The World Ocean Database (WOD) is a premiere database of in situ ocean measurements, made by scientific researchers around the globe:
"The World Ocean Database (WOD) is the World's largest publicly available uniform format quality controlled ocean profile dataset. Ocean profile data are sets of measurements of an ocean variable at a single geographic location within a short (minutes to hours) temporal period in some portion of the water column from the surface to the bottom. To be considered a profile for the WOD, there must be more than a single depth/variable pair. Multiple profiles at the same location from the same set of instruments is an oceanographic cast.(Data dot Gov, emphasis added). The WOD folk even provide robust documentation with that data, including an online manual (WOD Manual).
There are more than 13 million oceanographic casts in the WOD 2013 (WOD13) initial release, from the second voyage of Captain Cook (1772) to the modern Argo floats (end of 2012).
Ocean variables in the WOD13 include temperature, salinity, oxygen, nutrients, tracers, and biological variables such as plankton and chlorophyll.
Quality control procedures are documented and performed on each cast, the results included as flags on each measurement."
Within that manual you will find a complete list of variables and variable codes at Table 3 (WOD Manual @ Page 9; PDF version @ page 19).
Today's post is about the reason why there is no variable for "heat content" in that list of crucial variables.
But there is a variable for Temperature (Variable Code #1), and heat is temperature, right?
No, temperature and heat are not the same thing (Difference: Heat v Temp, Difference Wiki, Heat and Heat v Temperature, Heat vs. Temperature).
II. Measurements of "Heat Content"
Scientists in China have stated that 2017 was the warmest ocean ever (2017 Sees Warmest Ocean on Record).
Some in the U.S. commentariat (The Warming Science Commentariat, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) evidently interpreted "warmest" in Chinese to mean "hottest" in English (Oceans During 2017 Were the Hottest on Record).
A commenter on that hot threat associated "heat content" with thermal expansion, an unfortunate but common misunderstanding (On Thermal Expansion & Thermal Contraction, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27).
In situ temperature (T), salinity (Sp), and pressure (P) measurements (not heat content) are the "coin of the realm" for computing thermal expansion (TEOS-10, The Layered Approach To Big Water - 3, On Thermal Expansion & Thermal Contraction - 16, Questionable "Scientific" Papers - 12).
In fact, the heat content is not necessary to know in order to calculate thermal expansion and/or contraction (The Art of Making Thermal Expansion Graphs).
The ARGO floats which the Chinese scientists used do not have a calorimeter on board with which to measure heat content (ARGO).
Those ARGO floats measure temperature and salinity: "At typically 10-day intervals, the floats pump fluid into an external bladder and rise to the surface over about 6 hours while measuring temperature and salinity" (ibid, emphasis added).
III. The Paper
The statement of Will Rogers ("All I know is just what I read in the papers") is not the full story, but ("All I know is just what I read in the papers, and that's an alibi for my ignorance") is the full story.
We can trust, but we must at some point also verify (The Pillars of Knowledge: Faith and Trust?).
So, when I read "the paper" (instead of simply trusting someone's interpretation of it), I took (among others) the following notes:
Title: "2017 was the Warmest Year on Record for the Global Ocean(Paper at Springer, p. 261-262, emphasis added). What this means is that they relied on data from about half of the ocean (median depth is about 3,688 meters) to determine their conclusion.
ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 34, MARCH 2018, 261–263 ..."
Authorship; "... according to an updated Institute of Atmospheric Physics, Chinese Academy of Sciences ... ocean analysis ..."
"The oceans in the upper 2000 m ..."
"The results support the provisional announcement by the World
Meteorological Organization in November 2017 that 'Global
ocean heat content in 2017 to date has been at or near record
high levels' ...”
"The IAP provides an observation-based ocean temperature analysis from the sea surface down to a depth of 2000 m, available from the year 1940 ..."
To me, that is insufficient to speak for the whole ocean, especially when the coldest portion was not measured (Questionable Scientific Papers, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16).
Denialists are always looking for chinks in our armor, which they call "climate porn" (Pole Dancing In The Lab).
We ought not to make it easy, or even easier, for them.
The previous post in this series is here.