An excursion to the driest desert in the World: Part I

The sharp topography is just one of the characteristics of the Atacama Desert

In October 2022, a group of biologists, geologists, geographers and meteorologists travelled to the Atacama Desert in northern Chile, the driest desert in the World.

This travel is under the umbrella of a big German project called CRC-1211: Evolution at the dry limit. The aim of the project is to understand how the life and landscape evolves in this hard environment condition, as well the interaction with the geological and meteorological processes.

The Atacama Desert lies between the bast Pacific Ocean and the Andes Cordillera, featuring low atmospheric humidity, scarce precipitation and almost no clouds. However, clouds do reach the Atacama, especially at the coast, thanks to the presence of an almost semi-permanent stratocumulus deck in the southeast Pacific. 

Next to the coast, the coastal cordillera (ranging between 800 and 1200 m ASL) “captures” these clouds, blocking the way to the interior of the desert. 

In the next time-lapse video, you can see clearly the coastal air trapped in the lower part of the atmosphere, something we called the Marine Boundary Layer (MBL). Here, the air is rather misty, full of marine aerosols that tend to produce a more foggy view of the landscape. This marks a big difference with the strong-blue, clear skies above in the free-troposphere. 

The MBL is capped by some clouds at ~1.000 m ASL, matching the coastal cordillera’s height, thus bringing liquid water in form of fog deposition or dew, especially during the night and the morning. In fact, this is almost the only source of liquid water for life because rainfall only happens every few years.

Time-lapse of the marine boundary layer along the coast of Atacama. The clear and dry from above contrast with the area with more aerosols and some clouds. Video: José Vicencio. October 2022.

More impressive, some plants are capable of surviving in these areas, only capturing the water from the clouds. In the next video, you can see the crown jewel of biologists: the Tillandsia. Because it is impossible to get water from the ground, this little bush does not develop any roots. Instead, it grows horizontally forming dunes that face the wind direction, allowing to capture of water that comes from the coast with the clouds.

Time-lapse of the clouds arriving to the Tillandsia field in the late afternoon. Video: José Vicencio. October 2022.

As was mentioned before, these plants are able to grow in curvy shapes over small dunes, facing the main wind direction and therefore maximizing the water capture.

Tillandsia field using a drone. Photo: Dr. Fabian Reddig.default
Dr. Johanna Möbus (B01 – Heidelberg Uni.) walking in the Tillandsia Field with the clouds approaching in the back. Photo: José Vicencio.
The Pacific Ocean and the small town of Paposo. Photo: José Vicencio.

The Atacama’s coastal cordillera is spectacular. Life blooms with just a few millimeters of cloud water, even in a dry and warm environment like this.

Along the coast, the main cities also grew, attracting people from all over the world due to the fishing, mining and tourism.

“La Portada” monument, a classic spot to visit in Antofagasta, Chile.

Maria S. Merian Cruise 114/2 – ARC Part 3 – 21.02.23

by Daria Paul and Lennéa Hayo

The last few days were quite rough. After crossing the 40° S, we encountered a heavy storm shaking us thoroughly. It gave us wind speeds of up to 140km/h, 12m high waves and rolling the ship from side to side by nearly 45°. Everything on the ship had to be fastened to not go flying about and walking became a real challenge – not even to mention in a straight line.

Luckily the storm weakened after two days bringing the relieve of a good night of sleep again. With the ships movement during the storm even that became impossible, rolling us around in our beds, feeling weightless in one moment and three times heavier than normally in the next.

While we are now passing the Falkland Islands and approaching the Magellan Straight, plenty of wildlife is popping up: albatrosses and other flocks of birds have been accompanying the ship since yesterday and some lucky people even saw whales!

Apart from watching wildlife, we are kept busy with writing cruise reports, backing-up data and preparing the instruments for packing. Tomorrow we will reach Punta Arenas and are sad that the campaign is already over. It was great fun working together with the amazing crew of Maria S. Merian, with so many enthusiastic scientists from very different fields, taking measurements in the middle of the Atlantic Ocean and especially very closely experiencing the features that we observed.

1.     An albatross seen from the ship’s observation deck. (Picture by Daria Paul UoC)
Meteorological situation while crossing the storm which had its strongest phase during the night between February 17 and February 18. (a) Air pressure (upper), temperature (middle) and wind speed (lower) measured by the on-board weather station. (b) Windspeed map from for the morning of February 18. The ship Maria S. Merian is marked by the white dot.

