⚠️ Decision Support Only — Not for Official Navigation
All calculations, wave height projections, and seismic risk alerts are informational tools intended to assist situational awareness. They are not substitutes for mandatory navigational warnings issued under SOLAS, IMO, or national maritime directives.
🌊 1. Significant Wave Height & Swell Partitions
WMO-No. 702
Significant Wave Height (Hs or H_1/3) is defined statistically as the mean height of the highest one-third of waves in a given record, corresponding mathematically to the zeroth moment of the wave energy spectrum:
Significant Wave Height: Hs ≈ 4 * sqrt(m0) [in meters]
where m_0 is the zeroth moment of the wave frequency spectrum S(f). The platform partitions total wave energy into wind sea (locally forced, steep, short period T_p < 9 s) and swell (distant generation, long period T_p > 10 s) to evaluate container ship roll resonance and port surging.
💨 2. Beaufort Scale Classification & Wind Stress
WMO Code 1100
Surface wind speeds (10m elevation, 1-hour sustained in knots) are classified according to WMO specifications. Surface wind stress tau_w transferred into wave generation follows:
Wind Drag Stress: tau = rho * Cd * U10^2 [N/m²]
- Force 0–3 (0–10 kts): Calm to Gentle Breeze (H_s ≈ 0.1 - 0.6 m) — Normal navigation.
- Force 4–6 (11–27 kts): Moderate to Strong Breeze (H_s ≈ 1.0 - 3.0 m) — Mooring precautions.
- Force 7–9 (28–47 kts): Near Gale to Severe Gale (H_s ≈ 4.0 - 7.0 m) — Pilot boarding suspended.
- Force 10–12 (48+ kts): Storm to Hurricane Force (H_s > 9.0 m) — Port operations halted.
🌋 3. Seismological & Tsunami Risk Filtering
USGS NEIC Criteria
Earthquakes reported in the live USGS GeoJSON feed are filtered against physical tsunamigenic criteria. Seismic moment M0 and moment magnitude Mw are computed via:
Moment Magnitude: Mw = (2/3) * log10(M0) - 6.07
• Criteria 1: Undersea / Subduction Zone location
• Criteria 2: Moment Magnitude (Mw) ≥ 6.5
• Criteria 3: Focal Depth ≤ 70 km (Shallow dip-slip displacement)
Events fulfilling these criteria are flagged for potential ocean floor deformation across the Sunda-Andaman megathrust and Makran subduction zones.
🏞️ 4. River Discharge & Manning Catchment Routing
GloFAS Routing
River discharge (Q in m^3/s) models downstream runoff using Gridded Catchment Routing across major Indian river basins. Open channel flow is evaluated via Manning's equation:
Manning Streamflow Discharge: Q = (1/n) * A * Rh^(2/3) * S0^(1/2) [m³/s]
Discharge rates are mapped against historical baseline percentile thresholds (p50, p75, p90) and CWC High Flood Levels (HFL) to project downstream delta inundation and barrage inflows over a 7-day forecast horizon.
🌊 5. Kallakkadal Mechanics & Group Velocity
INCOIS Terminology
Kallakkadal describes sudden coastal swell surges that strike without local storms. Generated in the Southern Ocean between 30^°S and 60^°S, waves propagate at deep-water group velocity:
Deep-Water Wave Group Velocity: cg ≈ 1.56 * Tp [m/s]
Upon entering shallow coastal bathymetry, wave physics decouples into two distinct hydrodynamic mechanisms:
1. Shallow-Water Wave Celerity (Phase Speed):
c = √(g · h) [m/s]
Governs propagation velocity as a function of bathymetric depth h (where g = 9.81 m/s²).
2. Green's Law (Shoaling Wave Amplification):
A₂ = A₁ · (h₁ / h₂)^0.25
Preserves onshore energy flux (F = E · c_g = const), driving exponential wave height growth as surges enter coastal shoals.
⚠️ 6. EMPIRICAL BPR & HARMONIC TIDAL MODELS
Model Transparency
The DART bottom pressure recorder (BPR) chart and coastal sea level departure charts provided in the dashboard are [EMPIRICAL BPR HYDROSTATIC MODEL] and [DERIVED HARMONIC TIDAL MODEL] simulations based on semi-diurnal astronomical harmonics (M_2, S_2) and hydrostatic water column integration:
Hydrostatic Seafloor Pressure: P(t) ≈ rho * g * (h + eta) + Pa
They do not reflect physical wire telemetry from physical NOAA DART BPR seafloor moorings or government tide gauge stations. They are provided solely for conceptual and educational analysis of surge dynamics.
