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EARTH’S WARMING OCEANS

Posted on: December 14, 2020

Oceans Are Warming Up Much Faster Than Previously Thought - Yale E360

THIS POST IS A CRITICAL REVIEW OF AN ARTICLE IN THE REVELATOR ON “EARTH’S WARMING OCEANS” LINK TO SOURCE ARTICLE: https://therevelator.org/ocean-climate-change/

ocean warming graphic

PART-1: WHAT THE SOURCE ARTICLE SAYS

Climate change has caused record-breaking ocean temperatures, and that means more dangerous storms, trouble for coral reefs and big changes for our marine ecosystems. Part of Joellen Russell’s job is to help illuminate the deep darkness — to shine a light on what’s happening beneath the surface of the ocean. And it’s one of the most important jobs in the world right now. Russell is a professor of biogeochemical dynamics at the University of Arizona. From that dry, landlocked state, she’s become a leading expert on how the climate is changing in the Southern Ocean — those vast, dark waters swirling around Antarctica. “This is an age of scientific discovery,” she says. But also, “it’s very scary what we’re finding out.”

Joellen | Leadership Programs
Joellen Russell

Researchers like Russell have been ringing alarm bells in report after report warning that the world’s ocean waters are dangerously warming. Most of the heat trapped by the greenhouse gas emissions we’ve spewed into the air for decades has actually been absorbed by the ocean. Over the past 25 years, that heat amounts to the equivalent of exploding 3.6 billion Hiroshima-sized atom bombs, according to Lijing Cheng of the Chinese Academy of Sciences and lead author of a new study on ocean warming. Now we’re beginning to witness the cascading repercussions of that oceanic warming — from supercharged storms to dying coral reefs to crashing fisheries.

