The Chinese scientific revolution aims to tackle climate change
Just a few days ago, the Chinese Academy of Sciences hosted a workshop which involved scientists from around the world that work on a device called the Expendable Bathythermograph, or XBT for short. The obscurity of the conference speaks volumes; it didn’t get much, if any, press attention.
XBTs are devices that are used to measure ocean temperatures. They were developed many decades ago to help navies determine the depth of the thermocline. Submarines positioned below the thermocline are more able to avoid detection. The devices are released from the deck of a ship and they fall through the water, recording temperatures along the way. As they fall, they unspool a copper wire which is connected to a data collection device so that temperatures can be recorded.
Each year, hundreds of thousands of these devices are dropped into the world’s oceans. A huge database, stretching back to the 1960s is available for climate studies. The problem is that the devices are designed to be, well, expendable and cheap. When their wire spool runs out, the wire breaks, and the torpedo-like device detaches from the ship and sinks to the ocean floor. The expendable nature of the device has forced the cost per device to be low.
As a result, no pressure sensors were installed on the devices so water depth cannot be determined directly. Depth has to be inferred from a correlation of prior experiments. If the correlation is not correct, a scientist will not accurately know the depth of the probe in the water and consequently, will not be able to calculate the energy of the ocean waters. Ocean heating is the hallmark of global warming. If we can’t use XBTs to get an accurate sense of ocean heating, we are flying blind.
So, understanding the accuracy of XBT fall rates (the rate that they descend in the water) is one of the most important and difficult issues in all of climate science. Part of the difficulty is that devices have changed as the years have passed (both device size and weight). Also, fall rates depend on the temperature of the water (colder water is more viscous and thereby retards probe motion). In addition, the height from which the devices are launched impacts the speed of their entry into the water, and their subsequent descent. All of this makes for time and spatially varying fall rates, real mess.
Despite this, only a small handful of scientists are actively working to improve XBT accuracy, and the Chinese Academy of Sciences decided to bring them all together. This unique group of individuals met for three days to try to hammer out a “best practices” standard. While we don’t know yet what the outcome is from this meeting, we see that China has taken a leading role as a scientific player. Approximately half the attendees were Chinese and travel funding was made available by the Chinese Academy of Sciences.
While in many parts of the world, like Australia and the USA in particular, funding for basic research is decreasing, in China things are different. Funding is increasing in critical scientific areas. Perhaps more importantly, in China, scientists are respected. In my country, as well as in Canada, and Australia, whenever you tell people you are a scientist, you must prepare for a negative reaction.