HadCRUT global numbers are out, and is at 0.43°C, still lower than the GISS number of 0.67°C.
Click for a larger image
Once again Jim Hansen’s NASA GISS is the highest global anomaly:
RSS (satellite)
2008 1 -0.070
2008 2 -0.002
2008 3 0.079
UAH (satellite)
2008 1 -0.046
2008 2 0.020
2008 3 0.094
HadCRUT (surface, land-ocean)
2008/01 0.056
2008/02 0.187
2008/03 0.430
GISS (surface, land-ocean, polar estimates)
Year Jan Feb Mar
2008 .12 .26 .67
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Considering that the USA is back to normal for March ( 0 ) where is the “warming” coming from in the non-satellite records?
HadCRUT global numbers are out, and is at 0.43°C, still lower than the GISS number of 0.67°C. Once again Jim Hansen’s NASA GISS is the highest global anomaly:
What’s the relevance of these comments? GISS has a lower baseline and hence will almost, if not always be higher than the other three. Didn’t you learn that in this post
A look at temperature anomalies for all 4 global metrics: Part 1?
http://wattsupwiththat.wordpress.com/2008/02/27/a-look-at-temperature-anomalies-for-all-4-global-metrics/
By the way wasn’t that supposed to be a three part post? Did I miss part three?
So that’s the news, HadCRUT numbers are lower than GISS’s? …
Note well that the ground measurements jump higher than the satellite measurements.
Could this be because of Heat Sink Effect (“HSE”) exaggerating the uptick? Note also that GISS showed an exaggerated downtick as well, which is consistent with HSE.
HSE would exaggerate increases in temp rises. Also decreases, as the effect “undoes” itself.
This would also be consistent with an exaggeration of the last warming trend and also the levelling of temps after 1998 (you have to have an actual increase in temps in the first place for a heat sink to exaggerate it).
Divergence between satellite and surface eh?
The reason that GISS has the highest is because he eliminated large grid areas from Southern Africa, South Pacific and North America that all showed cool anomalies.
There was also a warm spell over much of Asia that is common in the spring season during La Nina years.
Because of the different anomaly base periods Hadcrut is ON AVERAGE .09C
cooler than GISS ( its just a diffrent basis period)
So, if GISS were .67C you would guess hadcrut to come in at .58C.
They came in .43C
Anthony, I have recently become a regular visitor to this site and I just happened to be looking at the Hadcrutt3 data this morning – so your post is timely.
I note that the satellite data for March show a much lower rise from Jan and Feb compared with NASA GISS or Hadcrutt3- as reported here:
http://wattsupwiththat.files.wordpress.com/2008/04/uah_march_081.png
And I’ve also been following the SST anomalies throughout March and April – which even today show La Nina very much in control?
http://www.osdpd.noaa.gov/PSB/EPS/SST/climo&hot.html
So I’m finding it a bit difficult to reconcile the satellite temperature and SST data with the weather station data (NASA GISS and Hadcrutt3) and was wondering if you could venture an explanation why the weather station data have bounced while the oceans still have the blues?
Euan Mearns
REPLY: I’ll have some post in a few days tounching on this more.
You need to put them all on the same base period. Even then GISS sticks out.
But somebody will always stick out.
If you average out all four and you get something in the order of 0.30°C. Plot it and you have a 10 year downweard trend.
Stlll no sunspots.
Mike you wrote:
“HadCRUT global numbers are out, and is at 0.43°C, still lower than the GISS number of 0.67°C. Once again Jim Hansen’s NASA GISS is the highest global anomaly:
What’s the relevance of these comments? GISS has a lower baseline and hence will almost, if not always be higher than the other three. Didn’t you learn that in this post”
Yes, GISS has a lower baseline, because of a different anomaly period. Even when you correct for this, GISS is still the oddball. It’s about a 2sig or 3sig event. Nothing too out of the ordinary.
I hate to ask a stupid question – but I am still not 100% sure of what the definition of “Temperature Anomaly” is – as it applies to this graph.
Can someone enlighten me?
Thanks
@Bob
Anomaly means difference with respect to a reference number. The reference number here varies between the different temperature products. GISS compute the reference number as the average of temperature for the period 1951-1980. Hadley uses the period 1961-1990. Hence the non-sense of comparing directly both anomalies and stating that one is lower than the other …
Here is a comparison of the different anomalies once corrected for the different definitions:
http://atmoz.org/blog/2008/03/10/4-of-4-global-metrics-show-agreement-in-trends/
REPLY: Actually the non-sense is that GISS uses 1951-1980 in the first place.
Divergence between satellite and surface eh?
Yes. Both up and down; consistent with HSE.
I read, I examined, I found the bias…
Please explain this one to me:
http://www.woodfortrees.org/plot/sidc-ssn/normalise/from:1950/plot/hadcrut3vgl/from:1950/plot/esrl-co2/normalise
@Anthony
Why is the GISS reference a non-sense?
As far as long term trends are concerned, it does not seem to have any major incidence anyway, all products are consistent.