There’s still a lot left to learn about these problems, but here’s a look at some of the top findings from researchers, along with what they hope to uncover next. (1) Yes, It’s Definitely Getting Warmer
There’s no doubt among scientists that the ocean is heating and we’re driving it. Ocean heating is irrefutable and a key measure of the Earth’s energy imbalance. (2) Ocean waters in 2019 were the warmest in recorded history. And that follows a pattern: The past decade has also seen the warmest 10 years of ocean temperatures, and the last five years have been the five warmest on record. Every year the ocean waters get warmer, and the reason is that the heat-trapping gases that humans have emitted into the atmosphere,” says John Abraham, the study’s coauthor and professor in mechanical engineering at the University of St. Thomas. “It’s concerning for sure.” (3) The Southern Ocean Has Been Hit Worst. Much of this warming occurs between the surface and a depth of 6,500 feet. It’s happening pretty consistently across the globe, but some areas have experienced higher rates of warming. One of those is the Southern Ocean, which has acted as a giant sink, absorbing 43% of our oceanic CO2 emissions and 75% of the heat. (4) That’s because the ocean basin functions like an air conditioner for the planet. Strong winds pull up cold water from deep below, and then the cold surface water takes up some heat from the air. When the winds slow, the water sinks, more cold water rises, and the process repeats. The sinking water isn’t warm, per se, just a bit warmer than it was when the wind pulled it up. In this way the Southern Ocean can sequester a lot of heat well below the surface. For that reason what happens in the Southern Ocean is globally important. And it makes new findings all the more concerning. (5) Antarctic Waterfall. Normal upwelling of waters from deep in the Southern Ocean has traditionally brought nutrients to the surface, where they then get moved by the Antarctic Circumpolar Current, the world’s strongest ocean current, to feed marine life in other areas. But new research shows that this process will be disrupted as warm waters cause the Southern Ocean’s ice sheets to melt even faster. This will change the historical upwelling and could trap nutrients instead of pushing them out. That will begin to starve the global ocean of nutrients. (6) One of the most obvious results of ocean warming is higher sea levels. That’s caused in part because water expands as it warms and also because of the effect on sea ice. The warmer the water gets, the more sea ice melts as is happening in Antarctica. Not surprisingly rates of global sea-level rise are accelerating. This means more property damage, storm surges, and waves lapping at the heels of our coastal communities. (7) Warmer waters also mean more supercharged storms. An increase in heat drives up evaporation and adds extra moisture to the atmosphere, causing heavy rains, more flooding and more extreme weather events as seen in the aftermath of Cyclone Idai, one of the deadliest storms in history, in Mozambique, March 2019. In some places it can make drier conditions worse, too. When air rises and cools below the dew point, it turns into clouds or precipitation but in places like Arizona or Australia, where rain is generally formed when air is pushed upward over mountains, the warmer atmosphere might not be cold enough to cause rain so that a warmer atmosphere carrying more moisture might actually rain less and contribute to drought and wildfires. (8) The warming ocean is one of the key reasons why the Earth has experienced increasing catastrophic fires in the Amazon, California, and Australia in 2019 and 2020. (9) Warming ocean waters contribute to the rise of colonies of algae that can produce toxins deadly to wildlife and sometimes people. These harmful algal blooms pose a problem even way up in the Gulf of Alaska, where the annual algae season has gotten longer due to warmer water. Algal blooms are seen along the coast of the Bering Sea where water temperatures have historically been too cold for the blooms to occur. Now the water temperatures are warm enough to create harmful algal blooms. Toxins from the blooms can even show up in some marine mammals. (10) Marine Heat Waves are getting worse as the ocean warms. These heatwaves, which can be fatal to sea creatures, will continue to get more severe and more frequent as the ocean warms. By the end of the century, some areas may be in a permanent heatwave. That’s likely to be bad news for everything from seaweed to birds to mammals, and it could result in fundamental changes for food webs and the animals and coastal economies that depend on those resources. (11) Ocean warming may lead to irreversible loss of species or foundation habitats, such as seagrass, coral reefs and kelp forests. These changes likely aren’t far off. Marine heatwaves will emerge as forceful agents of disturbance to marine ecosystems in the near-future. We’re already seeing what that would look like. Marine heatwaves off Australia have spurred oyster die-offs and losses to the abalone fishery, and bleaching of the biodiverse Great Barrier Reef, triggering mass coral deaths. (12) The Blob, a mass of warm water that persisted off the Pacific Coast from California to Alaska from 2014 to 2016, led to the starvation of an estimated 1 million common murres a normally resilient seabird. The warm waters likely reduced and changed phytoplankton communities, an essential part of the marine food web. The warm waters of the Blob also increased the metabolism and the appetite of big fish like pollock and salmon. That demand spike crashed populations of forage fish that murres usually find plentiful. Tufted puffins, Cassin’s auklets, sea lions and baleen whales also suffered losses, although the murres were hit worst. A prolonged marine heatwave off the coast of Alaska led to the closure of region’s commercial Pacific cod fishery for 2020, the first time that’s ever happened. When you cancel whole fisheries, that really impacts people’s lives and livelihoods. (13) What We Don’t Know: We don’t know how warming will affect myriad species in the sea, the weather patterns, and coastal economies. One current line of research is to better understand how ocean warming affects weather. We know that a warmer ocean means more water evaporates into the atmosphere and makes the weather more severe because humidity drives storms but we don’t know how bad that will be.

mhw-gif
MARINE HEAT WAVES
MHW-SST-GIF
SST TRENDS

PART-2: CRITICAL COMMENTARY

{NOTE: This section refers to “RELATED POSTS” on this site. The links to these posts are listed below. It also refers to a bibliography on the subject of ocean heating. The bibliography appears below the list of related posts.}

