korallen-dhw-sandbox

Interactive NOAA Degree Heating Week (DHW) bleaching sandbox. Sibling UI to coral-reef-utac (P114), built from the same published constants. Deliberately has no UTAC/CREP/AFET bridge and no invented Γ value — see DISCLAIMER.md.

The interface is German. Numbers and citations stay in their original units.

For a plain-language German companion, see WHITEPAPER.md.

What's real here

• NOAA Coral Reef Watch — Degree Heating Week (DHW) — operational metric used to issue global bleaching alerts: 0–20 °C-weeks accumulated over a 12-week window, 5 alert levels (4 / 8 / 12 / 16 / 20 °C-weeks). The scale itself was expanded from 2 to 5 levels in December 2023 because 2023's heat stress exceeded what the original scale described.
• Four global bleaching events — reef area affected: 21 % (1998) → 37 % (2010) → 68 % (2014–2017) → 84,4 % (2023–2025) (NOAA / ICRI). Great Barrier Reef 2016: 91 % of individual reefs (Hughes et al. 2017, Nature).
• Hughes et al. (2018, Science) — 100 sites, 1980–2016: median return interval between severe bleaching events has fallen to 6 years — too short for many coral communities to fully recover.
• GCRMN & ICRI Status of Coral Reefs of the World: 2025 (DOI 10.59387/LFPR6347) — independent, much larger confirmation: current recovery window 5–6 years. Cover 30.2 % → 27.3 % (−9.5 % relative). Complementary metric (cover loss, not heat-stress area).
• Guillermic et al. (2021, Science Advances) — heat kills acidification compensation: at 28 °C corals can still raise calcifying-fluid pH; at 31 °C neither tested species sustained positive calcification.
• Walker et al. (2023, Evolutionary Applications) — honesty check: bleaching response is not uniform across genotypes (Acropora hyacinthus, Palau), and heat resistance carries a growth tradeoff.

What the controls do

1. DHW slider 0–20 with NOAA alert bands at 4 / 8 / 12 / 16 / 20.
2. Escalation chart of the four documented global events.
3. Recovery-window panel — Hughes 6 years vs GCRMN 5–6 years.
4. Toggle Heat + Acidification — Guillermic 2021.
5. Toggle „uniforme Reaktion?“ — always False, plus the Walker text.
6. Link to the Klimakatalog entry: klimakatalog.vercel.app/p/coral-reef-utac.
7. Disclaimer box.

Thresholds and events are 1:1 from the Python package. Tests lock those values.

License

Code: MIT. Documentation/data notes: see DISCLAIMER.md.

Citation

See CITATION.cff.