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Short-Term* Dynamic Changes in Sea Level

* Hours to Decades

Temperature Effects – The Gulf Stream

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Pressure Effects – Storm Surge

El Niño and the Southern Oscillation (ENSO)

208˚ W

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Warmer water extends to eastern Pacific

El Niño

La Niña Warmer water mostly in western Pacific

El Niño and La Niña

El Niño

La Niña

La Nada

Mechanics of ENSO

http://www.esrl.noaa.gov/psd/people/joseph.barsugli/anim.html

http://www.youtube.com/watch?v=DbNzw1CCKHo

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SST anomalies - El Niño

SST anomalies - La Niña

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frequency = 2-7 years

Southern Oscillation Index or Multivariate ENSO Index

Wet winter in N.A. - decreased snowpack - water supply Warmer in midwest, cooler in southwest Decreased Atlantic Hurricane Activity Very wet in S. America Drying in S.E. Asia and Australia - numerous brush fires - air quality West of Antarctic peninsula - more sea ice

El Niño - driven Events

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Higher sea level - from thermal expansion of water Huge waves - massive sediment transport Wet conditions - sea cliff failures

Severe Beach Loss in Southern California

Seasonal Cycles

Typically, the effects of variation in sea surface temperature, barometric pressure, and strength/orientation of ocean currents. Note magnitude of variation. ~1 cm wse change per 1 mb (0.1 kPa) change in atmospheric pressure

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Storm surge – Hurricanes (localized)

Components: 1. Barometric 2. Wind Stress 3. Coriolis 4. Wave Setup

Storm surge – Nor’Easters (large regional extent)

Components: 1. Barometric 2. Wind Stress 3. Coriolis 4. Wave Setup

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Examples of storm surge

The onshore wind component of storm surge

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The size of the storm: Hurricanes vs. Nor’Easters