UPDATE: 8/18 10:30AM I spoke with Dr. Judith Curry by telephone today, and she graciously offered the link to the full paper here, and has added this graphic to help clarify the discussion. I have reformatted it to fit this presentation format (side by side rather than top-bottom) While this is a controversial issue, I ask you please treat Dr. Curry with respect in discussions since she is bending over backwards to be accommodating. – Anthony
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[Update] My thanks to Dr. Curry for showing the graphic above, as well as for her comment below and her general honesty and willingness to engage on these and other issues. She should be a role model for AGW supporters. I agree totally with Anthony’s call for respect and politeness in our dealings with her (as well as with all other honest scientists who are brave enough to debate their ideas in the blogosphere). I also commend the other author of the study, Jiping Liu, for his comments below.
However, as my Figure 2 below clearly shows, any analysis of the HadISST data going back to 1950 is meaningless for the higher Southern latitudes. The HadISST data before about 1980 is nonexistent or badly corrupted for all latitude bands from 40°S to 70°S. As a result, although the HAdISST graphic above looks authoritative, it is just a pretty picture. There are five decades in the study (1950-1999). The first three of the decades contain badly corrupted or nonexistent data. You can’t make claims about overall trends and present authoritative looking graphics when the first three-fifths of your data is missing or useless. – willis
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Guest Post by Willis Eschenbach
Anthony has posted here on a new paper co-authored by Judith Curry of Georgia Tech, entitled “Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice”. The Georgia Tech press release is here. Having obtained the paper courtesy of my undersea conduit (h/t to WS once again), I can now comment on the study. My first comment is, “show us the data”. Instead of data, here’s what they start with:
Kinda looks like temperature data, doesn’t it? But it is not. It is the first Empirical Orthogonal Function of the temperature data … the original caption from the paper says:
Figure 1. Spatial patterns of the first EOF mode of the area-weighted annual mean SST south of 40 °S. Observations: (A) HadISST and (B) ERSST for the period 1950–1999. Simulations of CCSM3 (Left) and GFDL-CM2.1 (Right): (C, D) 50-year PIcntrl experiment (natural forcing only),
Given the title of “Accelerated warming”, one would be forgiven for assuming that (A) represents an actual measurement of a warming Southern Ocean. I mean, most of (A) is in colors of pink, orange, or red. What’s not to like?
When I look at something like this, I first look at the data itself. Not the first EOF. The data. The paper says they are using the Hadley Centre Sea Ice and Sea Surface Temperature (HadISST) data. Here’s what that data looks like, by 5° latitude band:
Figure 2. HadISST temperature record for the Southern Ocean, by 5° latitude band. Data Source.
My first conclusion after looking at that data is that it is mostly useless prior to about 1978. Before that, the data simply doesn’t exist in much of the Southern Ocean, it has just been shown as a single representative value.
So if I had been a referee on the paper my first question would be, why do the authors think that any analysis based on that HadISST data from 1950 to 1999 has any meaning at all?
Next, where is the advertised “Accelerated warming of the Southern Ocean”? If we look at the period from 1978 onwards (the only time period with reasonable data over the entire Southern Ocean), there is a slight cooling trend nearest Antarctica, and no trend in the rest of the Southern Ocean. In other words, no warming, accelerated or otherwise.
Finally, I haven’t even touched on the other part of the equation, the precipitation. If you think temperature data is lacking over the Southern Ocean, precipitation data is much worse. The various satellite products (TRMM, SSM/i, GPCC) give widely varying numbers for precipitation in that region, with no significant correlation between any pair (maximum pairwise r^2 is 0.06).
My conclusion? There is nowhere near enough Southern Ocean data on either side of the temperature/precipitation equation to draw any conclusions. In particular, we can say nothing about the period pre-1978, and various precipitation datasets are very contradictory after 1978. Garbage in, you know what comes out …
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oeman50 says:
August 18, 2010 at 9:47 am
I can’t resist commenting on this, even though I have seen some reference to it in Anthony’s original thread:
From the GT Press Release:
“This increased precipitation, mostly in the form of snow, stabilized the upper ocean and insulated it from the ocean heat below. This insulating effect reduced the amount of melting occurring below the sea ice. In addition, snow has a tendency to reflect atmospheric heat away from the sea ice, which reduced melting from above.”
