Relative Sea Level Trend
stationid city, state
The relative sea level trend is #trendmmyr millimeters/year with a 95% confidence
interval of +/-
#sterrmmy mm/yr based on monthly mean sea level data from
#startyear to #endyear which is equivalent to a change of feet in 100 years.
Plots show monthly mean sea levels without the regular seasonal fluctuations from coastal ocean temperatures, salinity, wind, atmospheric pressure, and ocean currents. The relative sea level trend is also shown with its 95% confidence interval. Relative Sea Level trends at the coast can be positive or negative. A negative trend does not mean the ocean surface is falling; It indicates the land is rising more quickly than the ocean in a particular area. Trends close to zero indicate the land is rising at nearly the same rate as the ocean.
Plotted values are relative to the most recent Mean Sea Level datum established by CO-OPS. Calculated trends are available as a table in millimeters/year and in feet/century (0.3 meters = 1 foot). If present, solid vertical lines indicate dates of any major earthquakes in the vicinity of the station. Dashed vertical lines bracket any periods of questionable data or a possible datum shift.
Annual Mean Relative Sea Level Since 1960 and Regional Scenarios
stationid City, State
The projection of future sea levels that are shown below were released in 2022 by a U.S. interagency task force in preparation for the Fifth National Climate Assessment. The projections for 5 sea level change scenarios are expected to assist decision makers in responding to local relative sea level rise. The 2022 Sea Level Rise Technical Report provides further detailed information on the projections.
SAVE IMAGE
The figure shows the station's annual mean sea level since 1960 and five regionalized sea level rise scenarios plotted relative to a 1996-2014 baseline period, with the year 2005 as the 'zero' for the figure. The relative position of the Mean Sea Level datum established by CO-OPS is also shown. The relative position of the geodetic datum NAVD88, which is the 'zero' used for land elevations, is also provided if it has been determined for the station.
Interannual Variation
stationid City, State
The plot shows the interannual variation of monthly mean sea level and the 5-month running average. The average seasonal cycle and linear sea level trend have been removed. Interannual variation is caused by irregular fluctuations in coastal ocean temperatures, salinities, winds, atmospheric pressures, and ocean currents. The interannual variation for many Pacific stations is closely related to the El Niño Southern Oscillation (ENSO). If present, solid vertical lines indicate times of any major earthquakes in the vicinity of the station and dashed vertical lines bracket any periods of questionable data or datum shifts.
Interannual Variation Since 1990
stationid City, State
The plot shows the interannual variation of monthly mean sea level and the 5-month running average. The average seasonal cycle and linear sea level trend have been removed. Interannual variation is caused by irregular fluctuations in coastal ocean temperatures, salinities, winds, atmospheric pressures, and ocean currents. The interannual variation for many Pacific stations is closely related to the El Niño Southern Oscillation (ENSO). If present, solid vertical lines indicate times of any major earthquakes in the vicinity of the station and dashed vertical lines bracket any periods of questionable data or datum shifts.
Average Seasonal Cycle
stationid City, State
The average seasonal cycle of mean sea level, caused by regular fluctuations in coastal temperatures, salinities, winds, atmospheric pressures, and ocean currents, is shown along with each month's 95% confidence interval. For local and regional comparisons, the calculated average seasonal values for all non CO-OPS and CO-OPS Stations are available as tables in meters.
Variation of 50-Year Relative Sea Level Trends
stationid city, state
Linear relative sea level trends were calculated in overlapping 50-year increments for stations with sufficient historical data. The variation of each 50-year trend, with 95% confidence interval, is plotted against the mid-year of each 50-year period. The solid horizontal line represents the linear relative sea level trend using the entire period of record.
Previous Relative Sea Level Trends
stationid City, State
As more data are collected at water level stations, the linear relative sea level trends can be recalculated each year. The figure compares linear relative sea level trends and 95% confidence intervals calculated from the beginning of the station record to recent years. The values do not indicate the trend in each year, but the trend of the entire data period up to that year.
Although the trend may vary with the end year, there is no statistically significant difference between the calculated trends if their 95% confidence intervals overlap. Therefore, the most recent calculated trend is not necessarily more accurate than the previous trends; it is merely a little more precise. If several recent years have anomalously high or low water levels, the values may actually move slightly away from the true long-term linear trend.
The main effect of including a few more years of data is to narrow the 95% confidence intervals. The figure below (from Sea Level Variations of the United States 1854-2006, NOAA Technical Report NOS CO-OPS 53) shows estimated widths of the 95% confidence intervals derived from all the calculated trends at long-term CO-OPS water level stations. A 30-year data set should provide a trend with a +/- 1.5 mm/yr confidence interval; a 60-year data set should provide a trend with a +/- 0.5 mm/yr confidence interval.
