Blog EXPORT expedition

 

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.

 

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. 

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.

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

Since my last blog post, we have left the dust outbreak, crossed the equator, and returned—straight into the dust again. This allowed us to observe the transition between the dust outbreak and the equatorial zone twice. While the sky in the dust regions was mostly cloud-free but hazy, with stable northeasterly trade winds, the equatorial zone was different: more clouds, more rain, variable winds, and even a pretty thunderstorm.
We have now arrived in Cape Verde, where dust concentrations have increased further - at times exceeding PM10 levels of 150 µg/m³! This means there is a lot of work for us at the moment: conducting photometer measurements as frequently as possible and also preparing for the end of our journey so that our colleagues can take over seamlessly on February 12.

I will report to you one more time - until then, cheers!

Arne from the EXPORT Team

On the 11th, we arrived on the Cape Verdes, marking the end of our expedition M207! Scientifically, the expedition was a great success, particularly with the observed dust outbreaks. 

On a personal level, we also greatly enjoyed spending such a long time on a research vessel. For my colleagues and me, the journey ended in Mindelo, where we left the ship. But this is not the end – our research and this blog will now be continued by Simon from the EXPORT team: 

 

Great news—the food container arrived in port on time! We picked it up on the 21st at 8 AM and loaded it as fast as possible. Hard to believe how much flour and milk fit into the storage room.

From there, we headed east into the Etna oxygen minimum zone for measurements conducted by our biologists, chemists, and physical oceanographers. Each day, visibility worsened, almost as if white fog hung in the air—surprisingly, that was actually dust, not the reddish haze some might expect. By the 25th, we finally entered a denser dust plume, with particle concentrations soaring beyond 300 mg/m³. Some of us could even taste the difference in the air.