MARITIME – TIDE & TIDAL TREAM CALCULATOR
Meteorological Surge
A precise tool.
What is the Meteorological Surge & How does it work?
Meteorological surge is the rise in sea level caused by atmospheric conditions such as low pressure and strong winds, independent of the astronomical tide. When a storm lowers the sea‑level pressure, the water column expands, producing a pressure‑driven rise that can add several decimetres to the observed water level. Wind stress on the ocean surface pushes water toward the coast, creating a wind‑driven surge. The magnitude depends on wind speed, duration, fetch, and coastal geometry. In narrow bays or shallow shelves, the surge can be amplified, leading to significant flooding even when the astronomical tide is low. To isolate the true tide from storm‑induced effects, a meteorological surge correction is applied. By estimating the pressure‑induced and wind‑induced components, the observed water level can be adjusted to reveal the underlying astronomical tide, which is essential for accurate navigation and flood forecasting.
S_{met}=frac{(1013,text{hPa}-P)}{rho,g}+C_{w},frac{V^{2}}{g},F_{c}
S_{met} = total meteorological surge (m)
P = observed atmospheric pressure (hPa)
rho = seawater density (~1025 kg·m⁻³)
g = gravitational acceleration (9.81 m·s⁻²)
C_{w} = wind‑stress coefficient (≈0.001)
V = wind speed (m·s⁻¹)
F_{c} = coastal amplification factor (dimensionless)
P = observed atmospheric pressure (hPa)
rho = seawater density (~1025 kg·m⁻³)
g = gravitational acceleration (9.81 m·s⁻²)
C_{w} = wind‑stress coefficient (≈0.001)
V = wind speed (m·s⁻¹)
F_{c} = coastal amplification factor (dimensionless)
Parameters
Result
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Frequently Asked Questions
What is a meteorological surge?
A meteorological surge is the rise in sea level due to atmospheric factors such as low pressure and wind, independent of tides.
How does low sea-level pressure affect the water level?
Low sea-level pressure causes the water column to expand, leading to a pressure-driven rise in sea level.
What role do winds play in creating a meteorological surge?
Wind stress on the ocean surface pushes water towards the coast, contributing to a wind-driven surge.
How does fetch affect the magnitude of a meteorological surge?
Fetch, or the distance over which wind blows across open water, influences the size of the wave and thus the surge.
Can you explain how coastal geometry impacts a meteorological surge?
Coastal geometry, such as bays and inlets, can amplify or reduce the impact of a meteorological surge by focusing or dispersing the incoming water.
What are the factors that determine the magnitude of a meteorological surge?
The magnitude of a meteorological surge depends on wind speed, duration, fetch, and coastal geometry.
How does a meteorological surge differ from a tsunami?
A meteorological surge is caused by atmospheric conditions and is relatively short-lived, while a tsunami is triggered by underwater disturbances like earthquakes or volcanic eruptions and can last for hours.
Results are for informational purposes only and do not constitute professional advice.