SAOCE helpSouthern African Ocean Conditions & Extremes

Help and methods · 12

Roadmap and planned layers

SAOCE provides statistical answers to questions about ocean conditions and their ecological context. The SST archive now covers all seven African large marine ecosystems (LMEs), while work continues on what users can learn from that record. This overview was reconciled on 21 October 2026. Planned methods and data products have no promised delivery date; each needs a defined question, documented methods and validation before release.

NEWS records software changes by release date. Current interface additions include four independent Hovmöllers, pointer-anchored timeline zoom and map-date selection, and a saved rivers-and-estuaries overlay preference.

What exists today

Nine SST map layers from either OSTIA or OISST and each product’s marine heatwave and cold-spell archive (temperature, anomaly, trend, seven-day change, uncertainty, SST gradient, degree heating weeks and the two event category maps), an event overlay, tide gauge stations with relative sea-level slopes and extreme water-level analyses, point, area, buffer and line selections, and a menu of over thirty statistical methods organised under seven questions, each documented under Statistical methods. Advanced trend, changepoint, seasonal, variability and event-count analyses are implemented. Their assumptions and method-specific limits remain part of each result.

A dismissible six-step guide starts with one docked Benguela example. Selection and line-tool cards share Arrange, Dock and vertical resizing; events open from selectable lollipops or date selection, with threshold departure optional. Figure downloads offer descriptive names and saved image preferences, including physical column width, text size and resolution for journal figures. Supported formats depend on the figure renderer. Saved analyses reconstruct, and completed results can be preserved.

The basemap, original boundary files and published SST now cover all seven African LMEs. The SST grid spans 26°W–60°E and 50°S–51°N, including the original Southern African footprint, and a new view fits the published coverage. The daily worker job starts at 09:30 SAST for the whole domain and publishes matching SST and MHW/MCS dates after the required products pass. Provider gaps remain visible.

Consolidated SAOCE archive and pipeline on the new fast SSD

E12 · Awaiting hardware. When the new SSD arrives, all SAOCE datasets will be migrated to it and their storage consolidated around one authoritative SST archive and serving configuration. The expanded archive already includes the original Southern African footprint, and future SST acquisition is one full-domain NetCDF per date. Another full download or spatial merge is therefore not currently needed. Any unique original assets will first be checked for matching dates, grid coordinates, masks, units, source versions and overlap values before using CDO or NCO.

The migration requires a complete inventory, destination checksums, preserved source history and gaps, measured processing and serving performance, and a reversible switch verified against the live site. Duplicate archives will be retired only after those checks. Until then, the expanded SST archive remains on OceanData_2 and the original archive is retained for rollback. Ocean regimes now covers the expanded domain and each of the seven LMEs. Broader northern and tropical ecological-season definitions remain separate work.

Additional data coverage and layers

ERA5 wind maps, vectors, series, roses and the Wind–SST relationships analysis suite are implemented for the South African coastal domain. The wider African SST archive is now in production. Other families remain candidates, with provider choice and scientific definitions subject to review.

