The cure for anything is salt water—sweat, tears, or the sea.

Guest Post by Willis Eschenbach

There’s an interesting study in Science magazine, entitled “Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000” by Durack et al. (paywalled here, hereinafter D2012). The abstract of D2012 says:

Fundamental thermodynamics and climate models suggest that dry regions will become drier and wet regions will become wetter in response to warming. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous. We show that ocean salinity patterns express an identifiable fingerprint of an intensifying water cycle.

Our 50-year observed global surface salinity changes, combined with changes from global climate models, present robust evidence of an intensified global water cycle at a rate of 8 T 5% per degree of surface warming. This rate is double the response projected by current-generation climate models and suggests that a substantial (16 to 24%) intensification of the global water cycle will occur in a future 2° to 3° warmer world.

Let’s start with salinity of the ocean, and how it varies around the globe.

Figure 1. Mean salinity of the ocean in “Practical Salinity Units” (PSU). Figure 1(D) from D2012.

One thing that we can see in Figure 1 is that where there is plenty of rain, along the equator and near the poles, the ocean is less salty (lower salinity). Conversely, where there is a lot of evaporation and little rain, the ocean is saltier.

Intrigued by their thesis that “dry regions will become drier and wet regions will become wetter in response to warming”, I pulled out my Argo surface data to take a look at the salinity records, and to get some idea of how the salinity varies with time, temperature, and location. What I found agrees with my general mantra, “Nature simply isn’t that simple”.

I started by dividing the globe up into five regions: North and South Pacific, North and South Atlantic, and Indian Ocean. I like to start my investigations by looking at a large scale, and then work downwards. Here’s the records for the Indian Ocean.

Figure 2. Temperature versus salinity for the Indian Ocean. Colors indicate the year that the observations were taken. Click on the image for a larger version.

There are several things that we can see in this plot. First, there has been no obvious change salinity during the decade. The earlier records (red) are distributed very similarly to the later records (blue).

Next, the shape of the curve is interesting in that it shows a very different salinity response at different temperatures. At the coldest end of the scale, and up to about 5°C, increasing temperature yields decreasing salinity. Next, from 5°C to about 20°C, as temperature rises, salinity increases, meaning less rain.

Finally, above about 20°C, increasing temperature correlates with decreasing salinity, meaning more rain.

Now, let’s consider their claim, that with increasing temperatures “dry regions will become drier and wet regions will become wetter”. This claim rests on the reasonable assumption that the salinity is inversely related to rainfall, because the fresh rainwater dilutes the salty ocean.

But here’s the problem with the claim. Let’s take a look at two areas, both with the same salinity, say 35 PSU.

Figure 3. As in Figure 2, with a yellow line indicating ~ 35 PSU salinity.

Note that the yellow line intersects two areas, one warmer and one cooler. Now presumably, since salinity is a proxy for rainfall, the two areas are equally wet, or are equally dry.

Now, if the temperature increases, one of the areas (the one on the left) will show an increase in salinity (decreasing rain), while the other one will show a decrease in salinity (increasing rain).

But we can replicate this result at each level of salinity. At each level of salinity (and therefore rainfall), when it warms, some areas get wetter and some areas get dryer. Therefore, it is not true to say that as temperature increases “dry regions will become drier and wet regions will become wetter”. In fact, some dry regions will get wetter, and some will get dryer, and the same is true for wet regions.

This is just the Indian Ocean, however. Let’s see what the other areas show. Here’s the same graph, for the South Atlantic.

Figure 4. Temperature-salinity plot for the South Atlantic, with the years indicated by colors.

As I said above, nature simply isn’t that simple, and the South Atlantic is different from the Indian Ocean. In the South Atlantic, as the temperature increases, rainfall decreases. Instead of the wet areas getting wetter and vice-versa, all areas get drier with increasing temperature.