This just does not make sense to me. Does snow behave differently in Anarctica than it does in the US? In my experience, when snow falls on water, even water at 0 degrees C, the water absorbes into the snow crystal, making it ice and water, the whiteness of the snow and thus its reflective properties are nulified. Snow’s insulative properties are at least partly due to the air incorporated into the structure it forms when packed, which again gets nulified when it fills with water.
——————–
The paragraph you quote is perhaps not quite sufficient to explain what is going on. The argument concerns not the insulative properties of snow, but the effect of snow on salinity. Precipitation (either snow or rain) falling into the ocean will reduce the salinity at the surface, making it less dense than the bulk of the ocean below. This salinity gradient will inhibit water column mixing, and the thin fresher layer is easily cooled. So the sea ice is bathed in relatively cold water, which insulates it from the relatively warmer more saline water below.
The second effect of snow is that snow falling on the sea ice it increases the albedo of the sea ice.
George E. Smith says:
August 18, 2010 at 9:28 am
Maybe I have it all wrong; perhaps the snow is on top of the sea ice rather than the salty water; and the hot ocean salty water is below the sea ice, but can’t get heat to the bottom of the sea ice to melt it, because of the snow sitting on top of the sea ice.
I’m going to go and get a cup of Capuchino; and then I’m going to come back and read that paragraph from Georgia Tech for the eleventh time; because I know there’s a trick in there somewhere !
______________
How about a sea ice sandwich with snow underneath to insulate from the hot water and snow on top to reflect the sun? Where the ice comes from in this scenario is a mystery. But life is like that – full of mysteries. I don’t think rereading the paragraph will help, but I could be wrong. Life is like that too.
>> George E. Smith says:
August 18, 2010 at 9:28 am
Maybe I have it all wrong; perhaps the snow is on top of the sea ice rather than the salty water; and the hot ocean salty water is below the sea ice, but can’t get heat to the bottom of the sea ice to melt it, because of the snow sitting on top of the sea ice. <<
Clearly you misunderstood the paragraph. The snow landed on top of the sea ice and quantum-mechanically tunneled to the bottom so it could insulate the ice from the boiling sea water surrounding Antarctica.
And we know this has happened because of comprehensive reports from all of the billions of sailors taking daily temperature and salinity readings (scuba divers going 'down below 1000 meters') in that part of the globe.
Sarcasm aside, My impression about this paper is that Dr. Judith Curry graciously lent her name and assistance so that Dr Jiping Liu could salvage SOMETHING from the money given to him by NASA and NSF and thereby justify future funding (and his salary). There is clearly nothing there unless one twists and tortures the data and claims the pre-satellite data to be far more meaningful than anyone with common sense would concede.
Thank you, Dr. Curry for coming by and please know that many of us appreciate any clarification you can offer. It’s IMPERATIVE to the discussion such critique/defense. I strongly urge patience on your part and polite civility on the part of our commenters.
This isn’t yahoo.
Mark
The Antarctic is beset with many oceanic and atmospheric teleconnections without considering AGW. One of my favorite papers on Antarctic sea ice anomalies is this one: http://www.cgd.ucar.edu/oce/pubs/04pubs_files/ms_holland_jcl-5157revised.pdf
I haven’t read your paper yet but am interested in your take on this one.
Thanks Dr Curry for letting us have the whole paper. I hope you don’t mind that I have saved it in my Climate Folder; I’m rather choosy as to what I save in that. I also printed it out; since I like to have actual dead tree to scribble notes on. But rest assured that it won’t propagate anywhere else from me; and If I mention anything from it, I will give proper credit.
Also I liked the Abstract more than I liked the Georgia Tech Page statement; which seemed like gobbledegook to me.
I’m not overjoyed to learn that much of the paper is computer simulations; but at least I can read what you actually are presenting rather than some newspeak rendition.
And again; thank you for accommodating us in this way.
George
It seems the first question to be settled before spending tax payer money is if there is adequate (real) data so that the potential exists to get meaningful results. It seems too often climate scientists try to tease something meaningful from a thimble full of data and end up publishing incredible results. It seems the very first step would be to ask if there exists adequate data to possible achieve a statistically meaningful result. If not, why waste the time and money in the first place?
“…first Empirical Orthogonal Function of the temperature data…”
I get the force of Willis’ argument, but can anyone enlighten me what “EOF” means in layman’s terms?
I am sorry but I must be totally missing something.
