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Mode Waters

The Mode Waters feature displays the detection and time series visualization of mode water layers in Argo float profiles.

Mode Waters

This page describes the Visual Lab view, which summarizes mode water detections by three-month period. For coloring the markers in your current map search by profile-level mode water detection, see Mode Water Data Layer.

This tool provides:

  • Detection of mode water layers in profiles based on specified criteria
  • Count of profiles containing mode water by three-month period
  • Time series visualization of mode water thickness trends
  • Statistical display of thickness values (median and quartiles)

Accessing Mode Waters

Mode Waters is available to signed-in users.

  1. Sign in to OceanGraph
  2. Open the app menu
  3. Select Visual Lab > Mode Waters

Detection Criteria

Mode water detection uses the latitude/longitude bounds, density range, and potential vorticity threshold displayed on the screen. A global minimum detected-layer thickness of 10 m is also applied.

The same profile-level detection results are also used by the data layer. Visual Lab aggregates those detections into three-month time series, while the data layer shows the selected mode water on individual search-result markers.

Results Display

The panel displays:

  • Total Profiles: Number of profiles containing detected mode water layers
  • Mean Thickness: Average of the three-month median thickness values shown in the time series

Graphs

Time Series Graph

Displays mode water thickness over time:

  • Median Thickness: 50th percentile (solid blue line)
  • Lower Quartile: 25th percentile (dashed gray line)
  • Upper Quartile: 75th percentile (dashed gray line)
  • Time Scale: Three-month periods from 2001 onwards

Profile Count Graph

Shows the number of profiles containing mode water:

  • Blue Bars: Number of profiles per three-month period
  • Time Scale: Three-month periods from 2001 onwards

Included Profiles

Only profiles inside the displayed region that reach at least 500 dbar and contain enough finite pressure, temperature, and salinity values are analyzed. Detected layers must be at least 10 m thick. Where potential vorticity cannot be calculated at a depth, the density criterion is used alone. These automatic criteria support exploration; they do not guarantee a research-grade water-mass classification.

Three-Month Periods

Data is grouped by month rather than by hemisphere-specific season names:

  • DJF: December, January, February
  • MAM: March, April, May
  • JJA: June, July, August
  • SON: September, October, November

Northern and Southern Hemisphere seasons are opposite, so a label such as DJF identifies only the months, not a local season. DJF uses the year of January and February: 2024 DJF covers December 2023 through February 2024. Graph tooltips show only the concrete month range, such as Dec 2023–Feb 2024 or Mar–May 2024.

For background on mode-water formation and interpretation, read What Is Mode Water? in OceanGraph Articles.