08 January 2020 (N51°21'9", E12°26'5")

Lidar data now online

The lidar data of the TROPOS PollyArielle in the OCEANET container from the 1st leg of MOSAiC are now online in the TROPOS database: http://polly.tropos.de/?p=lidarzeit&Ort=35

All stations of the worldwide lidar network PollyNet are available under: http://polly.tropos.de/  as well as http://picasso.tropos.de/

More about PollyNet, which is part of ACTRIS, at: https://www.tropos.de/en/research/projects-infrastructures-technology/coordinated-observations-and-networks/pollynet

PollyNet. Source: TROPOS.de

05 January 2020 (N87°4; E115°19)

Minus temperatures and darkness

...can't shock Hannes Griesche. The "Morgenpost am Sonntag" reports about the MOSAiC expedition (in German).



01 January 2020 (N86°44; E117°36)

New Year & northernmost New Year's Eve party in the world

Happy New Year!

We have almost felt -50°C here on the ground today (with actual -31 and with about 10m/s wind). In the atmosphere above us it is even colder: -78°C is measured by the radiosonde at 18km altitude.

The next station point is the North Pole and therefore the distance to it is always displayed. Currently it says: 197.45 NM - that is nautical miles. That's 365km - compared to the 4361km only a stone's throw ;-)

Our time is Moscow time by the way. So we were 2 hours ahead of Germany in 2020 and we have indeed a bright starry sky again.

Many greetings!



PS. By the way, New Year on RV Polarstern sounds like this: https://www.awi.de/fileadmin/user_upload/AWI/Expedition/Schiffe/Downloads/Polarstern-Horn2.mp3

Nördlichste Silvesterparty der Welt. Bei 86°38,25N/118°04.06E begrüßte das MOSAiC-Team die neue Dekade. Julia Wenzel vom Deutschen Wetterdienst (DWD) hatte die Ehre, das Schiffshorn um Mitternacht erschallen zu lassen. Foto: Michael Ginzburg

29 December 2019 (N86°38; E115°52)

Still 202.22 NM to the North Pole

Hello home,

here's a little inter-year-old e-mail. But not much has happened here in the last few days. We had two visits from an arctic fox (enclosed a photo). But even though they were always around polar bears, we have not seen them yet.

Our lidar "Arielle" got a small Christmas cleaning from me on 23.12. And right in the evening the computer restarted itself. But since then everything is running as usual again. Only interesting traps are left out. In the last days we had more and more low clouds again, so that there are rarely signals from above 2km. And if there are, I keep my eyes open for Polar Stratospheric Clouds (PSCs). But so far I have seen nothing like that in the data. The rest of the instruments are measuring diligently and the Cimel photometer is eagerly waiting for the moon to rise again.

Christmas Eve we had a nice Christmas party (which we defined as the northernmost in the world), with speeches from the captain and cruise director, a visit from Santa Claus and gnome presents for everyone.

On Christmas Day we had excursions on foot or, whoever had some, by ski (I was able to borrow a pair and was in the ski group). On New Year's Eve the next official celebration was already on the agenda, with a greeting of the New Year on the bridge.

I wish everyone a happy new year!

Many greetings from the ice,


Visit in the darkness of the polar night. An arctic fox passes near the Polarstern. Usually they feed on the leftovers that polar bears leave behind on the ice after the seal hunt and follow them. But this time no polar bear was seen. Photo: Hannes Griesche, TROPOS

24 Dezember 2019 (N86°38; E113°46)

Christmas eve

The MOSAiC expedition team is enjoying a cheerful Christmas eve aboard Polarstern. Santa did pay us a visit!

Photo: Folke Mehrtens, AWI

21 Dezember 2019 (N86°41;E112°24)

Winter solstice

From now on the days will be longer!

Hello to Leipzig,

here comes an update from the floe. In the container I was able to look in regularly and my predecessor Ronny arranged everything very nicely for me. I only had to restart a software to copy all the data to the central data center here, but everything else runs fine and measures.

Yesterday evening the deep clouds finally disappeared and our Lidar Polly-Arielle could measure aerosol layers again. And there were two of them the whole evening below 2km and one at 5km. And I'm not sure, but above 11km could be the stratospheric aerosol that we have seen here so often lately. The tropopause is now again at 11km altitude.

Yesterday we had the shortest of our non existing days and celebrated it properly. We had mulled wine with it and it is recommended to enjoy it in thermos cups. Otherwise it is said to be frozen faster than drunk. .-)

Merry Christmas holidays to all!

