Tendencies, variability and persistence of sea surface temperature anomalies

In the paper

“Changes in the AMV are coupled with the North Atlantic Oscillation and Atlantic Meridional Overturning Circulation (AMOC), with a positive phase of the AMV associated with warmer SSTs30.”

What the sources say

• Supported

  The AMV MECHANISMS section describes interactions among the NAO, AMOC, and AMV. The figure description in CONCLUDING REMARKS identifies warmer SSTs with positive AMV. Page numbers are not provided in the supplied passages. (LLM, conf=0.94)

  cites [30] Sutton, R. T. et al. Atlantic Multidecadal Variability and the UK ACSIS Program. BAMS 415–425 (2018). source

In the paper

“In turn, ENSO state influences SSTA persistence in the Indian Ocean, where SSTA variability is comparatively small7.”

What the sources say

• Partly supported

  The Summary (page unavailable) reports that SSTA persistence barriers in parts of the tropical Indian Ocean weaken or disappear during weak or normal ENSO conditions, supporting the claim that ENSO state influences persistence. The paper does not establish that Indian Ocean SSTA variability is comparatively small overall; Section 3 (page unavailable) describes very small anomalies only for normal ENSO cases. (LLM, conf=0.85)

  cites [7] Ding, R. & Li, J. Influences of ENSO Teleconnection on the Persistence of Sea Surface Temperature in the Tropical Indian Ocean. Journal of Climate 25, 8177–8195 (2012). sourceExperimental — accuracy not yet measured

In the paper

“The North-East Pacific between 45–55 N and 130–150 W is of interest due to the significant warm anomaly in the SST seen between 2014–2016, which had impacts on fisheries and regional weather32.”

What the sources say

• Partly supported

  The Abstract says the anomaly affected downwind air temperatures in Washington state, and Biological Impacts describes unusual salmon movements and tuna catches in 2014. The Introduction reports anomalously warm SSTs persisting through March 2015; this paper does not establish the claimed 2014–2016 span. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  cites [32] Bond, N. A., Cronin, M. F., Freeland, H. & Mantua, N. Causes and impacts of the 2014 warm anomaly in the NE Pacific. Geophysical Research Letters 3414–3420 (2015). sourceExperimental — accuracy not yet measured

In the paper

“Western boundary currents (WBCs) are turbulent areas of water characterised by strong ocean-atmosphere interaction, poleward heat transport and ocean-atmosphere heat exchange20.”

What the sources say

• Supported

  The Introduction describes exceptionally strong atmosphere–ocean interaction over western boundary currents and their extensions. It also describes poleward ocean heat transport and heat transfer to the atmosphere concentrated near these currents; the Abstract identifies mesoscale eddies as important in these regions, consistent with the description of turbulent waters. (LLM, conf=0.90)

  cites [20] Kwon, Y.-O. et al. Role of the Gulf Stream and Kuroshio-Oyashio Systems in Large-Scale Atmosphere-Ocean Interaction: A Review. Journal of Climate 23, 3249–3281 (2010). source

In the paper

“Winter SST anomalies persist at depth during the summer months below the shallow mixed layer, reemerging in the SSTA the following winter as the summer seasonal thermocline is eroded.”

What the sources say

• ?Not checked — no full text of the sourcecites [9] Byju, P., Dommenget, D. & Alexander, M. A. Widespread reemergence of sea surface temperature anomalies in the global oceans, including tropical regions forced by reemerging winds. Geophysical Research Letters, https://doi.org/10.1029/2018GL079137 7683–7691 (2018). source
• Supported

  Section 3 ([12]) describes anomalous water formed in the deep winter mixed layer being capped by the shallow seasonal thermocline during the warming season, then entrained as the mixed layer deepens in the next cooling season. Section 4 ([13]) reports that winter SST anomalies reemerge the next winter in several regions, although in two others they reemerge in early fall and are subsequently refreshed. (LLM, conf=0.91)

  cites [10] Hanawa, K. & Sugimoto, S. ‘Reemergence’ areas of winter sea surface temperature anomalies in the world’s oceans. Geophysical Research Letters 31, https://doi.org/10.1029/2004GL019904 (2004). source
• ?Not checked — no full text of the sourcecites [11] Alexander, M. A. & Deser, C. A Mechanism for the Recurrence of Wintertime Midlatitude SST anomalies. Journal of Physical Oceanography 25, 122–135 (1994). source
• ?Not checked — no full text of the sourcecites [12] Alexander, M. A., Timlin, M. S. & James, D. S. Winter-to-winter recurrence of sea surface temperature, salinity and mixed layer depth anomalies. Process in Oceanography 49, 41–61 (2001). source
• ?Not checked — no full text of the sourcecites [13] Namias, J. & Born, R. M. Temporal Coherence in North Pacific Sea-Surface Temperature Patterns. Journal of Geophysical Research 75, 5952–5955 (1970). source

