Fiji Waters

Guest Post by Willis Eschenbach

As I’ve mentioned in my previous posts, I’ve been using a home-made thermometer setup to measure the air and water temperatures of the waters around Fiji. To start with, I’ve been thinking about just why I did it.

The answer, as with many things in my life, is “I’m not sure.” (As an aside, I generally laugh when people ascribe motives to my work, like the ludicrous claim that I’m in the pay of big oil, or the false idea that I am prejudiced against the myriad sunspot claims. In fact, all of us do things all the time without being certain just why we are doing them, and my choice to take scientific measurements was another example.)

One of the strongest motives was simple—I’ve never done it, and the undone is always fascinating to me. One of my lifelong rules of thumb is “If there’s a choice between something I’ve done before and something new, always choose the new”. I see part of my purpose on this planet is to go do strange and unusual things, and then report back on what I’ve seen. I let my eyes feast on the unknown, and then I try my utmost to put that into words and pictures for my friends.

Next, there has been recent coral bleaching in Fiji, and I wanted to look at the water temperatures. Also, I wanted to work toward a deeper understanding of what the fluctuations in temperature might actually relate to in the real world. Another point impelling me to take the measurements was that for reasons only know to himself, my friend Dave sent me a NIST high-accuracy thermometer, and it was getting lonely doing nothing.

I also wanted to answer a couple of questions. One was about the accuracy of bucket measurements versus actual measurements of the ocean itself—how fast does a bucket of water change temperature due to evaporation and cooling? Also, I wanted to look at the vertical temperature difference over the top few metres of water. Another was, people often use nighttime marine air temperature (NMAT) as a proxy for sea temperature, so I wanted to look at that relationship. Finally, I wanted to see if the rain cools the sea and by how much. Of course … not all questions in this world get answers …

Finally, I wanted to get a better understanding of the pains and problems of doing data collection … at least that part was a success.

Here is my experimental setup. The thermometer is inside a piece of plastic pipe that I drilled holes in for throughflow.

fiji last 5Inside the pipe, the thermometer is held away from the pipe walls by a very thin plastic case that it was originally shipped in. I cut the thin plastic to allow free flow around the thermometer, especially the bulb. I put duct tape over the ends of the pipe to prevent the thermometer from being washed out the end, and punched holes in the duct tape to allow circulation.

My procedure was to tie the thermometer in a spot where it was exposed to the wind but shaded from the sun (red arrow).

fiji last 4In between measurements of the sea temperature, the thermometer dried out and after about fifteen minutes or so it equilibrated with the air temperature. At each observation I first took the air temperature, and then the sea water temperature. After several experiments with the bucket I saw that I could avoid the fun and danger of filling a bucket from a moving boat, because I got the same temperature by just trailing the thermometer behind the boat where it stayed mostly beneath the surface.

I chose to make measurements generally at two-hour intervals. In part this was to allow the thermometer to dry completely between measurements, although I later found it dried much more quickly than that. And in part it was to give me time to attend to my other duties aboard the ship, like adjusting the sails, drinking beer, standing watch, squinting at the horizon in a most heroic fashion, and swapping lies with the crew … at the end I found that I had taken forty measurements over the ~ eighty hours of the voyage, about one every two hours.

So what did I find out? Well, to begin with I came away with an increased admiration for those folks who do this kind of data collection. I had initially thought I would take measurements around the clock, but the lack of sleep soon put paid to that plan. And I marveled to think that I was doing this in the most pleasant conditions possible … what’s it like for others doing it in driving sleet and the like? I also found out how easy it is to miss something, like the time I tossed the thermometer in the water without first measuring the air temperature … grrr. And then, of course, I was reminded that you should never, ever use raw data without quality control … after a run from 175° East to 174° East, I wrote down the longitude as 147° … grrr again.

Overall, I found out that as expected, the air temperature porpoises above and below the water temperature. Here are the results of the forty measurements:

air and sea temps off fijiA few comments to begin with. The first and last measurements were taken inside of the reef, in inshore waters. The rest were offshore, generally in deep water (1 – 2 km depth). All measurements have been converted from Fahrenheit to Celsius. The blue dotted vertical line marks when we turned around to go back to Fiji. The gray dashed vertical lines mark two rainstorms, the first lasting fifteen minutes, and the second lasting half an hour. The first and last days were clear, but on Saturday afternoon we sailed through a large area of a fully developed cumulus field with a number of thunderstorms.