Hannes Griesche

Photo: Stefan Hendricks, AWI

Measurement of the TROPOS lidar PollyArielle from 21 Dec 2019

"The many high clouds up to 11 km indicate (once again) that the Arctic is not a closed system. Again and again air masses from rather middle latitudes cross the pole. The stable air masses (and embedded aerosol layers) further down (below 5-6 km) are probably more typical for winter Arctic conditions", Albert Ansmann (head of the TROPOS Ground Based Remote Sensing working group) interprets the measurement of 21.12.2019. Graph: Hannes Griesche, TROPOS

19 December 2019 (N86°40; E112°52)

Change Leg 1 to 2 finished

The Russian supply icebreaker Kapitan Dranitsyn left the MOSAiC ice floe on December 18 2019 at 14:30 ship time (12:30 CET). Thereby the supply and exchange between leg 1 and leg 2 is completed. Photo: Alfred-Wegener-Institut / Folke Mehrtens (CC-BY 4.0) 

Departure of the Kapitan Dranitsyn. Photo: Alfred-Wegener-Institut / Folke Mehrtens (CC-BY 4.0)

18 December 2019 (Leipzig/Dresden)

Shift change at the North Pole in the media

The change between cruise section 1 and 2 at MOSAiC is reported by others in German:

+ Sächsische Zeitung am 19.12.19: "Schichtwechsel am Nordpol" > https://www.saechsische.de/plus/schichtwechsel-am-nordpol-arktis-expedition-mosaic-saechsische-wissenschaftler-tropos-leipzig-5152729.html

+ MDR-Sachsenspiegel am 17.12.19: "Wie Leipziger Forscher in der Arktis am Klima forschen" > https://www.mdr.de/video/mdr-videos/a/video-366150.html

+ MDR-Radio-Sachsen am 17.12.19: "Schichtwechsel auf der Polarstern - Leipziger Forscher im Interview" > https://www.mdr.de/sachsen/leipzig/leipziger-forscher-polarstern-expedition-100.html

Rendesvouz in the Arctic. Photo: Ivo Beck, PSI (CC-BY 4.0)

17 Dezember 2019 (Leipzig)

Performance "POLARZEIT: Expedition extrem"

The performance at the Natural History Museum Leipzig was accompanied by a telephone conversation with researcher Ronny Engelmann (TROPOS) from Leipzig who, as part of the international MOSAiC expedition, is currently drifting through the Arctic on an ice floe with the research icebreaker Polarstern near the North Pole, to help for the first time to providing global climate researchers with coveted data from the polar night. Tuesday, 17.12.19, from 19:30
More information at http://www.schaubuehne.com/programm/polarzeit-expedition-extrem/

The cooperation project "Expedition 4x6" between the Natural History Museum Leipzig and the Schaubühne Lindenfels is now dedicated to expeditions into the ice worlds of the polar regions. Photo: Tilo Arnhold, TROPOS

Around 40 people from Leipzig experienced the polar time performance of the Schaubühne Lindenfels at the Natural History Museum in Leipzig and listened intently to the telephone conversation with the Polarstern in the Arctic. (Photos: Tilo Arnhold, TROPO

17. Dezember 2019 (Potsdam)

UFA SHOW & FACTUAL zeigt erstes Material

"Kamerateams der UFA SHOW & FACTUAL begleiten die MOSAiC-Expedition ... exklusiv über den gesamten Zeitraum. ... Abschnitt für Abschnitt stellen UFA SHOW & FACTUAL und das Alfred-Wegener-Institut einige Minuten Material zur Verfügung"


Video bei Youtube:


Foto: Alfred-Wegener-Institut / Stefan Hendricks (CC-BY 4.0)

16 Dezember 2019 (N86°37; E117°52)

Change of Shifts at the North Pole

As the second leg of the one-year-long MOSAiC expedition begins, participants review the mission so far

After exchanging research teams and crewmembers, the greatest expedition to the Central Arctic of all time is now entering the next phase, during which urgently needed research into the Arctic climate system will be conducted. In the following paragraphs, the team from the first leg of the journey, which was dominated by thin sea ice, review the mission so far: despite extremely challenging conditions, they maintained a steady flow of scientific data. The new team will now face the darkest and coldest research phase: the Arctic winter, which has never been researched before.

