Dr. Roy Spencer sent me a notice of his most recent post in email. He offers an invitation for anyone to help “figure this one out”. The result could be “worse than we thought”. – Anthony
(edited 8/23/09 0710 CDT: Changed plots & revised text to reflect the fact that NCDC, not CRU, is apparently the source of the SST dataset; also add discussion of possible RFI interference in satellite measurements)
(edited 8/22/09 1415 CDT: added plot of trend differences by month at bottom)
By Dr. Roy Spencer
In my previous blog posting I showed the satellite-based global-average monthly sea surface temperature (SST) variations since mid-2002, which was when the NASA Aqua satellite was launched carrying the Advanced Microwave Scanning Radiometer for EOS (AMSR-E). The AMSR-E instrument (which I serve as the U.S. Science Team Leader for) provides nearly all-weather SST measurements.
The plot I showed yesterday agreed with the NOAA announcement that July 2009 was unusually warm…NOAA claims it was even a new record for July based upon their 100+ year record of global SSTs.
But I didn’t know just HOW warm, since our satellite data extend back to only 2002. So, I decided to download the NOAA/NCDC SST data from their website — which do NOT include the AMSR-E measurements — to do a more quantitative comparison.
From the NOAA data, I computed monthly anomalies in exactly the same manner I computed them with the AMSR-E data, that is, relative to the June 2002 through July 2009 period of record. The results (shown below) were so surprising, I had to go to my office this Saturday morning to make sure I didn’t make a mistake in my processing of the AMSR-E data.
As can be seen, the satellite-based temperatures have been steadily rising relative to the conventional SST measurements, with a total linear increase of 0.15 deg C over the 7 year period of record versus the conventional SST measurements.
If the satellite data are correct, then this means that the July 2009 SSTs reached a considerably higher record temperature than NOAA has claimed. The discrepancy is huge in terms of climate measurements; the trend in the difference between the two datasets shown in the above figure is the same size as the anthropogenic global warming signal expected by the IPCC.
I have no idea what is going on here. Frank Wentz and Chelle Gentemann at Remote Sensing Systems have been very careful about tracking the accuracy of the AMSR-E SST retrievals with millions of buoy measurements. I checked their daily statistics they post at their website and I don’t see anything like what is shown in the above figure.
Is it possible that the NCDC SST temperature dataset has been understating recent warming? I don’t know…I’m mystified. Maybe Frank, Chelle, Phil Jones, or some enterprising blogger out there can figure this one out.
UPDATE #1 (8/22/09)
Here’s the trend differences between the satellite and in-situ data, broken out by calendar month. The problem seems to be mainly a Northern Hemisphere warm season phenomenon.
UPDATE#2 (8/23/09)
Anthony Watts has suggested that the radio frequency interference (RFI) that we see in the AMSR-E 6.9 GHz data over land might be gradually invading the ocean as more boats install various kinds of microwave transmitters. While it’s hard for me to believe such an effect could be this strong (we have never seen obvious evidence of oceanic RFI before), this is still an interesting hypothesis, so this week I will examine the daily 1/4 deg. grids of AMSR-E SST and compute a spatial “speckle” statistic to see if there is any evidence of this kind of interference increasing over time. I should note that we HAVE seen more RFI reflected off the ocean from geostationary TV communication satellites in the AMSR-E data in recent years.
UPDATE#3 (8/24/09)
OK, gang, this is what I found out today before having to leave work. I downloaded the monthly grids of SST from NCDC (both their v2 and v3b products), and I computed the monthly anomalies at each gridpoint relative to the June 2002 through July 2009 period (since that is the period we have AMSR-E measurements for).
I then differenced the later part of the period (since 2007) with the earlier part (during and before 2004), separately for the NCDC and AMSR-E products.
Then I differences THOSE differences.
What it shows is that AMSRE has either spuriously warmed, or NCDC has spuriously cooled, by 1 to 2 deg C over all of the ‘warmer’ waters of the globe. The problem seems to diminish and then go away poleward of about 30S latitude, and poleward of 45N latitude.