So … what was of interest in the results? One thing I noted was that the sea runs about a degree warmer than the air during most of the twenty-four hours, but the air is warmer for a short period in the afternoon. However, this was not true in areas of active thunderstorms. After the storms on Saturday afternoon, the air temperature was a couple of degrees below the sea temperature.

I also noted something I’ve discussed before, which is that the coolness precedes the storm. What happens is that air from the condensation level where the clouds form is entrained in with the rain, making a vertical wind. When this wind strikes the surface it spreads out in all directions, cooling the surrounding area well before the rain hits. This cool wind has a characteristic smell which of course I can’t describe as our language doesn’t really cover smells … but it has a fresh clean smell that is quite distinct once you notice it.

Before and after the storms I took temperatures every fifteen minutes or so. I couldn’t see any effect of the rainfall on the ocean temperature, which surprised me until I thought about the relative volumes of fresh and salt water … even a hard rain doesn’t add much water to the ocean.

However, the air temperature changes were quite dramatic. After the first storm, which was in the morning, the air temperature warmed back up in a couple of hours. The second storm, however, was in late afternoon, and after that the air was very slow to warm. In any case, it leads me to think that I might be able to identify storms in e.g. the TAO buoy data by using a combination of sea and air temperature measurements. It also makes the use of NMAT as a proxy for sea temperatures something I need to investigate further.

Overall, sea temperatures in Fiji are still quite high. The peak open ocean temperature was on Sunday afternoon, when it got to 30.25°C (86.5°F). Both of the high temperatures were not far from the main island, which leads me to think that the islands heat the sea around them. This would happen through the warming of the water in the extensive barrier reef system around the islands, where water is held in shallow areas. Seems obvious in retrospect, but I had never considered that the lagoons were affecting the open ocean.

Regarding the other questions, I measured the sea temperature right at the surface, down two metres, and down three metres at a couple of points. One was in the open ocean, and one was in the lagoon. In neither case was there any detectable difference in temperature with depth, showing that the “mixed layer” is more than just a name.

Regarding the bucket question, I first measured the air and water temperatures. The air at the time was about a degree F (5/9°C) cooler than the water, with about a six knot wind. I put a bucket of seawater on deck, and took the temperature every fifteen minutes for an hour. I fully expected that with the smaller volume, the evaporation would cool the water down … not so. At the end of the hour, I could detect no change in the temperature of the water in the bucket. My conclusion was that despite the larger volume of the mixed layer, the evaporation factors (wind speed, air vapor pressure, air temperature) were the same for the mixed layer and the bucket … and that the mixed layer was already at equilibrium with the prevailing conditions. As a result, the bucket was already at the temperature dictated by evaporation.

Anything else? Well, we came across a “tide rip”, a line demarcating two different bodies of water. They are a great place for fishing, animals and plants generally like the edges of ecozones. So I checked the temperature on both sides of the rip … nada. They were identical.

Now, the limitations of this data are glaringly obvious. Not anywhere near enough measurements, the thermometer is moving, you can’t swim in the same ocean twice, and it is in the tropics. For example, I suspect (although I don’t know) that bucket vs. in-ocean temperatures in the polar regions might show very different results. However, given all of that … I know I learned a lot.

Today, I’m in the hotel restaurant drinking a latte. I have Tom Waits on my computer, he’s singing:

“Leavin’ my family, leavin’ my friends, my body’s at home but my heart’s in the wind

Where the clouds are like headlines on a new front-page sky,  tears are salt water, and the moon’s full and high …”

Turns out our bar tab is the same as the hotel bill, and the rooms weren’t cheap … bad swabbies, no cookies. In a couple hours I’m off from Fiji with the rest of the crew to the land of Oz and the Aussies, one of my favorite places. Mike has invited us all to hang with him for a week or so. I have an appointment to meet the tattoo god and his good lady (also an awesome artist) on Wednesday. Other than that, it’s likely fast motorcycles and sloe gin for the next week, and then back to the gorgeous ex-fiancee and my beloved hills and forest …

And for all of you, I can only wish that your lives be as full of sun and moon and rain and clouds as mine,

w.