Cloud radar action at Ny-Ålesund

Kerstin Ebell

This week Mario and myself traveled to Ny-Ålesund, Svalbard, to exchange our cloud radar MiRAC-A with the cloud radar JOYRAD94. Since MiRAC-A is needed for campaign preparations, it has to travel back to Germany. Swapping the instruments on the roof of the atmospheric observatory of AWIPEV ( went very smoothly.

Crane operation to lift the cloud radar JOYRAD94 on top of the AWIPEV atmospheric observatory 

Thanks also to the AWIPEV and Kingsbay support! What a wonderful place to do measurements!

JOYRAD94 at his new location

Maria S. Merian Cruise 114/2 – ARC Part 2

by Daria Paul and Lennéa Hayo

Last week, we left the ITCZ and are now heading straight toward Punta Arenas. The new free time, we, therefore, spend with first data analysis. During the third crossing of the ITCZ we for example experienced and measured a strong doldrum with no wind and very little water vapor content in an otherwise very moist environment.

Apart from the data analysis, we used the last few days for two new projects: we launched three more radiosondes during AEOLUS satellite overpasses to help validate its wind profiles and started a little test series with a KT19. The KT19 is a passive infrared “camera” measuring the sea surface skin temperature to estimate the sea emissivity. 

After three weeks alone on the ocean, we saw the first ship on the horizon yesterday since we left the port in Mindelo! As we’re currently approaching the “roaring forties”, we have very rough weather ahead of us the next few days before we cross the “furious fifties” and finally reach the Magellan Strait, where we hopefully have some chances of seeing whales 😊.

Vertical profile of the atmosphere’s relative humidity up to 10.000m within the central ITCZ during the third crossing.
The KT19 sitting at the ship’s bow looks down at the water surface with a special mirror construction. (Picture by Daria Paul, UoC)
Time series of the integrated water vapor (IWV) from the HATPRO as a black line, IWV computed from the radiosonde’s humidity measurements as red dots.

Maria S. Merian Cruise 114/2 – ARC PART 1

Post by Daria Paul and Lennéa Hayo

Two weeks ago, we, Lennéa and Daria, joined the cruise MSM114/2 (ARC) on the RV Maria S. Merian together with an interdisciplinary group of scientists from the MPI-M in Hamburg, the Hafencity University, the University of Cologne, the Royal Dutch Meteorological Institute, and the Polish Academy of Sciences.

The goal is to use the vessels transit from Mindelo on Cabo Verde to Punta Arenas in Chile (23.1. – 23.2.23) to investigate tropical convection within the Intertropical Convergence Zone (ITCZ), which we zig-zagged three times on our way south. On the way, we collect meteorological reference measurements. In contrast, others measure the ocean depth with sonars and conduct CTDs to learn more about the protistan community’s diversity and composition.

We joined the cruise with a microwave radiometer HATPRO (Humidity And Temperature PROfiler). The HATPRO faces the sky and measures microwave radiation emitted by the atmosphere. Through this, we get continuous profiles of temperature, humidity, liquid water content and water vapor content for the entire cruise.

In addition to the radiometer, we help Laura and Julia from Hamburg launch radiosondes every 3 hours during our journey through the ITCZ for ten days. Getting up at 4:30 in the morning to launch the first radiosonde of our shift isn’t particularly easy, but at least it brings the joy of beautiful tropical sunrises!

Sunrise in the ITZC in the middle of the Atlantic Ocean after an early radiosonde launch. (Picture by Lennéa Hayo, University of Cologne)
Launch of a radiosonde by Daria Paul (University of Cologne) (Picture by Olaf Tuinder, KNMI)
Radiosonde launch on Maria S. Merian seen from a drone with sensors for atmospheric profiling (Picture by Daniel Kępski, Institute of Geophysics Polish Academy of Sciences
Heavy rain clouds shortly before leaving the ITCZ during the third crossing. (Picture by Julian Wagenhofer, University of Cologne)

Wetoo documentary: the video!

After all this time, a pandemic, and lots of efforts, the video is finally out. Take the chance to watch it, let us know your thoughts, and stay tuned… we are working on a live event soon in Cologne 🙂

Videodocumentary on women in science produced by the University of Cologne.