The pictures submitted by Dr. Curry basically show a neutral trend (about +/- 0.1deg C per decade from 1950 – 1999) over the southern ocean but the paper states
Abstract
The observed sea surface temperature (SST) in the Southern Ocean shows a substantial warming trend for the second half of the 20th century.
I am completely unable to reconcile these.
Sounds like ocean current “weather” to me. Without knowing the heat distribution of the global ocean from bottom to top it’s difficult to say much about what’s going on system-wide.
Unless precision sea-level measurements are showing an accelerating thermal expansion then any extra warming in one volume of water must be offset by cooling in a different volume. This is really the only way we have of measuring total heat content of the global ocean.
At this point I am guessing that Willis Eschenbach’s laymans analysis is not worthy of reply.
Andy
REPLY: Dr. Curry seems to think so, and has offered a new graph. See top of story. – Anthony
Anthony/moderators!
I think you should consider some major snipping. Dr Curry has been courteous to those who frequent your blog and the snarkyness and name calling is inappropriate. Even the use of the term garbage WRT the data is bad form. What do people think this is: Real Climate?
REPLY: I agree, and unfortunately there have been some whom have spoiled the debate here and I have not been able to moderate as much as I’d like due to other obligations. And, unfortunately it is a catch22 post facto, going forward however, I will aggressively remove such comments or portions thereof, from both sides, that don’t advance the discussion in a courteous way. – Anthony
Tom,
I think I have seen this movie somewhere before. The bad guys are coming at me, shrieking and yelling with their spears and swords out, and cursing about my mother cowering under the verandah; and there you are back inside the house yelling; “Don’t worry George, I’ve got your back ! ”
What ever happened to the old idea of simply installing the insulation BETWEEN the source of heat, and the stuff to be protected from that heat ? I must not have paid my dues this month or something !
To me The Southern Ocean is salt water; we Kiwis know all about sailing, and we do not sail on either snow or ice; just salt water. So I discriminate between the Southern Ocean, and the Antarctic Sea Ice.
But now that we do have Dr Curry et al’s full paper it’s time to get serious.
Now this seems like a new approach 🙂
1) Model the “natural internal variability” with a computer model.
2) Capture the actual variability as “calculated” by CRU Hadley Centre.
3) Subtract 1) from 2) and hey presto you get AGW.
So now they are proving AGW by hind casting.
Sure beats rolling the dice to make a forecast that can be shown to be wrong.
100% AGW guaranteed in every packet of AGW Pops…
Try new formulae AGW Pops so you are not left out in the cold!
Coming to your favourite MSM outlet soon!
I still do not get the warming. The HadISST graphic covering Southern ocean laditudes show a peak or near peak for all laditudes around 1985. Since then all laditudes show a decline. Am I incorrect in seeing this?????
Also Why did the study apparently only use data to 1999? “Jiping Liu says:
“We performed the EOF analysis on the area-weighted annual-mean observed SST south of 40 °S for 1950–1999.”
@Willis
There’s a positive one degree step change in the raw data that happened between 1940 and 1945 then basically no change or, if anything, very slight cooling since then.
What’s up with that?
Large step changes like that are often artifacts of changes in the way data is collected and/or collated. It seems very unlikely that a billion cubic miles of water heated up by 1 degree over the course of a few years. There’s something rotten in the state of that raw data for sure.
“”” Steve Keohane says:
August 18, 2010 at 9:56 am
George E. Smith says: August 18, 2010 at 9:28 am
George, I think you are on to something here. Every time I have put snow on water, the snow gets wet. It’s the darndest thing! On the occasions when the water was of a temperature such that the snow did not melt, the snow acted like an iceberg with a small fraction above the surface of the water. But that which was above the water was still wet. And to think for the past fifty years I thought the insulating capacity of snow was the air between the flakes. Boy, did I have my head screwed on wrong! “””
Steve, Only in Hollywood, does snow come down as six feet of “partly cloudy”. Everywhere else it comes down in small clumps of ice crystals that have accummulated enough mass to fall to the surface. Now the Southern Ocean could be below zero C and may be that tiny puff of snow would stay frozen; but I’ve never ever heard of snow persisting if it falls on water. I’ll accept that snow falling on frozen sea ice will change the character of the thermal processes at the air interface; fresh snow has a much higher reflectance that ice; but it doesn’t remain that way for very long in the presence of sunlight; because the multi-crystalline nature of snow acts very much like an optical anechoic surface; and the light can penetrate deep into the snow; and once it refracts into the crystals, it gets largely trapped by Total Internal Reflection and heats the snow to melting point. That is why the reflectance of snow drops radically after only a few hours.