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Analitik

Take some pH readings while you’re at it, Willis. Might as well get the picture on “ocean acidification” too.

Willis Eschenbach

Thanks, Analitik. I thought about that, but the equipment to do it accurately is something I don’t have, and I don’t think that pH paper is gonna do it …
w.

Analitik

I think pH paper is fine. Finer resolution changes would not affect sea life

Willis Eschenbach

I suspect that in the region I traversed, the pH wouldn’t vary by more than 0.01 pH units …
w.

Analitik

Worth proving for the cost of some pH paper and a few extra seconds per temp reading. If only because no one else has actually taken ANY measurements for climate studies – just endless modelling

ah, just estimate it, seems good enough for ground temp stations. I suggest dip your thumb in the water and taste three times a day and you should be able to measure to fractions of a unit.

Willis, I was just kidding when I asked the same to you… Nowadays they have maintain less equipment to record a lot of things like pH (colorimetric to 0.001 pH unit and better), pCO2, temperature,… on commercial ships, but still too large for a sailboat I suppose. The main problem still is that those ships are going mostly over the same trade routes and very few are in more remote areas like the Southern Ocean. Only research ships are doing that on a (ir)regular base, leaving large areas and periods without measurements.
What I remember of the trips I made – already 50 years ago – is that the temperature of the seawater inlet for the motor cooling could go up or down with several °C within minutes when passing some ocean current. Even color differences could be seen and probably other differences were present, but not measured…

Kevin M

Analitik
Every effort is worth it if someone else does the work.

Analitik

Kevin, the point it that Willis is already going through quite a lot of effort to take these temperature readings so why not spend a few more seconds wetting a piece of pH paper and recording the indicated value.
Yes, I’m not doing it but I’m not sailing about the Pacific, either. It’s an opportunity to take some measurements, however crude, to counter the modelling hysteria on ocean acidification. We know what the results will be but the greenwash always cry out that their models are valid representations of reality in the absence of proof.
But we can just try using common sense on them instead – that’s working well, right?

William

You are obviously in need of assistance.
I will work for food.

Ron Cook

I’m a chemist and can do Ph measurement BUT then I get sea sick really easily.
R-COO- K+

RayG

Ever try scopolamine patches? They seem to work for crew mates when racing in the waters off of San Francisco Bay.

Steve Fraser

Willis: Your comments about the consistency of bucket/water and air temps leads me to imagine an experiment where such things are tested at many latitudes, air and water temps.. And then compared with nearby buoy data.

Santa Baby

In the Tropics the water and air temperature are close? In polar region in the winter they are not?

Penelope

Santa Baby, The water temperature changes more slowly seasonally; hence the moderating effect of the ocean on coastal temps, no? Maintenance of much of a differential over long periods of time– I’d guess not. But then there never is a long period of time during which neither air or water is not subject to exterior flux.

ossqss

Full sails Willis!

Retired Engineer John

Willis; you have great adventures, what a life! Something that I read once and can’t find anywhere you might be experiencing. I read that on a hot tropical calm night, you can hear the Ocean bubbling. Have you noticed anything like that?

Peter C

Your depth measurements surprised me. I was expecting the water to be warmer near the surface. That has been my experience when snorkeling at the surface, and then diving down. Maybe that is an effect in shallow waters only.
How did you measure the temperature at 2m and 3m below the surface?

Bill Treuren

The temps are falling at this time of year, its winter sort off now or soon. But the sun is at its lowest in Fiji nearly.

South River Independent

Smell is chemical in that some molecules are detected by chemoreceptors in our noses, which pass on electrical signals to our brain that interprets the signals as smell. The change in smell that you detect must be a change in the molecules in the atmosphere. Could you be detecting ozone? Possibly another gas formed by a chemical process higher in the atmosphere? Some scientists must have studied such atmospheric changes and know what is going on.

noaaprogrammer

I’ve always interpreted the smell of downdrafts from thunderstorms as ozone – perhaps made by the storm’s electrical discharges.