Read more at AWI here: https://www.awi.de/en/about-us/service/press/press-release/change-of-shifts-at-the-north-pole.html


Group photo of the first team shortly before the end of Leg1. Our colleague is standing behind, but - as befits an atmospheric scientist .-) - at the top. Photo: Alfred-Wegener-Institut / Esther Horvath (CC-BY 4.0)

Around 100 people swap places between the research icebreaker Polarstern, which has been drifting with Arctic sea ice since October, and the Russian supply icebreaker Kapitan Dranitsyn.

  • Polarstern meets Captain Dranitsyn at MOSAiC ice floe for Leg 1 and Leg 2 exchange. (Photo: Esther Horvath and Jakob Stark)

  • Scientific team and crew of Leg 2 visit Polarstern after arriving to the MOSAiC ice floe with Captain Dranitsyn. (Photo: Esther Horvath)

  • Crew and scientific team proceed cargo operation on Polarstern helicopter deck. (Photo: Esther Horvath)

  • Crew and scientific team proceed cargo operation on Polarstern helicopter deck. (Photo: Esther Horvath)

  • Team BGC science hand over between Leg 1 and Leg 2. Scientific teams conduct scietific hand over. BGC Leg 2 team member Adela Dumitrascu and Partic Simoes Pereira (l)) cores at BGC coring site on MOSAiC oce floe as a part of the scientific handover. (Photo: Esther Horvath)

  • Team BGC science hand over between Leg 1 and Leg 2. BGC Leg 1 team member Dorothea Bauch (l) and BGC Leg 1 team lead Katarina Abrahamsson do a scientific hand over for BGC Leg 2 team member Adela Dumitrascu (r) and Partic Simoes Pereira (standing) execute the scientific hand over at BGC coring site on MOSAiC oce floe. (Photo: Esther Horvath)

14 Dezember 2019 (N86°36 E118°31)
First film shoots on German television

"Arktis-Expedition: Erste Filmaufnahmen der "Polarstern"

ARD's Tagesschau and Tagesthemen show the first films from the ice on the occasion of the UN climate conference COP25. (Das Erste, 14.12.19, 20:00 & 23:30)



Film crew at work in the ice. Photo: Esther Horvath, AWI

12 Dezember 2019 (Madrid)
UN Climate Conference COP25

At the invitation of the BMBF, the German Pavilion at the UN Climate Conference COP25 hosted a side event entitled "Aerosol-Cloud Interactions in a Changing Climate: Opportunity or Threat". Experts connected by live transmissions to measuring stations at key locations on different continents and to the research vessel "Polarstern" in the Arctic presented the influence of changing air pollution on local weather and global climate change. We were also able to talk to our colleague Ronny Engelmann via satellite telephone.

More in German unter
and English


The MOSAiC expedition is present at the COP25 in Madrid - via satellite telephone. Photo: Konstantin Engelbrecht, BMZ

10 Dezember 2019 (N86°32 E120°59)
„So you could almost call it North Pole .-)“

Shortly before the end of the first leg of MOSAiC we were able to talk to our colleague Ronny Engelmann on the Polarstern via satellite telephone on Tuesday evening. The 5min telephone call was a test for the live connection to observatories worldwide during the UN climate conference COP25 in Madrid, where on Thursday a side event will inform about the international lidar network PollyNet, the EU research infrastructure ACTRIS and the importance of short-lived climate drivers such as aerosols, clouds and trace gases.

Dr. Ronny Engelmann from TROPOS at his workplace, the OCEANET container on Polarstern during the first leg of the MOSAiC expedition. Photo: Esther Horvath, AWI

Phone call in German with Dr. Ronny Engelmann from TROPOS - currently on the RV Polarstern in the central Arctic (10 Dezember 2019, 18:00 MEZ)

8 December 2019 (Leipzig/Tromsø/Arctic)

New equipment and replacement on the road

Sensors for the big TROPOS tethered balloon “BELUGA“ on their way to MOSAiC

For the upcoming operations of the TROPOS tethered balloon “BELUGA” on the MOSAiC expedition from April to June 2020, instruments for the study of the atmospheric boundary layer in the Arctic are now on their way into the ice. The first supply vessel “Kapitan Dranitsyn” will bring the sensors for the measurement of aerosols, turbulence and radiation to the icebound Polarstern. The result of intensive developments at TROPOS is also present: the two, new platforms “CAMP 1 & 2”. With highly sensible instruments, they are capable to measure even lowest concentration of Black Carbon and other aerosol properties. Christian Pilz, TROPOS

BELUGA equipment before transport. Photo: Tilo Arnhold, TROPOS

In November several boxes were sent from TROPOS in Leipzig to Tromsø (Norway). From there, a Russian icebreaker will take them to Polarstern so that the equipment can be used on the ice in spring 2020. Photos: Tilo Arnhold, TROPOS

An other colleague from our Lidar group started with the "Kapitan Dranitsyn" in Tromsø (Norway) at the end of November to replace the current caretaker of the OCEANET container. The icebreaker is expected at Polarstern for about 13 December.

