# GNSS Profile from the Greenland Korth Expeditions in the Context of Satellite Data
## 3 Greenland North Expeditions Profile  
In this section, figures with the Greenland North Expeditions profile projected on several maps compiled from satellite data are presented; they will also be referred to in later sections. Figure 3 shows the surface topography of Greenland together with towns having more than 1000 inhabitants and the Greenland North Expeditions profile. The ice sheet covers around 80% of the surface of Greenland, and most settlements and towns are situated along the more accessible west coast. In Figure 4 the east-west Greenland North Expeditions route is shown together with campsite numbers. They have been defined during the first 2002 trek, but due to changing local conditions already the 2008 expedition did not repeat measurements at a first few sites (C1-C4) [11]. In the next section, for comparing the GNSS data with altimetry, we will use a slightly reduced subset of the measurement sites; we used only the sites covering the full Greenland traverse where the complete time series of observations from the Greenland North Expeditions expeditions in 2002, 2006, 2010 and 2015 existed. \begin{table}
\begin{tabular}{l l l c} \hline \hline
**Year** & **Scientific Director** & **Method of Measurement** & **Remark** \\ \hline
1912 & A. de Quervain & barometric & 39 camps;accuracy in the coastal area \(\pm\)3–5 m \\
2002 & W. Korth & GPS static & 34 positions; \(\pm\)3 cm \\
2006 & W. Korth & GPS static & 34 positions; \(\pm\)3 cm \\
2010 & W. Korth & GNSS static & 34 positions; \(\pm\)2 cm \\
2012 & W. Korth & GNSS static & only east coast; 17 positions \(\pm\)2 cm \\
2015 & W. Korth & GNSS kinematicand static & continuous profile; spot spacing 2–6 m; 700 km; \(\pm\)3 cm \\
2017 & W. Korth & GNSS kinematic & continuous profile; spot spacing 2–6 m; approx. 180 km; \(\pm\)3 cm \\
2020 & T. Hitziger & GNSS kinematic & continuous profile; spot spacing 2–6 m; approx. 500 km; \(\pm\)3 cm \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Overview of geoscientific expeditions on the historic [PERSON]’s route. Figure 2: Geodetic and glaciological measurements during the expeditions: (**a**) Kinematic GNSS measurement on the pulka; (**b**) [PERSON] carries out glaciological measurements. Figure 5 is a cross-section of Greenland along the Greenland North Expeditions profile. Although not to scale, it depicts clearly that during a 700 km long traverse from east to  
Figure 3: Greenland—surface topography, towns having population over 1000 inhabitants [21] and the Greenland North Expeditions route. west, the Greenland Korth Expeditions team must climb up to the highest point of 2600 m (between sites No. 19 and 20) and descend afterwards. The majority of the measurement sites are located on a thick layer of snow and ice. The lowest point on the bed beneath the Greenland Korth Expeditions route corresponds to the location of Jakobshavn Glacier. Figures 3-5 make use of the BedMachine data for Greenland [22; 23]. The currently available BedMachine (v3) is a self-consistent dataset of the Greenland ice sheet based on the conservation of mass; it includes the spatial grids for bed topography, surface elevation and ice thickness [24]. The BedMachine dataset compiles radar-derived ice thickness measurements from 1993 to 2016 with a nominal date of 2007; the horizontal resolution of the bedrock topography and ice thickness is about 400 m.  
In Figure 6, the Greenland Korth Expeditions profile is plotted on the ice velocity grid from synthetic aperture radar interferometry data of Sentinel-1 [25]. The zero velocity areas dividing the ice sheet into several large drainage basins are clearly evident. In Figure 6b we highlighted two large glaciers that are not far from the Greenland Korth Expeditions route, namely Helheim Glacier in the east and Jakobshavn Glacierin the west. The data in Figure 6 (and also in Figure 7) were produced within the ESA Greenland ice sheet CCI project [26]. Figure 4: Surface topography of the Greenland Korth Expeditions region from the BedMachine dataset.