In the paper

“In the sub-polar gyre we see significant warming in the 1990’s and cooling in the 2010’s whilst the reverse is true for the north-east Pacific in the region of the recent warm anomaly32.”

What the sources say

• Supported

  The citation follows “the recent warm anomaly,” and Bond et al. identify and locate that anomaly in the Introduction. The preceding decadal comparison is framed as the citing authors’ own observation, not as a finding attributed to Bond et al. (LLM, conf=0.87)

  cites [32] Bond, N. A., Cronin, M. F., Freeland, H. & Mantua, N. Causes and impacts of the 2014 warm anomaly in the NE Pacific. Geophysical Research Letters 3414–3420 (2015). source

In the paper

“It is also consistent with the subsurface temperature trends (warming from the mid-80’s to 2006 and cooling thereafter), with a time-lag between subsurface temperatures and subsequent surface temperature signals41.”

What the sources say

• Supported

  The Results section reports a 1985–2005 warming trend followed by post-2006 subsurface cooling. It also says subpolar gyre SST and heat-content anomalies peaked in 2006–2007 before cooling, and that surface thermal variations there lag subsurface subtropical variations by about five years. No page number is available in our copy. (LLM, conf=0.90)

  cites [41] Ruiz-Barradas, A., Chafik, L., Nigam, S. & Hakkinen, S. Recent subsurface North Atlantic cooling trend in context of Atlantic decadal-to-multidecadal variability. Tellus 70 (2018). source

In the paper

“The “global warming hiatus”47,48, is seen in Fig. 1e, referring to a decade (2000 to 2009) during which global mean SSTA changed less than in the previous or subsequent decade.”

What the sources say

• Partly supported

  The Introduction (page unavailable) calls the slowed rise in global mean temperature during the 2000s a “hiatus or plateau.” The paper discusses global surface temperature, not the claimed decade-by-decade comparison of global mean sea-surface temperature anomalies; published in 2013, it does not establish how 2000–2009 compares with the subsequent decade. (LLM, conf=0.86)

  cites [47] Trenberth, K. E. & Fasullo, J. T. An apparent hiatus in global warming? Earth’s Future 1, 19–32 (2013). sourceExperimental — accuracy not yet measured
• Partly supported

  The Concluding remarks say that global mean surface temperature warmed more slowly in the early 21st century than in the previous few decades. But the Figure 1 caption starts the slowdown in 2001, and the paper discusses it through 2014; it does not define the hiatus as 2000–2009 or establish the claimed comparison with the subsequent decade in global mean sea-surface temperature anomaly (SSTA). (LLM, conf=0.87)

  cites [48] Fyfe, J. C. et al. Making sense of the early-2000s warming slowdown. Nature Climate Change 6, 224–228 (2016). sourceExperimental — accuracy not yet measured

In the paper

“SSTA variability in this region has been linked to the AMOC, which was moving into a positive phase in the 1990’s (warming trend in SSTAs), peaking in the 2000’s and then declining in the 2010’s (cooling trend in SSTAs)37–40.”

What the sources say

• Partly supported

  The Introduction (page unavailable) links subpolar-gyre surface properties to the AMOC, but says the connection between surface changes and the AMOC remains under discussion. The passages do not establish that the AMOC entered a positive phase in the 1990s, peaked in the 2000s, or declined in the 2010s; the paper’s SST observations do not by themselves establish that AMOC chronology. (LLM, conf=0.84)

  cites [37] Reverdin, G. et al. North Atlantic extratropical and subpolar gyre variability during the last 120 years: a gridded dataset of surface temperature, salinity, and density. Part 1: Dataset validation and RMS variability. Ocean Dynamics 69, 385–403 (2019). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [38] Deser, C., Alexander, M., Xie, S.-P. & Phillips, A. S. Sea Surface Temperature Variability: Patterns and Mechanisms. Annual Review of Marine Science 2, 115–43 (2010). source
• ?Not checked — no full text of the sourcecites [39] Chen, X. & Tung, K. K. Global surface warming enhanced by weak Atlantic overturning circulation. Nature 559, 387–391 (2018). source
• Partly supported

