Blog EXPORT expedition
13. Jan 2025
On January 3, 2025, we saw our research vessel, the FS Meteor, in the port of Belém, Brazil, for the first time. Excitedly, we boarded the ship that was to be our home for the next six weeks. The containers with the measuring instruments arrived at the port with some delay, which meant loading them stretched late into the night. The next day, we left the port as planned, heading south along the Brazilian coast. Time was of the essence: all the measuring instruments for atmospheric observation as part of the EXPORT project needed to be unpacked and securely installed at their measurement positions.
The instruments on the top deck—a disdrometer, a solar radiation measurement station, and a particulate matter measurement unit—had to be installed before the ship’s radar could be switched on. Additionally, our ceilometer and wind lidar needed to be secured before we left the Bay of Belém and encountered open waters. Everything went smoothly, and over the following days, we were able to gradually connect and activate the instruments. Since then, all the instruments have been continuously operational—except for the wind lidar, which was damaged during transport. Unfortunately, the issue proved unsolvable during the voyage. Thankfully, we have a Plan B with other onboard instruments that allow us to conduct wind profile measurements, albeit with lower temporal resolution.
In addition to the stationary instruments described, we also brought portable devices, such as photometers. Whenever we had clear views of the sun in recent days, we aligned the photometers to measure the aerosol optical depth.
For days, we traveled southwards along the coast. At 10°S, we finally left the coastline so our colleagues in oceanography could begin their initial measurements. I’ll report more about these and the EXPORT project another time.
Until then, Arne from the EXPORT team
20. Jan 2025
Once we left the coast, the oceanographers began their measurements. The goal was to map a cross-section of the Western Boundary Circulation. For this, we used two methods over the following days: CTD casts and moorings.
CTD stands for the primary parameters measured: Conductivity, Temperature, and Depth. In addition, oxygen levels and ocean currents are also recorded. Sensors for these measurements are mounted on a metal frame, which is lowered from the ship to just above the seafloor and then hauled back up. This process provides a vertical profile of the measured parameters.
Moorings consist of a heavy metal weight anchored to the seafloor, with a long cable extending upward. Sensors and flotation devices are attached to the cable at regular intervals. The floatation devices keep the cable taut, enabling the sensors to capture vertical profiles of the same parameters as the CTD. Unlike CTD casts, moorings can autonomously collect data over 2–3 years, providing valuable time series. The downside of the moorings though is that the parameters can only be collected at discrete depth levels in contrast to the profiling CTD.
Over one week, we traveled away from the coast, conducting 22 CTD casts and retrieving four moorings. After cleaning the sensors and flotation devices, we redeployed the moorings. Handling the nearly 4000-meter-long cables was physically demanding, requiring careful work to guide them onto the winch.
Now, we are heading north. After reaching 5°S, we will turn back toward the coast for more CTD measurements.
Until the next update,
Arne from the EXPORT team
27. Jan 2025
We crossed the equator for the first time today! That means we have now arrived in the Northern Hemisphere, and we are looking forward to measuring the dust outbreaks of the Sahara soon. But before diving back into the science, I would like to take this opportunity to give you a glimpse into life on board.
Our daily routine is shaped by a steady rhythm, given by the meal times. Between meals, we take care of our measurements. While most of them run automatically, we regularly operate our sun photometers manually. But there is also time for leisure: some of us enjoy reading or working out in the gym.
One of the highlights is enjoying the views from the deck: the clear blue water and the wildlife are truly fascinating. We often spot flying fish gliding ahead of the ship or birds diving after them. We’ve even seen Portuguese man o’ wars and dolphins. In the evenings, aerosols over Brazil color the sunset in brilliant hues. Afterward, you can enjoy the starry sky on deck or relax in the bar with a round of cards. Sometimes, there are movie nights for extra entertainment. It is never getting boring here.
That was a little insight into what life on board is like. Next time, I will report back on our meteorological measurements. See you then!
Cheers,
Arne from the EXPORT team
30. Jan 2025
We have finally reached the Northern Hemisphere! Heading east, we are approaching the Sahara – the world’s largest source of atmospheric dust aerosols. The storms that form here can lift big amounts of dust particles into the air and transport them over long distances, even across the Atlantic. Understanding this dust transport is a key focus for us in EXPORT. Dust particles have a wide range of effects on our climate and environment: it influences cloud formation, affects the radiative Transfer in the atmosphere, and can provide essential nutrients to ecosystems on land and in the ocean.
To study the dust transport in EXPORT, we are using multiple measurement instruments aboard the RV Meteor. Since yesterday, we are recording our first Saharan dust outbreak over the central Atlantic. The particle concentrations in the air have increased noticeably, and the optical properties of the atmosphere have changed compared to the first weeks at sea. As you can see in the image, the sky now is hazy due to the scattering of sunlight.
We are excitied about these measurements and look forward to sharing more updates soon!
Cheers,
Arne from the EXPORT Team
