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Femke de Jong

@fmkdejong.bsky.social
2.4K followers 1.5K following 334 posts

Physical oceanographer at the Royal Netherlands Institute for Sea Research (NIOZ). Measuring the Meridional Atlantic Ocean Circulation (AMOC). Interested in ocean, climate, diversity, sailing, creativity. Views my own. Posts in English and Dutch

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Femke de Jong @fmkdejong.bsky.social · 07/10/2026
For those outside science thinking “scientists are always complaining about money, how bad can it be…” I maintain five moorings that are part of an AMOC array between Canada, Greenland and the EU since 2014. The competitive science funding in the Netherlands is particularly unsuited to do this
Photo at the aft deck of research vessel Neil Armstrong. One of our team is preparing the instruments that will go in the water later that day.
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Femke de Jong @fmkdejong.bsky.social · 29/09/2026
In Bergen, Norway, resting in the sun a little after many interesting science talks at the @bjerknes.uib.no. They will be presenting interesting new strategic projects soon
Photo of a sunlit pool and fountain in Bergen city center
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Femke de Jong @fmkdejong.bsky.social · 27/08/2026
Our NIOZ director Han Dolman is retiring. In his farewell speech he stressed that the evidence is all around us that climate is changing so fast and dramatically that it is not even a climate crisis, but a climate rupture. He is urging scientists and policymakers to keep advocating for change
Photograph of Han Dolman giving his retirement speech at the NIOZ. The room is dark, but a slide showing the temperature extremes of this summer is standing out. The title is “the climate rupture”
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Femke de Jong @fmkdejong.bsky.social · 08/06/2026
Today is Ocean Day. Started with an excellent talk of @helenczerski.bsky.social that included the importance of the ocean from ancient history till now.
Phote of the stage and screen at the Dutch Ocean Day conference. The slide shows a map with the setting of the sea battle of Actium in 31 BC. Helen is very energetically explaining how this battle transpired and how ocean conditions might have affected it
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Femke de Jong @fmkdejong.bsky.social · 23/04/2026
En de variaties in de tijd zijn groot. Deze grafieken laten maandelijkse gemiddelden zien. Het varieert van maand-tot-maand, seizoen-tot-seizoen en jaar-tot-jaar. Wij bestuderen wat ten grondslag ligt aan die veranderingen. agupubs.onlinelibrary.wiley.com/doi/10.1029/...
Grafieken met de tijdserie van 2014 tot 2022 op de OSNAP lijn. Bovenaan volume transport, dan warmte transport en onderaan zoetwater transport. De oranje lijn is het transport oost van Groenland, groen west van Groenland en de zwarte het totale poolwaardse transport
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Femke de Jong @fmkdejong.bsky.social · 23/04/2026
We moeten zo nauwkeurig zijn omdat hele kleine temperatuur (T) en zout (S) verschillen veranderingen in de dichtheid geven die uiteindelijk grote transport geven. Watermassa’s met verschillende oorsprong hebben andere T en S. De nauwkeurigheid die we nodig hebben is 0,003 gram zout per kg water.
Doorsnede van de oceaan langs de OSNAP lijn met het zoutgehalte aangeven in kleur. Het minst zoute water, in het westen en aan het oppervlak, heeft een zoutgehalte van 34.85. Het zoutste water, dat uit de subtropen aangevoerd wordt in het oosten heeft een zoutgehalte van 35.5. Dat scheelt dus 0.65 gram per kilogram water
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Femke de Jong @fmkdejong.bsky.social · 23/04/2026
Dat is voor mij het spannenste. Komt alles heel aan dek en hebben alle instrumenten twee jaar gewerkt? Er zijn nogal wat dingen die mis kunnen gaan met elektronica onder de druk van 3 km zout water. De instrumenten hebben dan ook een dikke roestvrijstalen of titanium behuizing.
Foto van het centrale lab in het onderzoeksschip waar alle instrumenten klaar gemaakt worden om uitgezet te worden
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Femke de Jong @fmkdejong.bsky.social · 23/04/2026
Om alle verankeringen in OSNAP te servicen (uit het water, data uitlezen, nieuwe batterijen, terug in water) zijn er drie tot vier losse vaartochten van een maand nodig. We werken 24 uur per dag, in wachten, en doen ook metingen vanaf het schip waarmee we die van de verankeringen kunnen calibreren.
Tekening van de OSNAP array die de oceaancirculatie tussen Canada, Groenland en Europa meet. De tekening is 3D en de verankeringen onder water zijn aangegeven met verticale lijnen met rode punten (instrumenten) en gele boeien.