  The Abstract links rapid subpolar-gyre warming in the mid-1990s to a strengthening AMOC and reports cooling since 2005 consistent with weaker ocean circulation. It does not establish an AMOC peak in the 2000s; instead, it says measurements suggest circulation strength has declined since the mid-1990s. (LLM, conf=0.85)

  cites [40] Robson, J., Ortega, P. & Sutton, R. A reversal of climatic trends in the North Atlantic since 2005. Nature Geoscience 9, 513–517 (2016). sourceExperimental — accuracy not yet measured

In the paper

“The areas with the strongest warming trends during 2010–2018 are the North and East Pacific, the trend being driven by the warm anomalies observed here between 2014–201632,49.”

What the sources say

• Partly supported

  The Introduction (page not available) documents unusually warm NE Pacific waters in 2014 and says anomalously warm sea surface temperatures persisted through March 2015. It does not assess which regions had the strongest warming trends in 2010–2018 or establish that anomalies through 2016 drove those trends. (LLM, conf=0.88)

  cites [32] Bond, N. A., Cronin, M. F., Freeland, H. & Mantua, N. Causes and impacts of the 2014 warm anomaly in the NE Pacific. Geophysical Research Letters 3414–3420 (2015). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [49] Gentemann, C. L., Fewings, M. R. & Garcia-Reyes, M. Satellite sea surface temperatures along the West Coast of the United States during the 2014-2016 northeast Pacific marine heatwave. Geophysical Research Letters 44, 312–319 (2017). source

In the paper

“Decadal temperature trends here are consistent in sign with the sub-polar gyre, but much smaller in magnitude with an overall neutral trend between 1981–2018, also seen in-situ data records37.”

What the sources say

• Partly supported

  Section 3.3 (page unavailable) reports good agreement between two surface-temperature records in the subpolar gyre and regions farther south. Section 4 (page unavailable) reports spatially varying temperature trends, including cooling near West Greenland and the central Labrador Sea. Neither passage establishes a smaller trend south of Greenland or an overall neutral trend for 1981–2018; the paper’s reported trend analysis ends in 2015. (LLM, conf=0.82)

  cites [37] Reverdin, G. et al. North Atlantic extratropical and subpolar gyre variability during the last 120 years: a gridded dataset of surface temperature, salinity, and density. Part 1: Dataset validation and RMS variability. Ocean Dynamics 69, 385–403 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Where dust events are not flagged as cloud in the retrieval, they tend to bias the retrieved SST cold2,61,62 and can cause an artificial timescale in the SSTA correlation, which then appears as short-term SSTA persistence.”

What the sources say

• Partly supported

  The Usage Notes (Fitness-for-purpose assessment) say that unscreened desert dust causes intermittent cold biases in retrieved SST and an exaggerated trend in SST anomalies. They do not say that dust creates an artificial timescale in SSTA correlation or apparent short-term persistence. (LLM, conf=0.84)

  cites [2] Merchant, C. J. et al. Satellite-based time-series of sea-surface temperature since 1981 for climate applications. Scientific Data 6, https://doi.org/10.1038/s41597-019-0236-x (2019). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [61] Corlett, G. K. et al. The accuracy of SST retrievals from AATSR: An initial assessment through geophysical validation against in situ radiometers, buoys and other SST data sets. Advances in Space Research 37, 764–769 (2006). source
• Partly supported

  Section 3 (Data comparisons; page unavailable) reports that Saharan dust aerosols may bias infrared SST retrievals cold, with negative biases observed in AVHRR data. It does not establish that dust events escape cloud flagging or that they create an artificial timescale in SSTA correlations or apparent short-term persistence. (LLM, conf=0.86)

  cites [62] Reynolds, R. W., Gentemann, C. L. & Corlett, G. C. Evaluation of AATSR and TMI Satellite SST Data. Journal of Climate 23, 152–165 (2009). sourceExperimental — accuracy not yet measured

In the paper

“This is typically characterised as winter-to-winter re-emergence although the time lag can be variable, ranging from 7–13 months15, and is usually seen in the mid-latitudes12,15–19.”