In related post RP#1 we show observed complex temperature patterns and trends in the data for ocean heat content are not consistent with a uniform atmospheric source for the heat. Specifically we find certain peculiarities of the Pacific and of the differences between the hemispheres. In the case of the Pacific the steady and sustained upward trend in OHC at 2000M is not found in the 700M data where no trend is evident until the 1990’s. This pattern is not consistent with an atmospheric source of the heat that is causing ocean warming. We also note that the sustained warming at a steady rate seen at 2000M is not found in the data for 700 meters where we see violent and unsynchronized swings of cooling and warming periods with North cooling while the South warms and vice versa. This disconnect between North and South and between the deep and shallow notwithstanding, the data still indicate rising Ocean Heat Content (OHC) for both the Northern and Southern segments in the Atlantic and Pacific Oceans. But a very different pattern is seen in the Indian Ocean where the whole of the gain in OHC at either depth derives from warming in the South with no trend seen in the OHC of the North. The non-uniformity patterns in the data for the warming of the ocean implies that the ocean itself must play the major if not exclusive role in creating ocean heat content. The interpretation of ocean heat content exclusively in the context of the atmospheric science is not credible under these circumstances. The data suggest that the ocean’s own vast sources of heat must also be taken into consideration for an unbiased understanding of of ocean heat content. The relevant bibliography provided below provides additional support for this view. Significant evidence is presented in these papers for a significant if not overwhelming role for the ocean itself in the creation of ocean heat content. Moreover, the observed patterns and dynamics in the ocean heat content data are more consistent with oceanic sources of heat than with an atmospheric source.

In related post RP#2 we present the data for marine heat waves (MHW) along with long term SST trends. Although SST is fairly uniform at any given time out in the open sea, anomalous SST is seen in ENSO events at specific locations where ENSO SST anomalies are known to occur; and similarly in the Indian Ocean Dipole. In addition to those SST anomalies in the open sea, MHW SST anomalies are also found in shallow waters near land and along continental shelves. These SST anomalies are thought to be related to shallowness and proximity to land as seen in the bibliography below. In these SST anomalies there can be significant departures from the mean ocean SST in both directions – hotter than average (marine heat wave or MHW) and colder than average (marine cold wave (MCW). See for example, Schlegel (2017) in the bibliography below. The warmer than average anomalous SST “hotspots” can persist and hang around for days and even weeks. As a rule, these SST anomalies are classified as MHW only if they persist for at least 5 days. It is generally agreed that since these anomalies tend to occur in proximity to land that proximity to land may be a factor in the creation of these anomalies. Another location oddity of the MHW is that their location is not random but that they tend to be found in the same location over and over. The video display of MHW above shows their location and intensity over time. MHW locations are marked with color coded markers from yellow through orange, red, dark red, brown, and black. Intensity is proportional to the darkness of the color code of the MHW location – the darker the more intense. These data do not include cold waves. As the video steps through time one month at a time we find that hardly any MWH lasts longer than a month except for those in the extreme North-East of Canada and in Northwest Greenland where a small cluster of MHW appears to persist for longer time periods. Also in the video, we see that the MHW locations month to month are not random but that MHW tends to recur in the same location over and over and at similar intensities. This behavior may imply that MHW is location specific. An apparent oddity of the spatial pattern of MHW events in this video is that most MHW SST anomalies tend to occur in polar regions both north and south. This pattern is stronger in the more intense SST anomalies.
We find in this video and in the bibliography below, that locations of SST anomalies described as Marine Heat Waves do not follow a pattern that would imply a uniform atmospheric cause. Significantly, not all papers in the bibliography claim a uniform atmospheric cause although most eventually make a connection to AGW climate change. An oddity is that though the REVELATOR article presents MHW as a climate change horror in terms of irreversible climate change and the end of the ocean as we know it, and that “all the coral will die” etc, the bibliography does not. There are of course some impacts on ocean ecosystems in the MHW regions and these are described in the bibliography but they are localized and limited in time span. It is also of note than many of the papers ascribe these MHW events to known natural cyclical and localized temperature events such as the Indian Ocean Dipole and ENSO events. To that we should also add geological activity as a possible driver of these events because they are localized both in time and place, because they recur in the same location, and because of their prevalence in the geologically active polar regions in both the Arctic and the Antarctic.
It is highly unlikely that these events can be related to AGW climate change particularly so in the context of the Internal Climate Variability issue described in RP#6. No evidence is provided for that attribution.