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Femke de Jong @fmkdejong.bsky.social · 23/04/2026
Tekening van een verankering, niet op schaal. Deze worden al varend uitgezet. Op de Noordzee zou een bootje van 70 m die een kabel van 3 km trekt wel een beetje een probleem zijn, maar op de Irmingerzee zien we in een maand misschien twee andere boten op de horizon en hebben we de ruimte.
Schematische tekening van een verankering. Verschillende instrumenten zijn bevestigd aan een lange kabel. Een anker met releases houdt deze op de bodem. Boeien (geel, oranje) houden de kabel omhoog
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Femke de Jong @fmkdejong.bsky.social · 18/04/2026
Voor deze meetarray betekent dat concreet dat deze omhoog gehouden wordt door 8 individuen in 5 landen die daar geld voor proberen te regelen uit competative projectvoorstellen. Met het geld worden nieuwe batterijen voor instrumenten betaald, technici, promovendi en de scheepstijd
Een schematische tekening van de meetarray die door de Irmingerzee loopt. Je ziet een doorsnede van de oceaan ter hoogte van Groenland, met de stromingen en lokaties van instrumenten aangegeven
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Femke de Jong @fmkdejong.bsky.social · 18/04/2026
Al sinds 2003 ga ik ‘s zomers naar de Irmingerzee om metingen te doen. De Irmingerzee is het gebied tussen Groenland, IJsland en de Mid-Atlantische Rug. De zomerdagen zijn hier koud, grijs en mistig of helder en winderig. Maar wat er boven water saai uitziet wordt onder water gecompenseerd
Foto van de Irmingerzee. Vanaf de blauwe railing van het schip uitzicht op een grijs wolkendek en een grijsblauwe zee met kleine golven
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Femke de Jong @fmkdejong.bsky.social · 26/03/2026
Last night got stuck full of sensors and wires and got told “sleep like everything’s normal”. Of course you don’t. Now I am even more tired and still have a head full of clay (for holding electrodes). Tired me thinks this better lead to something. Nerd me wants to get the data to make plots.
Photo of bundled up wires and sensors for sleep measurements. Electrodes for brain activity, breathing, heartrate, leg movement. Basically you are wired up like a robot, or hospital escapee
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Femke de Jong @fmkdejong.bsky.social · 17/03/2026
They are not all recognizable, since it’s now a national park and they’re trying to balance preserving history and nature
Photo of a pond in the park. There are rectangular structures in the water, that likely represented the shape of a harbour.
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Femke de Jong @fmkdejong.bsky.social · 17/03/2026
In the Netherlands, on the land claimed from the sea, is a forest with old scale models. With a water network in between to run them. Some have been restored, wave generators and all.
Photo of a test basin. There are rail tracks over the water that carry a measuring bridge, which could carry instruments and scientistsPhoto of a row of old wave generators on the edge of a test basin
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Femke de Jong @fmkdejong.bsky.social · 12/03/2026
Mainly I am excited to see everything we thought out on paper in terms of lab and science requirements in reality. I hope she will sail well
Photo of a lab space inside. Still mainly empty workbenches, screens and large viewing ports
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Femke de Jong @fmkdejong.bsky.social · 12/03/2026
This is a ocean class research vessel and the replacement of Pelagia. Quite a bit bigger (wider and taller mainly), which means it can be a temporarely home and workplace for twice the number of scientists
Photo of the Anna Weber van Bosse from the side. A blue hull labeled “Sea research” and a white top. She has many cranes for putting oceanographic equipment in the water and masts for meteorological sensors
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Femke de Jong @fmkdejong.bsky.social · 12/03/2026
Today the Royal Netherlands Institute for Sea Research NIOZ welcomed her new research vessel. Christened by queen Maxima, in a typical Texel storm
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Femke de Jong @fmkdejong.bsky.social · 16/10/2025
Today we said goodbye and thank to our research vessel Pelagia. She has taken oceanographers around the oceans since 1991. She isn’t huge, but she and her crew sure were dedicated and not easily daunted. Many old collegues and many memories today 💙 🌊 ⚒️
Photo of research vessel Pelagia in the NIOZ harbour.
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Femke de Jong @fmkdejong.bsky.social · 16/09/2025
On the Texel ferry with a few of RV Pelagia
Photo of a rainy and cloudy Marsdiep with a vessel in the back. It is supposed to say “sea research” on the side of the vessel, but you can’t read it from here
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Femke de Jong @fmkdejong.bsky.social · 11/08/2025
Last week there was too much wind and I needed to get back to work. This weekend I invited a friend and sailed back home. The helping hand was very welcome in the locks.
