The first two days at sea were relatively calm and pleasant, and the medication has had the desired effect. In the night to Saturday the "Roaring Forties" and the "Furious Fifties" showed a bit of what they had in them. A low pressure area gave us waves 3.5 m high from the southwest and caused the S.A. Agulhas II to rock regularly back and forth to match the rhythm of the South Atlantic. What helped us to fall asleep early in the night became unpleasant swaying in the course of the early morning hours, accompanied by creaking, squeaking, and vibration throughout the whole ship. Nevertheless, according to other passengers who were sea-tested, this was nothing special but more like pleasant to normal conditions.
After leaving Cape Town last Thursday at temperatures around 25°C, the thermometer on Saturday showed only 9°C, and then on Sunday temperatures around 2°C. In the early morning of 27 January at 57° southern latitude we finally saw the first icebergs. In addition, the biologists had been reporting for days sightings of many whales kilometres away that they had detected from their lookout high up on the deck. Now I also had the privilege of observing a group of humpback whales as they devoured their morning portion of krill near the sea surface.
Humpback whales fishing for krill and the first tabular iceberg on 27 Jan. 2020.
In the course of the first few days I was able to speak with a number of people in charge on board about using satellite data during the rest of the trip. They are very interested in the possibilities of various applications. The hope was that remote sensing data could help with decisions ranging from the question of the stability of the shelf ice edges where S.A. Agulhas II will stops to unload freight for the Antarctic stations to the quickest routes through expected sea ice.
Two days before our planned arrival in the Antarctic I received directly from the captain detailed information about our first Antarctic stop. With the help of Sentinel-1 data it could be seen that the unloading place in Crown Bay was still full of ice and that we ought to call at an alternative site at short notice. The shelf ice formation at 25° E – appropriately called the "Dog’s Head" because of its shape – was now the goal. Between the northern shelf ice block "Dog’s Ear" and "Dog’s Neck" extending toward the south there is a protected bay where the freight for the Belgian Antarctic station Princess Elizabeth had to be unloaded. That made it clear that wide-area as well as high-resolution images of the bay need to be part of the planning.
TerraSAR-X wide ScanSAR image from 29 Jan. 2020 and the ship route. On the bridge printed maps are used along with the ship radar.
The map generated from the latest TerraSAR-X recordings showed that the approach to Dog’s Head would be hampered by sea ice for a stretch of 15 to 20 sea miles. Originally the captain had planned to go south between 24° E and 25° E to the ice shelf mooring point. He changed this initial plan and on the basis of the TerraSAR-X image decided to use a shipping lane free of sea ice to the west of 23° E. Between the time of recording around 02:14 o'clock and our local arrival around 13 o'clock it had shifted westward a few miles but had kept its shape and could be used for a quick passage in a south-southeast direction. S.A. Agulhas II encountered mighty ice floes at 23.3° E and manoeuvred around the area in a southwest direction until finally at 70.1° S and 23.5° E the journey could be continued in an almost ice-free area.
S.A. Agulhas II on 29 Jan. 2020 breaking ice, and a few hours later again in a calmer shipping lane.
Overnight, or rather during the three hours and 12 minutes between sunset and sunrise, the ship was moored north of Dog’s Head where loading initially began on the following morning But after about 2 hours, because of the high waves that made it very difficult to place the containers onto the ice shelf, the rest of the unloading was shifted to a more southerly bay in the shelf ice The SpotLight image recorded three day before suggested that freight could be unloaded there much easier onto an apparently stable sheet of sea ice. However, when moving into the bay it was soon clear that this area had broken up on the previous day and now presented us with a spectacular mosaic of ice floes. Once again it was clear to all of us that Antarctic conditions can change very fast!
TerraSAR-X SpotLight image of 27 Jan 2020 shows a bay covered with sea ice and the ship track (orange) on 30 Jan. 2020. A mosaic of see ice floes on 30 Jan. 2020 and no trace of a closed ice cover.
Tonight S.A. Agulhas II will set out westward to Akta Bay near Neumayer Station III. No TerraSAR-X recordings could be scheduled for a passage out of the sea ice, so the maps automatically generated at DLR in Oberpfaffenhofen based on Sentinel-1 data need to be made available for such situations. The wider coverage of these data products is also useful for evaluating the immediate sea ice situation and makes it easier to plan detailed TerraSAR-X recordings. Thanks to reliable data access via EOC's Internal Data Access (IDA) and the Copernicus Data and Exploitation Platform – Germany (CODE-DE) these data could also be used in near-real-time on the ship.
An Antarctic greeting is of course being sent to all TerraSAR-X Mission colleagues in light of a special event: Congratulations on the 70,000th orbit of TerraSAR-X! The work that I am not only carrying out but also directly and personally experiencing is, above all, only possible because of the tremendous commitment and support of the many who are involved at EOC.
On board everyone is now looking forward to our stop at Atka Bay. I learned from Christine Wesche in the morning that shore leave is being organised for us as part of a visit to AWI's Neumayer Station III. Until then the word is: "After the sea ice is before the sea ice!"