Mode Waters

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

This page describes the Visual Lab view, which summarizes mode water detections by season. For coloring the markers in your current map search by profile-level mode water detection, see Mode Water Map Overlay.

This tool provides:

• Detection of mode water layers in profiles based on specified criteria
• Count of profiles containing mode water by season
• 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 criteria displayed on the screen (latitude/longitude bounds, density range, potential vorticity threshold, and minimum thickness).

The same profile-level detection results are also used by the map overlay. Visual Lab aggregates those detections into seasonal time series, while the map overlay 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 seasonal 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: Seasonal data from 2001 onwards

Profile Count Graph

Shows the number of profiles containing mode water:

• Blue Bars: Number of profiles per season
• Time Scale: Seasonal data from 2001 onwards

Data Processing

Quality Control

The analysis applies strict quality control measures to ensure reliable results:

1. Geographic Filtering

   • Only profiles within the specified target region are analyzed
   • Profiles outside the geographic bounds are excluded

2. Profile Depth Requirements

   • Minimum profile depth: 500 dbar (approximately 500m)
   • Profiles that are too shallow are excluded from analysis

3. Data Completeness

   • Minimum 10 valid data points required per profile (temperature, salinity, pressure)
   • Minimum 5 valid density data points required for mode water calculation
   • Minimum 3 valid data points required for potential vorticity calculation
   • Profiles with insufficient temperature, salinity, or pressure data are excluded
   • Missing or invalid data points are removed before analysis
   • Mode water layers must be ≥10m thickness to be included in analysis

Seasonal Grouping

Data is grouped by meteorological seasons:

• Winter: December, January, February
• Spring: March, April, May
• Summer: June, July, August
• Autumn: September, October, November

Background

Mode waters are water masses characterized by weak vertical gradients in temperature and salinity, forming relatively uniform layers. They are created by deep winter mixed layers and play important roles in ocean circulation.

This feature displays basic statistics and time series of detected mode water layers in the specified region.