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© Springer Nature Switzerland AG 2020
A. Mitra, Mangrove Forests in India,
https://doi.org/10.1007/978-3-030-20595-9_2
Chapter 2
Mangroves: A Shield Against Storms
and Wave Actions
Abstract Storms and subsequent wave actions and tidal surges are common in
coastal zones, bays and estuaries. Mangrove forests play a great role in the protection of coastal communities from the fury of cyclones and storms. In the coastal
region, mangrove vegetation has the ability to attenuate wave which are generated
by severe storms and tidal surges. SWAN model helps to determine the effect of
mangrove vegetation on the wave height, which has been explained in this chapter
considering dominant mangrove species of Indian Sundarbans.
Keywords Storms · Waves · Tidal surges · SWAN model
Storms and subsequent wave actions and tidal surges are common in coastal zones,
bays and estuaries. In tropical and some subtropical regions of the world, organized
cloud clusters form in response to perturbations in the atmosphere. When a cloud
cluster forms in an area sufficiently removed from the Equator, then the magnitude
of Coriolis accelerations are not negligible and an organized, closed circulation may
occur. A tropical system with a developed circulation, but with wind speeds of less
than 17.4 metres/second (i.e., 63 kilometres/hour or 39 mph), is termed as tropical
depression. Given that conditions are favourable for continued development (basically warm surface waters, little or no wind shear and a high pressure area aloft),
this circulation can intensify to the point where sustained wind speeds exceed
17.4 metres/second, at which time it is termed a tropical storm. If development continues to a level where the maximum sustained wind speed equals or exceeds
33.5 metres/second (121 kilometres/hour or 75 mph), the storm is referred to as
cyclone (Indian Ocean), typhoon (Western Pacific) or hurricane (Atlantic and
Eastern Pacific). Cyclone is often associated with storm surges, high tidal amplitudes and heavy rainfall. The Bay of Bengal region in the eastern part of India is
noted for cyclonic depressions (Table 2.1).
All tropical cyclones are areas of low atmospheric pressure near the Earth’s surface. The pressures recorded at the centers of tropical cyclones are among the lowest
that occur on Earth’s surface at sea level. Tropical cyclones are characterized and
driven by the release of large amounts of latent heat of condensation, which occurs
© Springer Nature Switzerland AG 2020
A. Mitra, Mangrove Forests in India,
https://doi.org/10.1007/978-3-030-20595-9_2
Chapter 2
Mangroves: A Shield Against Storms
and Wave Actions
Abstract Storms and subsequent wave actions and tidal surges are common in
coastal zones, bays and estuaries. Mangrove forests play a great role in the protection of coastal communities from the fury of cyclones and storms. In the coastal
region, mangrove vegetation has the ability to attenuate wave which are generated
by severe storms and tidal surges. SWAN model helps to determine the effect of
mangrove vegetation on the wave height, which has been explained in this chapter
considering dominant mangrove species of Indian Sundarbans.
Keywords Storms · Waves · Tidal surges · SWAN model
Storms and subsequent wave actions and tidal surges are common in coastal zones,
bays and estuaries. In tropical and some subtropical regions of the world, organized
cloud clusters form in response to perturbations in the atmosphere. When a cloud
cluster forms in an area sufficiently removed from the Equator, then the magnitude
of Coriolis accelerations are not negligible and an organized, closed circulation may
occur. A tropical system with a developed circulation, but with wind speeds of less
than 17.4 metres/second (i.e., 63 kilometres/hour or 39 mph), is termed as tropical
depression. Given that conditions are favourable for continued development (basically warm surface waters, little or no wind shear and a high pressure area aloft),
this circulation can intensify to the point where sustained wind speeds exceed
17.4 metres/second, at which time it is termed a tropical storm. If development continues to a level where the maximum sustained wind speed equals or exceeds
33.5 metres/second (121 kilometres/hour or 75 mph), the storm is referred to as
cyclone (Indian Ocean), typhoon (Western Pacific) or hurricane (Atlantic and
Eastern Pacific). Cyclone is often associated with storm surges, high tidal amplitudes and heavy rainfall. The Bay of Bengal region in the eastern part of India is
noted for cyclonic depressions (Table 2.1).
All tropical cyclones are areas of low atmospheric pressure near the Earth’s surface. The pressures recorded at the centers of tropical cyclones are among the lowest
that occur on Earth’s surface at sea level. Tropical cyclones are characterized and
driven by the release of large amounts of latent heat of condensation, which occurs