Float WMO_ID: 5901639

Float WMO_ID: 5901639




Table of Contents

  1. Float Information
  2. Float Location
  3. Surface Pressure
  4. Potential Temperature-Salinity Plot
  5. Temperature-Salinity Comparison with Nearby Floats
  6. Inversions
  7. Salt Hooks
  8. Parameter Sections and Initial QC Notes
  9. WJO/OW Results
  10. Anomaly Plot
  11. Comparison with Nearby Argo
  12. Salinity Drift Assessment
  13. Float Summary



Section 1: Float Information

The table below provides basic information about the float, including primary sensors, mission parameters and current status of profiles.


Institute CSIRO
Principal InvestigatorSusan Wijffels
Pressure SensorDruck (serial number=2385259)
CTD SensorAPEX-SBE-41 (serial number=3304)
CTD Sampling ModeBurst Sampler
Controller BoardAPF 8
Additional Sensors/SoftwareNone
Park Depth1000 m
Profile Depth2000 m
Launch Date18-11-2007
Number of D-moded Profiles81
Calibration Date29-07-2010
Pressure DriftSurface Pressure Offset corrected
Salinity DriftNo salinity drift detected





















Section 2: Float Location

Float trajectory and location plot

This float was located in the central Indian Ocean, in an area bounded by 86 to 91 ºE and 14 to 18 º S.


Section 3: Reported Surface Pressure

The surface pressure for this float is shown in the plot below.


Surface Pressure plot

Section 4: Potential Temperature-Salinity Plot

Potential Temperature-Salinity (a), Location (b, Max Temperature (c) and Sea Surface Salinity (d) plots located below.

Potential Temperature-Salinity, Location and Max Temperature and Sea Surface Salinity plots

Surface temperatures generally varied between 23.5 and 28 ºC and surface salinities from 33.9 to 35.0.


The plot below shows the potential-temperature/salinity relationship for the deepest theta levels where the relationship between the two parameters should show the least variation.

Potential Temperature-Salinity deepest theta levels alternate plot Potential Temperature-Salinity deepest theta levels plot

There is considerable spread in the profiles at depth. The later profiles are significantly more variable and saltier throughout the water column. The float is in a dynamic region and even though the later profiles trace the earlier float path (and may therefore be expected to be similar) the profiles are 30 cycles apart (i.e.~300 days) and water masses and fronts may have moved in that time - therefore the float is probably reflecting real variability.


Section 5: Temperature-Salinity Comparison with Nearby Floats

The two plots below show a). the location of this float (black circles) in relation to the position of other nearby argo floats (coloured circles) and b). The potential-temperature/salinity curve for this float (in black) compared to nearby argo floats (coloured).

Potential Temperature-Salinity nearby comparison plot

The potential-temperature/salinity relation for the deepest theta levels for this float (in black) and nearby argo floats (coloured) is displayed below.


Potential Temperature-Salinity nearby deep comparison alternate plot Potential Temperature-Salinity nearby deep comparison plot

There are not many other floats to compare this float with.


Section 6: Inversions

There were inversions in profiles; 3,44,48,92. These were not significant and were not flagged.


Section 7: Salt Hooks

Salt hooks were located in profiles; 6,8,11,12,15,17,19,25,26,27,30,31,32,33,34,36,38,41,43,44,49,51,53,55,57,59,61,63,65,67,69,71,73,75,77,80. These were flagged as QC 4 for both T & S.


Section 8: Parameter Sections and Initial QC Notes

The float grounded on profiles; 20 to 22, 29, 41 and 42. A large high salinity spike in profile 3 at the base of the mixed layer was QC'd as 4 for both T & S at 44m. Similarly, a spike in profile 1 in midwater was QC'd as 4. The last value of profiles 2 and 24 were QC'd as 4 for both T & S.


Float trajectory overlayed on bathymetry, (left) and over climatological salinity (right)
Float trajectory and bathymetry plot Float trajectory and salinity plot

Potential temperature section with time, (left) surface to 2000m and (right) surface to 500m

Potential Temperature Plot - Full Depth Range Potential Temperature Plot - Surface to 500m

Salinity section with time, (left) surface to 2000m and (right) surface to 500m

Salinity Plot - Full Depth Range Salinity Plot - Surface to 500m

Potential density section with time, (left) surface to 2000m and (right) surface to 500m

Potential Density Plot - Full Depth Range Potential Density Plot - Surface to 500m

Section 9: WJO/OW Results

The plot below shows the analysis of salinity drift using the WJO/OW software.


WJO/OW plot

Section 10: Anomaly Plots

The four plots below show the salinity anomalies on theta surfaces compared to (a) the Gouretski and Kolterman climatology, (b) the CARS (CSIRO Atlas of Regional Seas)/WOA (World Ocean Atlas) climatology, (c) the anomalies within the float series itself, (i.e. the salinity anomaly of each profile from the mean profile average for the float and (d) the raw float salinity compared to the CARS and G&K climatological salinity on a theta surface of 0.xx degrees C.


Anomaly Plot

The float was close to both CARS and G&K in a highly variable region and is therefore behaving well.


Section 11: Comparison with Nearby Argo

The plots below show the raw float salinity data (solid blue line) compared to neighbouring argo floats (coloured symbols) on a potential temperature surface of xx degrees C. The locality map shows the location of the profiles for this float and for neighbouring floats.


Nearby Argo Comparison Plot Nearby Argo Location Plot

This float is similar to some other nearby floats, however there is a huge variation at depth and a comparison with other floats is not conclusive. It looks okay above 5 degrees C but below this level there is lots of variation. Check this float once more profiles become available, to see if it goes right off or comes back into line!


Section 12: Salinity Drift Assessment

This float required no salinity drift correction.



Section 13: Float Summary

Final Check Plot

The plot below summarises the QC flags and salinity differences for the raw and adjusted salinity fields in the final delayed mode files submitted to the GDAC.



Created 29-07-2010