RV Investigator Voyage IN2015_V02 ADCP Data

Full description

This record describes the Acoustic Doppler Current Profiler (ADCP) data collected from the Marine National Facility RV Investigator voyage IN2015_V02, titled: "Sustained monitoring of the East Australian Current: Mass, heat and freshwater transports." The voyage took place between May 15 and May 26, 2015 departing Sydney (NSW) and returning to Brisbane (QLD).

Data was collected during in2015_v02 for the duration of the voyage. Data was collected using VMDAS and post-processed using CODAS.
Both the OS75 and the OS150 ADCPs were operated for the duration of the voyage.
Due to issues with VMDAS acquiring serial data, all navigation data was regenerated from Techsas acquired NMEA strings.
Significant work was conducted by the science party to investigate the correct ADCP settings, which involved various permutations of broadband vs narrowband modes, and different keel depths. The findings are summarised in the report ‘ADCP_Report_INV2015_V02_Wijffels_final.pdf, supplied as part of the processed dataset. Additional documentation is in the ‘docs_from_voyage’ folder. The summary from that report is as follows:
• both ADCP Ocean Surveyors had transducer alignment errors. The current estimate of the angles to put into VMDAS are: OS150 = 44.35 ( EA= 4435 in config file); OS75 = 52.44 (EA=5244 in config file)
• Both OS’s were losing comms every 20 mins to 3 hours, then autostarting Sometimes the loss of comms would permanently stop acquisition (not auto restart). Changing out the Serial-USB comms cable might have fixed this.
• the OS150 has several issues in BroadBand Mode which degrades the data:
1. It is badly affected by bubbles flowing under the ship. This is lessened with reduced shipspeed and lowering the drop keep. It never really disappears unless the ship is stopped. The first 1-5 bins need to be carefully screened for unrealistic shears. This affect is reduced in Narrow Band mode.
2. It suffers from strong interference from the OS75 and the EK60.
• The OS75 suffers much less from bubble problems. It does however suffer from interference from both the OS150 and more weakly the EK60 (needs checking).
• It is clear from the echograms that the sADCP’s interfere with the EK60. This would have to either be edited out or prevented for quantitative use of the EK60 output.
Each permutation of settings used was processed separately, and the files concatenated together post processing. Please see ‘ADCP_Report_INV2015_V02_Wijffels_final.pdf’ for details of different settings used.

This dataset was processed and then archived within the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart.

Lineage

Progress Code: completed

Maintenance and Update Frequency: asNeeded

Statement: Data source: original field data. Data processing and quality control: Performed by Hugh Barker O&A DAP Group. Note that 1min average data is provided as a special request, however it is unedited and has data quality implications. For general use, the 5min average data (os150nb.nc) should be used.

Notes

Credit
ADCP data processed by Hugh Barker (CSIRO O&A, MNF Data Acquisition and Processing group).