There are many factors which can produce short-term (a few minutes to 14 months) changes in sea level such as tides, waves, storm surges, earthquakes and seasonal variations.
Table 1: Short term and periodic changes of sea level (http://en.wikipedia.org/wiki/Sea_level_rise)
| Short-term (periodic) causes |
Time scale (P = period) |
Vertical effect |
| Periodic sea level changes |
| Diurnal and semidiurnal astronomical tides |
12-24 h P |
0.2-10- m |
| Spring tides |
Twice a month |
* |
| Rotational variations (Chandler wobble) |
14 month P |
* |
| Meteorological and oceanographic fluctuations |
| Atmospheric pressure |
Hours to months |
– 0.7 to 1.3 m |
| Winds (storm surges) |
1-5 days |
Up to 5 m |
| Evaporation and precipitation (may also follow long-term pattern) |
Days to weeks |
|
| Ocean surface topography (changes in water density and currents) |
Days to weeks |
Up to 1 m |
| El Nino southern oscillation |
6 months
every 5-10 yr |
Up to 0.6 m |
| Seasonal variations |
| Seasonal water balance among oceans (Atlantic. Pacific. Indian) |
* |
* |
| Seasonal variations in slope of water surface |
* |
* |
| River runoff floods |
2 months |
lm |
| water density changes (temperature and salinity) |
6 months |
0.2 m |
| Seasonal Seiches |
| Seiches (standing waves) |
Minutes to hours |
Up to 2 m |
| Earthquakes |
| Tsunamis (generate catastrophic long-period waves) |
Hours |
Up to 10 m |
| Abrupt change in land level |
Minutes |
Up to 10 m |
| * Effects change locally. Source: http://en.wikipedia.org/wiki/Sea_level_rise |