Atmospheric gravity waves and the ‘Rissaga’ phenomenon

Monserrat, Sebastià; Ibbetson, A.; Thorpe, Alan

doi:10.1002/qj.49711749907

Cited by 45 publications

(35 citation statements)

References 2 publications

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“…Around the Balearic Islands in the western Mediterranean Sea large sea level oscillations with amplitudes up to 1.5 m can occur (Monnserrat et al 1991). These waves are known locally as "rissaga" and have been attributed to forcing by low pressure systems with translation speeds near the shallow-water wave speed exciting edge waves on the islands' continental shelf (Liu et al 2002) and seiches within specific inlets (Rabinovich and Monserrat 1998).…”

Section: Introductionmentioning

confidence: 99%

Long Barotropic Waves Generated by a Storm Crossing Topography

Vennell

2007

Journal of Physical Oceanography

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Storms crossing topography are shown to radiate long surface gravity waves. The waves are transients generated by changes in the depth-dependent amplitude of the atmospherically forced pressure wave beneath a storm. This generation mechanism for long waves, known as "meteorological tsunamis" or rissaga, does not appear to have been previously discussed. The transients have periods equal to the passage time of the storm, of order 30 min for small fast-moving storms. A 1D model is used to give the amplitudes of the transient waves generated by a small fast-moving storm crossing a topographic step on to a continental shelf and across a ridge. Large transients are generated by storms whose translation speed is subcritical in deep water and supercritical in shallow water, that is, faster than the shallow-water wave speed. Surprisingly, when the depth difference between the deep water and the continental shelf is large, a gentle transition from deep to shallow water over 10 storm widths only slightly reduces the amplitudes of the transients. The influence of a finite-width shelf on the enhancement of coastal storm surge is also discussed. A 2D numerical model illustrates the topographic transients generated by sub-and supercritical storms moving across a ridge. Topographic transients are suggested as a source of energy for seiches on shelves and within embayments. The energy may come from a storm crossing the adjacent continental slope and possibly from distant open-ocean storms crossing multiple ridges and seamounts.

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Section: Introductionmentioning

confidence: 99%

Long Barotropic Waves Generated by a Storm Crossing Topography

Vennell

2007

Journal of Physical Oceanography

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“…These relatively small areas are influenced by mesoscale phenomena such as sharp or periodic changes in atmospheric pressure (in some cases caused by cold fronts). Examples are: Nagasaki Bay, Japan [ Hibiya and Kajiura , 1982] and Menorca, Spain [ Monserrat et al , 1991; Rabinovich and Monserrat , 1998]. Larger sea areas are influenced by complete low‐pressure areas, giving rise to the so‐called “inverted barometer” effect that causes a water level increase (in some cases combined with an additional wind set‐up) that can initiate the oscillations.…”

Section: Introductionmentioning

confidence: 99%

Low‐frequency sea waves generated by atmospheric convection cells

Jong

2004

J. Geophys. Res.

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[1] The atmospheric origin of low-frequency sea waves that cause seiches in the Port of Rotterdam is investigated using hydrological and meteorological observations. These observations, combined with weather charts, show that all significant seiche events coincide with the passage of a low-pressure area and a cold front. Following these front passages, increased wind speed fluctuations occur with periods on the order of 1 hour. The records show that enhanced low-frequency wave energy at sea and the seiche events in the harbor occur more or less simultaneously with these strong wind speed fluctuations. These oscillatory wind speed changes are due to convection cells that arise in an unstable lower atmosphere in the area behind a cold front, where cold air moves over the relatively warm sea surface. It is shown that the moving system of a cold front and trailing convection cells generates forced low-frequency waves at sea that can cause seiche events inside the harbor. The occurrence of such events may be predictable operationally on the basis of a criterion for the difference in temperature between the air in the upper atmosphere and the water at the sea surface.

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“…Large sea level oscillations (up to 3 m trough‐to‐crest wave heights) are periodically observed in both inlets. These anomalous oscillations have been successfully linked to the passage of atmospheric pressure disturbances, generating long ocean waves on the continental shelf surrounding the islands that in turn, force the resonance response in the inlets [ Tintoré et al , 1988; Monserrat et al , 1991; Gomis et al , 1993; Rabinovich and Monserrat , 1998]. This phenomenon, locally known as “rissaga,” is responsible for damage to boats and infrastructures in both locations, although the destructions are usually more severe in Ciutadella, where a harbor is located at the end of the inlet.…”

Section: Introductionmentioning

confidence: 99%

Coupling between two inlets: Observation and modeling

et al. 2003

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[1] The resonance coupling between two adjacent inlets is investigated. Field evidence of this natural phenomenon is found for two elongated inlets in the region of Ciutadella, Menorca Island, in the Western Mediterranean (Ciutadella and Platja Gran). To illustrate the fundamental features of the problem, analytical solutions for two rectangular inlets with constant depth are constructed and analyzed. The theoretical results mimic well the field data and demonstrate the resonance coupling characteristics of the inlet responses. The phenomenon is also examined with a numeric model so that the effects of real bathymetry can be considered. Numerical computations show the specific resonant features of local topography and the agreement between field data and numerical results is very good.

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Atmospheric gravity waves and the ‘Rissaga’ phenomenon

Cited by 45 publications

References 2 publications

Long Barotropic Waves Generated by a Storm Crossing Topography

Long Barotropic Waves Generated by a Storm Crossing Topography

Low‐frequency sea waves generated by atmospheric convection cells

Coupling between two inlets: Observation and modeling

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