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A graph that should be front-page news

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Re: A graph that should be front-page news

#3

Post by l1chorpe »

Looking at the graph left me wondering just what it means exactly. I'm not well versed in statistics so "the standard deviation is 3.5°C" doesn't mean much. Also, what's up with that other line going down to -3.5°C? And what do the colors mean? In the sense that I'm not sure whether a darker blue means closer to or further from today.

Re: A graph that should be front-page news

#5

Post by ArnoVW »

l1chorpe wrote: post #3

Looking at the graph left me wondering just what it means exactly. I'm not well versed in statistics so "the standard deviation is 3.5°C" doesn't mean much. Also, what's up with that other line going down to -3.5°C? And what do the colors mean? In the sense that I'm not sure whether a darker blue means closer to or further from today.

my layman understanding, a real statistician will surely intervene.

standard deviation is a measure that informs about the distribution. A high standard deviation means a "wide bell curve". A low standard deviation means that all values are closely clustered around the middle of the curve.

So if your value is 2 x standard deviation (for example) that means it is a relatively rare outlier, since 2 x standard deviation covers 95% of the bell curve. In particle physics I believe they require 5 standard deviations to confirm an observation.

Re: A graph that should be front-page news

#6

Post by bestouff »

l1chorpe wrote: post #3

Looking at the graph left me wondering just what it means exactly. I'm not well versed in statistics so "the standard deviation is 3.5°C" doesn't mean much. Also, what's up with that other line going down to -3.5°C? And what do the colors mean? In the sense that I'm not sure whether a darker blue means closer to or further from today.

> Each blue line represents a different year since 1982. The red line is this year. It doesn't just set a new record. It has departed entirely from the range of previous observations.

Re: A graph that should be front-page news

#7

Post by danhau »

l1chorpe wrote: post #3

Looking at the graph left me wondering just what it means exactly. I'm not well versed in statistics so "the standard deviation is 3.5°C" doesn't mean much. Also, what's up with that other line going down to -3.5°C? And what do the colors mean? In the sense that I'm not sure whether a darker blue means closer to or further from today.

I'm not an authority on this, but here's is my understanding - I'd appreciate if someone could correct my mistakes.

The baseline of 0.0 represents the average of all years. Anything above / below the baseline is a (standard) deviation from the average. The blue lines are the individual years since 1991 [1] while the red line is the year 2026.

If a line is above the baseline, then the sea-surface temperature was hotter on that day than average. If below, it was cooler than average.

The year 2026 is an outlier, dwarfing all the others starting around June / July. The Nino 3.4 sea-surface temperature is significantly hotter than any previous year during that time. New record, I guess?

[1]: I'm confused about the two date ranges given: 1982-2026 and 1991-2020. I'm assuming this graph is based on measurements from 1982-2026 to calculate the average, but the lines shown are only from 1991-2020, for some statistical reason I don't understand.

Re: A graph that should be front-page news

#8

Post by jones89176 »

Shouldn't the y-axis better be called "Standard DeviationS"?

According to one comment on the site, the 3.5 means "3.5 times the SD", which makes much more sense to me.

I initially tried to make sense of "SD being 3.5 on that day of the year", which seems to be a wrong interpretation.

Re: A graph that should be front-page news

#9

Post by blaze33 »

l1chorpe wrote: post #3

Looking at the graph left me wondering just what it means exactly. I'm not well versed in statistics so "the standard deviation is 3.5°C" doesn't mean much. Also, what's up with that other line going down to -3.5°C? And what do the colors mean? In the sense that I'm not sure whether a darker blue means closer to or further from today.

You can go to the source website https://climatereanalyzer.org/clim/sst_daily/?dm_id=nino3.4

There's is an interactive chart that's easier to understand

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