Next, I looked at the South Pacific:

Figure 5. As in Figure 4, for the South Pacific

In the South Pacific, we see yet another pattern. There’s not a whole lot of change in salinity as the temperature varies. How about the North Pacific?

Figure 6. As in Figure 5, for the North Pacific. 

Again, the change in salinity is much smaller that in e.g. the Indian Ocean. However, the same thing is true—for every place that is dry that will get drier if it warms, there is another place that is dry that will get wetter if it warms.

Finally, for complexity, nothing matches the North Atlantic.

Figure 7. As in Figure 6, for the North Atlantic.

Once again, we see that there are dry areas that would get wetter, and wet areas that would get drier, with a temperature increase. However, there are a lot of areas in the North Atlantic that seem not to be following any general trend … complex nature strikes again.

Having looked at how the temperature is related to the salinity for large areas, I decided to look at how the salinity and temperature changed with time for smaller areas. I started with the Pacific, and I picked an area where I could look at ten-degree latitudinal bands. Figure 8 shows those bands.

Figure 8. Salinity map as in Figure 1. Yellow boxes show the delineation of the areas analyzed.

First I looked at the Northern Hemisphere in the Pacific.

Figure 9. North Pacific salinities by ten-degree bands. Colors indicate from coldest to warmest for each individual band. Purple dotted line shows the average for the entire North Pacific region. Black line shows a 200-point gaussian average of the salinity. “Sal. Chg.” is the salinity change (expressed as a change per 50 years for comparison with the D2012 study, along with the “p-value” for the trend rounded to three digits. “Temp. Chg.” is the temperature change (expressed as a change per 50 years for comparison with the D2012 study, along with the “p-value” for the trend rounded to three digits. “Sal. Anom.” is the salinity anomaly expressed in relation to the area salinity average (purple dashed line). “PA” is the “pattern amplification” discussed in the paper, which is the salinity change divided by the salinity anomaly. Note that some of the changes are not statistically significant (p greater than 0.05).

The claim made in the paper is that when the salinity is high (positive salinity anomaly), the salinity change should be positive with increasing temperature (dry gets drier), as well as the reverse—when salinitiy is low, the salinity change should be negative with increasing temperature (wet gets wetter).

However, in four of the six areas shown above, this is not the case. Nature is simply not that simple.

Next, Figure 10 shows the corresponding chart for the South Pacific:

Figure 10. As in Figure 9, for the South Pacific.

Once again, nature is not cooperating. First, in many areas there is little change in salinity. From 50°S to 40°S, the annual swing in temperatures is 14°C, but there is almost no annual change in salinity. In addition, the overall change is in the wrong direction. For another example, look at the band from 20°S to 10°S. Salinity is above the area average, but despite that, salinity is higher during the cool part of the year. In addition, temperature dropped, but contrary to predictions, the previously high salinity increased …

I append the corresponding charts for the Atlantic Ocean, which show much the same thing as we see in the Pacific—a confusing mix of responses.

My conclusions? Well, my main conclusion is that there is no general “wet get wetter and dry get drier” changes. For every dry area that is getting wetter with increasing temperature, there is another area which is just as dry that is getting drier with increasing temperature.

My second conclusion is that different parts of the ocean react very differently to increasing temperature. In some areas, neither annual nor decadal changes in temperature make much difference to the salinity. In others they are positively correlated, and in yet others, they are negatively correlated.

Does this make the D2012 paper incorrect? I don’t know, because they didn’t archive the data that they used for the 50 year period 1950-2000. It does, however, indicate that as is usual with the climate, generalizations are hard to draw. Humans always want things reduced to simple relationships like “if temperature goes up, wet areas get wetter and dry areas get drier.” Like Aesop, we prefer simple morals for our fables. Unfortunately, nature is nowhere near that simple.

My best to all,

w.

PS—I have not commented on the use of a combination of traditional salinity measurements and Argo float measurements, and I do not find any comments by the authors of D2012 regarding the topic. However, it would seem that it should be discussed and the two measurements compared where they overlap in time and space.