South River Independent

I believe you are correct. That would be my guess.

Since ozone levels are used to set smog “spare the air days” does that mean thunderstorms are smog?
Just sayin’…

Tom in Florida

SMOG was originally a combination of the words smoke and fog to describe the nasty air in L.A.
Don’t know if that is still the current definition.

Billy Liar

Tom in Florida. Smog pre-dates the LA problem by more than forty years. The term was reputedly first used by Dr. H.A. des Voeux, treasurer of the Coal Smoke Abatement Society in 1905 in London.
http://www.etymonline.com/index.php?term=smog
http://www.marketplace.org/2014/07/14/sustainability/we-used-be-china/la-smog-battle-against-air-pollution

DonK

I wonder if it’s the same distinctive smell one encounters in the Southwestern deserts after a thunderstorm. It’s not restricted to deserts. I’ve smelled it a few times in Vermont.. Maybe once every five years. Not unpleasant, but not like any indoor or normal vegetation smell. Ozone? Could be. But I’d always expected Ozone to smell “electrical”.

Penelope

In Arizona one smells the rain approaching from neighboring areas because it wets the creosote bushes, which give off a pleasant chemical smell. Sometimes afterwards you almost smell the soil/sand steaming? outgassing?

I’ve had the equivalent smell, usually prior to rain, and until further detective work, I could accept it as an ozone sort of smell.

PaulH

Not only smell, but sound! It may be just the imagination of a landlubber kid growing up in a railroad town more decades ago than I would care to admit, I believed that I could “hear” an approaching rainstorm from the train whistle. Somehow the pitch or tone of the train whistle would be different when a storm was imminent, as opposed to fair weather. 🙂

Somehow the pitch or tone of the train whistle would be different when a storm was imminent

There is a new style of thermometer that measures temp by measuring the speed of sound in a tube, humidity is one of the properties they account for, because it change the speed of sound, so you are likely correct, train whistles do likely sound different with approaching storms.

tgmccoy

Ozone, for sure. I just smelled this the other day here in NE Oregon, as I walked
out of our local hardware store, and smelled that distinctive scent, with
an intense thunderstorm going on…
Smelled that scent from the Rio Grande to Fairbanks, btw..

Penelope

Once on Christmas day I was cross-country skiing in Vermont. The sun was bright, but it was snowing. Everyone was giddy, and I remember a terrific sense of well-being. No lightening, but people said it was the ozone which made us so giddy. ??

South River Independent

In a previous post I asked if bathythermographs are still used to measure thermoclines (i.e., temperature/depth profiles, but I did not see an answer. Does anyone know? Is the data available anywhere?

Penelope

Once on Christmas day I was cross-country skiing in Vermont. The sun was bright, but it was snowing. Everyone was giddy, and I remember a terrific sense of well-being. No lightening, but people said it was the ozone which made us so giddy. ??

Penelope

South River Independent, NOAA uses expendable bathys, 6 at a time on XBT Autolauncher.

South River Independent

Thanks for your response, Penelope. (You are probably not my sister Penelope.) I will check out the NOAA website.

South River Independent

Here in Annapolis on the mouth of the South River, it has been raining almost every day with temperatures generally in the 50s and 60s for going on two weeks now. The Dark Sky app indicates it will start raining in 20 minutes with the temp dropping to 57.

zemlik

I used to do that ” follow your nose” you find that your brain is more capable than you can find the words to express so ” follow your nose” and work out why later.
It is like ” I know that person is full of shit but I can’t quite say why” sort of thing. It is intuition.

zemlik

and the other thing about all this stuff is calibration. I saw this thing in a boook that if you want to measure the temperature of something you also need something the same measuring the temperature somewhere else. So you are not measuring temperature but a difference between 2 places. It’s calibration but I just know what it means you guys know the details.

gary turner

@Willis
” The peak open ocean temperature was on Sunday afternoon, when it got to 30.25°C (86.5°C).”
86.5°C? That’s the temp I usually sterilize my ice cream base. Two minutes at 85°C meets the specs for hi-temp short time sterilization.
cheers,
gary
[Reply: Fixed. Thanks! -ModE ]

Willis Eschenbach

Thanks, guys, appreciated.
w.

sonofametman

Reservations about buckets for measuring sea water temps arise from the use of leather and canvas buckets. They ‘wet’, and can therefore cool more in a breeze. No plastic buckets in them olden days. Also, you cant quite so easily trail a thermometer in the sea behind a ship as you can in a yacht with only a metre or so of freeboard.