Distribution_of_hydrothermal_vent_fields
HYDROTHERMAL VENT LOCATIONS

RP#3: THE BLOB: In the REVELATOR article the Blob is understood in terms of global warming and ocean heat content driven by global warming. In the related post we show that as in ocean heat content, these attributions have been made without due consideration of the oceanic geology and geothermal heat sources. The geologically active region known as the Pacific Ocean Ring of Fire contains 75% of the world’s active volcanoes. As such this region contains significant geothermal heat sources to create not only the two monster El Nino warming events in 1998 and 2016 but also the so called “Northern Pacific Blob”, a large mass of water that is warmer than the surrounding water (shown in red in the charts below). There is no long term trend or structure in the blob. Its formation and disappearance are events. In RP#3 we show that these events coincide with significant geological activity that can explain these localized and random events better than global warming. The REVELATOR paper presents no evidence to relate the blob to AGW climate change but simply assumes that relationship. In RP#3 we show that the the more rational geological explanation of the blob makes it imperative that the claim of AGW causation can only be made with significant evidence. This causation cannot be assumed as the Revelator has done.

blob

RP#4: IS AGW WARMING THE DEEP OCEAN? In the related post a Phys.Org article claims that at shallower depths temperatures fluctuated roughly monthly by up to a degree Celsius but in the deeper ocean temperature fluctuations were minute, but changes followed an annual pattern, indicating seasons still have a measurable impact far below the ocean surface. The average temperature at all four locations went up over the course of the decade, but the increase of about 0.02 degrees Celsius per decade was statistically significant at depths of over 4,500 meters. The authors claim that these results show that the temperature of the deep ocean are therefore atmosphere driven by AGW climate change. We argue however, that the geographical location of the data is close to Antarctica and it is generally recognized that the the Antarctic Ocean is subject to significant geothermal heat that plays a role in the ice melt events and also explains the relative warmth of the Deep Circumpolar Current in that region. The South Atlantic and specifically the Argentine Basin where these data were taken is located immediately north of this geologically active area and it is known to be geologically active such that the observed abyssal warming of 0.02 to 0.04C over a decade can be explained as a geological event. A relevant bibliography is provided below that supports this evaluation. The additional consideration is that a brief decadal warming event in the geographically limited region of the Argentine Basin of the Southwest Atlantic must be understood as an internal described in RP#6 below. The temperature variability described does not have an interpretation in terms of anthropogenic global warming and climate change. That theory relates to long term trends in global mean temperature and not to temperature events particularly so when they are geographically and time scale constrained. It is not possible to understand the localized decadal warming event in a geologically active region in terms of anthropogenic global warming. A relevant bibliography is provided in related post RP#4.

Climate change and the ocean

CONCLUSION: THE REVELATOR ARTICLE ON OCEAN HEAT CONTENT INCLUDES THE UNSUPPORTED ASSUMPTION THAT ALL DEEP OCEAN TEMPERATURE CHANGES FOUND CAN BE ATTRIBUTED TO AGW CLIMATE CHANGE BUT NO EVIDENCE IS PROVIDED FOR THAT ATTRIBUTION. IN RESPONSE WE HAVE PROVIDED SIGNIFICANT EVIDENCE AND REFERENCES AGAINST SUCH AN ASSUMPTION.

THE ATMOSPHERE AND THE OCEAN TOGETHER WEIGH 1.36E18 METRIC TONNES OF WHICH THE OCEAN IS 99.62% AND THE ATMOSPHERE 0.38%. .