Before closing this post, we want to exploit the chance to really thank all the people who made it possible to realize this video. From the videomakers to the commission members, including all the colleagues that contributed somehow to the realization of the project. It is a collective effort to raise interest on the issue of gender gap in research and find new solutions for a better life for everyone.

Article in “Kölnische Rundschau”: „Botschaften vom Ende der Welt“ – „Messages from the end of the world“

In December, Kerstin was interviewed by a journalist in the local newspaper “Kölnische Rundschau”. The article (in German) about climate change in the Arctic and about our measurement activities in the Arctic, in particular at AWIPEV (Ny-Ålesund, Svalbard), was published on Dec 27, 2022.

What is it about?

The article highlights the importance of long-term data and data analysis for climate studies. It is always great to have the chance to communicate our science to the broader public! And of course it is a challenge as well…

American Meteorological Society (AMS): The return of face-to-face conferences

When the COVID-19 pandemic started, scientist around the world migrated quickly to online meeting and zoom conferences. However, if there is something that we all can conclude after this experience, it is the fact that nothing can replace the experience of face-to-face meetings. Not only because of the interactions between the colleagues and scientific discussions that take places everywhere, but also the experience to visit different places, cities, and cultures. Next, you can read the experience of Kerstin Ebell, member of AWARES:

In August, Susanne, Rosa and me went to the American Meteorological Society (AMS) Collective Madison Meeting at Madison, Wisconsin. The conference collection was about cloud physics, polar meteorology and oceanography, atmospheric radiation and satellite applications. After 2 years, this was my first international travel, and I was very excited to go. It was really great to meet international colleagues again and see old and new faces!

We had very good discussions during and around the conference and could enjoy the city of Madison (with an impressive water ski show!) and the hospitality of our American colleagues. My non-conference highlight was the corncob that we had for dinner at a friends place. So delicious! Sometimes the simplest things are the best things in life…

Conference link:


Hey hey, there’s an upcoming science slam to attend! In Bonn, young scientists will funnily present their science.

Among them there’s also our Imke! Imke is doing her phD in our group and will talk about her research: here’s her title:

Aren’t you curious? I am! let’s all meet there to see the show!

WHERE: Aula der Universität, Regina-Pacis-Weg 3, 53113 in Bonn

WHEN: at 19:30


Polarstern Cruise PS131 – ATWAICE (WALSEMA)

Polarstern cruise PS131 (ATWAICE) was a multidisciplinary expedition to investigate sea ice melting processes in the warming Arctic, ocean currents affecting nutrient supply for flora and fauna, ocean impacts on the melt of glaciers at Greenland’s east coast, and to deploy seismometers at the Aurora Vent Field. The expedition started on 28th June 2022 in Bremerhaven and led us to the Fram Strait, the marginal sea ice zone north-west of Svalbard, to fast ice at the east coast of Greenland and to Scoresby Sund, before returning to Bremerhaven on 17th August 2022.

Our working group also joined the expedition with atmospheric measurements using microwave radiometers (HATPRO and MiRAC-P) and radiosondes (weather balloons). The microwave radiometers faced the sky and primarily measured radiation emitted by the atmosphere (oxygen, water vapor, and liquid droplets). An additional sky camera consisting of a GoPro Hero 10 Black and an infrared sensor was mounted next to the radiometers on the guard rail of Polarstern to give us information about the sky conditions.
From the HATPRO data, we could already retrieve preliminary temperature and humidity profiles, as well as the total amount of water vapor (known as Integrated Water Vapour or IWV) and cloud liquid water path (LWP) with a high temporal resolution (1 second). Complementary to the radiometers, radiosondes give us high vertical but low temporal resolution of temperature and humidity profiles. An example of this is shown for an extraordinary warm and moist air intrusion event from 15th to 19th July 2022. IWV peaked at 35 kg m-2 (comparable to mid-latitude summer conditions), and the temperatures reached more than 18 °C at a few hundred meters altitude.
With a mirror construction designed by Pavel Krobot and Rainer H.-Lind and attached to the radiometers, we could also directly observe the radiation emitted by the sea ice and ocean. These measurements will later be compared to skin temperature measurements of the sea ice taken by an infrared camera to estimate the sea ice emissivity. Another GoPro is also mounted on the infrared camera to provide a visual context of the sea ice conditions.