APPENDIX 1: Salinity charts by latitude band for the Atlantic Ocean. See the captions for Figures 8 and 9 for details.

Appendix 2. Data and code (in the computer language “R”) are here as a zipped archive (WARNING: 32 Mb archive). Data is in an R “save” file called “argo temps.tab”. WARNING 2: The code is not “user-friendly” in any sense, and might best be termed “user-aggressive”. It is NOT designed to be run as a single piece.

Advertisements

  Subscribe  
newest oldest most voted
Notify of
Lance Wallace

Neat stuff as usual, Willis. I had read that piece in Science and confidently predicted that you would debunk it, but it’s always amazing how fast you operate.
Some of the p-values in Figs 9 & 10 are given as “p=0” –can you fix?

Paul Vaughan

Willis wrote: “Humans always want things reduced to simple relationships like “if temperature goes up, wet areas get wetter and dry areas get drier.””
Well-said.
Varying aggregation criteria easily introduces statistical paradox, so to learn terrestrial climate fundamentals, we need to pay special attention to variables that are globally constrained.
The education system badly needs a compulsory course for all students: Paradox 101. Generations later, humanity might look a whole lot less goofy than climate & solar scientists do today.
Precipitable Water:
http://i52.tinypic.com/9r3pt2.png
Monthly Maximum of Daily Precipitation:
http://i41.tinypic.com/34gasr7.png
Evaporation Minus Precipitation:
http://i43.tinypic.com/2isvynb.png
Column-integrated Water Vapor Flux with their Convergence:
http://i51.tinypic.com/126fc77.png
Credit: Climatology animations have been assembled using JRA-25 Atlas [ http://ds.data.jma.go.jp/gmd/jra/atlas/eng/atlas-tope.htm ] images. JRA-25 long-term reanalysis is a collaboration of Japan Meteorological Agency (JMA) & Central Research Institute of Electric Power Industry (CRIEPI).
http://i49.tinypic.com/fp1edv.png
http://i49.tinypic.com/219q848.png

Dexter Trask

“User-aggressive” would also seem to be an apt description of nature as well…

a jones

Yes. Indeed seawater gets rid of Triffids too you know. Less sure about what it does to so called climatologists though: where many seem to inhabit a science fiction world of their own where they are invincible. In their dreams anyway.
Kindest Regards

If they cover the 1950 to 2000 time frame, how do they handle the cooling from 1950 to 1978, representing the majority of this time frame? Or do they use somebody’s “adjusted” data that disappears this cooling phase? Do they report “intensification” throughout this period or did it decrease with cooling?

Done with your usual thorough analytic thought, Willis. I appreciate your contributions and thank you for them. It would appear from this analysis that we are faced with another poorly done paper in the name of science. I am disappointed with the dismal performances of much in science today.

Kasuha

Thanks for pointing out an interesting paper, and thanks for interesting play with numbers and dots, but I don’t really see how they connect to each other.
First thing that I can see on the paper is, it’s yet another paper saying that models got it wrong.
Second thing is, it is known fact that in historical times when the temperature was higher than today, water cycle was more intense as well. Among others, some 6000 years ago Sahara was much greener than today.
And third thing is, the approach “that’s nice what you found there but when I analyse the data my way I see nothing” does not prove anything. Looking at your graphs I’d even say that they support conclusions of the paper, but more detailed analysis would need to be done.

Thank you Willis for yet another very readable and informative post and a further example of why the debate is not over.
It keeps me amazed how people try to simplify the climate’s behaviour to match their pre-perceived targets.
Over simplification is good for explaining processes, but not for explaining vast and complex systems (as oceans and climate).
The equation warmer=drier is, on its face, a simpilfied and childish claim.
We know that colder could be dryer too…

Great, Willis. Now why don’t you address what they actually did?
Lead author Paul Durack said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has become 4 percent stronger from 1950-2000. This is twice the response projected by current generation global climate models.
Your analysis above doesn’t say anything about evaporation.