What the sources say

• Supported

  The Introduction describes winter-to-winter recurrence of midlatitude sea-surface temperature anomalies. The Spatiotemporal Distribution section reports recurrence maxima around 7–8 months in some regions and winter recurrence at 11–13 months in others, supporting the stated variable lag. The paper also finds subtropical recurrence, which does not conflict with the claim that recurrence is usually seen in midlatitudes. (LLM, conf=0.88)

  cites [15] Zhao, X. & Li, J. Winter-to-Winter Recurrence of Sea Surface Temperature Anomalies in the Northern Hemisphere. Journal of Climate 32, 3835–3854 (2010). source
• ?Not checked — no full text of the sourcecites [12] Alexander, M. A., Timlin, M. S. & James, D. S. Winter-to-winter recurrence of sea surface temperature, salinity and mixed layer depth anomalies. Process in Oceanography 49, 41–61 (2001). source
• ?Not checked — no full text of the sourcecites [16] de Coetlogon, G. & Frankignoul, C. The Persistence of Winter Sea Surface Temperature in the North Atlantic. Journal of Climate 16, 1364–1377 (2002). source
• ?Not checked — no full text of the sourcecites [17] Timlin, M. S., Alexander, M. A. & Deser, C. On the Reemergence of North Atlantic SST Anomalies. Journal of Climate 15, 2707–2712 (2002). source
• ?Not checked — no full text of the sourcecites [18] Alexander, M. A., Deser, C. & Timlin, M. S. The Reemergence of SST Anomalies in the North Pacific Ocean. Journal of Climate 12, 2419–2433 (1999). source
• ?Not checked — no full text of the sourcecites [19] Sugimoto, S. & Hanawa, K. Remote reemergence of areas of winter sea surface temperature anomalies in the north Pacific. Geophysical Research Letters 32 (2005). source

In the paper

“The Pacific Decadal Oscillation (PDO) also transitioned from a positive to negative phase over the 1980’s-2000’s, becoming more neutral in the 2010’s.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Falvey, M. & Garreaud, R. D. Regional cooling in a warming world: Recent temperature trends in the southeast Pacific and along the west coast of subtropical South America (1979-2006). Journal of Geophysical Research 114 (2009). source
• Partly supported

  The Introduction (page unavailable) describes a positive-to-negative shift across 1979–2000 and the post-2000 period, but it identifies the oscillation as the IPO, not the PDO. It also describes a transition toward a positive IPO phase in 2014–2016, rather than saying it became more neutral in the 2010s. (LLM, conf=0.84)

  cites [78] Meehl, G. A. et al. Sustained ocean changes contributed to sudden Antarctic sea ice retreat in late 2016. Nature Communications 10 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Cooling in the Southern Pacific is consistent with the PDO becoming more negative (1980’s-2000’s) and warming consistent with a return towards a positive index (2010’s)35,78.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Falvey, M. & Garreaud, R. D. Regional cooling in a warming world: Recent temperature trends in the southeast Pacific and along the west coast of subtropical South America (1979-2006). Journal of Geophysical Research 114 (2009). source
• Partly supported

  The Introduction (page not specified) links below-normal southern-latitude sea-surface temperatures to a negative interdecadal Pacific oscillation (IPO) and describes a possible transition toward a positive IPO in 2014–2016. But it places the negative phase in 2000–2014 and the positive phase in 1979–2000, contrary to the claim’s 1980s–2000s timing. It discusses the IPO, not the PDO. (LLM, conf=0.86)

  cites [78] Meehl, G. A. et al. Sustained ocean changes contributed to sudden Antarctic sea ice retreat in late 2016. Nature Communications 10 (2019). sourceExperimental — accuracy not yet measured

In the paper

“this may suggest that natural decadal variability is also important73,76, or that the timing of different response mechanisms in the models is not adequately resolved74,77.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [73] Armour, K. C. & Bitz, C. M. Observed and projected trends in Antarctic sea ice. US CLIVAR Variations 13, 12–19 (2015).
• ?Not checked — no full text of the sourcecites [76] Fan, T., Deser, C. & Schneider, D. P. Recent Antarctic sea ice trends in the context of Southern Ocean surface climate variations since 1950. Geophysical Research Letters 141, 2419–2426 (2014). source
• Supported

  This source is cited for the timing of response mechanisms, not for natural decadal variability. The Results report that a CMIP5 bias in inversion depth may make models overestimate how quickly subsurface warming reaches the mixed layer; the Discussion links model climatology to how quickly the response shifts from cooling to warming. Page numbers are unavailable in our copy. (LLM, conf=0.87)

  cites [74] Kostov, Y. et al. Fast and slow responses of Southern Ocean sea surface temperature to SAM in coupled climate models. Climate Dynamics 48, 1595–1609 (2017). source
• Supported

