Acquiring my sea legs has taken me two days, and they're still not very steady. The swelling sea causes our vessel to pitch and roll constantly, making it hard for some of us, myself included, to concentrate on our work. Using highly toxic anti-nausea tablets backed up with homeopathic placebos I have been able to ward off the tremors but occasionally it's all too much and a retreat to my dark cabin must be made.
Two datasets are being recorded as we sail: sea level magnetic field data and multibeam (swath) sonar of the seafloor topography. The magnetometer looks like a small orange torpedo and tugs along quietly behind the boat at roughly 40 meters below sea level, adapting constantly to our cruising speed of around 10 knots. It records the total magnetic field observed along our course, meaning the current field, solar radiation and remnant magnetism of the seafloor. While analyzing the data we will have to clean out the Earth's current field and any solar interference in order to isolate what we're really interested in - the paleomagnetic field recorded in the oceanic crust over the past 130 million years.
The Simrad EM300 swath sonar resembles a large gondola welded to the bottom of the hull and sends out more than a hundred pings each instance. Using the travel time, amplitude and phase shifts in the return beams reflected off the bottom, the computer calculates the depth, i.e. bathymetry, of a ~1000meter wide slice perpendicular to our forward vector. Using these slices it is easy to comprise a 3D image of the seafloor which will be important when interpreting the magnetic anomalies in the data and choosing optimal dredge sites in a few days time. Of course, water salinity, temperature, density and conductivity also play a role in determining sound wave velocity - hence all these parameters are collected, albeit currently only at surface level. Currently we are getting depth readings ranging from 3900 to 5100 meters. This is well beyond the intended resolution of the EM300, but it nonetheless confirms we are above an abyssal plain.
Basically, our job is to make sure the instruments are recording correctly and that the magnetometer hasn't been torn off the back by some Great White mistaking it for a midnight snack. Logging down the data every 15mins in a notebook is our failsafe in case something unimaginable happens to the hard drives.
I have been placed in the graveyard shift: 2am to 8am. Together with my comrade at arms, Adriene Bronner a Ph.D. student from Strasburg, we keep log and raid the stores in the galley during the small hours of the night. The ships dinner is our breakfast, so starting the day with a Tbone steak and mash is a dream come true. I must hand it to Mick the steward et al. - they do keep us happy.
Keep in mind that the science is our main mission. When we pre-analyzed the data on line and discovered that we had just entered the Cretaceous Quiet Zone Superchron, an wave of muffled excitement broke out in the Op's room. This is what we are here for - boldly going where no man has gone before.
Two datasets are being recorded as we sail: sea level magnetic field data and multibeam (swath) sonar of the seafloor topography. The magnetometer looks like a small orange torpedo and tugs along quietly behind the boat at roughly 40 meters below sea level, adapting constantly to our cruising speed of around 10 knots. It records the total magnetic field observed along our course, meaning the current field, solar radiation and remnant magnetism of the seafloor. While analyzing the data we will have to clean out the Earth's current field and any solar interference in order to isolate what we're really interested in - the paleomagnetic field recorded in the oceanic crust over the past 130 million years.
The Simrad EM300 swath sonar resembles a large gondola welded to the bottom of the hull and sends out more than a hundred pings each instance. Using the travel time, amplitude and phase shifts in the return beams reflected off the bottom, the computer calculates the depth, i.e. bathymetry, of a ~1000meter wide slice perpendicular to our forward vector. Using these slices it is easy to comprise a 3D image of the seafloor which will be important when interpreting the magnetic anomalies in the data and choosing optimal dredge sites in a few days time. Of course, water salinity, temperature, density and conductivity also play a role in determining sound wave velocity - hence all these parameters are collected, albeit currently only at surface level. Currently we are getting depth readings ranging from 3900 to 5100 meters. This is well beyond the intended resolution of the EM300, but it nonetheless confirms we are above an abyssal plain.
Basically, our job is to make sure the instruments are recording correctly and that the magnetometer hasn't been torn off the back by some Great White mistaking it for a midnight snack. Logging down the data every 15mins in a notebook is our failsafe in case something unimaginable happens to the hard drives.
I have been placed in the graveyard shift: 2am to 8am. Together with my comrade at arms, Adriene Bronner a Ph.D. student from Strasburg, we keep log and raid the stores in the galley during the small hours of the night. The ships dinner is our breakfast, so starting the day with a Tbone steak and mash is a dream come true. I must hand it to Mick the steward et al. - they do keep us happy.
Keep in mind that the science is our main mission. When we pre-analyzed the data on line and discovered that we had just entered the Cretaceous Quiet Zone Superchron, an wave of muffled excitement broke out in the Op's room. This is what we are here for - boldly going where no man has gone before.
coool
ReplyDeletekeep posting, sounds interesting.
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