Parent record: Vertical coherence of currents in Jervis Bay: Winter deployment of an Acoustic Doppler Current Profiler (ADCP)

Researchers: Holloway, Peter (principalInvestigator) ,  Nunes-Vaz, Rick (collaborator) ,  Robertson, Robin, Dr (Point of contact) ,  Symonds, Graham (collaborator)

Brief description This record describes components of the 'Jervis Bay Baseline Studies' project conducted by the Department of Defence, CSIRO and Australian Defence Force Academy (ADFA). The initial aims of the project were to obtain current and wind observations from Jervis bay over a six week period in order to detail the wind driven circulation and provide a data set for comparison with the numerical modelling work being simultaneously undertaken. However, after this initial experiment it became clear that there were significant currents in the bay that are not simply related to direct wind forcing. Therefore, alternative mechanisms for driving the flow had to be investigated, through the measurement programs and data analysis, as well as through numerical modelling. The result was a series of approximately six separate experiments aiming to define the water circulation around the bay and through the bay entrance, to gain an understanding of the processes that drive the currents, and to investigate the influence of stratification on the nature of the currents. The fifth of these six experiments involved the winter deployment of an Acoustic Doppler Current Profiler (ADCP), moored in the central part of Jervis Bay (35o 05'S, 150o 44'E). An ADCP measures how fast water is moving across an entire water column. Anchored to the seafloor it can measure current speed not just at the bottom, but also at equal intervals all the way up to the surface. For this experiment, the ADCP was moored on the seabed, in a frame, with sensors looking upwards and approximately 0.5m above the seabed. Over the winter deployment, 26th July 1991 to 26th September 1991, the ADCP was set-up with a 60 minute sampling interval and currents were measured over 1m depth bins. Bin numbers and currents are referenced as a height above the seabed (due to the uncertainty in defining water depth because of tides and air pressure). As such Bin #1 is centered at 1.5m above the transducer face or 2.0m above the seabed. Bin #2 is centered at 3m above the seabed, Bin #3 at 4m and so on. The water depth was measured as 24m on deployment and the first 19 bins provided good data. Currents from bin 20 up were very noisy and it is inferred that contamination had occurred. These bins were removed from the dataset. As this is a parent record, no data is available to download. A pdf outlining the structure and hierarchy of metadata records relating to this project is available through this record. Also available is a pdf of a published working paper documenting this experiment and the results. There is only one subsiduary records that directly relates to this parent, through which the data is provided (see hierarchical tree): fef1f3c0-6d9f-11dd-8128-00188b4c0af8

Lineage Maintenance and Update Frequency: notPlanned

Lineage Statement: Currents from bin 20 up were very noisy and it is inferred that contamination had occurred. These bins were removed from the dataset.

Lineage Statement: Acoustic Doppler Current Profiler (ADCP) serial number 458. Conductivity, pressure and temperature sensors were turned off.

Notes Credit
Funded by The Department of Defence

Notes Credit
Funded by CSIRO Division of Fisheries Research

Notes Purpose
To investigate the vertical coherence of currents in the bay and the coherence between the wind and currents at different water depths.

Data time period: 1991-07-26 to 1991-09-26

151.5,-34.5 151.5,-35.5 150.5,-35.5 150.5,-34.5 151.5,-34.5

151,-35

text: westlimit=150.5; southlimit=-35.5; eastlimit=151.5; northlimit=-34.5

text: uplimit=24; downlimit=0