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. 🙂
What about the possibility of air currents over the oceans world wide having calmed down a bit so that there is less evaporation of the the ocean skin? Could the late start to the hurricane season this year be related? Are there regions of the oceans with unusual or extended doldrums, like the old-time sailors got stuck in from time to time? I guess that buoys would sample deeper than the skin.
Paul Vaughan: You asked regarding the two Southern Ocean SST anomaly graphs, “Bob, where do I find those exact series?”
They’re from my post “A Closer Look At The ERSST.v3b Southern Ocean Data”:
http://bobtisdale.blogspot.com/2009/04/closer-look-at-ersstv3b-southern-ocean.html
ERSST.v3b SST anomaly data is available through the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
One you’re there:
1. Select ERSST.v3b, click on “Select Field”.
2. Input the coordinates, enter a “0” in the “Demand at least” field, and click on “Make Time Series.”
3. Scroll down to third graph, which is the anomalies, and click on “Raw Data.”
Jimmy Haigh (16:05:37) :
Richard (15:02:40) :
“.. you can see what are termed ’spreading ridges’ running across the oceans … all up the middle of the Atlantic. Basically this is a line of underwater volcanoes which are constantly exuding basaltic lavas ..These waters are over 300C!! (570F!) So I guess this could have an effect on overall sea temperatures. ..
I would like to think that this phenomenon has been fairly stable over the last say 100 million years and will continue to be so..
This part I feel difficult to believe. Aside from ’spreading ridges’ which are constantly exuding basaltic lavas, there would be big undersea volcanoes that could erupt cataclysmically like Pinabuto. These wouldnt be felt or observed on the surface but would affect the local ecology and might affect SST’s by churning up the waters.
Many of the pacific Islands including Hawaii started off as undersea volcanoes.
I believe a giant undersea volcano was discovered off the coast of Sumatra 4,600 meters high with a diameter of 50 km, some 330 km west of Bengkulu city and another off Iceland.
http://www.thejakartapost.com/news/2009/05/28/giant-undersea-volcano-found-sunda-trench.html
Giant Undersea Volcano Found Off Iceland
http://news.nationalgeographic.com/news/2008/04/080422-iceland-volcano.html
These are very recent discoveries. There maybe many others undiscovered.
Jimmy Haigh (16:05:37) :
Here’s a link to Professor Mike Russell. As I mentioned he is researching into black smokers/ under sea volcanoes as the site of the origin of life at NASA in Pasadena, CA. He isa brilliant lecturer and is an excellent chap! There is a list of publications at this URL.
http://science.jpl.nasa.gov/people/Russell/
Richard (17:00:37) :
As I said: “I would like to think that this phenomenon has been fairly stable over the last say 100 million years and will continue to be so..”
I think what I was trying to say is that I think that the total heat flow from all of the undersea volcanoes has been stable over geological time but this is basically a gut feeling guess: to be honest I haven’t a clue! I’m sure that there has been some work done on this over the years and that there will be something in the literature about it.
I don’t know if this phenomenon is factored into the GCM’s…
IF the data above is a true then you must look for a reason why the atmosphere is warming at the height measured by the sensor but cooling at the very ocean surface.The most logical reason to me would be an alteration of the height at which clouds are forming, now trapping more heat in the height band of sensor.It is not necessary to have more clouds, just a different altitude.
There seems to be some confusion here…the issue I’ve raised is NOT what the global-average SST trend is during 2002 up to the present (which is a pretty short period of time climate-wise).
The issue is that two global SST datasets that should show very similar behavior over that period of time have DIVERGED by so much….and fairly consistently over time.
BTW, the SST are measured at 6.9 GHz, where the main signals in the data are SST (thermal emission by the surface), and wind roughening (which Frank Wentz has always been very meticulous at separating from the other signals). The dual polarization (H and V) measurements allow the separation of the wind and SST signals. Higher frequencies from AMSR-E provide additional information on rainfall, oceanic integrated cloud water and water vapor, and our FAVORITE variable (of course)…SEA ICE!