David A

Willlis says,
“Regarding the other questions, I measured the sea temperature right at the surface, down two metres, and down three metres at a couple of points. One was in the open ocean, and one was in the lagoon. In neither case was there any detectable difference in temperature with depth, showing that the “mixed layer” is more than just a name.”
——————————————————-
? Does not fit my limited experience . (I grew up in San Diego and did some diving) There was almost always a clear cooling within 3 meters of the surface. Sometimes this was very sharp. Perhaps the tropics are different. Perhaps near shore is different.

@David A.:
California has a stong cold current off shore, so surface heating is fighting very cold below. Mid tropics mid Pacific the ocean moves slower and there is much more time to solar heat. Essentially, our cold coastal current heads out to sea and a long time later gets to Fiji… all that time in the sun. Eventually it goes past Japan keeping it warm and arrives at Alaska to cool off, then returns to California cold…
Near San Francisco, it is about 45 F, and cold at the surface. By the time it gets to SoCal, the top has warmed enough to swim in, the bottom less so… Fiji? I think I need a grant to study the thermal profile for a couple of years 😉

toorightmate

The water is nice year round – and so are the people.

jolan

Willis. Did you come to any conclusions re: coral bleaching?

Willis Eschenbach

Just the conclusions I’ve listed in my previous post, The Dogs of Winter.
w.

crosspatch

I can’t describe as our language doesn’t really cover smells … but it has a fresh clean smell that is quite distinct once you notice it.

It is called petrichor and generally would only smell it when the wind is coming off land but thunderstorms also produce ozone and that also has a distinctive smell that will be present in the downdraft winds.
I think the “fresh clean” smell you describe is that of ozone.
http://www.smithsonianmag.com/science-nature/what-makes-rain-smell-so-good-13806085/?no-ist
http://earthsky.org/earth/whats-that-smell-in-the-air-when-its-about-to-rain

Oldseadog

Willis, for air temperature did you move the thermometer around so that it was always on the weather side? If the thermometer was on the lee side, in a 6 knot apparent wind the air could quite easily gain a degree or so by passing over/around a hot wheelhouse before reaching the instrument.

Willis Eschenbach

Hey, Seadog, always good to hear from a man who has worn out more seabags than I’ve worn out socks.
Indeed I did keep it to windward. However, there’s no stack. It has a wet exhaust down just above water level. The issue on the lee side was that it was blocked from the wind by the pilothouse, so I kept it where the wind could get at it.
Best wishes to you and yours, my friend,
w.

spangled drongo

Thanks for those SS temperatures, Willis. They explain some of our current weather. Before the days of sat-nav and GPS the only way you could tell you were in a current [set] was by constant sea surface temperature monitoring. When passage-making under sail you need to know about currents. When you get to the east coast of Queensland when the ocean suddenly warms you will be in the Southerly Set but you will pick it up [if you are traveling along the coast] by your noted change in speed on the GPS relative to your knot meter. If the wind blows from the southward, the current sets south and vice versa. It can have eddies too.

It is interesting that you did not see a difference in water temperature with the rain storm. Once in the Florida Keys, I was swimming before and after a strong deluge (probably an inch of rain). After the storm, there was a distinct cold layer of fresh water sitting on top of the warmer salt water. It was very noticeable, and took probably half an hour or so to fade to where you couldn’t feel it. Just keep chasing the unknown and sharing it with us Willis.