FamilyStatusPlanned scope
All seven African LMEsSST and native events released; seasonal extensions remainThe wider SST archive, fixed climatology, full-record MHW/MCS products and all seven original reporting polygons are served. Thermal-season definitions still need review for northern and tropical regions; the regimes classification now covers the expanded domain, with separate classifications inside all seven LMEs. Physical archive consolidation is E12 above.
WindSouth African product and coupled analyses implementedDaily speed, stress, curl, climatology, wind roses and vectors over SST, plus matched trends, lagged associations, forcing events, heterogeneity and coupled GAMs. Wind–SST relationships explains support and validation. Seven-LME ERA5 expansion is queued separately; no wind is extrapolated outside present coverage.
Sea level and geostrophic currentsCandidateHistorical and near-real-time satellite sea-level anomaly and absolute dynamic topography with supplied geostrophic vectors; regional series, seasonal departures and SST/circulation comparison. This is separate from the released tide-gauge analyses.
Circulation statisticsCandidate; depends on currentsMean currents, mean kinetic energy and eddy kinetic energy, each with its own baseline and averaging period, so that instantaneous and time-mean quantities are never confused.
Waves and swellCandidateTotal sea, wind wave and primary and secondary swell height, period and direction from a selected analysis and forecast product, with issue, valid and lead times stated and outages shown rather than filled.
Independent SST comparisonAvailableNOAA OISST v2.1 is available at 0.25° alongside 0.05° OSTIA, with independent archives, availability and baselines. Explicit daily and climatology difference layers compare them on the OISST grid. OISST is never substituted into OSTIA gaps.
Modelled currents and trajectoriesDeferredModel-labelled currents and particle trajectories, only once directions, temporal handling and a reduced-motion view are validated.
Ocean colourCandidateChlorophyll seasonal timing, bloom onset/duration and temperature–chlorophyll relationships. Source, coastal suitability, cloud/quality masks and statistical definitions remain to be selected.
Subsurface temperature and oxygenLater scoping candidatePotential thermal and low-oxygen exposure analyses, only with suitable depth-resolved data, matched coverage and reviewed thresholds. No provider or acquisition pipeline has been selected.

Bathymetry, coastline, relief, graticules and regional boundaries are contextual foundations and will keep improving, but they are not counted as science layers. Depth controls, further projections or additional variables arrive only with a selected product and a user task that needs them.

Rapid thermal transitions now support annual-point drill-down into daily area evolution, spatial heterogeneity and individual native-cell evolution. Spatial summaries retain their area weights and observation support. Coherent-patch transitions remain a separate S18/S41 extension requiring connectivity, temporal matching and split/merge definitions.

Priorities for additional statistics

Numbered citations link to the reference list and DOIs below.

The first additions build on existing SST and event records. Each needs its own method definition and validation; the list distinguishes implemented first steps from remaining work.

  1. Thermal dose and continuous exposure. Degree-days, days above or below a chosen threshold, longest uninterrupted exposure and the date a chosen thermal accumulation is reached within a defined season. These extend thermal-window counts and remain distinct from DHW and anomaly CUSUM. Marine degree-days and cumulative coral heat stress provide distinct starting points [19], [7].
  2. Event spacing and repeated exposure. Event-free intervals, closely spaced event sequences and their cumulative exposure. These describe opportunities for recovery; they do not measure ecological recovery. Repeated bleaching is an ecological analogue; the event definition supplies the SST catalogue basis [9], [1].
  3. Regional spatial exposure and synchrony. Area selections now offer native-cell MHW/MCS occupancy by intensity category and annual category trends. Affected-area threshold days (10% initially), observed km²·days, overlap-safe combinations and descriptive same-date synchrony are implemented, with shared coverage and overlap reported. An event in regional-mean SST is a different quantity. Related work describes affected area and spatial event evolution; SAOCE’s occupancy and synchrony rules require their own validation [25], [47], [23].
  4. Upwelling and relaxation: implemented for current wind coverage. Explicit coastal–offshore SST contrasts and coastline-relative stress, forcing duration/integral, relaxation, lagged response, event evolution and spatial heterogeneity are available under Wind–SST relationships. User-defined orientation and reference supports remain part of the interpretation.
  5. Thermal displacement and climate velocity. Event-scale displacement in kilometres and a separately defined long-term rate in kilometres per decade, with gradient, coverage and coast/barrier limitations. Neither measures species movement. These sources distinguish event displacement from long-term climate velocity [6], [5].

