密度跃层? 海中断崖? 掉深?

choi

My comment:
(1) It may be all bull_ _ _ _. Probably China and PLA endeavor to obfuscate the truth.
(2) I conduct relatively full research on the topic.It is almost certain that neither English nor Chinese (!) terms for the last two exist--and the Chinese terms for the last two appear only AFTER April, 2014 when China first talked about the so called submarine near-sink disaster.
(3) In Chinese language, there WAS 密度跃层 before April 2014. See the last posting.

choi

(a) 易成晨, 潜艇 ‘掉深’ 是怎么回事; 海水密度突变造成 ‘海中断崖.’ 中华解读第39期, Sept 4, 2014.
news.china.com/jiedu/20140904/
("如果海水跃层是上层密度大，下层密度小的状态，形成负密度梯度跃变层，海水浮力由上至下急剧减小，也就是 '海中断崖。' 潜艇在水下航行中，如突遭海中断崖，会立即失去浮力，急剧掉向海底，也就是俗称的 '掉深'")
(b) 关于中华网
www.china.com/zh_cn/general/about.html
("中华网股东为国广环球传媒控股有限公司。国广环球传媒控股有限公司（简称 ‘国广控股’ 或 ‘GMG’），系中国国际广播电台（CRI）与中国国际广播电视网络台（CIBN）传媒及文化产业全部可经营性资源的唯一运营平台")

In other words, it is owned by China’s government.

My comment: The report is full of crap.
(1) “1996年台海危机 * * * 美国派遣双航母舰队在台湾海峡炫耀武力。在我水下力量与美国航母捉迷藏和过招时”

The two US aircraft carriers were never at Taiwan Strait. Instead their locations were unknown. And China could not find them.

(2) USS Thresher had nothing to do with “跃变层引发的内波.”
(a) USS Thresher (SSN-593)
en.wikipedia.org/wiki/USS_Thresher_(SSN-593)
(Commissioned 1961; “Sank with all hands during deep diving tests, Apr 10 1963, 129 died”)

Quote:

“Deep-sea photography, recovered artifacts, and an evaluation of her design and operational history permitted a Court of Inquiry to conclude Thresher had probably suffered the failure of a salt-water piping system joint

“Submarines typically rely on speed and deck angle (angle of attack) rather than deballasting [release water from the ballast] to surface; they are propelled at an angle towards the surface. Ballast tanks were almost never blown at depth, and to do so could cause the sub to rocket to the surface out of control. Normal procedure was to drive the sub to periscope depth, raise the periscope to verify the area was clear, then blow the tanks and surface the sub.

(b) thresher shark
en.wikipedia.org/wiki/Thresher_shark

(3) INS Dakar
en.wikipedia.org/wiki/INS_Dakar

choi

(1) In Chinese language, there WAS 密度跃层 before April 2014. See, eg,
密度跃层. 百度百科, July 24, 2013.
baike.baidu.com/view/797183.htm

There is no need to read it, the takeaway being that for seawater (and actually all liquids and airs), the deeper the denser, which is natural--otherwise, the seawater will move around to eventually settle with the densest in the bottom.

(2) Seawater Properties that Control Density. Rhode Island College, undated.
www.ric.edu/faculty/PSCI103/Seawater/Seawater_notes.htm

Quote:

“The density increase with depth caused by the temperature decrease plays the greatest role in determining the density of a sample of water. Thus the increase in density due to the decreasing temperature with depth dominates over the salinity decrease and makes the deeper water more dense than surface water.  This means that in most regions the ocean is stable, that is, it will take energy to mix the ocean vertically.  This is not necessarily the situation in the polar regions[.]

“Sinking of surface water generally occurs where there is cold air to cool water at surface.  This situation found at high latitudes near the poles.  At these polar sites, surface waters cool and become dense enough to sink thousands of meters.  Sinking of surface waters is a very important mechanism to replenish waters in the ”deep sea‘ .

My comment: But 372 was not in Polar area or near the surface of the ocean. Rather the incident occurred “正在数百米深的大洋潜航.” 解放军报, Apr 9, 2014.

(3) Chapter 3 Physical Properties of Seawater, in Lynne Talley, George L Pickard, William J Emery and James H Swift, Descriptive Physical Oceanography; An introduction. Academic Press, 2011(appearing in the website of Physical Oceanography, UCSD)
www-pord.ucsd.edu/~ltalley/sio210/DPO/TALLEY_9780750645522_chapter3.pdf
(section 3.5.1 Effects of Temperature and Salinity on Density: "temperature dominates oceanic density variations for the most part. (As noted previously, an important exception is where surface waters are relatively fresh due to large precipitation or ice melt; that is, at high latitudes and also in the tropics beneath the rainy Intertropical Convergence Zone of the atmosphere)")

The exception does not apply to 372, either.

(4) Finally, 密度跃层 is “pycnocline” in English, though the concept has nothing to do with 跃 and everything to do with .层
(a) How is the pycnocline related to the thermocline and halocline?   Answers.com, undated
www.answers.com/Q/How_is_the_pyc ... cline_and_halocline
(Olivia Hoover answered: "A pycnocline is a type of ecocline (or ‘cline’ for short), just as thermocline and halocline are. An ecocline is where a series of biocommunities display a continuous gradient. A pycnocline is the difference in water density. A thermocline is the difference in water temperature. A halocline is the difference in water salinity")
(b) definitions
(i) cline (biology)
en.wikipedia.org/wiki/Cline_(biology)
(“an ecocline or simply cline (from Greek: κλίνω [klinein] ‘to possess or exhibit gradient, to lean’);”  The term was coined by the English evolutionary biologist Julian Huxley in 1938)
(ii) pykn- (combining form; variants: pykno-, pycn-, pycno- ): "close : compact : dense : bulky <pyknic>"
www.merriam-webster.com/medical/pykn-
(iii) hal- or halo- (combining form; Latin sāl, Greek hals): “salt”
www.merriam-webster.com/dictionary/hal-

(5) Eric Chassignet, Claudia Cenedese and Jacques Verron (eds), Buoyancy-Driven Flows. Cambridge University Press, 2012, at 253
books.google.com/books?id=sdYgAwAAQBAJ&pg=PA253&lpg=PA253&dq=buoyancy+Pycnocline&source=bl&ots=zsZKZFpH0k&sig=6UFiSesiwv1Cx4fk9IT7ZKjVydA&hl=en&sa=X&ei=5ywLVPXpHvPCsATjuoHoAw&ved=0CB4Q6AEwAA#v=onepage&q=buoyancy%20Pycnocline&f=false
(“Below the mixed layer, there is a transition layer of large vertical gradients of temperature (thermocline), salinity (halocline) and buoyancy (pycnocline) that separates the OBL [Ocean Boundary Layer] from the geostrophic ocean interior")