Photo looking at the back of the sailboat sailing on the IJsselmeer. Lots of wind turbines in the background
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Femke de Jong @fmkdejong.bsky.social · 28/07/2025
First time going solo for more than a short swing around the lake. It didn’t go perfect, but it didn’t go horribly wrong either 🤷‍♀️
Photo looking forwards on a sailboat
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Femke de Jong @fmkdejong.bsky.social · 21/07/2025
Beautiful weather
A photo taken looking upwards. We see blue sky with some small clouds and a sun halo around the top of the mast of a sailboat
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Femke de Jong @fmkdejong.bsky.social · 20/07/2025
It sails!
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Femke de Jong @fmkdejong.bsky.social · 14/07/2025
How to recognize a Swedish boat
Small wooden cabinet inside a boat. The cabinet holds one item, a small allen wrench. The type used for ikea furniture
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Femke de Jong @fmkdejong.bsky.social · 16/04/2025
De Staat van ons Klimaat 2024, het jaaroverzicht van het KNMI over het weer in Nederland in 2024, is uit. 2024 is samen met 2023 warmste jaar. 2024 was 2,9 graden warmer dan het gemiddelde over de periode 1901-1930.
Inhoudsopgave van het jaaroverzicht.
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Femke de Jong @fmkdejong.bsky.social · 22/01/2025
Coming out of social media hibernation to post for #CTDappreciationDay (22 Jan)🌊 Here is a photo of my favorite CTD rosette CTDs measure conductivity (salinity), temperature and depth in the ocean. A rosette includes water samplers (the grey tubes) that take a sample of ocean water to analyse
Photo of the CTD rosette on research vessel Pelagia. Electronic sensors are located in the middle, samplers on the outside. This CTD rosette is lowered over the side of the vessel down to the ocean floor to measure the water properties
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Femke de Jong @fmkdejong.bsky.social · 10/01/2025
Ondanks alle toezeggingen is van een daadwerkelijke afname van CO2 concentratie nog geen sprake. Zolang de CO2 omhoog gaat, gaat de temperatuur ook omhoog.
Monthly global mean atmospheric CO2 column-averaged concentration from satellites for 2003-2024 and the 12-month average. Data source: C3S/Obs4MIPs (v4.6) consolidated (2003–2023) and CAMS preliminary near real-time data (2024) GOSAT-2 records. Spatial range: 60°S-60°N over land.
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Femke de Jong @fmkdejong.bsky.social · 10/01/2025
climate.copernicus.eu/global-clima... 2024 het warmste jaar tot nu toe. En, als we niks doen, een van de koudste jaren van de toekomst met alle gevolgen van dien. Maar elke vermindering van CO2 uitstoot helpt om de opwarming te vertragen of te stabiliseren. Hoe eerder, hoe beter!
Graph of global average temperature increase compared to the mean temperature of the 1850 to 1900 preindustrial period. The graph shows a steep increase in temperature since 1970, with 2023 and 2024 being the warmest years.
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Femke de Jong @fmkdejong.bsky.social · 19/12/2024
Very proud of dr Nora Fried, who successfully defended her PhD thesis yesterday 🎉🌊
Photo of the cover of the printed PhD thesis of Nora Fried, who was a PhD student at NIOZ. The title is “Hidden below the surface. On the pathways, interactions and transport variability of the Irminger Current.”

The cover shows moorings below the ocean surface and the research vessel Pelagia at the surface.
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Femke de Jong @fmkdejong.bsky.social · 22/09/2024
A beautiful late September weekend
Photo of a sailboat on calm water with sunshine in the background
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Femke de Jong @fmkdejong.bsky.social · 17/09/2024
Mainly bread. But you can’t have two slices with the same sprinkles
12 slices of bread (arranged 3 by 4) all with different kinds of chocolate sprinkles. From dark chocolate to white chocolate to mixed
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Femke de Jong @fmkdejong.bsky.social · 29/06/2024
Danger: potential new hobby alert ‼️ Attended a glassblowing workshop today. It’s not easy, but it’s fun.
Set up for the workshop. Each two participants shared a table with burner, tweezers and lots of glassResult of our efforts. A collection of glass spoons with little figurines at the end. For example a misshaped cat or a tilted bird or asymmetric sun. We had fun making them though
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Femke de Jong @fmkdejong.bsky.social · 26/06/2024
Today was a research cruise prep day. We had a test run with various moored instruments with the students from Utrecht University who are joining the cruise. Also showed them some other mooring equipment.
