Robust warming of the global upper ocean

Lyman, John M.; Good, Simon; Gouretski, Viktor; Ishii, Masayoshi; Johnson, Gregory C.; Palmer, Matthew D.; Smith, Doug; Willis, Josh

doi:10.1038/nature09043

Cited by 340 publications

(317 citation statements)

References 25 publications

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“…A total change in heat content, top to bottom, is found (discussed below) of approximately 4 3 10 22 J in 19 yr for a net heating of 0.2 6 0.1 W m 22 , smaller than some published values (e.g., Hansen et al 2005, 0.6 6 0.1 W m 22 ; Lyman et al 2010, 0.63 6 0.28 W m 22 ; or von Schuckmann and Le Traon 2011, 0.55 6 0.1 W m 22 ; note that differing averaging periods were used), but indistinguishable from the summary Fig. 14 of Abraham et al (2013).…”

Section: A Framework: the State Estimatementioning

confidence: 64%

Bidecadal Thermal Changes in the Abyssal Ocean

Wunsch

Heimbach

2014

Journal of Physical Oceanography

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A dynamically consistent state estimate is used for the period 1992-2011 to describe the changes in oceanic temperatures and heat content, with an emphasis on determining the noise background in the abyssal (below 2000 m) depths. Interpretation requires close attention to the long memory of the deep ocean, implying that meteorological forcing of decades to thousands of years ago should still be producing trendlike changes in abyssal heat content. Much of the deep-ocean volume remained unobserved. At the present time, warming is seen in the deep western Atlantic and Southern Oceans, roughly consistent with those regions of the ocean expected to display the earliest responses to surface disturbances. Parts of the deeper ocean, below 3600 m, show cooling. Most of the variation in the abyssal Pacific Ocean is comparatively featureless, consistent with the slow, diffusive approach to a steady state expected there. In the global average, changes in heat content below 2000 m are roughly 10% of those inferred for the upper ocean over the 20-yr period. A useful global observing strategy for detecting future change has to be designed to account for the different time and spatial scales manifested in the observed changes. If the precision estimates of heat content change are independent of systematic errors, determining oceanic heat uptake values equivalent to 0.1 W m 22 is possibly attainable over future bidecadal periods.

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Section: A Framework: the State Estimatementioning

confidence: 64%

Bidecadal Thermal Changes in the Abyssal Ocean

Wunsch

Heimbach

2014

Journal of Physical Oceanography

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“…These bias corrections were used in addition to the common bias correction (Hanawa et al 1995) which is not time-varying. XBT biases are one of major sources of uncertainty in OHC estimation (Lyman et al 2010;Boyer et al 2016). Three time-varying bias corrections reduced the biases efficiently as reported by the above-listed literature.…”

Section: Uncertainties In Global Mean Temperaturesmentioning

confidence: 96%

“…Dense data coverage for the global oceans by the latest observation network is crucial in this approach. Only sampling errors in oceanographic observations are taken into account in evaluating the uncertainty after removing time-varying biases in expendable bathythermograph (Gouretski and Koltermann 2007;Lyman et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Accuracy of Global Upper Ocean Heat Content Estimation Expected from Present Observational Data Sets

Ishii¹,

Fukuda

Hirahara

et al. 2017

SOLA

Self Cite

144

153

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The simplest global mapping method and dense data coverage for the global oceans by the latest observation network ensure an estimate of global ocean heat content (OHC) within a satisfactory uncertainty for the last 60 years. The observational database conditionally presented a level high enough for practical use for the global OHC estimation when applying bias corrections of expendable bathythermograph, assuming that the other severe observational biases are not included in the database. Uncertainties in annual global mean temperatures averaged vertically from the surface to 1,500 m are within 0.01 K for the period from 1955 onward, when only sampling errors are taken into account. Those in annual mean global OHC of an improved objective analysis for 0−1,500 m depth is 16ZJ on average throughout the period. Compared to previous studies, the new objective analysis provides a higher estimation of the global 0−1,500 m OHC trend for a longer period from 1955 to 2015, which is an increase of 350 ± 57ZJ with a 95% confidence interval.(Citation: Ishii, M., Y. Fukuda, H. Hirahara, S. Yasui, T. Suzuki, and K. Sato, 2017: Accuracy of global upper ocean heat content estimation expected from present observational data sets.

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“…[40]), but not all (e.g., [41,42]), reported a sharp spike in ocean heat uptake in the early 2000s followed by a slowing of the rate of heat uptake (and thus ocean thermal expansion). Since then, Abraham et al [43] published a major review on the evolving observing system, the reduction of XBT biases, and estimates of heat content and thermosteric sea level trends over different periods, generally confirming the AR5 assessment of trends since 1971 and 1993.…”

Section: Sea Level Contributions Steric Sea Level Changementioning

confidence: 99%

Recent Progress in Understanding and Projecting Regional and Global Mean Sea Level Change

Clark

Church

Gregory

et al. 2015

Curr Clim Change Rep

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Considerable progress has been made in understanding the present and future regional and global sea level in the 2 years since the publication of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change. Here, we evaluate how the new results affect the AR5's assessment of (i) historical sea level rise, including attribution of that rise and implications for the sea level budget, (ii) projections of the components and of total global mean sea level (GMSL), and (iii) projections of regional variability and emergence of the anthropogenic signal. In each of these cases, new work largely provides additional evidence in support of the AR5 assessment, providing greater confidence in those findings. Recent analyses confirm the twentieth century sea level rise, with some analyses showing a slightly smaller rate before 1990 and some a slightly larger value than reported in the AR5. There is now more evidence of an acceleration in the rate of rise. Ongoing ocean heat uptake and associated thermal expansion have continued since 2000, and are consistent with ocean thermal expansion reported in the AR5. A significant amount of heat is being stored deeper in the water column, with a larger rate of heat uptake since 2000 compared to the previous decades and with the largest storage in the Southern Ocean. The first formal detection studies for ocean thermal expansion and glacier mass loss since the AR5 have confirmed the AR5 finding of a significant anthropogenic contribution to sea level rise over the last 50 years. New projections of glacier loss from two regions suggest smaller contributions to GMSL rise from these regions than in studies assessed by the AR5; additional regional studies are required to further assess whether there are broader implications of these results. Mass loss from the Greenland Ice Sheet, primarily as a result of increased surface melting, and from the Antarctic Ice Sheet, primarily as a result of increased ice discharge, has accelerated. The largest estimates of acceleration in mass loss from the two ice sheets for 2003-2013 equal or exceed the acceleration of GMSL rise calculated from the satellite altimeter sea level record over the longer period of 1993-2014. However, when increased mass gain in land water storage and parts of East Antarctica, and decreased mass loss from glaciers in Alaska and some other regions are taken into account, the net acceleration in the ocean mass gain is consistent with the satellite altimeter record. New studies suggest that a marine ice sheet instability (MISI) may have been initiated in parts of the West Antarctic Ice Sheet (WAIS), but that it will affect only a limited number of ice streams in the twenty-first century. New projections of mass loss from the Greenland and Antarctic Ice Sheets by 2100, including a contribution from parts of WAIS undergoing unstable retreat, suggest a contribution that falls largely within the likely range (i.e., two thirds probability) of the AR5. These new results increase confidence in the AR5 likel...

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Robust warming of the global upper ocean

Cited by 340 publications

References 25 publications

Bidecadal Thermal Changes in the Abyssal Ocean

Bidecadal Thermal Changes in the Abyssal Ocean

Accuracy of Global Upper Ocean Heat Content Estimation Expected from Present Observational Data Sets

Recent Progress in Understanding and Projecting Regional and Global Mean Sea Level Change

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