1. Introduction
OceanGraph is a web platform for visualizing and analyzing Argo float oceanographic data. It offers interactive tools and profile information for researchers, students, and ocean enthusiasts.
2. Main features
For everyone
- Search Argo floats worldwide by region and time (up to a 30-day date range)
- Search only profiles that include dissolved oxygen data
- Search by WMO ID for direct access to specific floats
- Track individual float trajectories
- Visualize time-series vertical sections of Argo float data
For signed-in users
All free features, plus:
- Search Argo floats with an extended date range (up to 90 days)
- Visualize vertical profiles of temperature, salinity, and oxygen
- View mixed layer depth from profile data
- Analyze T-S diagrams to explore water mass characteristics
- Download observation profile data for custom analysis
- Save screenshots of search results and visualizations
- Store up to 3 saved search conditions for repeated use (*)
- Bookmark up to 5 float profiles for later reference or comparison (*)
- Cluster Argo float profiles for pattern analysis
- Explore and compare ocean profiles with customizable tools — learn more
(*) Titles can contain up to 64 characters, and notes up to 200 characters.
3. Data source
These data were collected and made freely available by the International Argo Program and the national programs that contribute to it (http://www.argo.ucsd.edu, http://argo.jcommops.org). The Argo Program is part of the Global Ocean Observing System.
DOI: Argo (2000). Argo float data and metadata from Global Data Assembly Centre (Argo GDAC). SEANOE. http://doi.org/10.17882/42182
4. Data filtering policy
In OceanGraph, only carefully selected Argo float profiles are used according to the following conditions:
4-1. Selection of profiles
- Only real-time (
R,BR) and delayed-mode (D,BD) profiles are used. - If both real-time and delayed-mode profiles exist for the same cycle, the delayed-mode profile (D or BD) is preferred.
- Drift profiles (those with a
Dat the end ofCYCLE_NUMBER) are excluded.
4-2. Required variables
Only profiles that include all of the following variables are used:
PLATFORM_NUMBERCYCLE_NUMBERJULDJULD_QCLATITUDELONGITUDEPRES_ADJUSTEDPRES_ADJUSTED_QCTEMP_ADJUSTEDTEMP_ADJUSTED_QCPSAL_ADJUSTEDPSAL_ADJUSTED_QC
4-3. Date and position quality control
- Only profiles with
JULD_QCvalues of 1 or 2 are used. - Only profiles with
POSITION_QCvalues of 1 or 2 are used. -
Even if a profile passes the
POSITION_QCcheck, some data may still be unreliable. For example, as shown in the red circle below, caution is advised when interpreting such data.
4-4. Sorting of data
The profiles are sorted in ascending order of PRES_ADJUSTED, and the following variables are reordered accordingly:
PRES_ADJUSTED_QCTEMP_ADJUSTEDTEMP_ADJUSTED_QCPSAL_ADJUSTEDPSAL_ADJUSTED_QCDOXY_ADJUSTED(if available)DOXY_ADJUSTED_QC(if available)
4-5. Depth range restriction
Only data from depths shallower than 2000 dbar are retained.
4-6. Profile quality filtering
Only profiles where at least 80% of PRES_ADJUSTED_QC, TEMP_ADJUSTED_QC, and PSAL_ADJUSTED_QC flags are either 1 or 2 are kept.
4-7. Interpolation of missing values
For dissolved oxygen concentrations, which often contain missing (NaN) values, the following interpolation procedure is applied:
- Linear interpolation is used for internal (non-endpoint) missing values.
- Remaining missing values at the beginning or end of the profile are filled using backward-fill and forward-fill, respectively.
4-8. Layer-by-Layer filtering
- Only layers where the QC flags for pressure, temperature, and salinity are all 1 or 2 are kept.
- For dissolved oxygen (
DOXY_ADJUSTED):- Data are kept if the corresponding pressure, temperature, and salinity flags are all 1 or 2.
- The QC flag of DOXY itself is not used for filtering. This is because oxygen sensor quality can vary significantly, and applying its QC flag strictly may severely limit the available data.
- Users should carefully interpret dissolved oxygen data due to potential sensor uncertainties.
| pres_qc | temp_qc | psal_qc | doxy_qc | Judgment |
|---|---|---|---|---|
| 1 or 2 | 1 or 2 | 1 or 2 | 1 or 2 | PASS |
| 0 | 1 or 2 | 1 or 2 | 1 or 2 | FAIL |
| 1 or 2 | 0 | 1 or 2 | 1 or 2 | FAIL |
| 1 or 2 | 1 or 2 | 0 | 1 or 2 | FAIL |
| 1 or 2 | 1 or 2 | 1 or 2 | 0 (*) | PASS |
(*) DOXY quality flag is not used in filtering.
4-9. Decimal precision
To reduce data size, the values are rounded to the nearest values shown below:
| Variable | Precision |
|---|---|
| Pressure | 0.01 |
| Temperature | 0.001 |
| Salinity | 0.001 |
| Dissolved oxygen concentration | 0.001 |
5. Legal information
For details regarding the terms of use and privacy policy, please refer to the following documents:
For documents in Japanese:
6. Contact information
- If you encounter any bugs or have feature requests, please submit them via Issues.
- For other inquiries, feel free to contact us at support(at)unvelyze.com.
7. Limitations & Usage Notes
For known limitations and important usage notes, please refer to: