ween 2000/01 and 2005/06 (Joughin et al., 2010a) and were consistent with earlier velocity values from 1978 and the 1990s of around 800 m a−1 (Higgins, 1989, 1991; Rignot et al., 2001). Consequently, ice tongue collapse appeared not to significantly affect up-glacier ice velocities during 2000–2006. This could be due to its fragmented nature (Figure 4G), which would provide little resistive stress to the grounded inland ice. There are no documented surges at C. H. Ostenfeld Glacier although a large advance followed by retreat between 2000 and 2003 could suggest surge activity, but this remains untested.
C. H. Ostenfeld is one of the main outlet glaciers in northern Greenland. A large area of its floating tongue has been lost over the past two decades, yet ice velocities have changed little. However, it has recently lost the majority of its floating ice tongue and it may soon retreat back to become grounded, and then discharge grounded ice into the ocean. Thus, there is potential for enhanced velocities and ice discharge from the C. H. Ostenfeld catchment in the near-future, but large uncertainty remains on the glacier's current and future behavior.
Harder and Brikkerne Glaciers
Harder and Brikkerne are two outlet glaciers also draining into Victoria fjord (Figure 5B) which are 5.1 and 6.1 km wide, respectively (Table 1). Collectively, they drain an area of ~3000 km2 (Table 1) from local ice domes. Both glaciers previously coalesced with the floating tongue of C. H. Ostenfeld, with Harder Glacier merging on the eastern side. Brikkerne Glacier sits further north, has three branches, and a small floating ice tongue which is 1.2 km long (Table 1).
Little record of these glaciers exists in the literature and there are no records of terminus change at Harder Glacier. At Brikkerne, the only frontal position data available show that the northern and central sections of the glacier advanced 11 and 8 km, respectively, between 1953 and 1978 (Higgins, 1991). Data from the 1970s showed relatively low velocities at Harder Glacier (84–122 m a−1; Higgins, 1991). At Brikkerne Glacier, velocity was considered to be very slow in 1947, increasing to 150–360 m a−1 in 1963 and 500 m a−1 between 1971 and 1978 (Higgins, 1991). This velocity increase coincided with periods of glacier advance (Higgins, 1991). No records of surging exist for Harder Glacier, but Brikkerne Glacier was identified as surge-type glacier on the basis of variable velocity records (Higgins, 1991; Rignot et al., 2001). Since the early studies (Higgins, 1991; Rignot et al., 2001), little attention has been paid to these glaciers, despite their potential dynamic changes such as surging at Brikkerne Glacier.
Jungersen, Naravana Fjord and Henson Glaciers
Further north from Victoria fjord lie three further outlet glaciers, Jungersen, Naravana Fjord and Henson, which collectively drain 0.7% of northern Greenland (Table 1). Both Jungersen and Henson Glaciers are ~2 km wide (Higgins, 1991) and previously had floating sections (Rignot et al., 2001), although their length has not been reported in the literature. Naravana Fjord, located between these glaciers, is 2.5 km wide and has no floating section. Little is known about terminus changes at these glaciers. Grounding line data (Morlighem et al., 2015) shows they no longer have floating ice tongues (Figure 2A), suggesting their termini have retreated since previous observations (Rignot et al., 2001). Ice velocity data are limited, although Jungersen Glacier was estimated to flow at 350 m a−1 in the 1970s, whereas Henson was barely moving (1.7 m a−1; Higgins, 1991). More recent velocity estimates suggested similar velocities at Jungersen Glacier (395 m a−1), slower flow at Naravana Fjord (59 m a−1), and a much higher estimate for Henson Glacier (286 m a−1: (Rignot et al., 1997).
These glaciers have received little research attention and Rignot et al. (2001) suggested that their significance in terms of ice discharge may have been previously overstated by Koch (1928). This may explain their absence from the majority of northern Green