Interstellar Bill

Obviously none of the reviewers spent any time on any such critical analysis. Presumably they were too eager to affrim the predictibly bad news. When I read my snail-mail issue I was struck by the AGW-catechism tone of the very opening
“Fundamental thermodynamics and climate models suggest”
First of all, fundamental thermodynamics does NOT ‘suggest’, it enforces.
Second, tinker-toy models with harumphy official names are not in any way to be given equivalent judgemental weight to ‘fundamental thermodynamics’.
Third, the only suggestion in this entire paper is by your assumption of ‘fixed relative humidity’. Did you ever think to check any data to see if you assumed correctly? Hint: you didn’t. Did you ponder where all that extra heat is supposed to come from?
Also,, can we drop the ‘Reveal’ in the title? How about using the same word we use in deference to ACLU sensibilities: Ocean Salinities ALLEGE Strong Global Water-Cycle Intensification…
Wow! Not just any old ‘intensification’, but a “STRONG’ intensification, one that they ‘FOUND’ (paragraph 2) in 21st century climate projections. I wonder how hard they had to search for that? Hmmmmm.
They conclude with alleging that in ‘the 2-3 C warmer world’ of 2100, their ‘results’ imply a ’16-24% amplification’. This is twice as bad as what the best Gee-Whiz model had already ‘predicted’
So we’re just plain screwed, folks (but, conveniently, not right away).
I used to read Science & Nature for a weekly knowledge infusion, but now I get the bonus of laughing at their mawkish AGW pseudo-science, then waiting for WUWT to skewer it fully. History before my very eyes!

Paul Vaughan

Oakden Wolf (May 12, 2012 at 9:39 pm) wrote:
“[…] the water cycle has become 4 percent stronger from 1950-2000.”

http://i49.tinypic.com/219q848.png

gnomish

and if the rain falls back into the sea from whence it came – all the assumptions are invalid.

DavidA

I enjoyed reading it. Just a comment: “One thing that we can see in Figure 1 is that where there is plenty of rain, along the equator and near the poles” – ice melt around the poles comes into play?

Willis Eschenbach

Lance Wallace says:
May 12, 2012 at 8:41 pm

Neat stuff as usual, Willis. I had read that piece in Science and confidently predicted that you would debunk it, but it’s always amazing how fast you operate.
Some of the p-values in Figs 9 & 10 are given as “p=0″ –can you fix?

Actually, I’ve rounded the p-values to three digits, so the “0” is correct. Beyond that, the numbers become meaningless.
All the best,
w.
PS—I greatly dislike the term “debunk”, as it implies that the study is bunk. In addition, in this case I haven’t looked at what they looked at, because I don’t have the data. So I definitely am not making any claims that I have debunked anything.

Willis Eschenbach

Kasuha says:
May 12, 2012 at 9:27 pm

Thanks for pointing out an interesting paper, and thanks for interesting play with numbers and dots, but I don’t really see how they connect to each other.

Thanks, Kasuha. They connect because I am discussing their idea that increasing temperature means that “dry regions will become drier and wet regions will become wetter”. I think I have shown that it is much more complex than that.

First thing that I can see on the paper is, it’s yet another paper saying that models got it wrong.

Indeed they said that, but I have no faith in the models, so it’s not surprising to me that the models got it wrong, and not particularly worth comment … so I didn’t.

Second thing is, it is known fact that in historical times when the temperature was higher than today, water cycle was more intense as well. Among others, some 6000 years ago Sahara was much greener than today.

I’d have to see a citation for that. Describing anything that happened 6,000 years ago as a “known fact” seems like it is a bridge too far. Yes, we know that the Sahara was wetter back then … but whether the “water cycle was more intense” back then is pure speculation.

And third thing is, the approach “that’s nice what you found there but when I analyse the data my way I see nothing” does not prove anything.