🛡️ 7. 4-Stage Automated Quality Control (QC)
QC Assurance
All live telemetric streams undergo automated validation prior to client-side presentation:
- Stage 1 (Elevation & Zonal Physical Plausibility — Two-Tier Pressure Bounds): Scalar thermodynamic bounds are zonally adaptive (T in [-50^°C, +60^°C], accommodating Himalayan winter lows in Ladakh/Dras down to -50^°C; plains bound at -20^°C). To prevent false rejection of valid high-altitude station observations (e.g., Leh at 3,500 m where station surface pressure P_stn ≈ 670 hPa, or Shimla at 2,200 m where P_stn ≈ 780 hPa), the QC system enforces a two-tier evaluation:
Raw Station Pressure: P_stn in 550 to 1085 hPa (for elevation <= 4500m)
Mean Sea Level Pressure: P_MSL in 850 to 1090 hPa (hypsometrically reduced)
Mean Sea Level Pressure: P MSL = P stn ( g0 zRd Tv ) [850, 1090] hPa
The extreme WMO bounds [850, 1090] hPa apply strictly to Mean Sea Level Reduced Pressure (P_MSL / QNH), never rejecting raw elevated surface pressures.
- Stage 2 (Cross-Sensor Synthesis & Microclimate Synthesis): Reconciles surface aerodrome METAR observations against gridded numerical synoptic analyses (ECMWF/GFS). Incorporates microclimate tolerance (Delta T <= 5.0^°C, Delta P <= 5.0 hPa) during coastal sea-breeze frontal passages (e.g., Mumbai, Chennai) and urban heat island anomalies, utilizing multi-station consensus arbitration rather than premature sensor rejection.
- Stage 3 (Vertical Geoid Datum Harmonization): Harmonizes sensor elevations and oceanographic stage gauges from ellipsoidal coordinates (WGS-84) to Mean Sea Level (MSL / EGM2008) and local Port Chart Datum (CD).
- Stage 4 (3-Sigma Rate-of-Change Filter & Multi-Sensor Convective Corroboration): Evaluates barometric tendency dP/dt, rejecting electronic step discontinuities (|Delta P| > 4 hPa / 10 min). To avoid preserving false positives caused by radar ground clutter or anomalous propagation (AP), a convective override is permitted only if the radar echo (Z >= 45 dBZ) is corroborated by at least one independent physical metric:
Convective Override Criteria: (Z >= 45 dBZ) AND (CAPE >= 1000 J/kg OR Cloud Top TB <= -40°C OR Gusts >= 35 kts)
Isolated radar echoes without thermodynamic corroboration are flagged as suspected electromagnetic discontinuities or anomalous propagation.
📡 8. Doppler Radar Reflectivity & Regional Z-R Relations
Radar Calibration
Radar reflectivity factor $Z$ (in $\text{mm}^6/\text{m}^3$ or converted to logarithmic $\text{dBZ} = 10 \log_{10} Z$) is mapped to precipitation rate $R$ (in $\text{mm/h}$) via empirical power-law relations $Z = a \cdot R^b$. Rather than applying a single universal constant, the engine applies regionally and micro-physically calibrated parameters:
Marshall-Palmer:
Z = 200 · R^1.6
General stratiform precipitation & inland plains.
Tropical Coastal:
Z = 300 · R^1.4
Monsoonal maritime systems (Bay of Bengal / Arabian Sea).
Convective Core:
Z = 180 · R^1.35
Deep tropical convective updrafts & thunderstorms.
🏷️ 9. Operational Status & Telemetry Flags Legend
Architecture
Standardized UI badges denote telemetry health and provenance across all ingestion pipelines:
🟢 ACTIVE & SYNCHRONIZED: Live sensor or REST API responding within SLA (<140ms edge proxy) with valid HTTP 200 payload, fresh observations (<30 min), and normalized to WGS-84 / IST / UTC epochs without schema drift.
🟡 DERIVED MODEL: Secondary physics formulation, numerical runoff routing, or empirical calculation (e.g. Copernicus GloFAS / CWC 6-hr hydrodynamic runoff cycles, Manning streamflow, DART hydrostatic pressure model, harmonic tides).
🟠 STANDBY TRIGGER: Station in alert-ready listening mode; executes high-frequency polling (10s) upon threshold breach.
🟣 CACHED FALLBACK: Network boundary disruption or upstream rate-limit protection active; serving cryptographically verified local edge cache to maintain continuous situational awareness.