Land. This is ship.
The one with the radio today is Johan Edholm, and I’m a PhD student in physical oceanography with Polar Gliders from the University of Gothenburg. Our group is quite focused on heat transfer between the ocean and the atmosphere. This is quite important to know since excess heat from the atmosphere is taken up by the ocean, which dampens our warming effect on the climate.
There are four major processes that control this exchange:
1) Shortwave radiation. The direct effect of the sun, what you can feel on your skin on a sunny day.
2) Longwave radiation. This is the ocean radiating away heat, similar to how you can feel the heat from a rock by holding your hand just over it after the same sunny day.
3) Sensible heat flux. A conductive effect, like you heating up from actually touching the warm rock, or you freezing from wind chill when the wind picks up in the evening the same day.
4) Latent heat flux. This is evaporative, in the same way that you would lose heat by sweating in the warm summer sun.
The latter two are called turbulent heat fluxes, and very difficult to measure since we need to know quite a few parameters about both the atmosphere and the ocean. Luckily, we brought an instrument that can do just that! PimPim, our Sailbuoy as it is called, is and looks like a small sailboat that uses wind to sail, and solar panels to drive sensors and navigation. It sails completely on its own, we give it coordinates from land and they decide how to sail there. From the onboard sensors we get information about how the winds are blowing, temperature of the air and the sea, salinity of the surface waters, relative humidity of the air, and ocean currents. Put this all together and we can calculate the turbulent heat fluxes.
PimPim is sampling the ocean and atmosphere every 10 minutes, which allows us to track the small scales that Ali was talking about in a previous blog post, around 500 meters between measurements. Couple this with the ocean current data that PimPim is also collecting, and we have a way to not only calculate heat flux, but also compare it the underlying currents, and try to figure out how one affects the other.
The way to measure currents is very cool, using a well-known effect to do so! The sensor sends out a pulse of sound with a specific frequency, which is reflected by suspended particles and plankton in the water, and listens for the returning echo. Any difference in frequency in the echo relative to the sent out pulse is used to calculate if the particle or plankton is moving towards or away from the sensor. By using four different beams, and assuming that the particles and plankton are moving with the water, the sensor can calculate how the ocean is moving.
This is work that I will investigate during my PhD, and also compare our data to a lot of proven sensors and system to show that this is a viable way to increase our knowledge about small scale circulation in the upper ocean! Therefore QUICCHE is very important for us, not only in a purely physical sense, but also validating our methods.
I am super stoked to be onboard and to be able to do science again after three years on land. Have to say that I am impressed by the food onboard, we have two amazing cooks from the southern parts of the US. A lot of snacks and good food makes for mostly happy scientists. We have gotten a few delays and plans have shifted due to unusually bad weather which is not ideal, but that’s just the way the cookie crumbles sometimes…
Land, this is ship, over and out!