This does NOT look like an RFI issue…it is too uniform spatially. Someone has made a major boo-boo…and I hope it isn’t me. 🙂
@Bob Tisdale (13:00:38) :
“…The satellite data was causing a downward bias that some users didn’t like…”
NOAA also called this “a downward bias”.
do they simply mean, the (high precision) satellite data was just lower ?
Adam Grey (19:48:13) : “My contention a few threads ago should have been clearer – that warming stories come with doubts about it virtually every time. Cooling stories generally don’t. There are exceptions. This is the first post I’ve read that suggested the formal recoords may be understanding the warming trend consonant with global warming. Not having read every single post here, I allow that my generalisation may be off-base.”
Good of you to admit the off-base thing. Because there is as much friction here [airing dirty laundry over domestic disputes] as there is fighting with third parties.
So I have to correct this: no “there are exceptions.”
Reality: There are “normal, ordinary disputes”. But these are commonplace and not “exceptions” to the rule as you describe it.
Capice??
The main goal here is THE TRUTH whatever that may be.
CHRIS
Norfolk, VA, USA
Dr. Spencer mentioned the 6.9 gigahertz band was used for AMSRE measurements. Perhaps we have a growing RF interference problem:
Global Survey of 6.9 GHz Radio Frequency Interference and Implications for Future Remote Sensing
Ashcroft, P.; Njoku, E. G.; Li, L.; Wentz, F.
American Geophysical Union, Fall Meeting 2003, abstract #H32B-0570
The AMSR-E instrument on the AQUA platform affords a nearly unprecedented opportunity to monitor the Earth at the 6.9 GHz microwave band. In this respect, AMSR-E prefigures other instruments that will extend microwave remote sensing to even lower frequencies. These measurements have already proven useful for investigations of sea surface temperature and soil moisture. Unfortunately, expanding use of this band for telecommunications is increasingly leading to Radio Frequency Interference (RFI) conflicts with remote sensing needs. Drawing on an archive of more than one year of AMSR-E data, we present a global survey of RFI sources, focusing on both spatial and temporal characteristics. In many cases, RFI is easily recognizable either due to its intensity or its correlation with known population centers. While the obvious RFI, (almost all of which is over land), can be disregarded in studies of natural phenomena, the challenge is to identify RFI when the signature is not obvious. This discrimination will provide the dual benefits of salvaging data that would otherwise be discarded, while ensuring that only untainted data is used for studying natural phenomena. This paper explores several criteria that may be used for this purpose.
Here is the PDF:
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/40892/1/04-1697.pdf
In that PDF figure 7, which shows world 6.9GHz hotspots, speaks to me, I’ve uploaded it here:
http://wattsupwiththat.files.wordpress.com/2009/08/6pt9ghz_world_rfi.png
Dr. Spencer indicates in his update that “The problem seems to be mainly a Northern Hemisphere warm season phenomenon”. and when you look at the 6.9GHz world RFI map, the RFI is overwhelmingly in the NH.
Just like optical and radio astronomers have trouble steering clear of electromagnetic interference, our climate monitors may very well be having the same difficulty.
I realize the paper speaks mainly of land based RFI, but with the explosion of all sorts of high frequency gadgets, I don’t know how much the map has changed since 2003. I also don’t know if any of the new innovative electronics on ships and places that would be over the ocean would afffect AMSRE data.
For example, the lower end of Wifi at 2.3 to 2.4 GHz has a 3rd harmonic pretty close to 6.9 GHz.
I think its worth a look to rule out. Most hi-tech human activity is northern hemisphere, and humans do tend to get out more in the “warm season”.
RayB (12:30:44) :
My first reaction is to question Jim Hansen’s NASA. You know… Normal Anthropogenic Supplemental Adjustment, Normally Adjusted Somewhat Above.. yeah, that NASA. The same guys looking for a roughly +2.4º El Nino SST anomaly based on AGW forcing.
I’d like to see some -RAW- ARGO data to put next to this, not the filtered by warmers stuff.