Since nothing can ever be proven in science, I don’t understand your point. I am not trying to prove anything. I’m trying to show that nature is complex, and that simple conclusions may not be warranted. In addition, if the result of one analysis differs from another analysis, that is valuable information.

Looking at your graphs I’d even say that they support conclusions of the paper, but more detailed analysis would need to be done.

You’re welcome to say that, but unless you actually point out some errors in my logic, my facts, or my interpretations, it doesn’t mean much.
The problem I see is that some of the results that I highlight support their theory (in some places the wet is getting wetter and the dry is getting dryer with increasing temperature), in other locations the temperature is rising but the opposite is happening.
Which is my point—nature simply isn’t as simple as they make it out to be.
All the best,
w.

gnomish

heh-
“Since nothing can ever be proven in science”
prove that one!

Willis Eschenbach

Oakden Wolf says:
May 12, 2012 at 9:39 pm

Great, Willis. Now why don’t you address what they actually did?

Thanks, Ogden. The reason I don’t address what they actually did is because as far as I know they didn’t archive the data they actually used. If you can provide that, I’ll take a look at it. Instead, I used their study as the departure point for investigating their general claim, which was that “dry regions will become drier and wet regions will become wetter in response to warming”.

Lead author Paul Durack said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has become 4 percent stronger from 1950-2000. This is twice the response projected by current generation global climate models.

Meaningless to me. The models are known to perform no better than chance regarding precipitation, and this study simply confirms that. Why should I care? Instead of looking at the models, I looked at the real world, and I learned a lot along the way. That’s why I do science, not to establish a claim, but for the joy of learning. I learned a whole lot about salinity and the ocean that I didn’t know.
In the process, I think I have made a reasonable case that the Argo data doesn’t support the ‘wet gets wetter and the dry gets dryer’ meme. But heck, if you can find fault with the case I made, go for it … just don’t waste your time busting me for not discussing the models.

Your analysis above doesn’t say anything about evaporation.

True dat … and the reason is because neither I nor the authors have much data on evaporation. The authors fill that gap with models. Me, that’s not my style. Instead, I follow the lead of Robert Heinlein, who said:

“What are the facts? Again and again and again – what are the facts? Shun wishful thinking, ignore divine revelation, forget what “the stars foretell,” avoid opinion, care not what the neighbors think, never mind the unguessable “verdict of history” – what are the facts, and to how many decimal places? You pilot always into an unknown future; facts are your single clue. Get the facts!”

So that’s what I do. Every graph above is observations about the real world, in other words, facts. I just follow them and see where they lead. Your conclusions from those facts may be different than mine, that’s science. I just play the facts cards face up and draw what seem to me to be the conclusions.
Regards to you,
w.

Willis Eschenbach

DavidA says:
May 12, 2012 at 10:04 pm

I enjoyed reading it. Just a comment: “One thing that we can see in Figure 1 is that where there is plenty of rain, along the equator and near the poles” – ice melt around the poles comes into play?

Indeed it does, you can see it in the areas of very low salinity at the very left edge of the temperature/salinity plots.
w.

Scarface

Willis, it almost looks as if the graphs of the oceans need a 3rd dimension. Have you looked at that possibility?

Brian H

Ah, the map is strikingly different from the territory, it seems!

son of mulder

Has any consideration been given to how ocean currents contribute to the time evolution of salinity at any particular place as I’m sure ocean currents also contribute to evaporation and moving salty water? I assume salinity arose from salt deposits close to the seabed that are now exhausted (zero sum game) or is salinity subject to sources and sinks in any sort of way? Without consideration of these points I can’t see how conclusions can be drawn from the data or how the original predictions could be sensibly made.

