Hi there.
I have been looking at the information on the METBK package: METBK - Ocean Observatories Initiative. where it lists Wind Velocity at 10m as one of the data products. However, in the data explorer I cannot find this product for the Global Southern Ocean. The data products available are winds: Northward, and winds: Eastward. Is this the Wind Velocity at 10m? If not, how can I find what height these are measured.
Thank you,
Ann Johansen
If I had to guess, based on the data explorer metadata, the northward and eastward components are not referenced to 10m, but are instead used as ancillary variables to get windspeed at 10m. In short, the WIND10M data product is available in the metbk_hourly data product files, but does not appear to be displayed in data explorer.
For GS01SUMO, there are two streams of data associated with the METBK that you may be interested in. There is data recovered from the host computer/sensor (metbk_a_dcl_instrument*) which generally contains full resolution data. Then there is also the hourly data product stream (metbk_hourly). Looking at files for both of these streams, it seems like the metbk_hourly files only contain the parameter met_wind10m (which is what you are looking for). If you were to use DataExplorer to navigate to the Thredds files, it would eventually take you to the four links below for GS01SUMO.
There are actually two METBK sensors on GS01SUMO. For simplicity, I will only link the data recovered from the host computer/sensor.
METBK-#1-Instrument (Full Res - No met_wind10m)
METBK-#1-Hourly (Hourly - Yes met_wind10m)
METBK-#2-Instrument(Full Res - No met_wind10m)
METBK-#2-Hourly(Hourly- Yes met_wind10m)
Here is the comment for the met_wind10m data product in the metbk_hourly .nc files.
comment = “Standardized wind speed at a reference height of 10m adjusted from measurements collected at approximately 5 meters height above the waterline.”;
You can access buoy deployment configurations here. Navigate to Global Southern Ocean Array > Asset Information > Southern Ocean Surface Mooring. For the last deployment of the mooring (2018-11_00004 > GS01SUMO-00004.xlsx), it looks like the METBK wind sensor was measured 529cm above the buoy deck (which is not exactly the waterline). But the assumption of a 5m sensor height may be reasonable if you are looking to re-calculate the data product.
Some other info that might help.
Here is the OOI Data Product Specification for met_wind10m. Search for WIND10M.
Here is the Python code used for calculating met_wind10m.
Here is the link to the entirety of the OOI Thredds catalog.
To get data associated with METBK-#1 for GS01SUMO, you would need to search for (CTRL + F) GS01SUMO-SBD11-06-METBK.
To get data associated METBK-#2 for GS01SUMO, you would need to search for (CTRL + F) GS01SUMO-SBD12-06-METBK.
I have spent some time in the Thredds catalog, and this has made it a bit easier to understand. I think for the purpose of my research I would not want to use the relative wind speed (relative to the surface current), so knowing where to find the deployment configurations is very helpful, thank you! And it seems as though the 10m wind speed calculated from the python function you linked, uses the relative wind speed in its calculation, and thus would not be of use for me. So this has saved me some time.
Many thanks, again!
Hi Ann,
While the deployment configuration is a great reference document, there is also a publicly available resource with the deployed sensor elevations/depths. The METBK wind sensors are deployed at a height of about 6 m above the waterline on the Global Surface Moorings after accounting for the distance between the waterline and buoy deck (5 m for the Coastal Surface Moorings). This and other sensor heights or depths are listed in the file named vocab.csv in the oceanobservatories/asset-management repository on GitHub here: https://github.com/WHOIGit/ooicgsn-asset-management/blob/main/vocab/vocab.csv
You can filter down to the wind sensors for different arrays with METBKA007 in the search bar at the top of the CSV preview. If I were deriving my own 10 m winds time series, I would use these sensor heights for a more accurate result.
Cheers,
Kylene