——-
Also, NASA – Numerous Adjustments Significantly Above
Agree on the need for access to raw data, since overly aggressive manipulations may result in inappropriate reports.
timetochooseagain: You wrote, “That’s the RSS Lower troposphere data. We’re talking SST here.”
Understood. Just plotting more references. I followed that with the comparison of AVHRR based SST data (OI.v2) and in situ data (ERSST.v3b) at 19:40:32.
The AMSR-E data seems to be the odd man out, but again the OI.v2 data is bias corrected by NCDC to the point that its trend matches the ERSST.v3b data.
“Jimmy Haigh (15:05:46)
Can I add that it still measures freezing water at 0C (32F) and boiling water at 100C (212F)?”
So you live at sea level ?
looking at the vertical axis (Y) of the graphs/plots, and in terms of the signal to noise ratio idea, much ado is made about trends in noise, rather than signal.
🙂
Happens when your experience is limited to the desktop and not nature itself.
Might be timely to refresh our ideas of temperature.
Temperature is an intensive variable which is applied to a volume of matter to derive a computationally useful number, “stored heat”.
In itself temperature is no different to a telephone number, and when averaged, is as nonsensical as an averaged telephone number. But when applied to a volume of matter, it then serves a useful metric as a measure of heat.
I’ll leave it here for further comment.
When swimming in even small bodies of water there are anomalous patches of warm water. I am assuming here that the same thing happens in the oceans only on a much larger scale. It would make sense then that moored and drifting buoys would deviate especially in July August in the NH when these patches would be most apparent. In the case of a moored buoy a warm patch would drift on by registering a “peak”. A drifting buoy in a warm patch would tend to drift right along with the patch from formation to dissipation.
There might also be an element of this in ship data in that ships tend to follow the same course as natural currents where possible and so may travel with such a “patch” for much longer than a ship cutting at 90deg to the general drift.
I don’t know how gridded data is is calculated but if it were max/min based I imagine these anomalous patches cause huge problems as they drift through the fixed grids in the sense that each grid is registering the same moving anomaly as a peak static SST for that grid and all the others in it’s path.
It might be interesting to do the same thing in Feb. with the SH data.
Manfred: You asked, “do they simply mean, the (high precision) satellite data was just lower ?”
By removing the satellite data, SST anomalies rose a few hundredths of a deg C from the late 80s to present.
http://i30.tinypic.com/8yw4gh.png
Most of that, though, was in the high latitudes of the Southern Hemisphere.
maksimovich: You asked, “Can you separate signals by say firstly nh/sh ratios…”
And create maps? No.
But in Figure 3, Reynolds et al (2006) “A DAILY BLENDED ANALYSIS FOR SEA SURFACE TEMPERATURE” illustrated differences between AVHRR and AMSR-E satellite data for the the 18 month period of July 2002 to December 2003:
ftp://ftp.ncdc.noaa.gov/pub/data/papers/200686ams8.1rrfree.pdf
Tom in Texas: You asked, “Have you added 2.4°C to the AVHRR data and plotted?
“Graph from here: http://i30.tinypic.com/23ws5tv.png”
To what end?
Steve Fitzpatrick: You wrote, “The lower troposhpere temperature over the oceans ought to track the SST.”
Not necessarily. It depends on the ocean. Some track well; others don’t. ENSO and volcanoes impact SST and TLT in different ways, at different time lags, and to different magnitudes. I illustrated this with comparisons of SST vs TLT anomalies over the oceans here:
http://bobtisdale.blogspot.com/2009/07/part-3-of-comparison-of-gistemp-and-uah.html
UAH-Ocean trend:
http://www.klimadebat.dk/forum/vedhaeftninger/uahoceantemp.gif
It appears that the 1998 peak (+0,77K) is more than twice the 2009 peak (+0,38K)
It appears that ALL years with El Nino since 1997 has had bigger peak in UAH ocean than 2009.
It appears that the UAH OCEAN has a colder trend since 1997 than UAH global. The july2009 uah ocean peak is perhaps higher compared to UAH global than normal trend would suggest? If so indicating special winds etc?
