The Data Management and Archiving System (DMAS) stores all the data streaming in from instruments connected to the VENUS network. Scalar data are parsed into the database.
Web Services Description Language (WSDL) in combination with Simple Object Access Protocol (SOAP) tools developed by DMAS are used used to connect to the database and import data directly into MATLAB’s workspace. In order to make sure the time series is as regularly spaced as possible, some data reconstruction is required. MATLAB is used to insert evenly spaced NaN’s according to the instrument’s sample period to represent data gaps.
Once the original scalar time series has been reconstructed, MATLAB routines developed by the VENUS Data Team generate data products for web display. The Data Plots section automatically displays data from the last 24 hours, as well as the last week (7 days), the last month (31 days) and the last year (365 days). 24 hour plots are updated every 10 minutes and the longer term plots are updated daily. The longer time periods (last week, last month, last year, entire record) are constructed using sub sampled data because large data sets take longer to query and reconstruct. The sub sampled data sets are composed of the hourly maximum and minimum data values. Users can view these data products by clicking on the icons in the table on the Data Plots page. Higher resolution and PDF versions of the data plots are available for downloading. The figure to the left describes the text, axes and title for the scalar time series data plots. Click on the graphic for a larger view.
VENUS website users can view the 400×300 pixel PNG images displayed by default on the page with an option to download 800×600, and 1200×900 pixel PNG files as well as a PDF version for printing (see the Data Galleries section). The figure to the left describes the text, axes and title for the scalar time series data plots. Click on the graphic for a larger view.
VENUS users can also download data in the Download Data section. You can choose the time period, location, instrument, sensor, and data product you want to generate. Right now, users can only download the raw data streams. We are currently working on a new user interface with various analysis and processing options. The data product options in the Download Data section are:
- data plot in PDF or PNG format
- file for MATLAB users
- CSV (Comma Separated Value) text file
- ODV4 Generic Spreadsheet
More products will be available as they are developed.
Scalar Data Units
The table below lists some scalar instruments and sensors on VENUS including a description of their units of measurement:
| Instrument | Sensor | Units | Description |
|---|---|---|---|
| Aanderaa Optode 4175 SeaBird 43 Oxygen |
Oxygen | ml/l | Dissolved oxygen in mililitres per litre of seawater |
| Temperature | deg C | External Temperature | |
| Pro-Oceanus Systems, Inc. Gas Tension Device (GTD) | Temperature | deg C | Internal Temperature |
| Gas Pressure | mbar | Total Dissolved Gas Pressure | |
| Falmouth Scientific, Inc. NXIC CTD SeaBird Electronics, Inc. 16plus CTD Alec Electronics CTW |
Conductivity | S/m | Siemens (electrical conductance) per metre |
| Pressure | decibar | Pressure of Seawater (1 decibar ~= 1 m depth) | |
| Density | kg/m^3 -1000 | Density of seawater without the effect of pressure | |
| Salinity | psu | Practical Salinity Unit | |
| Temperature | deg C | External Temperature | |
| SeaTech Transmissometer | Transmission | % | % Light Transmission through Seawater |
| AquaDopp Current Meter | Current Direction Calculated | degrees | Current Direction calculated after data are received, before parsing into the database |
| Current Speed Calculated | m/s | Current Speed calculated after data are received, before parsing into the database | |
| Current Velocity (Beam1-X-East) | m/s | U / East Velocity with respect to True North | |
| Current Velocity (Beam2-Y-North) | m/s | V / North Velocity with respect to True North | |
| Current Velocity (Beam3-Z-Up) | m/s | W / Vertical Velocity with respect to True North | |
| Pressure | decibar | Pressure of Seawater (1 decibar ~= 1 m depth) | |
| Temperature | deg C | External Temperature | |
| SeaPoint Turbidity | Turbidity | FTU | Formazin Nephelometric Unit (device calibrated using Formazin) |
| WetLabs FLNTU Wetlabs ECO-NTU(RT) |
Turbidity | NTU | Nephelometric Turbidity Units |
| Chlorophyll | ug/l | Concentration (microgram per litre) |