But then there will be snow lower down that has not melted, and will be much air pocketed so have pretty good insulating properties.
But I’ve always believed that most melting of sea ice is from warmer water below (that came down from more tropical places a la Gulf Stream).
1. richard telford says:
August 18, 2010 at 10:29 am
1. oeman50 says:
August 18, 2010 at 9:47 am
I can’t resist commenting on this, even though I have seen some reference to it in Anthony’s original thread:
From the GT Press Release:
“This increased precipitation, mostly in the form of snow, stabilized the upper ocean and insulated it from the ocean heat below. This insulating effect reduced the amount of melting occurring below the sea ice. In addition, snow has a tendency to reflect atmospheric heat away from the sea ice, which reduced melting from above.”
This just does not make sense to me. Does snow behave differently in Antarctica than it does in the US? In my experience, when snow falls on water, even water at 0 degrees C, the water absorbs into the snow crystal, making it ice and water, the whiteness of the snow and thus its reflective properties are nullified. Snow’s insulative properties are at least partly due to the air incorporated into the structure it forms when packed, which again gets nullified when it fills with water.
——————–
The paragraph you quote is perhaps not quite sufficient to explain what is going on. The argument concerns not the insulative properties of snow, but the effect of snow on salinity. Precipitation (either snow or rain) falling into the ocean will reduce the salinity at the surface, making it less dense than the bulk of the ocean below. This salinity gradient will inhibit water column mixing, and the thin fresher layer is easily cooled. So the sea ice is bathed in relatively cold water, which insulates it from the relatively warmer more saline water below.
The second effect of snow is that snow falling on the sea ice it increases the albedo of the sea ice.
——————–
I can understand the effect of snow on the albedo of ice, but that is not the issue. It is the effect of warmer water sea ice is floating on. I have looked up the thermal conductivity of pure water (0.561 W/mK) and of seawater (0.563 W/mK). This small difference in no way makes fresh water an “insulator” from sea water or makes it easier to cool, in fact it appears to be the opposite.
@willis (con’d)
My educated guess about the 1940 step change in the southern ocean is that prior to 1940 temperature soundings of that ocean are as rare as hen’s teeth and somebody filled in the blanks from just a few hardly representative measurements. Then in 1940 there was a massive increase in shipping across the southern ocean related to the second world war and especially farther south off the normal trade routes to avoid cargo ships getting sunk by the enemy lying in wait over normal shipping routes. The wider coverage at that time gave a more representative picture of the whole southern ocean. Prior to 1940 if there’d been a representative sampling the whole southern ocean would have been measured at about the same temperature it is today.
I think Willis hit the nail on the head saying the older raw data is worthless in regards to being representative of the entire southern ocean while the more recent, reliable raw data shows a cooling trend if any trend at all.
[snip]
I get the idea of snow and sea ice leading to fresh(er) water on top. Ocean water in frozen form eliminates much of its salt content when freezing thus becoming a source, along with melting snow off the ice tops, of low salt top layer in the Antarctic ocean. This happens in the Arctic as well. But I believe there are much stronger naturally occurring oceanic and atmospheric oscillations than simply a warming Antarctic (AGW assumed) causing more snow to occur. The null hypothesis must ALWAYS be naturally occurring oscillations in Earth’s weather systems before any other forcing can be studied. Which leads me to my bone of contention. If the natural oscillations are not well understood, and not well modeled, why are you spending considerable talent, time, and money studying other forcings in your models? Judith, I think we need the likes of you to help fine tune the null hypothesis natural oscillations models.
I have read and re read the comments form top to bottom several times and cannot see any comments that could be termed unacceptable or rude or beyond what could be termed reasonable comment.
I have seen numerous comments thanking Judith Curry for her participation and I have seen many extremely valuable posts examining her paper, I myself have tried to keep my comments within reasonable limits as have many others.
Am I missing something here?
I see a genuine and interesting dialogue between interesting and intelligent people holding to a rational and on the whole polite discourse, if someone can can show me just what comments are rude or unacceptable or hurtful then I would be grateful.
This particular thread is IMHO one of the best I have read for some time with so many valid and interesting posts, if I were a scientist then I myself would be happy to submit my work to this kind of forum.
