China's 13th Arctic Ocean Scientific Expedition is already on its way back on board the "Xuelong 2" polar research icebreaker, and the reporters accompanying the main station are also continuing to send back precious pictures of the scientific research process. Not long ago, when the polar research icebreaker "Xuelong 2" sailed to the waters of the mid-ridge of the Gak Ocean in the Arctic Ocean, it encountered a lot of thick ice areas. Our reporter also recorded the entire journey of the "Xuelong 2" to break the ice.
Xing Hao, the first mate of the "Xuelong 2": This is a polar projection map. At 80 degrees north latitude, Inmarsat basically loses its signal, and it becomes very difficult to communicate with the outside world. From 80 degrees north latitude, we continued northwest to reach our mid-ridge operation area in the Arctic Ocean. At this time, we also reached 85 degrees north latitude.
Unexpectedly, just after reaching the mid-ridge of the Gak Ocean, the "Snow Dragon 2" encountered a thick ice area. The bridge stopped the boat after a collision and began to reverse the boat.
Xing Hao, first mate of the "Xuelong 2": We have encountered a lot of thicker and larger ice before, but during the voyage, we all go around the ice, and this time we need to break the ice and maintain it on this fixed route. The sea ice is more than 1.7 meters thick, and because it exceeds the continuous icebreaking capacity of our ships, we generally use impact to break the ice.
"Xue Long 2" can continuously break 1.5 meters of ice and 0.2 meters of snow. But in the Arctic Ocean, sea ice drifts with ocean currents and is likely to block the course. This survey in the mid-Gak Ocean ridge area had to follow the planned route, and it was inevitable to encounter thick ice. The change in the speed of the ship can be clearly felt with the rumbling crashing sound, and the sea ice is fractured and makes a breaking sound as the ship moves forward.
Xing Hao, first mate of the "Xuelong 2": The speed of the ship just now was 9.4 knots, which reached the fastest speed of our collision. Now that our ship has hit this piece of ice, we will slowly slow down until the resistance is increasing and we will finally stop at this position. After stopping at this position, we started to reverse, reverse the boat, and make the next collision.
When the ship retreats to a certain distance, a new round of forward ice-breaking collisions begins.
Xing Hao, first mate of the "Xuelong 2": Our propeller rotated backwards, and now the thrust generated by our ship is forward.
Carried out a number of geophysical experiments
At the Mid-Gak Ridge, the expedition carried out a series of geophysics-related experiments.
CCTV reporter Wang Nan: This is the stern deck of the "Xuelong 2" polar research icebreaker, and in this section, the team members will deploy this group of a total of seven submarine geomagnetometers to the bottom of the sea in a certain chronological order. Not only was it deployed, but in fact after seven days, the equipment had to be recovered one by one.
Shen Zhongyan, deputy captain of the ocean team of China's 13th Arctic Ocean Scientific Expedition: The seabed geomagnetometer measures the electromagnetic properties of the earth on the seabed to obtain some electrical structures of the entire lithosphere deep in it. The distance of the average one may be about 5 nautical miles, and the farthest one is 10 nautical miles. The entire span is not very large, it is perpendicular to the mid-ocean ridge.
Shen Zhongyan introduced that from the geological structure, the mid-ocean ridge is a seamount, is a very important feature of the earth, it is one of the places where the earth's magma is produced, Gake mid-ocean ridge in the mid-ocean ridge system, the slowest expansion rate, to the study of the mid-ocean ridge has a very important role.
In 2021, the mainland conducted its first scientific expedition to the Gak Ocean Mid-Ridge, when a volcanic area was discovered at about 100 degrees east longitude and some special phenomena were initially shown. This scientific expedition continues to focus on this area, and conducts refined research through the deployment of submarine geomagnetometer, submarine seismometer and other equipment.
Shen Zhongyan introduced that for this operation, it is not difficult to deploy, and the most difficult thing is recycling.
Shen Zhongyan, deputy captain of the Ocean Team of China's 13th Arctic Ocean Scientific Expedition: Because our current instrument has reached the bottom of the sea, the data it collects is the so-called self-capacitance, which is recorded in this instrument, because its data is relatively large, and if it is transmitted back through the water body, it is more difficult.
Recycling equipment is difficult to operate
The team's recovery of equipment such as the seabed geomagnetometer in the waters of the mid-Gak Ocean ridge is an extremely difficult operation, no less than finding a needle in a haystack.
It is understood that in the waters of the mid-ridge of the Gak Ocean, the "Xuelong 2" will recover 12 pieces of equipment such as the submarine geomagnetometer and the seabed seismometer. For example, the geomagnetometer will float up from the bottom of the sea at a depth of nearly 4,000 meters at a speed of about 20 meters per minute. On board, the team used hydroacoustic probes to locate and constantly measure distances to control the search area in a small area.
It is extremely difficult to determine the location of a device in the vast sea or even in the ice. It takes an average of four or five hours to recycle a device. If the sea surface happens to be covered by very thick sea ice, then it will need to be repeatedly positioned, the ice will be broken, and the operation time will be longer. Every time I look for an instrument, I gather a lot of team members on the bridge. Telescopes, telephoto cameras, drones, etc. are all used to search for targets. Once discovered, the team members will work together to salvage the instrument.
Shen Zhongyan, deputy captain of the Ocean Team of China's 13th Arctic Ocean Scientific Expedition: It should be said that the process of recovering subsea equipment is generally good. The analysis of these data can help us understand the structure of the Gak Ocean Ridge and its evolutionary process, magmatic action, etc. By understanding it, we can understand the system of the entire mid-ocean ridge, understand plate tectonics, and the evolution of some non-magmatic continental margins.
(CCTV reporter Wang Nan Li Xia)