PHYSICAL & NUMERICAL FORMULATIONS
Standards & Specifications
Scientific & Physical Methodology
Technical documentation of mathematical algorithms, oceanographic metrics, hydrological scaling, and seismological risk categorizations operationalized across the Ramji Weather Station platform.
⚠️ 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 ($H_s$ or $H_{1/3}$) is defined statistically as the mean height of the highest third of waves in a given record, corresponding mathematically to:
Hs ≈ 4 × √(m0)
where $m_0$ is the zero-th moment of the wave energy spectrum. The platform partitions total wave energy into wind sea (locally forced, steep, short period $T_p < 9\text{s}$) and swell (distant generation, long period $T_p > 10\text{s}$). This partition is vital for evaluating roll resonance in container ships and harbor basin surging.
💨 2. Beaufort Scale Classification & Port Flags
WMO Code Table 1100
Surface wind speeds (10-meter level, 1-hour average in knots) are classified according to the World Meteorological Organization (WMO) Beaufort scale (Force 0 to Force 12):
- Force 0–3 (0–10 kts): Calm to Gentle Breeze (Wave 0.1–0.6m) — Normal operations.
- Force 4–6 (11–27 kts): Moderate to Strong Breeze (Wave 1.0–3.0m) — Mooring precautions.
- Force 7–9 (28–47 kts): Near Gale to Severe Gale (Wave 4.0–7.0m) — Pilot boarding suspended.
- Force 10–12 (48+ kts): Storm to Hurricane Force (Wave 9.0m+) — 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:
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 & Catchment Inflow
GloFAS Routing
River discharge ($Q$ in $\text{m}^3/\text{s}$) models downstream runoff using Gridded Catchment Routing across major Indian river basins (Godavari, Krishna, Ganga, Cauvery, Narmada).
Discharge rates are mapped against historical baseline percentile thresholds (p50, p75, p90) to project potential downstream delta inundation and barrage inflows over a 7-day forecast horizon.
🌊 5. Kallakkadal Mechanics & Early Warning
INCOIS Terminology
Kallakkadal ("ocean thief" in Malayalam) describes catastrophic coastal swell surges that strike without local meteorological warnings (clear skies, calm local winds).
Generated in the Southern Ocean between 30°S and 60°S by deep polar low-pressure systems, these swells travel across thousands of kilometers at speeds up to 40 knots. Upon entering shallow coastal bathymetry, wavelength compresses while wave height amplifies dramatically, resulting in destructive overtopping of coastal barriers.
⚠️ 6. DART & Sea Level Model Limitations
Model Transparency
The DART bottom pressure recorder (BPR) chart and coastal sea level departure charts provided in the dashboard are illustrative empirical models based on semi-diurnal astronomical harmonics ($M_2, S_2$) and empirical wave setup ($0.15 \times H_s$).
They do not reflect live 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.
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