Rapid extreme thermal transitions now include the descriptive fixed-cell suite: last-day to first-day within user-defined n days, endpoint-category sensitivity, SST/anomaly changes and trajectories, complete/censored persistence, and broader fixed-interval warming/cooling rates. Moving-patch tracking remains separate work under S18. Severity definitions and inferential validation remain research. Wind–SST event composites are implemented. Further work includes, when suitable data exist, temperature–chlorophyll relationships and joint thermal/low-oxygen exposure. Northern and tropical thermal-season definitions are needed before comparing phenology across all African LMEs. Warm- and cold-event definitions [1], [48] do not validate the unpublished transition rule. Driver associations and compound ocean extremes provide context for observational driver and compound-event analyses [14], [15], [49]; shelf-sea thermal phenology informs the seasonal work [18].

Other retained scientific work

  • Agulhas front position: implemented. Explore → Agulhas front offers the owner’s South, South-East and East transects, each 235 km at its supplied initial heading. Daily thermal-gradient candidates, date-selected profiles, coverage, competing peaks and smoothing sensitivity are shown with downloads. These are descriptive candidates, without a claim to track one physical front or the current core. SST front detection and Southern Indian Ocean fronts provide context, not validation of this transect rule [4], [12].
  • Climate-mode context: implemented. ENSO, Indian Ocean Dipole and Southern Annular Mode indices are aligned with a selection’s monthly SST anomaly, with calendar-month lags, approximate autocorrelation-adjusted intervals, explicit source coverage and raw monthly tables. Choose one index and a maximum lag of 0–24 months in the method settings. These are descriptive associations [14], [15]. Leading spatial anomaly patterns and explained variance remain separate future work [16], [17].
  • Ecological context. Thermal refugia and hotspot rankings under explicit criteria, and a referenced species threshold library with taxon, life stage, experimental context and source. Thermal conditions alone do not establish habitat suitability. Thermal histories, MPA exposure and thermal limits motivate the criteria; they do not validate ecological refugia from SST alone [8], [20], [21].
  • Reporting units. Marine protected area reports from licensed boundaries, and a regional-exposure caveat explaining what a foundation SST can and cannot say about shallow and intertidal habitats. MPA exposure and the South African coastal satellite/in situ comparison provide relevant context [20], [11].
  • Events. Historical recurrence summaries, per-blob footprints and persistence, remaining intensity/departure products, and separate detrended or alternative-baseline detection runs. Event-count trend inference is already implemented with block-pairs Poisson uncertainty; it is no longer withheld. A recurrence or return-period model requires separate validation. The sources cover recurrence context, event geometry, definitions, sensitivity and dependence-aware inference [9], [23], [1], [25], [13], [26], [2], [24].
  • Uncertainty. Better display of uncertainty where a reviewed quantity supports it. Daily SST error alone is not anomaly uncertainty or a significance test. OSTIA provides the source-product error context [22].

Queued interface and workflow actions

  • Accessibility and guidance: extend contextual explanations and test keyboard, screen-reader, high-contrast and colour-independent use. The first-task guide is already available.
  • Result packages: one downloadable bundle per analysis with values, exact geometry, figures, parameters, data dictionary, method and source versions, licence, citation and checksums; and equivalent documented API, Python and R requests for every supported analysis.
  • Bulletins and chronology: monthly and annual regional state-of-the-ocean pages built from existing regional results, a curated chronology of notable events linking to their peak maps, and an embeddable dated regional status tile.
  • Opening prompts: on arrival, the largest active patch, the strongest anomaly of the day and what has changed since your last visit, each dated and drawn from server results.
  • Playback and animation export over 30, 90, 365 days or a chosen range, with date, legend and source on every frame and visible gaps kept.
  • Archive navigation: the whole-archive slider, heat/cold footprint ribbon, day detail, gaps and provisional boundary are available. Longer chosen-range playback and animation export remain planned; map dates and analysis intervals retain their separate meanings.

Communication and access

Regional event subscriptions by email or RSS, with provisional status and unsubscribe, are a candidate. Free registration remains a proposal: it would apply only to the historical event-map archive beyond a recent window, with statistics, methods and all SST tools staying public. No paywall is introduced by this roadmap, and a paid option, if ever offered, would cover batch exports, alerts and higher processing limits rather than access to the science.

