#coldblob — Public Fediverse posts

Auch sichtbar: das Nachlassen des Golfstroms (🏌🏼‍♂️+ 🔌) verringert den Zufluß warmen Wassers in den Nordatlantik (vor unsere Haustür). In der Folge wird es bei uns kälter 🥶werden, während es global weiter wärmer 🥵 wird.

Was passiert, wenn warme feuchte Luftmassen auf die kalten Luftmassen hier in Europa treffen, kann sich wohl jeder selber ausmahlen. #Unwetter #Klimawandel #ColdBlob #Golfstrom #AMOC #Klimakipppunkt

https://bildungsserver.hamburg.de/themenschwerpunkte/klimawandel-und-klimafolgen/klimawandel/amoc-gegenwart-746948

edit: added another image.
https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lol2.10455

Amazing!
And #openaccess °
Also, the references in the paper are a treasure trove.

20,000 days in the life of a clam shell 10 mio years ago in the Indonesian Throughway shows heavy rain events, seasons and what the authors say is a proto- #ENSO cyclicality, dominated by #LaNina .
https://www.sciencedirect.com/science/article/pii/S0031018224007004

When you hear "dominated by La Nina", is your mind jumping to AMOC slowdown and tipping? Mine does.

The longterm climate records stored in this clam species can indeed show early warning signals for AMOC's tipping behaviour. In this paper, Arellano-Nava and D.J. Reynolds et al 2024 look at up to 500 year old (!) clams from the Northern Atlantic, document the approach for finding Early Warning Signals, and see a slowdown since 1750 https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lol2.10455

Light slowdown since 1750 was already visible in Thornalley's #AMOC reconstruction from 2018. He used sortable silt grain sizes near Iceland and near the Canadian coast .
So a different proxy showing the same slowdown.
I took the liberty to superimpose Thornalley's and also Rahmstorf's AMOC reconstruction over vanWesten's AMOC in their freshwater experiment to show the striking similarity, see picture 3.

But a gradual, even slowdown isn't an actual Early Warning Signal for tipping behaviour where
"...it flickers, then it tips...".

For AMOC's tipping behaviour, van Westen's team last year identified various Atlantic locations in various depths, none are in the classical research locations in the Northern North Atlantic ! Particularly not in the #ColdBlob... See the two map images from the supplement with the AMOC schematic by Chidichimo et al 2023.
It's still only a preprint tho, first author Emma Smolders https://arxiv.org/pdf/2406.11738

If I understand it correctly, the clam species lives on continental shelves in shallow-ish waters, not in the ocean abyss. So most locations Smolders et al identified are probably not good for using clams in reconstructing AMOC during the late #Holocene or in #paleoclimate. But some are, eg around the Canary Islands near Africa on 30°N, and many on the shelf along South America.
Especially important because the monitoring arrays (dashed lines in Chidichimo's schematic) have only been installed very recently. But clams can provide a continuous, annual to daily climate record everywhere – in shallow-ish waters.

I'm feeling actual excitement in the hope that researchers are now combing the ocean floor for these shells in the identified locations...

Guter Podcast zum Cold Blob und AMOC https://www.ardaudiothek.de/episode/iq-wissenschaft-und-forschung/raetselhafte-kaelteblase-geraet-der-subpolarwirbel-aus-dem-takt/bayern-2/13795411/

Mit #Rahmstorf, eh klar, aber noch eine Forscherin ist dabei, die speziell Interessantes erzählt.

Hab wieder was dazu gelernt.
Zum Beispiel ziemlich am Anfang, zum Subpolaren Wirbel, wie der überhaupt entsteht.
Durch Wind!
Der treibt das warme Golfstromwasser auf der Höhe New Yorks nach Osten. Und dort gibt es dann irgendwo so eine Art Kreuzung, wo der Wind nach Norden oder weiter nach Osten geht.
Wenn er nach Norden geht, treibt er damit auch den Wirbel an.
Und dann weht er auch mal vo Ost nach West... im Winter wohl..