Now I can imagine that these products are not used for the sole purpose of studying long term trends, so in that context, why do you think it makes less sense to pick 1951-1980 than 1961-1990, besides the inconvenience of having different reference point?
REPLY: I think the GISS choice to use an older base period is not realistic. We have 4 global metrics. The one that consistently reads different than the rest uses a base period that is by general climatic standards, outdated. Many climate references that are published by NOAA use a sliding window that gets updated as time and data goes on. I suggest that it is time for GISS to use a more current baseline.
For example, let’s say I published a work and used a baseline for 1930-1950, but made claims regarding the present. It would probably be criticized for that given that there is more up to date climate data.
Sure, if you go through the process of adjusting them all to a common baseline, the offset goes away, but why should this be left to the consumer of the data when the data is used for so many public presentations and is published for general public consumption on their websites?
I think that GISS should use a more recent baseline. Ideally, since these 4 metrics are being compared regularly, it would seem prudent to have some sort of common presentation method for the data.
An anomaly is a change from normal trends.
For EACH of these temps datasets the period of normality is different. 1961-1981, 1981-2000, etc. Therefore if the period of normality just happens to be a cool period as for GISS 1961-1980, say then the anomaly may be greater than for a series normalised against a warmer period, e.g. HadCru.
So, for example, if the average temperature during 1961-1980 is 14.00 then for GISS march is 14.67 for HadCru, 14.43, etc
An anomaly is a change from normal trends.
For end of these temps datasets the period of normality is different. 1961-1981, 1981-2000, etc. Therefore if the period of normality just happens to be a cool period as for GISS 1961-1980, say then the anomaly may be greater than for a series normalised against a warmer period, e.g. HadCru.
So, for example, if the average temperature during 1961-1980 is 14.00 then for GISS march is 14.67 for HadCru, 14.43, etc
I wonder what the error bars are on these various mean temperatures. Are the month to month changes consistent with the uncertainty in the measurements? I know there are systematic differences between the surface and aerial measurements. But are the sampling uncertaintities each month compatible with the inconsistencies?
Anthony, has anyone ever “converted” GISS to the same baseline as the others?
Jack Koenig, Editor
The Mysterious Climate project
http://www.climateclinic.com
REPLY: yes it is routinely done in scientific analysis and presentations of those results, Atomz did it in the post “Gal” references for example.
But such capability to calculate and apply an offset is typically beyond the ability of the average press reporter to do so. So, when they reference a GISS graph like this one:
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
There is typically little understanding of the base period issue, particularly since GISS does not reference the base period used for that anomaly on that graph. Yet you’ll see that GISS anomaly graph used in thousands of places with wide viewing.
Wikipedia added it to the caption at least:
http://en.wikipedia.org/wiki/Global_warming
But the caption often doesn’t travel with the graphic. To be fair, I haven’t done that on my HadCRUT, UAH, or RSS graphs either, but now that I’ve pointed it out to myself I’ll do that.
I just think a common standard for baseline and presentation would be beneficial for everyone.
I assume that the “anomaly” is the measure of the difference between the given month and the average of that month for the reference period?
If so, why do these graphs seeem to show a seasonal cycle?
Just eyeballing the HadCRUT graph, the maximum negative anomaly for the year seems to disproportionately occur in the Nov-Jan period. The maximum positive (or least negative) anomaly for a year seems to disproportionately occur in the early spring.
Why would that be? Or is my eyeball out of register?
John Lederer – The Northern Hemisphere winter?
Anthony said:
“There is typically little understanding of the base period issue, particularly since GISS does no reference the base period used for that anomaly on that graph. Yet you’ll see that GISS anomaly graph used in thousands of places with wide viewing.”
Also, in order to show the most AGW, charts need to show the largest change above “normal” (ie, zero.) This is what GISS does.
And, there is still the debate between GISS and HadCRU as to who does a better job of charting the anomaly. GISS supporters like to use the “GISS tracks Arctic temps, HadCRU doesn’t” line. If both systems used the same reference period, GISS’s “extra” warming goes away.
The above statement can (and probably has been) proven by putting both on a common reference period (really doesn’t matter which one), and comparing the differences (the “anomaly” of the anomalies).
If GISS tracks the Arctic area better, there would be a consistant, positive difference in favor of GISS over the ENTIRE RANGE of the chart. If this does not occur, then neither one has a better handle on temp reporting.
Thanks for all the responses – I feel better that I was a little bit confused about it,
Ok – another stupid quesiton. What is the value of plotting temperature against a base-line if the base-line is somewhat arbitrary?
Peter Hearnden–
But shouldn’t that equalize over the years?
I am assuming that the temperature anomaly for December 2007 is the differeence between the average for December 2007 and the average of the averages for the Decembers of 1961-1980. If I look at the chart, just using my eyeball it would appear that 13 or 14 of the 20 years shown have a downward spike in Novcmber, December, or January of the 20 years, whereas one would expect only a random distribution of downward spikes.