Juneau, AK

Chart Interaction

Move your cursor over the chart to see individual data values. To hide or show a data trace, click the terms in the legend. For further instructions on how to interact with the chart, mouse over it, then mouse over the icons that appear in the upper right-hand corner.

Legend Abbreviations

To learn more about the terms and abbreviations used in the legend, expand the selections below.


Represented in light blue, the Monthly Mean Sea Level (MMSL) shows the height of the water at this particular tidal gauge averaged over a month of measurements. The sharp ups and downs reflect changes in water level due to storms, tidal variations, and changes in ocean and estuarine circulation. Height is measured relative to a standard elevation defined by the National Oceanic and Atmospheric Administration. See detailed discussion.

Quadratic Trend

The quadratic trend, shown in darker orange, indicates that sea level is not only rising at this tidal station, but that the rate of sea-level rise is accelerating with time. In other words, the rate of sea-level rise is best represented by a trend that is exponential (quadratic curve) rather than linear (straight line). As is evident by comparing the quadratic and linear projections, an exponential rise in sea level will result in a significantly higher sea level in future years. Analysis of the quadratic trend shows that the rate of sea level rise (β1) is 5.12 millimeters per year (0.2 inches/yr), and that the rise rate is accelerating by 0.127 mm each year (0.005"/yr2). See detailed discussion.

QHi95 and QLo95

Shown in lighter orange, these confidence intervals encompass 95% of the sea-level observations recorded during each month at this tidal station, whether above (QHi95) or below (QLo95) the mean. Extending these intervals forward implies that sea level could be as much as 0.18 meters (7 inches) higher or lower than the best (quadratic) estimate of sea level during any future month out to 2050. See detailed discussion.

Linear Trend

The linear trend, shown in green, indicates how quickly sea level would rise at this tidal station with no acceleration in the rise rate (our analysis suggests this is not the case). We display the linear trend to help clarify that linear projections result in a significantly lower sea level in future years than we expect given recent observations of an accelerating rate of sea-level rise at this station. See detailed discussion.

Decadal Signal

The decadal signal, shown in dark blue, portrays ups and downs in sea level due to relatively short-term interactions between the oceans and the atmosphere, with El Niño as an example. Projections to 2050 made during an upturn in the decadal signal will be higher than they would be if the decadal signal was nearing or at a low. See detailed discussion.

Station Facts