—-
In that PDF figure 7, which shows world 6.9GHz hotspots, speaks to me, I’ve uploaded it here:
http://wattsupwiththat.files.wordpress.com/2009/08/6pt9ghz_world_rfi.png
—–
Very interesting. Given that the resolution is a bit poor, I’d still like to know what big population centers exist along the Pak/Afghan border. 🙂 And why the Middle East has more interference than all of Europe.
Syl (04:13:15) :
—-
In that PDF figure 7, which shows world 6.9GHz hotspots, speaks to me, I’ve uploaded it here:
http://wattsupwiththat.files.wordpress.com/2009/08/6pt9ghz_world_rfi.png
—–
Very interesting. Given that the resolution is a bit poor, I’d still like to know what big population centers exist along the Pak/Afghan border. 🙂 And why the Middle East has more interference than all of Europe.
Syl, just a few thoughts about your questions.
For the Pak/Afghan border, think of military sources. This is the region where the remote controlled drones fly and a lot of military communication takes place.
There is a huge difference between Europe and the Middle East:
Vegetation versus sand deserts, moist lands versus very dry environments and cloudy air versus dry air.
The difference in these conditions could enhance the Middle East signal.
Do I remember reading here a little while ago that Argo sensors were changed (or adjusted) Perhaps there is a known (to the authorities) problem with certain types of sensors in certain situations, and equally that might mean there are unknown (as yet) problems also.
tonyb
Syl said
“Very interesting. Given that the resolution is a bit poor, I’d still like to know what big population centers exist along the Pak/Afghan border. 🙂 And why the Middle East has more interference than all of Europe.”
Along the border it could be refugees-mobile phones are widespread throughout the area, as are satellite phones.
tonyb
Links to updated charts on temperature-geomagnetic anomaly
Please note the geomagnetic anomaly gradient is negative
http://www.vukcevic.co.uk/TGa.gif
http://www.vukcevic.co.uk/TGc.gif
As one of a team who performed insight/oversight to the AMSR-E thermal design for the Aqua program, I can relate that the warm calibration target design was suspect, with a gradient issue. As a foreign “gift” instrument, our influence in getting the design issue addressed was inadequate. Not sure if this has anything to do with the observed trend, but just another tidbit to consider.
Vukcevic – Convincing indeed !
Thanks for the graphics!
Alexej Buergin (02:38:08) :
“So you live at sea level ?”
Pretty close – about 35 ft above!
So, let’s just assume that the Oceans ARE showing warmer. All my crops, and the crops of a whole lot of other folks assure me that NA is trending cooler. Let’s also stipulate that the spot free sun isn’t putting out that 1% extra energy or whatever the variation is. Lit’s stipulate that 1998 was the peak, as it was the peak sunspot year. So, if the atmosphere is cooling because of some lack of energy from the sun, release of heat from the oceans is the perfect damping mechanism. We should realize that changes in a system of this size are going to be relatively slow. How much cooler would it be if the oceans WEREN’T giving off some of their heat right now? IMHO, we’d be a lot better off to shut up and watch what’s going on than to keep screaming apocalypse all the time. “We” not being most of the folks at WUWT.
I have a great deal of trouble concluding anything with 7 years of data that is used to describe thousands of years of activity. Moreover, the data itself needs to be questioned since we don’t understand everything we know about it(similar to the ground-based data that is flawed by changing sites and site conditions). Gathering data from satellites sounds great but what are the potential errors? As noted by a previous poster, the floating sites may constitute a significant source of error and finally the fact that we are seeing interference suggests we don’t know all that we need to know before we attempt to draw conclusions.
REPLY: satellite data goes back to 1978, this is just one platform, AQUA. Dr. Spencer is looking into the RFI issue now and will have a spatial pattern analysis later this week. – A
Frank Lansner (05:50:26) :
“Vukcevic – Convincing indeed !
Thanks for the graphics!”
However, I am coming to a conclusion that correlation is not direct, but result of some intermediary factor, but it appears not to be the Svensmark’s effect.