thingadonta

“dry regions will become drier and wet regions will become wetter in response to warming”
Sounds cute, but you don’t even need graphs to sense that this doesnt necessarily work. A region which is dry because it is next to an adjacent cold area, will tend to get wetter if the adjacent cold area heats up, because the cold area is no longer as cold. So a warmer world, for these areas, will tend to make these dry areas wetter.
An example is the Sahara, it is well known to be wetter when the world was warmer in the Holocene, probably for the same sort of reasons as above; when adjacent Europe/Atlantic is colder, the Sahara is drier. The Amazon is also drier when colder, as in the Ice Ages.
Another example is the continental west coasts, which are dry because of the cold currents next to them, when this cold water heats up, they tend to get wetter-which is happening in the NW of Australia (but not in the SW of Australia, curiously).

dalyplanet

Thank you Willis Eschenbach for another beautiful exposition of ARGO data. And the thought provoking article. I also want to thank you for the amazing discussion produced from your Bern Model article. My understanding of the CO2 cycle puzzle was greatly enhanced. Thank you to all the great posters rgbatduke particularly but all. I really learned a lot, completely new conceptualization of the process by the descriptive words of rocket science and for simplicity, diagrams.
Only on WUWT !

Willis
I love your deconstructing work. Is there any way you can set it all on a more complete historical and objective basis, I mean, something like:
Nature etc major climate publications….. xxx
Same publications deconstructed by Willis here …. yyy
Same publications deconstructed by others here …. zzz
Roots of studies in alarmist statements… jjj
Conclusions for Science…… kkkkk
– well, written-up in a way that is a bit more, what is it, nuanced than that! Perhaps even a book. You know I still dispute your conclusions re some of the radically new material that challenges long-accepted physics and maths. But these deconstructions of yours, where standard methods and standard accepted laws of science are used, or rather, as you show, abused, and commonsense and patterned complexity are neglected in favour of shocking conclusions to trivial studies, are IMHO really important.

Willis, re evaporation – you may have seen the paper by Roderick et al in Geograpical Compass 2009 http://biology.anu.edu.au/CMS/FileUploads/file/Farquhar/271RodericketalPanreviewIGeogCompass2009_000.pdf
It shows pan evaporation reducing over the last 50 years contrary to expectations. I think Roderick was side lined at ANU as a result.

Philip Bradley

As the climate models are out by about a factor of 2 in their atmospheric temperature predictions (and probably rather more due to the problems with the pre-satellite surface temperature data), then their ocean evaporation predictions are wrong by a factor of 4 (or more).
Which indicates to me the increased salinity is predominately an increased solar insolation effect, with some contribution from increased winds.
Although these causes will increase the speed of the hydrological cycle.
Which leaves us with a problem. If the hydrological cycle is increasing, why isn’t global precipitation increasing?
http://cics.umd.edu/~yin/GPCP//ASSESSMENT/assessment.html
And why aren’t clouds increasing?
http://journals.ametsoc.org/doi/abs/10.1175/JCLI3461.1
The answer is (IMO) decreased cloud seeding and precipitation causing aerosols, which is also the cause of the increased solar insolation.

Stephen Wilde

“If the hydrological cycle is increasing, why isn’t global precipitation increasing?”
Our measuring systems aren’t up to the task as yet.
“And why aren’t clouds increasing?”
Clouds seem to decrease when the sun is more active leading to more solar energy into the oceans and a warming system. That is contrary to established climatology but it is what happened during the late 20th century.
According to Earthshine data cloudiness has been increasing since the late 90s which coincides with the declie in solar activity and a number of other changes including the cessation of warming.
Svensmark says that the reason is GCRs varying inversely with the level opf solar activity. I say it is because an active sun draws the air circulation poleward widening the equatorial air masses in particular the subtropical high pressure zones with their descending air which dissipates clouds. The opposite when the sun is less active.