  The citation is attached to the proposed explanation about model timing, not the separate suggestion about natural variability. The Conclusions report that the transition from cooling to warming is poorly constrained—20 years in one model versus 3–5 years in the other—and identify uncertain air–sea and ocean processes that affect it. The paper does not itself assess a failure of CMIP5 models to reproduce observed cooling. (LLM, conf=0.87)

  cites [77] Ferreira, D. & Marshall, J. Antarctic Ocean and Sea Ice Response to Ozone Depletion: A Two-Time-Scale Problem. Journal of Climate 28, 1206–1226 (2015). source

In the paper

“From the end of 2016 onwards, a sharp decrease in Antarctic sea-ice has also been observed78”

What the sources say

• Supported

  The Introduction reports a sudden decrease in Antarctic sea ice in late 2016. The Discussion says reduced sea-ice extent persisted through winter 2018, supporting the claim that the retreat continued after 2016. (LLM, conf=0.94)

  cites [78] Meehl, G. A. et al. Sustained ocean changes contributed to sudden Antarctic sea ice retreat in late 2016. Nature Communications 10 (2019). source

In the paper

“The strongest warming trends are in the Northern Hemisphere close to the Arctic sea-ice boundary, in the Mediterranean, in the Black Sea and along the northern edge of the Northern Hemisphere western boundary currents (Gulf Stream and Kuroshio Extension).”

In the paper

“SSTA fluctuations in the Nino 3.4 region have a range of ~3–5 K, with positive SSTA’s associated with El-Nino events.”

In the paper

“The median global short-term persistence length is 12 days in December, 14 days in March, 11 days in June and 12 days in September.”

In the paper

“Short-term SSTA persistence is observed over 70.9, 71.0, 71.6 and 78.5% of the global oceans in each season respectively.”

In the paper

“Moreover, the localised trends in SSTA are in general significantly smaller than in other decades, with a standard deviation in the SSTA trends of 0.33 K in the 2000’s compared with 0.49–0.66 K for the other decades.”

In the paper

“The cycle in the northern mid-latitudes is greater than that of the southern mid-latitudes51, with a mean standard deviation of 3.4 K for 30–50 N vs. 1.6 K for 30–50 S.”

What the sources say

• ?Not checked — no full text of the sourcecites [51] Casey, K. S. & Cornillon, P. A Comparision of Satellite and In Situ-Based Sea Surface Temperature Climatologies. Journal of Climate 12, 1848–1863 (1998). source

In the paper

“The warm anomaly maximum was observed in the offshore northerly region and along the west coast of the USA49.”

What the sources say

• ?Not checked — no full text of the sourcecites [49] Gentemann, C. L., Fewings, M. R. & Garcia-Reyes, M. Satellite sea surface temperatures along the West Coast of the United States during the 2014-2016 northeast Pacific marine heatwave. Geophysical Research Letters 44, 312–319 (2017). source

In the paper

“In the ENSO region the timeseries trend is also non-linear with a cooling in the 1980’s and 1990’s and a warming in the 2010’s following the hiatus period of the 2000’s.”

In the paper

“Temperature anomalies in the ENSO region of the tropical, eastern Pacific exhibit decadal variability - cooling in the 1980’s, warming close to the South American west coast in the 1990’s with cooling in the equatorial waters, weak warming in the 2000’s during the hiatus period, and a strong warming signal both close the the South American coast and in equatorial waters in the 2010’s.”

In the paper

“We see that some SST variability in western boundary currents can be attributed to SST processes operating on those timescales, although this may be aliasing given the relatively short length of the timeseries.”

In the paper

“In the ENSO region, SST power is dominated by SST processes on 1–5 year timescales, with a maximum SSTA variance of 1.9 K2.”

In the paper

“The annual cycle is small (~1 K) at equatorial and very high latitudes, and is at a maximum at mid-latitudes.”

In the paper

“There is considerable inter-decadal variation in within-decade temperature tendencies (Fig. 1c–f), which is particularly notable in the sub-Greenland gyre.”

In the paper

“Here we see that the fitting uncertainties are similarly distributed to those for the full timeseries, but are larger as the timeseries are shorter.”