  • Photo: Folke Mehrtens, AWI

  • Photo: Folke Mehrtens, AWI

  • Photo: Folke Mehrtens, AWI

7 December 2019 (N86°9; E122°9)

Winter storms and complete darkness

"Up to and including yesterday, there was a strong wind here for a few days with snow drift and low visibility. To make work on the ice easier and to illuminate the way home, the three Polarstern spotlights are used". https://follow.mosaic-expedition.org/  


The Polarstern on Polar Night. In the meantime there is darkness around the clock. Until noon a hint of twilight can be guessed, it will take more than a month. But until the sun will show up on the horizon much longer. Temperatures fall below -30°C - in a snow storm with windchill effect far below -40°C. Photo: Esther Horvarth, AWI

6 November 2019 (N85°55; E116°43)

Work in polar night

"Our ship clocks are currently on UTC+8, which puts us seven hours ahead of Central European time. From now on we will reset the clocks every Saturday night until we reach UTC +3. This is Moscow time, after which the next supply ship, Dranitsyn, will be lived and worked on." https://follow.mosaic-expedition.org/  

The Polarstern on Polar Night. The large on-board spotlights bring some light into the darkness. In front on the deck are various measuring containers, including the OCEANET container from TROPOS - recognizable by the green light of the laser reflected from the roof hatch of the container. The laser beam of the lidar itself is not visible because the air on the ground is very clean and the Polarstern's on-board headlights are much brighter. Photo: Esther Horvarth, AWI

25 October 2019 (N85°26 E127°50)

Polar Night & Weather

Polar Night

The polar night has arrived on the MOSAiC ice floe. Darkness characterizes the picture since the sun no longer comes over the horizon. Instead, there is very little residual light in the midday as in the homeland far after sunset at the end of twilight.


The floe is now drifting more and more northwest towards Spitsbergen: https://www.awi.de/fileadmin/user_upload/MET/PolarsternCoursePlot/psobse.pdf 


What is the weather like on FS Polarstern in the Arctic right now?

The current data on temperature, precipitation and wind are now also available hourly from the Norwegian Weather Service - incl. forecast: https://www.yr.no/en/forecast/daily-table/0-82/Polarstern

Read more in the PolarPredictNews: https://www.polarprediction.net/news.html

These data come from the Polarstern on-board weather station, which is operated by the German Weather Service (DWD). The current weather data are also online
at the DWD https://www.dwd.de/DE/fachnutzer/schifffahrt/maritimberatung/mosaic/polarstern/polarstern_node.html
and AWI https://www.awi.de/nc/en/science/long-term-observations/atmosphere/polarstern.html


Die Polarstern in der Polarnacht. Foto: Alfred-Wegener-Institut / Esther Horvath (CC-BY 4.0)

04 Oct 2019: MOSAiC expedition begins its ice drift on a floe at 85 degrees north and 137 degrees east

The MOSAiC team has now selected the floe that will serve as the base of operations for their one-year-long ice drift around the North Pole with the German research icebreaker Polarstern. This was preceded by an intensive search combining satellite imagery and helicopter flights over the target area in the Central Arctic, which were supported by the icebreaker Akademik Fedorov, operated by Russia’s Arctic and Antarctic Research Institute (AARI). The participating researchers closely examined 16 floes that, on the basis of satellite imagery, were potentially large enough to accommodate the ice camp. They subsequently met on board Polarstern to compare their findings, ultimately agreeing that the ice drift should be prepared for on a floe measuring roughly 2.5 by 3.5 kilometres, and located at 85 degrees north and 137 degrees east. The floe, which Polarstern will allow herself to become frozen to, is currently drifting in alternating directions, at up to 10 kilometres per day.

