Quick Start: Your First 10 Minutes
Follow this path from a map search to one float’s trajectory and an optional signed-in analysis.
Open OceanGraph and follow along.
Before You Start
Search, WMO ID lookup, the Trajectory View toggle, and time-series View section work without an account. You can therefore complete steps 1–3 below anonymously. Step 4 and the derived displays that follow require signing in.
See Features for the complete access and usage-limit reference.
Step 1: Search the map
- Set a Date Range (anonymous: up to 30 days; signed in: up to 90 days).
- Set the Geographic Bounds by interacting with the map.
- Optionally check Only profiles with BGC to keep only profiles that include a biogeochemical parameter (dissolved oxygen, chlorophyll, nitrate, backscattering, pH, irradiance at 490 nm, or PAR).
- Run the search. Matching profiles appear as markers on the map.
If you already know a float, enter its WMO ID in the Profile Details panel and press Enter to load all of its profiles.
Too many results? Narrow the date range or geographic bounds. θ–S and Clustering accept at most 500 profiles, so a tighter search keeps those features available.
See Search and Bookmark for details.
Step 2: Select a marker
Click a marker and read its profile context first: WMO ID, cycle number, date, latitude, and longitude. These details tell you which float, profile, place, and season you are about to interpret.
Signed-in users can also inspect the selected profile graph. Start with the overall shape of temperature or salinity and note the surface layer, the main gradient, and the deeper structure before moving to a multi-profile view.
Step 3: Follow One Float (Trajectory and Section)
- In the map command bar, turn on Trajectory View to load every cycle along the selected float’s trajectory.
- Open Analyze and select View section to see the time-series vertical section.
The dashed line marks the selected profile. Gray or blank areas can result from source gaps, quality masking, absent cycles, or too few adjacent observations to draw a section. If profile values exist but a section cannot be drawn, the section area explains the limitation; parameters with no usable profile data are disabled.
See Trajectory and Time-Series Vertical Section.
Step 4: Choose an Analysis — Signed In
Open Analyze in the map command bar and select Generate θ–S. With Trajectory View off, the diagram uses the current search results. With Trajectory View on, it uses every cycle loaded for the selected WMO ID. Selecting a marker highlights that profile’s temperature-salinity line. Open Analyze again and select Close θ–S to hide it.
Use θ–S to compare temperature-salinity structure. To group profiles by vertical structure instead, select Run clustering; markers are colored by cluster when processing finishes. Analyze shows progress and provides cancel or retry actions. On narrower layouts, use Map tools.
Both analyses accept at most 500 search-result profiles with Trajectory View off or 500 cycles with it on. OceanGraph does not sample, split, or page an oversized input. Narrow a search to recover availability; an oversized trajectory remains disabled with its cycle count shown in the reason.
See θ–S Diagram and Clustering.
Continue With Derived Data Layers
After the first workflow, signed-in users can compare automatically derived profile metrics from the map controls. Only one data layer can be active at a time.
- MLD — Open Data layer and choose MLD. Mixed Layer Depth is computed from potential temperature, absolute salinity, and potential density. It does not require BGC data, so it works on core Argo profiles. Profiles with no valid MLD are shown in gray.
- SOM — Open Data layer and choose SOM. Subsurface Oxygen Maximum requires dissolved oxygen, so it needs BGC profiles. Use Only profiles with BGC in your search first. Profiles without oxygen or a valid result are shown as no-data markers.
- Mode Water — Open Data layer and choose a type such as NPSTMW or NASTMW. Profiles with the selected mode water are colored by detected layer thickness; profiles without that selected mode water are shown as no-data markers.
When Trajectory View and the matching section chart are open, the MLD or SOM data layer also appears on the section. Mode water coloring applies to map markers.
See Mixed Layer Depth (MLD), Subsurface Oxygen Maximum (SOM), and Mode Water Data Layer.
If something doesn’t work
| Symptom | Likely cause and next step |
|---|---|
| No search results | The date range or area is too restrictive, or the BGC filter is on. Widen the range/area, or uncheck Only profiles with BGC. |
| θ–S or Clustering won’t run | The disabled item in Analyze gives the current count. With Trajectory View off, narrow the date range or bounds to 500 profiles or fewer. With it on, a WMO with more than 500 cycles cannot be analyzed. |
| A feature is missing from the screen | θ–S, Clustering, MLD, SOM, mode water data layers, and downloads require signing in. Sign in and try again. |
| A parameter has no section chart | Irradiance at 490 nm can be searched and downloaded but is not charted. For other parameters, the selector is disabled when no usable profile data exists; when profile data exists but adjacent-cycle support is insufficient, the section area explains the limitation. |
| Vertical section is gray or blank | Source data may be unavailable, QC- or hard-limit-masked, too sparse for a contour cell, or absent for that cycle. See Limitations. |
| MLD, SOM, or mode water markers are gray / no-data | The profile lacks a valid derived result. For SOM, use BGC profiles with dissolved oxygen. For mode water, the selected type may not have been detected under the current criteria. |
| Vertical Profiles won’t open on mobile | Vertical Profiles is desktop-only. Open it on a desktop browser via Menu > Analysis Lab > Vertical Profiles. |
For more on why data can be sparse or missing, see Limitations.
Where to go next
- Review the full Usage Guide and choose the workflow that matches your goal.
- Compare your own Argo-format JSON files in Vertical Profiles (signed-in, desktop only).
- Browse precomputed views in Visual Lab.
- Read the Articles for background on Argo floats, T-S diagrams, BGC parameters, and more.