In the paper

“These correlations are strongest and have the greatest aereal extent from March to March.”

In the paper

“The most convincing are the positive correlations found in the ENSO region of the equatorial Pacific, in the sub-polar gyre south of Greenland, in the northern and southern Pacific, parts of the Southern Ocean in boreal winter and in the equatorial and southern Atlantic.”

In the paper

“In the north and eastern Pacific and sub-polar gyre south of Greenland some short-term SSTA persistence is observed but this is typically in the range of 15–30 days and does not encompass the entire aerial extent of these features.”

In the paper

“Statistically significant SSTA correlations occur over the sub-polar gyre south of Greenland in boreal winter, for the start months of December and March.”

In the paper

“Short-term SSTA persistence is also observed in the equatorial Atlantic, west of Africa, in the regions typically affected by wind-blown Saharan dust.”

In the paper

“These correlations are observed over six-month time periods year round, but are strongest from June to December.”

In the paper

“Positive SSTA correlations in the eastern north Pacific from March to March and in the northern hemisphere tropical Pacific from September to September are also statistically significant.”

In the paper

“Peaks in the uncertainties in 1982 and 1991 correspond to the major volcanic eruptions of El Chichon and Mount Pinatubo respectively71.”

What the sources say

• ?Not checked — no full text of the sourcecites [71] Merchant, C. J. & Saunders, M. Infrared Satellite Retrievals in the Presence of Stratospheric Aerosol. Journal of Atmospheric and Oceanic Technology 15, 835–840 (1997). source

In the paper

“The ESA CCI SST products validate well against Argo match-ups, with lower standard deviation of the SST differences than for other reanalysis products, including the Reynolds AVHRR optimal interpolation4.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [4] Rayner, N. et al. SST CCI Phase II Climate Assessment Report, http://www.esa-sst-cci.org/PUG/pdf/SST_CCI-CAR-UKMO-201_Issue_1-signed.pdf (2019).

In the paper

“The satellite data record enables the detailed characterisation of temporal changes in SST over almost four decades.”

In the paper

“This warming trend is consistent with other estimates made during the satellite era (1979–2012) cited within the Intergovernmental Panel on Climate Change (IPCC) Assessment Review 533,34.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [33] Hartmann, D. L., Albert M. G, Klein T. & Rusticucci, M. Intergovernmental Panel on Climate Change, Climate Change 2013, Physical Science Basis, Chapter 2: Observations: Atmosphere and Surface, https://www.ipcc.ch/report/ar5/wg1/ (2013).
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [34] Pachauri, R. K. et al. Intergovernmental Panel on Climate Change, Climate Change 2014, Synthesis Report, https://www.ipcc.ch/report/ar5/syr/ (2014).

In the paper

“Sustained SST anomalies of +/−0.4 K in this region over six months are indicative of El Nino or La Nina events respectively31.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [31] Shea, D. NINO SST Indices (NINO 1+2, 3, 3.4, 4: ONI and TNI), https://climatedataguide.ucar.edu/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni (2018).

In the paper

“ENSO SSTA variance is smallest in boreal summer and largest in winter6.”

What the sources say

• ?Not checked — no full text of the sourcecites [6] Xue, Y., Smith, T. M. & Reynolds, R. W. Interdecadal Changes of 30-Yr SST Normals during 1871-2000. Journal of Climate 16, 1601–1612 (2003). source

In the paper

“South of the Gulf Stream, a localised cooling trend (40°N, 60°W) is observed in the 1990’s, indicative of the northward shift in the Gulf Stream with a return to a positive phase of the North Atlantic Oscillation (NAO)42,43 (Fig. 1d).”

What the sources say

• ?Not checked — no full text of the sourcecites [42] Frankignoul, C., de Goetlogon, G., Joyce, T. M. & Dong, S. Gulf Stream Variability and Ocean-Atmosphere Interactions. Journal of Physical Oceanography 31, 3516–3529 (2001). source
• ?Not checked — no full text of the sourcecites [43] Hurrell, J., Kushnir, Y., Ottersen, G. & Visbeck, M. An overview of the North Atlantic Oscillation, The North Atlantic Oscillation: Climate Significance and Environmental Impact, 134, 1–36 (2003). source

In the paper

“SST anomalies in the Pacific respond to multiple processes: atmosphere-ocean interaction, ENSO, SST re-emergence and the SSTA patterns described by the Pacific Decadal Oscillation50.”