LIST OF RELATED POSTS (RP)

RP#1: OCEAN HEAT CONTENT DATA AND PATTERNS: https://tambonthongchai.com/2018/10/06/ohc/

RP#2: MARINE HEAT WAVES: https://tambonthongchai.com/2020/01/30/ohw/

RP#3: THE BLOB: https://tambonthongchai.com/2020/03/14/atmosphere-bias/

RP#4: AGW IS WARMING THE DEEP OCEAN: https://tambonthongchai.com/2020/10/14/climate-change-is-warming-the-deep-ocean/

RP#5: WARMING OF THE SOUTHERN CIRCUMPOLAR CURRENT: https://tambonthongchai.com/2020/08/11/the-ice-shelves-of-antarctica/

RP#6: THE INTERNAL CLIMATE VARIABILITY ISSUE IN CLIMATE SCIENCE: https://tambonthongchai.com/2020/07/16/the-internal-variability-issue/

New Marine Heatwave Emerges off West Coast, Resembles "the Blob" | NOAA  Fisheries

THE RELEVANT BIBLIOGRAPHY OCEAN HEAT CONTENT

  1. Johnson, Gregory C., et al. “Deep Argo quantifies bottom water warming rates in the southwest Pacific Basin.” Geophysical Research Letters 46.5 (2019): 2662-2669. Data reported from mid‐2014 to late 2018 by a regional pilot array of Deep Argo floats in the Southwest Pacific Basin are used to estimate regional temperature anomalies from a long‐term climatology as well as regional trends over the 4.4 years of float data as a function of pressure. The data show warm anomalies that increase with increasing pressure from effectively 0 near 2,000 dbar to over 10 (±1) m°C by 4,800 dbar, uncertainties estimated at 5–95%. The 4.4‐year trend estimate shows warming at an average rate of 3 (±1) m°C/year from 5,000 to 5,600 dbar, in the near‐homogeneous layer of cold, dense bottom water of Antarctic origin. These results suggest acceleration of previously reported long‐term warming trends in the abyssal waters in this region. They also demonstrate the ability of Deep Argo to quantify changes in the deep ocean in near real‐time over short periods with high accuracy.
  2. Thomson, Richard E., Earl E. Davis, and Brenda J. Burd. “Hydrothermal venting and geothermal heating in Cascadia Basin.” Journal of Geophysical Research: Solid Earth 100.B4 (1995): 6121-6141. Observations in Cascadia Basin on the eastern flank of the northern Juan de Fuca Ridge reveal significant bottom water modification as a result of regional conductive heating and local hydrothermal venting. Seafloor conductive heating occurs throughout the sedimented basin while hydrothermal fluid discharge is confined to small (∼1 km2) isolated igneous basement outcrops. In the northern sector of the plateaulike basin, the vertical fluxes of heat and mass associated with these seafloor processes lead to the formation of a 250‐ to 350‐m‐thick “geothermal boundary layer” characterized by anomalously high temperature, reduced vertical stability, and high dissolved silicate concentration. Using a basinwide average lithospheric heat flux of 0.3 W m−2 and the observed thermal anomaly structure of the water column, we obtain a mean residence time of 1 to 2 years for the deep water over Cascadia Basin. Detailed water property data collected in 1992 and 1993 within the immediate vicinity of three isolated igneous basement outcrops in the north‐central sector of the basin indicate that local bottom‐water heating arises from low‐temperature venting through the summit and flanks of the outcrops. Near the smallest edifice, especially well‐defined layers of anomalously warm, particle‐laden water were found within ±20 m of the outcrop summit depth of 2610 m. Maximum anomalies of temperature, light attenuation coefficient, and dissolved silicate concentration in the layers were 0.040°C, 0.015 m−1, and 5 μmol L−1, respectively. We estimate the local heat flux, Fo′ from the smallest outcrop to be (2.4±0.8)U × 109 W, where U (m s−1) is the mean horizontal current at the venting depth. For reasonable mean currents in the range 10−3 to 10−2 m s−1, we find Fo′ ≈ 0.2 to 2.4 × 107 W. Assuming that the depressed conductive heat flow of −0.05 W m−2 observed through the sedimented seafloor surrounding the smallest outcrop reflects the advective loss of heat through the outcrop, the radial distance over which crustal fluids must collect heat and converge on the outcrop is about 10 km.