Every addition must pass the following criteria

  1. A defined regional oceanographic or ecological question that the layer or method answers.
  2. A selected provider with versioned metadata, licence and citation, and an acquisition and revision policy.
  3. Validated numerical samples against the source, with coverage and missing data carried through unchanged; nothing is interpolated or substituted.
  4. Coherent time controls that distinguish observation dates, analysis intervals and forecast lead times.
  5. At least one useful statistical workflow, with fixed documented parameters and a science decision record, before the layer appears on the map.
  6. Desktop acceptance on 1280×800, 1440×900 and 1920×1080 displays in both themes, with measured first-use timing and keyboard operation.

References

These sources explain the methods and their ocean applications. General statistical foundations and related applications are identified beside each citation; they do not independently validate SAOCE’s particular settings or establish ecological impacts. Sources were selected through Consensus on 7 October 2026. Reference numbers match the scientific roadmap.

  1. Hobday, A. J.; Alexander, L. V.; Perkins, S. E.; Smale, D. A.; Straub, S. C.; Oliver, E. C. J.; Benthuysen, J. A.; Burrows, M. T.; Donat, M. G.; Feng, M.; Holbrook, N. J.; Moore, P. J.; Scannell, H. A.; Sen Gupta, A.; Wernberg, T. (2016). A hierarchical approach to defining marine heatwaves. Progress in Oceanography, 141, 227-238. DOI: 10.1016/j.pocean.2015.12.014. Consensus record.
  2. Oliver, E. C. J.; Donat, M. G.; Burrows, M. T.; Moore, P. J.; Smale, D. A.; Alexander, L. V.; Benthuysen, J. A.; Feng, M.; Sen Gupta, A.; Hobday, A. J.; Holbrook, N. J.; Perkins-Kirkpatrick, S. E.; Scannell, H. A.; Straub, S. C.; Wernberg, T. (2018). Longer and more frequent marine heatwaves over the past century. Nature Communications, 9, 1324. DOI: 10.1038/s41467-018-03732-9. Consensus record.
  3. Cayula, J. F.; Cornillon, P. (1992). Edge Detection Algorithm for SST Images. Journal of Atmospheric and Oceanic Technology, 9, 67-80. DOI: 10.1175/1520-0426(1992)009<0067:edafsi>2.0.co;2. Consensus record.
  4. Burrows, M. T.; Schoeman, D. S.; Buckley, L. B.; Moore, P.; Poloczanska, E. S.; Brander, K. M.; Brown, C.; Bruno, J. F.; Duarte, C. M.; Halpern, B. S.; Holding, J.; Kappel, C. V.; Kiessling, W.; O’Connor, M. I.; Pandolfi, J. M.; Parmesan, C.; Schwing, F. B.; Sydeman, W. J.; Richardson, A. J. (2011). The Pace of Shifting Climate in Marine and Terrestrial Ecosystems. Science, 334, 652-655. DOI: 10.1126/science.1210288. Consensus record.
  5. Jacox, M. G.; Alexander, M. A.; Bograd, S. J.; Scott, J. D. (2020). Thermal displacement by marine heatwaves. Nature, 584, 82-86. DOI: 10.1038/s41586-020-2534-z. Consensus record.
  6. Liu, G.; Heron, S.; Eakin, C.; Muller-Karger, F.; Vega-Rodriguez, M.; Guild, L.; De La Cour, J.; Geiger, E.; Skirving, W.; Burgess, T.; Strong, A.; Harris, A.; Maturi, E.; Ignatov, A.; Sapper, J.; Li, J.; Lynds, S. (2014). Reef-Scale Thermal Stress Monitoring of Coral Ecosystems: New 5-km Global Products from NOAA Coral Reef Watch. Remote Sensing, 6, 11579-11606. DOI: 10.3390/rs61111579. Consensus record.