Many thanks to all the posters on this thread, I believe it is your participation that makes a large contribution to the popularity of this wonderful site.
BarryW says:
August 18, 2010 at 11:02 am
“Even the use of the term garbage WRT the data is bad form.”
Hey! I resemble that remark.
Garbage is the commonly used term in the computer trade to describe bad data. It even has a four letter acronym that many people in the industry will recognize: GIGO – which stands for Garbage In, Garbage Out.
http://en.wikipedia.org/wiki/Garbage_In,_Garbage_Out
Now if I’d wanted to be snarky I’d have said Garbage In, Gospel Out. But I bit my tongue even though that is the more apt expression.
I have an hour to try to catch up on this, it is difficult to find the signal amidst the noise here. Please see the plot at the top of the thread, spatial trends of SST in the Southern Ocean for the period 1950-1999. As described in the paper, there is warming in the midlatitudes, with slight cooling in the higher latitudes. Willis’ plot is on a scale where you can’t eyeball anything. But I’m glad Willis raised this issue, since the actual SST data (not just the EOF) is needed for this discussion.
oeman50 says:
“This just does not make sense to me. Does snow behave differently in Anarctica than it does in the US? In my experience, when snow falls on water, even water at 0 degrees C, the water absorbes into the snow crystal, making it ice and water, the whiteness of the snow and thus its reflective properties are nulified. Snow’s insulative properties are at least partly due to the air incorporated into the structure it forms when packed, which again gets nulified when it fills with water.”
Snow in the high southern latitudes can fall on the open water, on sea ice, and on the glacier; its fate is different in each case. When it falls on water, it immediately melts.
When it falls on the glacier, it accumulates and undergoes various metamorphic processes that increases its density, and it sticks around unless it melts during the summer. The snow that falls on sea ice will accumulate as on the glacier (or on land), but melt as part of the seasonal cycle. The more snow on the ice, the slower it is to melt.
Precipitation in the Southern Ocean can be either liquid (rain) or solid (snow). At colder temperatures, the precip is more likely to be snow than rain; as temperatures warm there is a greater likelihood of rain. The snow versus rain is seasonal, snow in the cold season and rain in the warm season, with the warm season lengthening in a warmer climate.
When precip falls on the open ocean, it doesn’t matter too much whether it is rain or snow (there is a small latent heat of melting the snow), both have the same freshening effect on ocean, which reduces the density of the upper ocean, and stabilizes so the heat below doesn’t reach the surface. Note, the antarctic sea ice is patchy, you have a bunch of ice floes surrounded by open water, with an overall ice concentration typically of 80%. When precip falls on the sea ice itself, it does matter substantially whether it is snow or rain. Snow raises the reflectivity of the ice, so it is harder for the sun to warm the sea ice. Rain falling on snow covered sea ice will actually accelerate the melting owing to increasing the density of the snow which reduces its reflectivity.
Reading this thread has been a surreal experience for me.
Everyone at their worst, in different ways. Which I shall spell out below, together with suggestions for “how can we do better next time” – but right away, IMHO the first thing to do better next time is to thank Judith Curry and Jiping Liu for contributing to the discussion – and perhaps thank them in anticipation and mighty quick after they’ve appeared. Mods, perhaps you can help with this, in a situation where there are twenty posts in the queue?
Next, the amount of criticism and repetition. What Steve Mc calls “piling on” and snips mercilessly – thank God – perhaps a similar tactic is needed here, now we have so many responders and such long queues. Is that possible, moderators?
Next, Willis. I totally support your guts feeling, as a lifetime sailor as well as a climate skeptic, that something is seriously out of kilter here – and I support your right to say this even without all the facts. But just a little more facts, clarity, and layman’s explanations would have helped me. It would have helped me understand the paper from Judith’s point of view – and thus help prevent us talking ACROSS each other. I want to know what EOF means. And I think Mosher has a point, well, perhaps I just cannot read, but surely you cannot produce the map (A) from your graphs of data at different latitudes. Surely you need longitude data as well. And surely such data must exist for the map to have been produced – however much rubbish it may be. As to Oakden Wolf’s praise for your “excellent summary of the paper” I am totally bemused because that is very much what I cannot see. But perhaps I’m being dense.
Willis, you know I respect your work immensely, but to me you come across here as a little brash – and the trouble is, any hint of brashness in the title piece will get magnified in the replies.