Stephen Wilde

Willis’s observations would be accounted for by latitudinally shifting climate zones.
Note that highest salinity, lowest precipitation and highest sea surface temperatures are all under the subtropical high pressure zones in each hemisphere.
Expand and contract those zones in line with an external forcing such as the sun from above or an internal system forcing such as the oceans from below and all the pattern changes are readily explicable.
Note too that those climate zone shifts are a negative response to the solar or oceanic influences. They change the rate of energy transfer from surface to space in order to keep the system stable.
The same response would occur with more CO2 in the air but miniscule and unmeasurable compared to the effects of sun and ocean.

Philip Bradley

In the pan evaporation study above note the outliers.
Large increases in evaporation in hot dry climates (Israel and Kuwait) and large decreases in hot humid climates (Thailand and India).
I’ll suggest that is due to increased solar insolation combined with increased humidity. The former being more important in dry climates and the latter more important in humid climates.

Willis Eschenbach

cementafriend says:
May 13, 2012 at 1:40 am

Willis, re evaporation – you may have seen the paper by Roderick et al in Geograpical Compass 2009 http://biology.anu.edu.au/CMS/FileUploads/file/Farquhar/271RodericketalPanreviewIGeogCompass2009_000.pdf
It shows pan evaporation reducing over the last 50 years contrary to expectations. I think Roderick was side lined at ANU as a result.

I’d seen such studies, although not that particular one. The reason for the reduced pan evaporation in the last while is still a mystery as far as I know. I haven’t seen what I thought was a cogent explanation, although one may be out there.
Thanks,
w.

Willis, I forgot to link to Roderick’s second paper which I have been looking for but only just found on the website of one of the secondary authors Prof Farquar http://biology.anu.edu.au/CMS/FileUploads/file/Farquhar/272RodericketalPanreviewIIGeogCompass2009_000.pdf
I think Farquar has broken from the Climate Dept. at ANU which is full of alarmist. The paper gives some reasons for the decline. As you say in your post nothing is straight forward.

Willis, I should have mentioned that I have had Rodrick’s first paper for some time but I found the link I had no longer works, when writting my comment. I then searched on the ANU site and that brought up Farquar and the link that I gave earlier (which worked before I posted it). I then noted the second paper (above which also works) which I have been looking for since I found the first.

Silver Ralph

>>> Among others, some 6000 years ago Sahara was much greener than today.
I think it is more likely that the ITCZ, and there fore the position of the Sahara, moved south a bit. It would not take much of a movement, to make much of North Africa wet and flora-fauna productive.
Its easier to spot ancient decicated flora and fauna in the Sahara, than confirm an ancient arid zone south of the present Sahara.
.

kMc2

For some reason the title brought Isak Dinesen to mind.

Mark Cooper

Two Comments…
One:
The original paper and your commentary seem to ignore Thermohaline Circulation?
http://en.wikipedia.org/wiki/Upwelling
Deep water upwelling to the surface is a very common phenomenon and surface temperatures can be much lower than the “normal” ambient surface temperature. Also, deep water tends to be much more saline than surface water, so typically if you have a relatively low surface temperature you will have a correspondingly high salinity. Simply correlating surface temperature to surface salinity is ridiculous.
Two:
Re pan evaporation. The paper “Pan evaporation trends and the terrestrial water balance” insinuates that the reason the pan evaporation is declining is that water in the surrounding terrain is evaporating at an increased rate due to global warming, increasing the moisture in the air so it is “harder” for the water in the pan to evaporate. (An alternative theory might be that pan evaporation is declining in line with global cooling…)

cba

Willis,
Nice work going through the information you had available. I think it is important that you segregate the debunking between the science done or attempted in the paper and the presence of unfounded conclusions based upon opinion. These people might have gotten a lot of science right in collecting and processing the data. However, it would seem that they lack your skills in deconstructing what they’ve done and apparently any skill to form an opinion based upon their what is actually in their data without resorting to warmist hype. Perhaps a few examples such as yours might convince them to improve those skills and avoid future embarassments from the pitfalls of rash claims that are unfounded from their results. Besides, james hansen is the master of leaping to conclusions not supported by existing data or theory. These guys have a long ways to go to reach hansen’s level.