Something isn’t right here -If the implication is that sea temps are warmer than 1998, than why aren’t the air temps at similar level – given the small lag between air temps & water temps?? If this is right is suggests there is a very strong forcing mechanism with next cooling being seen in the signal to generate the difference between 1998 & current air temps. Could that actually be the case??
Question: if the oceans were losing heat into space more rapidly than before, what would be the impact of temperatures at the water/air phase boundry? Would they not increase with the increased transfer rate?
The main effect of heat transfer from the oceans to the atmosphere would be increased humidity (water vapour content) near the surface. The heat would then be transported to where ever rain droplets form, warming the atmosphere at that location. Typically higher up in the atmosphere and to a significant extent over land.
Warming of the near surface atmosphere over warmer SSTs would occur primarily from an increased greenhouse effect from higher water vapour content.
Dr. Spencer: I tried to duplicate the graph you created (without the Satellite Minus In-Situ Plot), using the RSS MSU Ocean (70S-82.5N) data here:
http://www.remss.com/data/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Ocean_v03_2.txt
And comparing it to the NCDC SST (ERSST.v3b) data using as close to the same latitudes that the dataset would allow. The ERSST.v3 is available through the KNMI Climate Explorer, thanks to Geert Jan van Oldenborgh:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
The results are decidedly different than the graph you provided. The satellite data has a steeper negative trend than the in situ data:
http://i28.tinypic.com/2wnmcsw.png
This part I feel difficult to believe. Aside from ’spreading ridges’ which are constantly exuding basaltic lavas, there would be big undersea volcanoes that could erupt cataclysmically like Pinabuto.
Conventional wisdom, which is probably right, says volcanoes along the mid-ocean ridges don’t erupt cataclysmically. Cataclysmic eruptions only occur with volcanoes on or along the continental plates. Incidentally there is a Phillipines continental plate.
Although, the statement this phenomenon has been fairly stable over the last say 100 million years refers to geological timescales and does not preclude significant variation over shorter timescales (say less than a 1,000 years). Which is not to say there is significant variation over shorter timescales.
Very odd discrepancy. Especially odd when the satellite based MSU lower troposphere readings over the ocean apparently do not show a similar discrepancy with the standard SST’s (I think I am right about this, but not certain). The lower troposhpere temperature over the oceans ought to track the SST.
Could the accuracy of the RSS satellite SST readings be verified by comparing readings for specific ocean regions where there exist a reasonable number of temperature measurements actually taken at the surface of the those same regions?
One other possible way to resolve the discrepancy would be to compare the trend in ARGO data for the ocean temperature at/near the surface since 2003-2004 with both the trends in conventional SST average and the RSS satellite based SST. The Argo data may not be dense enough (1 transmission per float each 10 days I think) to give good short term estimates, but longer term trends in the ARGO surface temperature data set could turn out to be a reasonable “reality check” for the longer term trends reported by the other measures.
Bob Tisdale (18:08:15) : That’s the RSS Lower troposphere data. We’re talking SST here. RSS does that to:
http://ssmi.com/sst/microwave_oi_sst_browse.html
That the two are different isn’t surprising. What is surprising is the differential’s sign…
Philip_B (18:23:49) :
The oceanic crust sea floor spreading volcanoes are associated with ‘chemically basic’ basaltic lavas are indeed fairly benign in comparison to often cataclysmic explosions of ‘acidic’ continental lavas. Sea flor spreading is a more or less continuous event compared to the sporadic and random eruptions of the likes of Toba, Krakatoa, Vesuvius, Mont Pelee and the possibly geologically imminent Yellowstone.
The Atlantic ocean ridge comes ashore on iceland which is a very thick accumulation of basaltic lavas very close to the pole of rotation of the spreading.
Ther have been periods through geological time of increased volcanic activity. One such was during the early Tertiary when the Deccan basalts of India were deposited. At around the same time, the North Atlantic finally opened (after trying to for a good few million years!) and the West of Scotland volcanoes of Ardnamurchan, Skye and Rhum were active. The Permian age Karoo lavas of South Africa are another example.
