## 2 Materials and Methods
### Deployments  
A total of 14 Cryologger ITBs were deployed during the 2018 and 2019 summer expeditions of the CCGS Amundsen icebreaker, and 2 ITBs were also deployed by helicopter in the summer of 2019 on ice island fragments located near the Milne Ice Shelf, Ellesmere Island (Figure 3). Deployments from the CCGS Amundsen were made by helicopter on icebergs and ice islands (Figure 4) along the coast of Ellesmere Island, Baffin Island, and Greenland. An additional 4 beacons were deployed on the terminus of the Petermann Glacier in anticipation of the next major calving event, which could produce an ice island up to approximately 185 km\({}^{2}\) in size (determined by delineating the area down-glacier from rifts in a Sentinel-2 satellite image). The overall suitability of potential targets was determined by assessing the iceberg's size, shape, and location. Additionally, strict safety protocols specific to our deployment context were implemented to mitigate the inherent risks associated with working on icebergs. This included only landing on sizable icebergs that are tabular in shape, which are not prone to roll, minimizing time spent on the ice surface, and maintaining a safe distance away from edges. Where possible, tracking beacons were deployed on icebergs that were large enough to potentially survive drifting south to the Grand Banks of Newfoundland Labrador and far enough away from the coast to increase the chances of being carried southward by the currents and avoid becoming grounded in shallow coastal areas typical of these areas. Detailed information regarding the timing and locations of Cryologger ITB deployments, as well as estimates of the iceberg's physical characteristics, can be found in the Iceberg Tracking Beacon Database [40], a new joint project between the Canadian Ice Service and Carleton University that aims to compile historical iceberg tracking beacon data from the northern hemisphere into a single data repository. At the time of deployment, information about the iceberg's shape, size, and position was recorded (Figure 5a). Estimates of the iceberg's waterline length were made visually from the air (Figure 5b), and the helicopter's onboard altimeter (accuracy of \(\pm 0.9\) m) was used to determine the height of the iceberg while landed on its surface. Satellite imagery was later used to obtain more precise measurements of iceberg dimensions. A compass heading measurement of the orientation of the tracking beacon was also recorded at the time of deployment (Figure 5c), which can be used to determine the orientation of the iceberg and to track changes in its relative rotation over time. When weather conditions permitted, aerial photo surveys of the iceberg were performed to further assist in classifying the morphology of the iceberg and for later identification in satellite imagery. During the 2019 field campaign deployments, it was possible to revisit an iceberg previously instrumented with ITB 300434063411050 in 2018. After an inspection of the enclosure for any signs of damage or water ingress, it was determined that the system was in good working condition, did not require servicing, and was left to continue its monitoring of the iceberg. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **Unit** & **Description** & **Size (Bytes)** \\ \hline \hline unixtime & s & Unix time (seconds since 1970-01-01 epoch) & 4 \\ temperature\_int & °C & Internal temperature & 2 \\ pressure\_int & hPa & Internal pressure & 2 \\ pitch & ° & Pitch angle & 2 \\ roll & ° & Roll angle & 2 \\ heading & ° & Tilt-compensated magnetic heading (0–360°) & 2 \\ latitude & ° & GNSS latitude & 4 \\ longitude & ° & GNSS longitude & 4 \\ satellites & & Number of GNSS satellites in view & 2 \\ hdop & & GNSS horizontal dilution of precision & 2 \\ voltage & V & Battery voltage & 2 \\ transmit\_duration & s & Transmission time of SBD message & 2 \\ message\_counter & & Number of transmitted messages & 2 \\ \hline \hline \end{tabular}
\end{table}