  7. Heron, S. F.; Maynard, J. A.; van Hooidonk, R.; Eakin, C. M. (2016). Warming Trends and Bleaching Stress of the World’s Coral Reefs 1985–2012. Scientific Reports, 6, 38402. DOI: 10.1038/srep38402. Consensus record.
  8. Hughes, T. P.; Anderson, K. D.; Connolly, S. R.; Heron, S. F.; Kerry, J. T.; Lough, J. M.; Baird, A. H.; Baum, J. K.; Berumen, M. L.; Bridge, T. C.; Claar, D. C.; Eakin, C. M.; Gilmour, J. P.; Graham, N. A. J.; Harrison, H.; Hobbs, J. P. A.; Hoey, A. S.; Hoogenboom, M.; Lowe, R. J.; McCulloch, M. T.; Pandolfi, J. M.; Pratchett, M.; Schoepf, V.; Torda, G.; Wilson, S. K. (2018). Spatial and temporal patterns of mass bleaching of corals in the Anthropocene. Science, 359, 80-83. DOI: 10.1126/science.aan8048. Consensus record.
  9. Lamont, T.; García-Reyes, M.; Bograd, S. J.; van der Lingen, C. D.; Sydeman, W. J. (2018). Upwelling indices for comparative ecosystem studies: Variability in the Benguela Upwelling System. Journal of Marine Systems, 188, 3–16. DOI: 10.1016/j.jmarsys.2017.05.007. Consensus record.
  10. Smit, A. J.; Roberts, M.; Anderson, R. J.; Dufois, F.; Dudley, S. F. J.; Bornman, T. G.; Olbers, J.; Bolton, J. J. (2013). A Coastal Seawater Temperature Dataset for Biogeographical Studies: Large Biases between In Situ and Remotely-Sensed Data Sets around the Coast of South Africa. PLoS ONE, 8, e81944. DOI: 10.1371/journal.pone.0081944. Consensus record.
  11. Kostianoy, A. G.; Ginzburg, A. I.; Frankignoulle, M.; Delille, B. (2004). Fronts in the Southern Indian Ocean as inferred from satellite sea surface temperature data. Journal of Marine Systems, 45, 55-73. DOI: 10.1016/j.jmarsys.2003.09.004. Consensus record.
  12. Oliver, E. C. J. (2019). Mean warming not variability drives marine heatwave trends. Climate Dynamics, 53, 1653-1659. DOI: 10.1007/s00382-019-04707-2. Consensus record.
  13. Holbrook, N. J.; Scannell, H. A.; Sen Gupta, A.; Benthuysen, J. A.; Feng, M.; Oliver, E. C. J.; Alexander, L. V.; Burrows, M. T.; Donat, M. G.; Hobday, A. J.; Moore, P. J.; Perkins-Kirkpatrick, S. E.; Smale, D. A.; Straub, S. C.; Wernberg, T. (2019). A global assessment of marine heatwaves and their drivers. Nature Communications, 10, 2624. DOI: 10.1038/s41467-019-10206-z. Consensus record.
  14. Pyper, B. J.; Peterman, R. M. (1998). Comparison of methods to account for autocorrelation in correlation analyses of fish data. Canadian Journal of Fisheries and Aquatic Sciences, 55, 2127-2140. DOI: 10.1139/f98-104. Consensus record.
  15. Hannachi, A.; Jolliffe, I. T.; Stephenson, D. B. (2007). Empirical orthogonal functions and related techniques in atmospheric science: A review. International Journal of Climatology, 27, 1119-1152. DOI: 10.1002/joc.1499. Consensus record.
  16. Monahan, A. H.; Fyfe, J. C.; Ambaum, M. H. P.; Stephenson, D. B.; North, G. R. (2009). Empirical Orthogonal Functions: The Medium is the Message. Journal of Climate, 22, 6501-6514. DOI: 10.1175/2009jcli3062.1. Consensus record.
