netCDF for Temperatures

HelpDesk
1

Hi,

I’m trying to download Temperature (degC) information from one of the Coastal Pioneer profiler moorings via the online server. I selected the following parameters for download:

  • Mooring: Coastal Pioneer: CP02PMCI
  • Date range: 2015-05-01 to 2015-09-01
  • variables requested: Temperature

These options led me to the following link:
https://opendap.oceanobservatories.org/async_results/ivana@utexas.edu/20201212T040934428Z-CP02PMCI-WFP01-03-CTDPFK000-recovered_wfp-ctdpf_ckl_wfp_instrument_recovered/

I use Python’s xarray package to work with netCDF files, and have attached screenshots of codes through a Jupyter Notebook. When I loaded the data, there was no data variable for the temperature available (see attached).

After that failure, I attempted to download all available parameters and got a data variable with the name temperature that has units of counts. This variable leads to a wild range for temperature values, but the the values look like they could be related to the actual temperature values in degC (see attached again).

How is the value of counts related to the value of degC? How can I download the temperatures for a given date range and for given profiler mooring via the OOI User Interface?

Thanks,

Ivana Escobar

2

The “temperature” variable is indeed the raw data. For the processed data in degrees Celsius, you need to use the “ctdpf_ck_seawater_temperature” variable.

ctdpf_ck_seawater_tempeature uses temperature (recorded in counts) and converts it using the instrument calibration values and the Data Processing Algorithm ctd_sbe52mp_tempwat.

3

That’s exactly what I ended up doing after emailing for support. It would be nice to have a description linking the temperature and actual temperature values in the netCDF attributes.

Also is the temperature potential temperature?

4

This is not potential temperature.
We do not have a Data Product Specification document for the data processing algorithm. The code was developed using the vendor documentation (https://www.seabird.com/asset-get.download.jsa?id=54627862508) (see page 37).

5

Were you able to figure out how to download particular time sets of data through the OOI Data Portal?