What the sources say

• ?Not checked — no full text of the sourcecites [50] Newman, M. et al. The Pacific Decadal Oscillation, Revisited. Journal of Climate 29, 4399–4427 (2016). source

In the paper

“The SSTA data are detrended using a local linear fit, but in these regions (Fig. 1) we see that the long-term signal is non-linear.”

In the paper

“corresponding to the time of year where the Indian Ocean Dipole is most likely to transition into its strongest phase as it is phase-locked to the annual cycle66.”

What the sources say

• ?Not checked — no full text of the sourcecites [66] Saji, N. H., Goswami, B. N., Vinayachandran, P. N. & Yamagata, T. A dipole mode in the tropical Indian Ocean. Nature 401, 360–363 (1999). source

In the paper

“El Nino tends to be a single-year event, with equatorial Pacific SST anomalies decaying in boreal spring (March to May)55,63,65.”

What the sources say

• ?Not checked — no full text of the sourcecites [55] Zhao, X., Li, J. & Zhang, W. Summer Persistence Barrier of Sea Surface Temperature Anomalies in the Central Western North Pacific. Advances in Atmospheric Sciences 29, 1159–1173 (2012). source
• ?Not checked — no full text of the sourcecites [63] Stein, K., Timmermann, A. & Schneider, N. Phase Synchronization of the El Nino Oscillation with the Annual Cycle. Physical Review Letters 107 (2011). source
• ?Not checked — no full text of the sourcecites [65] Spencer, H. Role of the atmosphere in seasonal phase locking of El Nino. Geophysical Research Letters 31 (2004). source

In the paper

“These may arise from the significant warming signal in the north Pacific within the 2010s.”

In the paper

“The primary control on both is the mixed layer depth and in regions where this has significant intra-annual variability, re-emergence may be seen.”

In the paper

“The significance is calculated point-by-point across a data field containing spatial correlation and therefore, for any chosen confidence level, some local areas of statistical significance are expected to arise by chance, which should be kept in mind when interpreting the hatching.”

In the paper

“If present, re-emergence will skew an exponential fit to the auto-correlation timeseries, and result in erroneously long SSTA persistence timescales.”

In the paper

“Fan et al.76 observed a 0.2–0.4 K cooling per decade in the annual mean SST over the Southern Ocean between 1979–2011 with a corresponding 12% increase in the annual mean Antarctic sea-ice concentration.”

What the sources say

• ?Not checked — no full text of the sourcecites [76] Fan, T., Deser, C. & Schneider, D. P. Recent Antarctic sea ice trends in the context of Southern Ocean surface climate variations since 1950. Geophysical Research Letters 141, 2419–2426 (2014). source

In the paper

“As this only occurs over a small fraction of the time series it does not dominate the long-term trends we see in the satellite era.”

In the paper

“As climate models in the Coupled Model Intercomparison Project Phase 5 (CMIP5) do not simulate SST cooling in this region or reproduce the suggested mechanisms for SST cooling76”

What the sources say

• ?Not checked — no full text of the sourcecites [76] Fan, T., Deser, C. & Schneider, D. P. Recent Antarctic sea ice trends in the context of Southern Ocean surface climate variations since 1950. Geophysical Research Letters 141, 2419–2426 (2014). source

In the paper

“The results are then sensitive to the temporal resolution of the data used, the definition of persistence and the time window over which the exponential fit is made.”

In the paper

“So in the South Pacific, both ERSST and HadISST products will relax towards the SST prior in the absence of observations.”

In the paper

“SSTAs are advected within the ocean over time, and in high-resolution data there is greater likelihood that an anomaly re-emerges in a different resolved location.”

In the paper

“it is common practice to represent anomaly decay over time using an exponential function16,57.”

What the sources say

• ?Not checked — no full text of the sourcecites [16] de Coetlogon, G. & Frankignoul, C. The Persistence of Winter Sea Surface Temperature in the North Atlantic. Journal of Climate 16, 1364–1377 (2002). source
• ?Not checked — no full text of the sourcecites [57] Deser, C., Alexander, M. & Timlin, M. S. Understanding the Persistence of Sea Surface Temperature Anomalies in Midlatitudes. Journal of Climate 16, 57–72 (2003). source

In the paper

“Using decad products increases the temporal resolution of the data over monthly averages, resolving mesoscale features whilst ensuring independence by recognising the temporal error correlation in the analysis product; of order 3 days due to the analysis observation window.”