Willis Eschenbach

Thanks, Jeff. I’ve experienced the exact same thing myself, and it was what I expected. Two things. First, the rainstorms were short-lived. I’ve been in lots that were real tropical downpours. So there wasn’t a whole lot of cold water. Next, when I experienced it, it was in the form of a very thin layer of cold water on top of the warm. Unless you could somehow skim off that layer and take its temperature, or you were measuring using an infrared thermometer from above, you wouldn’t notice it.
Also, in this case I might have seen the difference between a bucket dip and just trailing the thermometer as I was doing.
Onwards,
w.

Russell Dyer

Willis, thanks for sharing.
When you drag the thermometer behind the boat you are reading water that the screws have churned up from below, additional the boat has pushed the cooler rain water to the sides.
Cheers

Willis Eschenbach

Russell Dyer May 10, 2016 at 10:05 am

Willis, thanks for sharing.
When you drag the thermometer behind the boat you are reading water that the screws have churned up from below, additional the boat has pushed the cooler rain water to the sides.

True dat … however, given that it was just a couple mils of rain, I doubt it made much difference.
w.

A C Osborn

It’s a tough life doing this “Scientific” stuff, but someone has to make the sacrifice.
Nice job Willis and keep up the good work, I know it’s hard but we all appreciate your efforts.
And wish we were there.

Empirical testing ??!!?? Blasphemy I tell you !

AndyG55

OT, USCRN anomaly drops 3°F (1.67°C) from March to April
This value is pretty much the same as the drop in UAH USA48 and RSS US
Trend in all real US data since 2005 is still indistinguishable from ZERO.
http://s19.postimg.org/ps2geu8qb/USCRN_et_al.png

John Haddock

How’s your FAST (Fijian Air Sea Temperature) model coming along? You know, the one that tells you whether your temperature data’s any good.

Greg

Excellent stuff Willis. I love this kind of hands on science too.

It also makes the use of NMAT as a proxy for sea temperatures something I need to investigate further.

That is clearly a very unscientific proposition and I’m sure your in situ measurements will be interesting. It will probably provide you with some ideas that you can follow up in the major datasets.
Re. buckets. Also very interesting. Hadley centre did some quite detailed work on this issue using wind-tunnels. I assume you’ve read the relevant papers. One key factor missing in a wind tunnel is tropical sun. Real in situ measurements give an interesting ground truth comparison. As you say the situation will likely be very different in polar regions and I don’t recall this being examined in the Hadley tests.

… and that the mixed layer was already at equilibrium with the prevailing conditions. As a result, the bucket was already at the temperature dictated by evaporation.

Surface to mass ratio of a bucket of water is very different from an ocean of water. I’m surprised you’re not seeing any difference. Early measurements that give rise to much of the data “corrections” were allegedly taken using canvas buckets. These will show a lot of evaporative cooling on the surface, whereas your plastic buckets will probably shed more of water from their surface.
I think the thing about buckets cooling is mainly the walls , not water surface.

Willis Eschenbach

Thanks, Greg, interesting points all. I always assumed that they were using wooden buckets, but canvas buckets make sense too. They would be less insulated that the plastic ones, as you point out, and would cool faster.

Surface to mass ratio of a bucket of water is very different from an ocean of water. I’m surprised you’re not seeing any difference.

As was I … however, once I thought about it it made more sense. Tropical temperatures change very slowly. This gives time for the mixed layer to equilibrate with the average atmospheric conditions, in particular evaporation. In addition, the mixed layer is being cooled by thunderstorms, including the greatly increased evaporation caused by the storm winds. Evaporation is roughly proportional to wind speed, so that leaves the mixed layer cooler than it would otherwise be.
Now, I come along and dip up a bucket of that relatively cool mixed layer. It is equilibrated to a greater rate of evaporation due to thunderstorms … since the wind when I’m measuring it is not thunderstorm wind, the evaporation would be LESS than the mixed layer is equilibrated to, so it would not cool further.
Another issue is skin effects. In relatively calm weather such as I was in, the skin layer can be warmer than a few centimetres below the surface. But when you dip it into a bucket, this is no longer true. Again, this would lead to less evaporation from the bucket, per Clausius-Clapeyron.
Caveats. First, with canvas buckets, we used to keep water in canvas waterbags because it would stay cooler than ambient. However, the canvas ship’s buckets were likely tarred or sealed in some fashion so I doubt that would make much difference.
And in the polar regions all bets are off. You can get air that is well below freezing blowing hard over an ocean which is above freezing by definition if you’re taking sea temperatures …
w.