  3. Purkey, Sarah G., et al. “Unabated bottom water warming and freshening in the South Pacific Ocean.” Journal of Geophysical Research: Oceans 124.3 (2019): 1778-1794. Abyssal ocean warming contributed substantially to anthropogenic ocean heat uptake and global sea level rise between 1990 and 2010. In the 2010s, several hydrographic sections crossing the South Pacific Ocean were occupied for a third or fourth time since the 1990s, allowing for an assessment of the decadal variability in the local abyssal ocean properties among the 1990s, 2000s, and 2010s. These observations from three decades reveal steady to accelerated bottom water warming since the 1990s. Strong abyssal (z > 4,000 m) warming of 3.5 (±1.4) m°C/year (m°C = 10−3 °C) is observed in the Ross Sea, directly downstream from bottom water formation sites, with warming rates of 2.5 (±0.4) m°C/year to the east in the Amundsen‐Bellingshausen Basin and 1.3 (±0.2) m°C/year to the north in the Southwest Pacific Basin, all associated with a bottom‐intensified descent of the deepest isotherms. Warming is consistently found across all sections and their occupations within each basin, demonstrating that the abyssal warming is monotonic, basin‐wide, and multidecadal. In addition, bottom water freshening was strongest in the Ross Sea, with smaller amplitude in the Amundsen‐Bellingshausen Basin in the 2000s, but is discernible in portions of the Southwest Pacific Basin by the 2010s. These results indicate that bottom water freshening, stemming from strong freshening of Ross Shelf Waters, is being advected along deep isopycnals and mixed into deep basins, albeit on longer timescales than the dynamically driven, wave‐propagated warming signal. We quantify the contribution of the warming to local sea level and heat budgets.
  4. Speer, Kevin G. “The Stommel and Arons model and geothermal heating in the South Pacific.” Earth and planetary science letters 95.3-4 (1989): 359-366. The model of Joyce and Speer (1987) [2] for the large-scale influence of a geothermal heat source in an ocean basin is applied to the South Pacific, taking into account observed isopycnal depth variations and tracer distributions. These observations are used with the model to estimate the required geothermal heating and strength of the background Stommel and Arons flow. Both heating and background flow are necessary in the model for agreement with observations.
  5. Joyce, Terrence M., Bruce A. Warren, and Lynne D. Talley. “The geothermal heating of the abyssal subarctic Pacific Ocean.” Deep Sea Research Part A. Oceanographic Research Papers 33.8 (1986): 1003-1015. Recent deep CTD-O2 measurements in the abyssal North Pacific along 175°W, 152°W, and 47°N indicate large-scale changes in the O-S characteristics in the deepest kilometer of the water column. Geothermal heat flux from the abyssal sediments can be invoked as the agent for causing large-scale modification of abyssal temperatures (but not salinities) in the subarctic Pacific Ocean. East-west and north-south thermal age differences of about 100 years are inferred using a spatially uniform geothermal heat flux of 5 x 10-2 WrmW m-2.
  6. Adcroft, Alistair, Jeffery R. Scott, and Jochem Marotzke. “Impact of geothermal heating on the global ocean circulation.” Geophysical Research Letters 28.9 (2001): 1735-1738. The response of a global circulation model to a uniform geothermal heat flux of 50 mW m−2 through the sea floor is examined. If the geothermal heat input were transported upward purely by diffusion, the deep ocean would warm by 1.2°C. However, geothermal heating induces a substantial change in the deep circulation which is larger than previously assumed and subsequently the warming of the deep ocean is only a quarter of that suggested by the diffusive limit. The numerical ocean model responds most strongly in the Indo‐Pacific with an increase in meridional overturning of 1.8 Sv, enhancing the existing overturning by approximately 25%.
  7. Zilberman, N. V., D. H. Roemmich, and S. T. Gille. “The East Pacific Rise current: Topographic enhancement of the interior flow in the South Pacific Ocean.” Geophysical Research Letters 44.1 (2017): 277-285. Observations of absolute velocity based on Argo float profiles and trajectories in the ocean interior show evidence for an equatorward current, the East Pacific Rise current, between 42°S and 30°S, along the western flank of the East Pacific Rise. The East Pacific Rise current carries predominantly intermediate water masses, including Subantarctic Mode Water and Antarctic Intermediate Water, and deeper waters, from the southern edge of the subtropical gyre toward the Equator. The 2004 to 2014 mean East Pacific Rise current transport extrapolated through the 0–2600 m depth range is 8.1 ± 1.6 sverdrup (Sv) (1 Sv = 106 m3 s−1), consistent with a wind‐driven interior transport influenced by the East Pacific Rise topography. While deep ocean mixing and geothermal heating can both create pressure gradients that support geostrophic flows in the deep ocean, this study indicates that about half of the East Pacific Rise current transport is associated with topographic steering of the deep flow over the East Pacific Rise.