Dr Spencer, thank you for explaining how the sensor works.I can now see how alarming this divergence is!!
Hmm. AVHRR data (NCDC’s OI.v2) show a result that’s different than the TLT data from my 18:08:15 comment and Dr. Spencer’s results above. It’s trend is approximately the same as the in situ (ERSST.v3b) data since June 2002:
http://i30.tinypic.com/23ws5tv.png
But with all the adjustments made by the NCDC to accomodate cloud cover issues (not a problem with the AMSR-E satellite, if memory serves me well) and the high-latitude biases, etc., it’s not surprising that they match.
The bias corrections NCDC makes are discussed in a number of papers. Here’s two:
ftp://ftp.emc.ncep.noaa.gov/cmb/sst/papers/reynolds_1988.pdf
ftp://ftp.emc.ncep.noaa.gov/cmb/sst/papers/oiv2pap/oiv2.pdf
Philip_B (18:23:49) :
Conventional wisdom, which is probably right, says volcanoes along the mid-ocean ridges don’t erupt cataclysmically. Cataclysmic eruptions only occur with volcanoes on or along the continental plates.
By Cataclysmic I meant large. If they are undersea then generally no Cataclysm should occur like Pinatubo. Most of the plate boundaries run along the sea.
Here’s one: “This was a Mount St. Helen-size volcanic event..”
http://www.oar.noaa.gov/spotlite/archive/spot_nurp.html
No cataclysm occurred.
This was some time ago: “Undersea Volcanic Eruptions Linked to Ancient Die-Off”
http://news.nationalgeographic.com/news/2008/07/080716-mass-extinction.html
ERSST.v3b SST anomaly data is available through the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
Bob, Paul
I just downloaded the data, and crafted the following graphic:
http://i32.tinypic.com/ht8v4p.jpg
We’re looking at trends in the trend (seasonal differences, raw and smoothed). There is clearly a pattern of natural variability on a decadal time frame, and we’re currently in the warming part of the cycle. But it will eventually end, probably ~2012, and a cooling trend will begin.
I’m not sure if this bears on Dr. Spencer’s puzzlement, but looking at the recent years more closely, we get this:
http://i26.tinypic.com/6t3ivl.jpg
Here I’ve zeroed in on the “satellite era” and added the UAH Ocean series. Now I know that he’s comparing CRU-SST to AMSR-E, and here I’m comparing ERSST to UAH_Ocean. But at least in this case, any divergence between the satellite “ocean” series and the surface/sst has the latter rising more rapidly in recent years. However, this could just be an “end artifact” of the smoothing process.
Here’s a look at the two series differenced:
http://i32.tinypic.com/2hpufet.jpg
In viewing these graphs, bear in mind that they are not the anomalies themselves, but are the rates of change in the anomalies.
So much for the unfounded criticisms that WUWT never has any “warming” stories.
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. But perhaps someone would like to stand up and say there is a roughly even balance here.
Tsk, “understanding” should have been understating.
Bob Tisdale (19:40:32) :
Can you separate signals by say firstly nh/sh ratios.
Then say SH by 30/45/ 60 latitudes (so as to ascertain zonal climatology) hence we can differentiate with model (ensemble sampling ) error,and causative mechanisms.
eg http://www.temis.nl/protocols/o3field/data/forecast/today_sp_sm.gif
Bob T.: Have you added 2.4°C to the AVHRR data and plotted?
Graph from here: http://i30.tinypic.com/23ws5tv.png
Mark (15:48:10) :
I can’t believe all those temperature sensors in the oceans are wrong.
And I can’t believe, after all the satellite problems of late, that this isn’t just another one going haywire with all the changes in the Solar System Environment.
Something I do not understand, and perhaps someone can explain, is why the atmosphere is supposed to add heat to the ocean that can hide for years, but volcanoes on the sea floor add heat that is supposed to disappear.
What makes the two different heat sources effects on the ocean polar opposites?
I’m sorry to interrupt, but this has to be one of the most interesting comment threads I have ever read! (Sorry to have to relegate you to second place Dr. Svalgaard)
Truly marvellous to behold…