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There are a number of factors that contribute to dynamic fluctuations
in sea level over a period of months to a decade or so.
These fluctuations are generally about 0.1 – 0.3 m but in some cases
may range up to 1M.
Seasonal cycles occur as a result of fluctuations in barometric pressure ,
sea surface temperature ,and changes in location of ocean currents
Storm surge :
During storms changes in sea level occur as a result of wind stress on
the water surface
and changes in atmospheric pressure leading to
displacemnet of the water level.
Storm surge elevation is determined primarily by wind speed and wind
direction relative to the shoreline , by the duration and fetch over
which the wind blows , barometric pressure , coastal configuration and
by the track and speed of movement of the storm .
Climate change and sea level rise :
The results of a large number of studies worldwide suggest that over
the past one thousand years sea level globally rose , there are
anumber of components which control chnages in sea level , the two
major contributors to present sea level rise are :
1-steric height variations produced by the expansion or contraction of
the water in the oceans as a result of changing temperature and
density.
2- variations in the mass of water in the oceans . In this case the major
process is melting of glaciers and snow packs worldwide.
Future rates of sea level rise :
There is still uncertainty as to forecast of global temperature change
and consequently even greater uncertainty in how fast oceans will
respond to this.