…canvas ship’s buckets were likely tarred or sealed…
Or maybe permeability was a “feature.”

…sampling with general-purpose ships’ wooden buckets would have been impractical and dangerous on the steamships that gradually replaced slower sailing vessels of lower freeboard in the late 19th century. Such buckets bounce along the sea surface when suspended from ships travelling in excess of ~ 7 kt (~ 3.5 ms-1) and considerable drag is generated once they dip beneath the surface. Canvas buckets do not bounce along the surface and those used aboard steamships appear to have been of fairly small volume (2–4 L, Brooks, 1928; referred to as B28) and often weighted to help them sink (e.g. with a wood base)…rubber buckets are known as “insulated”, wooden as “partially-insulated” and canvas as “uninsulated”.

http://www.ocean-sci.net/9/683/2013/os-9-683-2013.pdf
In any case, given all the assumptions that must be made, it seems that SST correction for canvas bucket evaporative cooling based solely on date of sampling is absurdly subject to constant re-evaluation.
One of the sources for the above paper:
ftp://podaac.jpl.nasa.gov/allData/gosta_plus/retired/L2/hdf/docs/papers/1-crrt/1-CRRT.HTM

Greg

… which leads me to think that the islands heat the sea around them. This would happen through the warming of the water in the extensive barrier reef system around the islands, where water is held in shallow areas.

I don’t think this the islands heating the sea, it’s just that almost by definition sea is shallow around land. Same energy input, less “mixed layer” so more temp rise. In terms of heat content it’s probably similar to open water except that higher surface temps will provide more neg. feedback.
Probably a good case for eliminating in port SST measurements from the datasets.

Willis Eschenbach

Greg May 10, 2016 at 5:03 am

I don’t think this the islands heating the sea, it’s just that almost by definition sea is shallow around land. Same energy input, less “mixed layer” so more temp rise. In terms of heat content it’s probably similar to open water except that higher surface temps will provide more neg. feedback.

Thanks for your comment, Greg, made me think. But no, I doubt that’s the case, for a couple of reasons.
First, volcanic islands like Fiji are quite “steep-to” in nautical terms, meaning that the sides of the volcano drop off rapidly. Depth increases quickly as you go offshore. Hang on … OK, a look at the chart (Navionics on my iPhone) shows that where we went through the reef, by the time you’re a mere 2 km (1.2 miles) offshore, the water is already a hundred metres deep. That’s typically the depth of the mixed layer.
The other is, you likely underestimate the extent of the fringing reef system in Fiji. There are hundreds of square kilometers of shallow areas enclosed by fringing reefs on each of the islands. The water in these areas is actively pumped through the shallows by two mechanisms. One is the tides, and the other is that in any kind of wind waves break over the reef and add water to the shallows. So this heated water is then pumped back into the surrounding areas … where I measured it at the beginning and the end of the trip.
w.

Leo Norekens

Shiver me timbers !

Pat Paulsen

I never hear much about the transfer of energy from water to air. It seems to me that if the air is cold above a warm water source, then the heat will transfer from the water to the air. Now, if we have indeed been cooling for circa 18 years, then the air would be cooler than the water, hence, larger El Nino’s as the oceans gave up more heat than normal due to colder air? I’m just wondering about the mechanism but it seems that there might be a relationship between El Ninos, La Nina’s and Little Ice Ages? Just wondering. 😉

Willis, I share your curiosity, and need to examine things for myself, but you also have a gift for the written word, me I’m far less elegant.

Eustace Cranch

Willis, I thoroughly enjoy your little “diaries.” And I have to say- any Tom Waits fan is halfway to being a soul mate in my world.

Retired Engineer John

” This cool wind has a characteristic smell which of course I can’t describe as our language doesn’t really cover smells … but it has a fresh clean smell that is quite distinct once you notice it.”
Some electronic air cleaners have a feature that will release negative ions that are supposed to cause a fresh smell like the smell after a thunderstorm.