Im Filmchen sieht man die v-Wind Komponente in den Wintermonaten. V-Wind ist rot, wenn der Wind nach Norden weht. Und blau, wenn er nach Süden weht. Daten: https://climatereanalyzer.org/research_tools/monthly_maps/

Der Subpolar Gyre / Cold Blob ist auch nich immer an derselben Stelle, fest eingemauert oder so. Nee! Das wabert alles so fuzzy rum, mal mehr rechts und mal mehr links.
Und je nachdem ob mehr rechts oder mehr links, gibt es in Zentraleuropa starke Hitze.

Muss auch gucken, dass ich ein paper von ihr finde. Vll steht ja in der "Introduction" noch mehr Interessantes um Subpolar Gyre drin.

#AMOC #ColdBlob #SPG #SubpolarGyre

My girlie chart with 490ky years of #Milankovic cycles, CO2, sea level, and the top line is d18O of a sediment core from within the #ColdBlob, see map. I think, it records AMOC shutdowns in the past.

Would be intriguing to know why it shut down. Eg, 427ka, "just" before the interglacial MIS11.
And why it not shut down during that very long interglacial which was ~as warm as the Holocene,
and had an ice-free West #Greenland (with a leaf found just 2 years ago at rock-bottom of an ice core from there),

and why AMOC instead collapsed in the middle of the following #iceage.

The very long interglacial MIS11 with its ice-free West Greenland and stable AMOC throughout tells me that the amount of freshwater input from melting ice on its own isn't the trigger for a collapse. But instead, the speed at which freshwater is added: very slowly like during #MIS11 won't do it.

Also intriguing: why the stuttering motor during the last glacial before the #Holocene?

#d18O from sediment cores at other locations strictly follow the ups and downs of #sealevel and #CO2. This one site #IODP #U1308 is exceptional.
#paleoclimate #AMOC

Germany has a warning for tonight, a storm coming from the South West. I thought, SouthWest is unusual for winter, hence I checked the broader conditions @ #EarthNullschool https://earth.nullschool.net/#current/ocean/primary/waves/overlay=significant_wave_height/orthographic=-30.24,41.58,281/loc=-27.995,53.889
Top left:
So there's this #PolarVortex #SSW split still ongoing, as seen in windspeeds at 10hPa.

Top right: the normal #jetstream at 250hPa races from North America straight to Europe because, I reckon, there's the hard border between the Azores High pressure system and the Iceland Low. (not in picture). Where the jet "hits" Spain, it gets driven North East. Dunno why. (And creates that storm in Germany. #weather )

Bottom left: sea surface temperature anomaly in the #Atlantic with a location in the #ColdBlob highlighted. It's currently 0.1°C colder than its longterm average. Yay. And for real it's 2.1°C warm there. #AMOC

And now the eyeopener🥁
the bottom right pic shows "significant wave height". The cold blob sees 9-10m waves = ocean mixing, bigly.
Are waves 1 of the 🌡️ reasons that blob forms where it does?

A new study suggests that the Atlantic overturning circulation AMOC “is on tipping course”

"It’s observational data from the South Atlantic which suggest the AMOC is on tipping course. Not the model simulation, which is just there to get a better understanding of which early warning signals work, and why."

Stefan Rahmstorf: https://www.realclimate.org/index.php/archives/2024/02/new-study-suggests-the-atlantic-overturning-circulation-amoc-is-on-tipping-course/ @climate

#AMOC #EWS #warningSignals #climateChange #dataViz #maps #map #Scotland #Iceland #Norway #Denmark #climate #ColdBlob #NorthSea #Atlantic

Back to the #AMOC - my #DMI colleague Steffen Olsen who is *the* expert in #Denmark talking about what has actually been observed in the #NorthAtlantic - the #WarmingHole + #ColdBlob + how #CMIP models represent it...
High variability + little trend (so far).