The scientific work of the Maud expedition was led by Harald Ulrik Sverdrup, ably assisted by several of the crew. Various scientific measurements were made, and their subsequent analysis resulted in several interesting discoveries. From the tidal surveys came one of the most important, which was the probable absence of large land masses in the Arctic Ocean. The importance to oceanography of the expedition’s research is widely recognized, helping to lay the foundations as it did for our modern understanding of the ocean systems in the Northern Hemisphere.
Astronomical observations and navigation
Astronomical observations were absolutely essential to knowing where the expedition was, and to calculating the ship’s drift through different periods and regions. Observations were made several times a week, weather permitting, with either a theodolite or a sextant, and a wall of snow blocks was built on the ice by the ship for the purpose. Here, the observer could be sheltered from the weather in the structure they named “Uranienborg”.
An angle-measuring instrument used mostly at sea for navigation, consisting of a telescope, a mirror system and an arc graduated in degrees and minutes. Standard use involves measuring the vertical angle between the horizon and a known celestial body, usually the sun, and calculating a position from this with the aid of astronomical tables and a clock. When the horizon is not available, in foggy conditions for example, an artificial horizon can be created using water in a container or the like.
An angle-measuring instrument consisting of a telescope and graduated arcs, from which horizontal and vertical angles can be read with great precision.
Of six theodolites that were on board Maud at departure in 1918, this instrument was one of Harald Ulrik Sverdrup’s favourites.
Studies of the earth’s magnetic field were made using a magnetometer. The measurements had to be carried out at a good distance from the ship so that they were not disturbed by the iron objects on board, and the first were made with only an ice block as protection from the wind. But in the winter of 1922–23, the crew built a small ice house that they named “The Crystal Palace” and equipped it with electric lights and a non-magnetic stove. Summer observations were made in a tent. The equipment was lent by the Carnegie Institution in Washington and specially adapted to polar conditions. As well as determining the declination, inclination and intensity of the earth’s magnetic field, the magnetic surveys were important for determining the local compass deviation for navigational purposes.
- Magnetometer: Instrument used to measure the strength and direction of the earth’s magnetic field.
Measurements were also made of electrical activity in the atmosphere, using an electrometer borrowed from the Smithsonian Institution in Washington and modified by Odd Dahl so that its operation was more automated.
For three years, regular meteorological observations were made six times a day; these included air pressure, temperature and humidity, wind, sunshine and snow depth. Wind measurements at altitude were performed by releasing balloons and following them with telescopes; every minute, the direction and angle of elevation was recorded as the balloon drifted away. From these observations, they could calculate the balloon trajectory over time and thus the wind direction and strength at different heights. In the winter and in the dark, they suspended small paper lanterns beneath the balloons so they could follow them from the ice. More than 500 balloons were launched.
Atmospheric temperature profiles were measured by sending up instruments with box kites, both supplied by the U.S. Weather Bureau. The kites were tethered with a steel wire and could reach heights of several thousand metres in favourable conditions. Motorised winches were to be used to haul the kites in – one with a hot-bulb engine and one with a motorcycle engine – but both failed in the cold.
Ocean and ice
Sverdup and Malmgren made several studies of the sea ice. The ice depth was measured daily, and water samples were gathered for measuring the water’s density, salinity, oxygen content and hydroxyl value. Temperatures of the sea and ice were also recorded at various depths.
Tides were studied and recorded using various methods. When they found that the current meter they had with them didn’t work in low temperatures, they eventually made their own on board.
Samples were collected of marine plankton and seabed-living organisms, but in the absence of a biologist on board these were conserved until they could be studied later.
Harald Ulrik Sverdrup:
“The Norwegian North Polar Expedition with the ‘Maud’ 1918-1925. Scientific Results”, published by the Geofysisk Institutt, Bergen, in cooperation with other institutions. Bergen, A.S. John Griegs Boktrykkeri, 1927-39 📜.
“Maud-ekspedisjonens videnskabelige arbeide 1922-1925” [“The Maud expedition’s scientific work 1922-1925”], Naturen, nr. 6, juni 1926, 50. aargang. 📜.
“Tre aar i isen med «Maud»” [“Three years in the ice with ‘Maud'”], Gyldendal, Oslo, 1926 📜 .
“Havsisen, resultat från Maudexpeditionen” [“Sea ice, results from the Maud expedition”], Naturen, nr. 3, mars 1926, 50. aargang 📜.
“Studies of humidity and hoar-frost over the Arctic Ocean”, Geofysiske publikasjoner, vol. 4, no. 6, 1926 📜.
“On the properties of sea-ice”, in: Norwegian North Polar Expedition (1918-1925). Scientific results. Vol. 1a. Special reports (5). Bergen: Geofysisk Institutt, 1927.