  8. Scott, Jeffery R., Jochem Marotzke, and Alistair Adcroft. “Geothermal heating and its influence on the meridional overturning circulation.” Journal of Geophysical Research: Oceans 106.C12 (2001): 31141-31154. The effect of geothermal heating on the meridional overturning circulation is examined using an idealized, coarse‐resolution ocean general circulation model. This heating is parameterized as a spatially uniform heat flux of 50 m W m−2 through the (flat) ocean floor, in contrast with previous studies that have considered regional circulation changes caused by an isolated hot spot or a series of plumes along the Mid‐Atlantic Ridge. In our model results the equilibrated response is largely advective: a deep perturbation of the meridional overturning cell on the order of several sverdrups is produced, connecting with an upper level circulation at high latitudes, allowing the additional heat to be released to the atmosphere. Rising motion in the perturbation deep cell is concentrated near the equator. The upward penetration of this cell is limited by the thermocline, analogous to the role of the stratosphere in limiting the upward penetration of convective plumes in the atmosphere. The magnitude of the advective response is inversely proportional to the deep stratification; with a weaker background meridional overturning circulation and a less stratified abyss the overturning maximum of the perturbation deep cell is increased. This advective response also cools the low‐latitude thermocline. The qualitative behavior is similar in both a single‐hemisphere and a double‐hemisphere configuration. In summary, the anomalous circulation driven by geothermal fluxes is more substantial than previously thought. We are able to understand the structure and strength of the response in the idealized geometry and further extend these ideas to explain the results of Adcroft et al. [2001], where the impact of geothermal heating was examined using a global configuration.
  9. Liang, Xinfeng, et al. “Vertical redistribution of oceanic heat content.” Journal of Climate 28.9 (2015): 3821-3833. Estimated values of recent oceanic heat uptake are on the order of a few tenths of a W m−2, and are a very small residual of air–sea exchanges, with annual average regional magnitudes of hundreds of W m−2. Using a dynamically consistent state estimate, the redistribution of heat within the ocean is calculated over a 20-yr period. The 20-yr mean vertical heat flux shows strong variations in both the lateral and vertical directions, consistent with the ocean being a dynamically active and spatially complex heat exchanger. Between mixing and advection, the two processes determining the vertical heat transport in the deep ocean, advection plays a more important role in setting the spatial patterns of vertical heat exchange and its temporal variations. The global integral of vertical heat flux shows an upward heat transport in the deep ocean, suggesting a cooling trend in the deep ocean. These results support an inference that the near-surface thermal properties of the ocean are a consequence, at least in part, of internal redistributions of heat, some of which must reflect water that has undergone long trajectories since last exposure to the atmosphere. The small residual heat exchange with the atmosphere today is unlikely to represent the interaction with an ocean that was in thermal equilibrium at the start of global warming. An analogy is drawn with carbon-14 “reservoir ages,” which range from over hundreds to a thousand years.

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  • chaamjamal: Thanks. A specific issue in climate science is correlation between time series data where spurious correlations are the creations of shared trends, s
  • Jack Broughton: I remember a paper published in the 1970s by Peter Rowe of UCL in which he showed how even random numbers can be processed to seem to correlate by usi
  • chaamjamal: https://tambonthongchai.com/2020/10/09/a-data-selection-bias/
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