Willis Eschenbach says:
May 12, 2012 at 10:47 pm
Which is my point—nature simply isn’t as simple as they make it out to be.

True. Also, it appears – “they” are as simple as nature makes them out to be.
🙂

Chuckarama

Is there nothing AGW theory doesn’t predict? More rain, less rain, floods, droughts, heavy snow, less snow, more hurricanes, fewer hurricanes. It might be nice for someone to compile all the weather/climate “extreme” predictions on a single page, so we know what we’re up against in the future, because I’m starting to lose track…

Paul Murphy

umm .. quick question:
I haven’t looked at the internals of the sensors used to get the data but it seems possible to me that the salinity measures are affected by the density of the solution and thus by the interaction between local (near the sensor or sampling point) surface temperature and local depth. If so, you’d expect the north atlantic ridge to combine with north atlantic weather to produce results very different from those you get in the pacific basin with indian ocean floor topology and local surface weather producing a kind of halfway house between them. So, question: do marginal changes over time in the data outside estuarial plumes reflect rainfall or something else?

hunter

AGW promoter claims seldom if ever hold up under scrutiny. AGW believer media seldom if ever bother to check the promoter’s claims.
AGW true believers nearly always accept promoter claims in believer media without question.

Mickey Reno

From the “Science” article abstract: “…observed global surface salinity changes, combined with changes from global climate models, present robust evidence of…”
Output from climate models does NOT CONSTITUTE EVIDENCE, let alone robust evidence! But this statement is clear evidence that yet another line has been crossed by the alarmists, and that they think model output IS evidence. This is a crime against science.
Let me rewrite this sentence to make it scientfically correct: “…observed global surface salinity changes, combined with changes from global climate models, suggest a correlation between…”

michael hart

Thought provoking stuff. Especially that vertical line in Fig. 7 which is suggestive of a phase change [i.e. sea-water freezing/ ice melting] and the sinking of the resulting higher density waters in the far Northern/Polar regions..
This graph shows the isohalines by temperature and salinity.
http://linkingweatherandclimate.com/ocean/figs/density2.png
Fig. 6 is also pretty cool. Look at the scarcity of data points below 0 degrees Celsius in the North Pacific as compared to the other polar regions. Presumably that is due to both the net Northward movement of water through the Bering straits and the inability of large quantities of ice to escape from the Arctic? Or might it be a data artefact due to not actually having Argo floats reaching the higher latitudes in significant numbers?

michael hart

typo correction.
The link I gave is for “”Isohalines by Temperature And Density”

Steve Keohane

Thanks Willis for another great examination. I am amazed at the work you put into each article.
Regarding comments on evaporation, it seems to me that if the atmospheric RH% is dropping, so is evaporation. http://i38.tinypic.com/30bedtg.jpg

George Steiner

What is a “water cycle”?

Duncan B

Fascinating as always. Some of your’ plotting/graphing is rather beautiful.
Reminds me of ‘flocking starlings’ if you know what I mean.
Duncan B

Frank K.

Mickey Reno says:
May 13, 2012 at 6:43 am
From the “Science” article abstract: “…observed global surface salinity changes, combined with changes from global climate models, present robust evidence speculation of…
There – fixed it.

Billy Liar

I think the Argo plots are fascinating. You can plainly see that the least variation of salinity occurs at 4°C – the maximum density of water. The bifurcation in the N Atlantic and N Pacific plots show the local effects of fresh water from ice – not much ice around when the water reaches ~8°C according to those plots. As someone else mentioned, the freezing line at ~-2°C is also very evident and clearly shows a slope to a higher temperature at lower salinity.
Brilliant plots!

Billy Liar

George Steiner says:
May 13, 2012 at 8:13 am
http://www.funwatercraft.com/
/sarc

Billy Liar

One might also be tempted to conclude that for the N Atlantic the cloud of points at high salinity might come from the Sargasso Sea (the N Atlantic gyre).