My office table with several moored instruments to practice with (a current meter, thermistor and microcat), cables to connect, laptop and lots of mooring diagrams and manualsPhoto of the mooring buoyancy and anchors (basically a 700 kg block of steel) sitting outside
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Femke de Jong @fmkdejong.bsky.social · 23/06/2024
A bit of cycling along the seaside today. Summer has finally arrived
Photo from the dike in Den Helder looking at two sailboats
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Femke de Jong @fmkdejong.bsky.social · 06/06/2024
Today is the Dutch National Ocean Sciences conference at Naturalis in honour of Ocean Day on 8 June. Today’s meeting brings together natural sciences, humanities and policy makers taking about how to give the ocean a voice
Photo of the opening slide at the meeting of the first Dutch National Ocean Science Conference
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Femke de Jong @fmkdejong.bsky.social · 26/05/2024
Little project yesterday. Not sure if I like it yet, but hadn’t made anything in a while so this is progress
Five flower petals cut out of silver sheetThe end result, a silver flower pendant. Practicing how to get from super flat artificial surfaces to something more natural
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Femke de Jong @fmkdejong.bsky.social · 28/04/2024
De fietsenrekken zijn wel alvast uitgegraven, die verdwijnen altijd onder het zand in de winter
Photo of the bike racks at the beach that have just been dug out of the sand. They get completely covered in winter
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Femke de Jong @fmkdejong.bsky.social · 28/04/2024
Het stormt nog niet, maar het ziet er al wel lekker dreigend uit #DenHelder
Photo of the beach in Den Helder. The sea is still calm, but the clouds are dark gray and threatening
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Femke de Jong @fmkdejong.bsky.social · 27/04/2024
It’s King’s Day 👑 in the Netherlands. The day when everything, including the weather radar map, turns orange. Not too nice weather for all the outdoor activities though
Screenshot of buienradar, the Dutch weather radar app. The Netherlands is orange in the map, not the usual green. There’s a lot of rain coming towards us from the North Sea
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Femke de Jong @fmkdejong.bsky.social · 23/04/2024
The NWO Polar Day took place in the Museon in Den Haag. Nice overview of Dutch polar research
Photo of the introduction screen at the NWO Polar Day 2024
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Femke de Jong @fmkdejong.bsky.social · 18/04/2024
Next time I’ll put the dye in a test tube before I add them to my pet AMOC
Screenshot of a video I made for a class. Using red dye in warm water and blue dye in ice cubes to make show a circulation that resembles the Atlantic Meridional Overturning Circulation in a fishtank
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Femke de Jong @fmkdejong.bsky.social · 17/04/2024
Well, the end of the poster session wraps up the North Atlantic #EGU24 session. Lots of interesting science and old and new colleagues
Photo of the poster session, with rows of poster boards along the two sides and people engaging in interesting discussions
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Femke de Jong @fmkdejong.bsky.social · 15/04/2024
At 10:45 I’m giving a talk on summer fresh layers and winter mixed layers in the western Subpolar Gyre, also in room E2
Screenshot of EGU program. Summer fresh layers and winter mixed layers in the western Subpolar Gyre by Femke de Jong and Nora Fried
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Femke de Jong @fmkdejong.bsky.social · 15/04/2024
Advertising two talks tomorrow in the North Atlantic session. At 11:45 Sasha Fedorov is talking about the future of the Greenland Tip Jet in room E2.
Screenshot of EGU program. Oral presentation “Greenland Tip Jet in the future: Declining heat loss in a high-resolution CESM simulations” by Aleksandr (Sasha) Fedorov, Claudia Wieners, Femke de Jong and Henk Dijkstra
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Femke de Jong @fmkdejong.bsky.social · 15/04/2024
Well, at least you know you’re in the right spot #EGU24
Photo of the EGU entrance with a giant (20x5m?) blue screen above the doors saying Welcome to EGU
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Femke de Jong @fmkdejong.bsky.social · 14/04/2024
Very impressed by whoever maintains this garden. Very glad it’s not me
Photo of a corner of the park where there’s perfectly straight beech hedges as well as perfectly round spheres
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Femke de Jong @fmkdejong.bsky.social · 14/04/2024
In Vienna for #EGU24. Some proposal writing in the morning and some sightseeing in the afternoon. Enjoying Schonbrunn’s garden in the sun was very nice.
Photo of the view of castle Schonbrunn from Neptunes fountain
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Femke de Jong @fmkdejong.bsky.social · 04/04/2024
Richard Engelen told us more about Copernicus data storage and services. Waiting for ERA5 downloads during the talk 😇@copernicusecmwf.bsky.social
Photo of Richard Engelen presenting Copernicus: working with or within the EU's Earth ObservaMon programme
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Femke de Jong @fmkdejong.bsky.social · 04/04/2024
Keynote talk of Gennadii Donchyts on the possible applications of google earth engine for science
Photo of Gennadii Donchyts presenting Google Earth Engine - a plaGorm for planetary-scale earth science data & analysis
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Femke de Jong @fmkdejong.bsky.social · 04/04/2024
Keynote talk by Ilse Aben on detection of super emittors of methane through a combination of different satellites. This is now an operational project, where governments are notified of super emitters (typically fossil fuels plants and landfills)
A photo of Ilse Aben presenting How satellites can support to reduce methane emissions – focus on super emitters
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