Read more: https://www.awi.de/en/about-us/service/press/press-release/a-fortress-of-ice-and-snow.html


First group of scientists on ice floe (Photo: Esther Horvath, AWI)

22 Septemberg 2019: On the way to the pack ice

Polarstern is on its way to the northeastern Arctic. The preparations for the work on the ice floe are running at full speed during this transfer trip. At night, the Barents Sea offered spectacular views of northern lights, the Aurora Borealis: 

"Anchors Aweigh for MOSAiC Leg 1" - first post in Polarstern blog by Marcel Nicolaus (AWI) from 22 Sep 2019: https://blogs.helmholtz.de/polarstern/en/2019/09/anchors-aweigh-for-mosaic-leg-1/

You can use the MOSAiC web app to follow Polarstern’s drift route live: https://follow.mosaic-expedition.org/


Foto: Alfred-Wegener-Institut / Stefan Hendricks

Farewell party for the departure of FS Polarstern in the harbour of Tromsø (Norway) on 20.09.2019

  • Foto: Ronny Engelmann, TROPOS

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Andreas Macke, TROPOS

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

  • Foto: Alfred-Wegener-Institut (CC-BY 4.0)

20 September 2019: Polarstern departure

News and media reports about the start:

Radio interview on detektor.fm with Prof. Dr. Andreas Macke, interview "Die größte Arktis-Expedition der Geschichte", 19-09-2019

Report in the Tagesspiegel, article "Eiskalte Forschung Warum Wissenschaftler den Winter in der Arktis verbringen", 18-09-2019

Report in the Sächsische Zeitung,  article "Sachsen lassen sich am Nordpol einfrieren. Heute beginnt Mosaic, die größte Arktis-Expedition aller Zeiten. Sächsische Forscher sind dort mit dabei - und auch die SZ", 20.09.2019

The last containers are loaded in Tromsö. The white OCEANET container from TROPOS (centre right) is already standing on the deck. Photo: Esther Horvarth, AWI

Transport of container & equipment on 26 August 2019

Here we go! Our OCEANET container with PollyNet lidar & other devices left Leipzig today. Destination: Tromsö.


Photo: Tilo Arnhold, TROPOS


The Leibniz Institute for Tropospheric Research (TROPOS) will play a leading role in two central measurements of the MOSAiC campaign: Firstly, the OCEANET remote sensing container will continuously explore the vertical aerosol and cloud distribution for the entire ice drift using lidar, radar and microwave radiometers. On the other hand, a 90 cubic metre tethered balloon on sections 4 and 5 will bring several measuring devices up to 1500 m altitude in summer 2020 in order to measure the Arctic boundary layer as precisely as possible. TROPOS will also be integrated into the expedition leadership of section 5: The expedition leaders for this section will be Prof. Dr. Dieter Wolf-Gladrow from AWI and TROPOS Director Prof. Dr. Andreas Macke.

see press release from 27 June 2018


From mid-January to mid-February 2019, a field campaign was conducted at the TROPOS Melpitz station near Torgau to prepare for the MOSAiC expedition.

see report of the campaign from February 2019 and video on the test campaign by MDR Wissen


In winter, the Leipzig team tested in Melpitz the assembly and disassembly of the tethered balloon including the attached measuring technology. (Photo: Tilo Arnhold, TROPOS)

For one year frozen in the Arctic ocean

MOSAiC - Multidisciplinary drifting Observatory for the Study of Arctic Climate

It'll be the biggest Arctic expedition ever: Starting in autumn 2019, the German research icebreaker Polarstern will drift frozen through the Arctic Ocean. On the MOSAiC expedition, scientists from 19 nations will explore the Arctic over the course of the year. They spend the winter in a region that is almost inaccessible at polar night. The natural force of the ice drift alone gives this unique opportunity. A research camp will be set up on an ice floe and connected to a kilometre-wide network of measuring stations.

Hardly any other region has warmed as much in recent decades as the Arctic. Therefore the aim of the expedition is to better understand the influence of the Arctic on the global climate. This milestone for climate research and its data will be valuable for generations to come. The mission led by the Alfred Wegener Institute is associated with unprecedented challenges. An international fleet of icebreakers, helicopters and airplanes supplies the team on this extreme route. This expedition can only succeed with joint efforts.

Trailer MOSAiC expedition by Alfred Wegener Institute

Stock photo (Polarstern expedition ANT-XXIX/6 2013): Alfred Wegener Institute/Stefan Hendricks

The MOSAiC expedition of the German research icebreaker Polarstern. Map: AWI/BMBF