anlomedadMay 25

Nino and Nina compared.

Nino seasons have deep consequences in rain amounts. And with all the talk about the forecasted Super-El Nino, I wanted to know what the differences were.
You too? Here you go.

Maps show seasonal differences between Nino and Nina anomalies.
The first image shows rain data from #GHCN weather stations and sea surface temperature from ErsstV6.
The second image shows tmax from the weather stations and sst.

The underlying data are anomalies over 30-year running averages from 1870-2025, but computed as percent which makes plotting and merging different units in Panoply easy.
After the monthly anomalies were computed, the data got split into Nino and Nina months and seasons.

Made with https://www.giss.nasa.gov/tools/panoply/
using data from https://www.ncei.noaa.gov/data/sea-surface-temperature-extended-reconstructed/v6/access/
and GHCNdaily
https://www.ncei.noaa.gov/pub/data/ghcn/daily/

Show threadanlomedadApr 4

#2 So the movie above shows the °C teleconnection from any pixel on land to the Early Warning zones in the Atlantic.
A pixel got plotted if its seasonal temperature difference year-on-year matched >5 times per decade and that in at least 3 decades. The colour scale denotes the strength of the season's teleconnection.

The seasonal sea surface temperature I compared the land pixels to is from Era5 and from ErsstV6. The movie shows both comparisons merged.

Teleconnections can be immediate – as shown in the Berkeley movie. But they can also exist years and years removed. Like the Tasmanian corals in the paper in #1 which dictate AMOC strength from 46 years in the past!

I didn't go that far back ^^
But I did also compare for example the season JJA of the zones with every pixel's 4 last and 4 next seasons.

Why I did that: it bugged me that Asia only had very few pixel matches if I confine the comparison to same_season.
I couldn't believe that Siberia really had no teleconnection to one of the AMOC zones at all.

So I looked at the 8 Early Warning zones
with their teleconnected pixels on land, iterated from 4 seasons back to 4 seasons into the future.
The same "bingo" criteria applied.

And Asia lit up!
The data in this movie is not Berkeley but weather stations in #NOAA's global station network #GHCN.
These station data series had to first meet quality criteria before they entered the comparison.
This results in far fewer pixels than Berkeley would have produced in this "4x4 season" perspective.

It's rather boring to watch.
Altho not boring if you actually want to use the pixels to then search for temperature proxies for the AMOC!

To make it less boring, the audio track here is from #JesusChristSuperstar . The incredible Ian Gillan of #DeepPurple sings Jesus' prayer in the Garden of Gethsemane.
"Take this cup away from me for I don't want to taste its poison",
very apt, don't you agree, with Easter, #climateChange , AMOC collapse and all?

Want more? There's another 😁

anlomedadMar 1

How come, ibtracs doesn't map the winter storms that pummelled Ireland, UK, Portugal, Morocco?
I cycled through the most recent 30 listed storms (in "time") and also checked the txt file for their names, Kristin, Leonardo, Marta, Chandra. They're not there. Does ibtracs exclude European storms altogether? Because... our national(ist) meteorological services don't want to participate in the "international best-track-archive for climate stewardship"?
Very odd.

https://www.ncei.noaa.gov/data/international-best-track-archive-for-climate-stewardship-ibtracs/v04r01/access/netcdf/

GHCN-d is still unusable for stations outside USA-affiliated countries.
So I don't know how to get observation data to play with. Dang.

#ibtracs #GHCN #NOAA #NCEI

Index of /data/international-best-track-archive-for-climate-stewardship-ibtracs/v04r01/access/netcdf/

anlomedadMay 18, 2024

@Fury
Ah... missing data... like in China in the #GHCN daily collection. Until 2005 or so, rain gets reported diligently without any missing dates. From then on, more and more stations only report 10 days or so per month. Since 2013, no station is reporting complete anymore.
I suspect, it's China's nation-wide adoption of rain-making since 2013. Before that it was only testing and sort of voluntary. But when they went full on cloud-seeding they stopped reporting daily data to obscure success or failure.

@ai6yr

Show threadanlomedadJan 19, 2024
@CelloMomOnCars
Thank you for sharing!
I'm wondering how the involved mechanisms then work to cool Western and Northern Europe. That it is via changes in the atmospheric currents is clear because else, the African #monsoon #weather wouldn't be affected as well.
Additionally, it is the winter which cools so significantly in a partial #AMOC collapse. While summers still - yet maybe more pronounced in collapse? – get heat from Africa via the #jetstream .
And if it is the winters that cool so significantly: how does it come to pass? In other words: is this current winter a harbinger? (Altho this winter is meddled-with by #HungaTonga 's impact on the jetstream particularly over Western Europe, see #MartinJucker preprint 2023 "Long-term climate impact of large stratospheric water vapor perturbations": the figure on jetstream in 300hPa in this first winter after eruption)
The atmospheric changes might be like this: when the subpolar gyre still worked, it created a barrier that prevented winter jetstream from lapping up cold polar air and spit it out over Western Europe.
With a changed (ie, cooler?) #SubpolarGyre in a partial AMOC collapse, the jetstream is able to meander more over that region, or maybe, not meander more but meander at a changed location, so the lapping tongue no more occurs over West Russia but then over West and Northern Europe.
If this were already happening, how would we see it in data from weather stations? The #GHCN has long-running weather stations from Scandinavia and Russia. I'm going to look for changes in winter low temperatures there. https://www.theguardian.com/environment/2024/jan/17/greenland-losing-30m-tonnes-of-ice-an-hour-study-reveals
Greenland losing 30m tonnes of ice an hour, study reveals

Total is 20% higher than thought and may have implications for collapse of globally important north Atlantic ocean currents

The Guardian