  17. Thomas, A. C.; Pershing, A. J.; Friedland, K. D.; Nye, J. A.; Mills, K. E.; Alexander, M. A.; Record, N. R.; Weatherbee, R.; Henderson, M. E. (2017). Seasonal trends and phenology shifts in sea surface temperature on the North American northeastern continental shelf. Elementa: Science of the Anthropocene, 5, 48. DOI: 10.1525/elementa.240. Consensus record.
  18. Huret, M.; Bourriau, P.; Doray, M.; Gohin, F.; Petitgas, P. (2018). Survey timing vs. ecosystem scheduling: Degree-days to underpin observed interannual variability in marine ecosystems. Progress in Oceanography, 166, 30-40. DOI: 10.1016/j.pocean.2017.07.007. Consensus record.
  19. Bruno, J. F.; Bates, A. E.; Cacciapaglia, C.; Pike, E. P.; Amstrup, S. C.; van Hooidonk, R.; Henson, S. A.; Aronson, R. B. (2018). Climate change threatens the world’s marine protected areas. Nature Climate Change, 8, 499-503. DOI: 10.1038/s41558-018-0149-2. Consensus record.
  20. Pinsky, M. L.; Eikeset, A. M.; McCauley, D. J.; Payne, J. L.; Sunday, J. M. (2019). Greater vulnerability to warming of marine versus terrestrial ectotherms. Nature, 569, 108-111. DOI: 10.1038/s41586-019-1132-4. Consensus record.
  21. Donlon, C. J.; Martin, M.; Stark, J.; Roberts-Jones, J.; Fiedler, E.; Wimmer, W. (2012). The Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) system. Remote Sensing of Environment, 116, 140-158. DOI: 10.1016/j.rse.2010.10.017. Consensus record.
  22. Sun, D.; Jing, Z.; Li, F.; Wu, L. (2023). Characterizing global marine heatwaves under a spatio-temporal framework. Progress in Oceanography, 211, 102947. DOI: 10.1016/j.pocean.2022.102947. Consensus record.
  23. Künsch, H. R. (1989). The Jackknife and the Bootstrap for General Stationary Observations. The Annals of Statistics, 17, 1217-1241. DOI: 10.1214/aos/1176347265. Consensus record.
  24. Hobday, A.; Oliver, E.; Sen Gupta, A.; Benthuysen, J.; Burrows, M.; Donat, M.; Holbrook, N.; Moore, P.; Thomsen, M.; Wernberg, T.; Smale, D. (2018). Categorizing and Naming Marine Heatwaves. Oceanography, 31(2), 162–173. DOI: 10.5670/oceanog.2018.205. Consensus record.
  25. Smith, K. E.; Sen Gupta, A.; Amaya, D.; Benthuysen, J. A.; Burrows, M. T.; Capotondi, A.; Filbee-Dexter, K.; Frölicher, T. L.; Hobday, A. J.; Holbrook, N. J.; Malan, N.; Moore, P. J.; Oliver, E. C. J.; Richaud, B.; Salcedo-Castro, J.; Smale, D. A.; Thomsen, M.; Wernberg, T. (2025). Baseline matters: Challenges and implications of different marine heatwave baselines. Progress in Oceanography, 231, 103404. DOI: 10.1016/j.pocean.2024.103404. Consensus record.
  26. Frölicher, T. L.; Fischer, E. M.; Gruber, N. (2018). Marine heatwaves under global warming. Nature, 560, 360-364. DOI: 10.1038/s41586-018-0383-9. Consensus record.
  27. Schlegel, R. W.; Darmaraki, S.; Benthuysen, J. A.; Filbee-Dexter, K.; Oliver, E. C. J. (2021). Marine cold-spells. Progress in Oceanography, 198, 102684. DOI: 10.1016/j.pocean.2021.102684. Consensus record.
  28. Gruber, N.; Boyd, P. W.; Frölicher, T. L.; Vogt, M. (2021). Biogeochemical extremes and compound events in the ocean. Nature, 600, 395-407. DOI: 10.1038/s41586-021-03981-7. Consensus record.