@article{fdi:010070868,
  title = {{O}cean heat content variability and change in an ensemble of ocean reanalyses},
  author = {{P}almer, {M}. {D}. and {R}oberts, {C}. {D}. and {B}almaseda, {M}. and {C}hang, {Y}. {S}. and {C}hepurin, {G}. and {F}erry, {N}. and {F}ujii, {Y}. and {G}ood, {S}. {A}. and {G}uinehut, {S}. and {H}aines, {K}. and {H}ernandez, {F}abrice and {K}ohl, {A}. and {L}ee, {T}. and {M}artin, {M}. {J}. and {M}asina, {S}. and {M}asuda, {S}. and {P}eterson, {K}. {A}. and {S}torto, {A}. and {T}oyoda, {T}. and {V}aldivieso, {M}. and {V}ernieres, {G}. and {W}ang, {O}. and {X}ue, {Y}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}ccurate knowledge of the location and magnitude of ocean heat content ({OHC}) variability and change is essential for understanding the processes that govern decadal variations in surface temperature, quantifying changes in the planetary energy budget, and developing constraints on the transient climate response to external forcings. {W}e present an overview of the temporal and spatial characteristics of {OHC} variability and change as represented by an ensemble of dynamical and statistical ocean reanalyses ({ORA}s). {S}patial maps of the 0-300 m layer show large regions of the {P}acific and {I}ndian {O}ceans where the interannual variability of the ensemble mean exceeds ensemble spread, indicating that {OHC} variations are well-constrained by the available observations over the period 1993-2009. {A}t deeper levels, the {ORA}s are less well-constrained by observations with the largest differences across the ensemble mostly associated with areas of high eddy kinetic energy, such as the {S}outhern {O}cean and boundary current regions. {S}patial patterns of {OHC} change for the period 1997-2009 show good agreement in the upper 300 m and are characterized by a strong dipole pattern in the {P}acific {O}cean. {T}here is less agreement in the patterns of change at deeper levels, potentially linked to differences in the representation of ocean dynamics, such as water mass formation processes. {H}owever, the {A}tlantic and {S}outhern {O}ceans are regions in which many {ORA}s show widespread warming below 700 m over the period 1997-2009. {A}nnual time series of global and hemispheric {OHC} change for 0-700 m show the largest spread for the data sparse {S}outhern {H}emisphere and a number of {ORA}s seem to be subject to large initialization 'shock' over the first few years. {I}n agreement with previous studies, a number of {ORA}s exhibit enhanced ocean heat uptake below 300 and 700 m during the mid-1990s or early 2000s. {T}he {ORA} ensemble mean (+/- 1 standard deviation) of rolling 5-year trends in full-depth {OHC} shows a relatively steady heat uptake of approximately 0.9 +/- 0.8 {W} m(-2) (expressed relative to {E}arth's surface area) between 1995 and 2002, which reduces to about 0.2 +/- 0.6 {W} m(-2) between 2004 and 2006, in qualitative agreement with recent analysis of {E}arth's energy imbalance. {T}here is a marked reduction in the ensemble spread of {OHC} trends below 300 m as the {A}rgo profiling float observations become available in the early 2000s. {I}n general, we suggest that {ORA}s should be treated with caution when employed to understand past ocean warming trends-especially when considering the deeper ocean where there is little in the way of observational constraints. {T}he current work emphasizes the need to better observe the deep ocean, both for providing observational constraints for future ocean state estimation efforts and also to develop improved models and data assimilation methods.},
  keywords = {{H}eat content ; {T}emperature ; {V}ariability ; {C}limate change ; {G}lobal warming ; {E}nergy budget ; {O}cean reanalyses ; {O}cean state estimation ; {O}cean models ; {I}nter comparison ; {O}cean ; {O}bservations ; {D}ata assimilation ; {MONDE}},
  booktitle = {{O}cean estimation from an ensemble of global ocean reanalyses, consisting of papers from the {O}cean {R}eanalyses {I}ntercomparison {P}roject ({ORAIP})},
  journal = {{C}limate {D}ynamics},
  volume = {49},
  numero = {3 ({N}o sp{\'e}cial)},
  pages = {909--930},
  ISSN = {0930-7575},
  year = {2017},
  DOI = {10.1007/s00382-015-2801-0},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070868},
}