I have had those, and I agree, they do tend to smell like a storm has passed by.

bit chilly

nice post willis. glad you did the bucket experiment as well. sheds some light on karlization. a proper comparison would be required to be sure, but i would put money on the results being the same , ie immeasurable change within the timescale of the bucket contents being measured. i doubt people taking those measurements left the bucket lying around on deck at all, and took the measurements within seconds of it hitting the deck.
did you have a look at stated sea surface temps for the area during your measurements ? i appreciate there may be little variation in the tropics compared to northerly latitudes so the opportunity for discrepancies may be smaller.

Mike

Willis,
Much enjoy your sea-faring yarns.
This is off topic but I would really like your input.
We, my very own gorgeous ex-fiancée of 45 years and myself, will be visiting Fiji and other south pacific islands on one of our bucket list cruise adventures next year, Auckland NZ back to Vancouver BC. As usual the cruise line offers over priced, sanitized and culturally insulated land excursions, not our taste. The below extract shows the island stops. Your suggestions for sights, experiences for these island stops would be gratefully accepted. We enjoy sitting and drinking a beverage and trying new food listening to good lies or indulging in physical activity to burn off the calories like walking, swimming etc. ( My very own gorgeous ex-fiancée was born and grew up in the lesser Antilles and so I tend to think of her more as my very own gorgeous ex-fiancée mermaid.)
TUE 11APR17 Noumea, New Caledonia 10:00am 10:00pm
WED 12APR17 Easo, Lifou, New Caledonia 2,6 8:00am 5:00pm
THU 13APR17 Sea Day
FRI 14APR17 Lautoka, Fiji 8:00am 5:00pm
SAT 15APR17 Dravuni Island, Fiji 2 8:00am 4:00pm
SAT 15APR17 Cross International Dateline 3
SAT 15APR17 Sea Day
SUN 16APR17 Pago Pago, Tutuila, American Samoa 10:00am 6:00pm

Coldish

Thanks, Willis, for sharing your scientific investigations. One question: on your temperature/time graph, do the short ticks just above the words Fri, Sat and Sun represent midday? Or what time of day?

Willis Eschenbach

Good question, Coldish. It’s midnight.
w.

..it’s likely fast motorcycles and sloe gin for the next week..

Now I’m REALLY jealous. Did a ride through the Mt Glorious area many years ago. First and only time I ever actually heard a Kookaburra outside of a Tarzan movie!

James Fosser

I live in the northern suburbs of Brisbane and two or four Kookaburra often wake me up in the summer chatting to each other. A wonderful sight to see is one sitting majestically in a tall tree totally ignoring the many smaller birds that constantly keep swooping up to its face (The Kookaburra could swiftly end their days if it so felt like because it is a kingfisher and its food is not worms!)

joelobryan

More QC: May not March on the graph

Willis Eschenbach

Fixed, thanks. My motto is, “Perfect is good enough”.
w.

I was really impressed by how much thought could be generated by your simple, real time, raw data measurements of sea and air temperatures. There is something about reality that beats the cr@p out of computer models, (or imagining things from a bunker in a mother’s basement).
My ears perked right up when you got curious about whether the rain shower would have any effect on the water temperatures. It may not have been noticeable in the small scale, but I wonder about situations in typhoons, where a foot of rain falls.
I also wonder about storms with tropical origins as they die out in the arctic. In that case the heavy rain is much warmer than the water, even as the water is poised at a delicate state where a slight change in salinity and temperature can be the difference between a current staying at the surface or diving beneath other waters.
All I can say is that, to sate my curiosity, you really have your work cut out for you. Cancel plans in Australia. Sail north, and, as I sit on my not-so-fat @ss by my computer, catch the eye of a typhoon and chase it north past Japan and up into the icebergs of Bering Strait, taking measurements in the bucket thermometer as you go.
Thanks in advance.

Willis explained: “If there’s a choice between something I’ve done before and something new, always choose the new”
I prefer the version of this attributed to May West:
“Whenever I have to choose between two evils I always pick the one I haven’t tried before”