 2 nmi (3.7 km), so an area of in total 40 x 28 nmi (74 x 52 km) could be mapped. This covered the entire vent field, the central valley and the adjacent rift flanks. At the transition from the northern Lena Trough into the western Gakkel Ridge, three flights recording six northwest-southeast trending lines of approx. 70 nmi (130 km) length each were conducted. With a line spacing of 2 nmi (3.7 km), an area of 70 nmi x 10 nmi (130 km x 185 km) was surveyed. This covered not only the Gakkel Ridge, but also adjoining parts of the Nansen and Amundsen basins.