# Presentation: 297655

## CPIES:  Current and Pressure recording Inverted Echo Sounder 

- Measures:
-  Round trip travel times of acoustic
-     pulses to sea surface and back.
-  Bottom Pressure
-  Bottom Temperature
-  Currents 50m above bottom
- Acoustic release and relocation aids
- Data Telemetry available
- Deployments of up to 5 years

## Results from PIES & CPIES measurements

- One PIES 		profiles of specific volume anomaly,
- 				steric height & mass-loading component SSH
- ________________________________________________________
- Two PIES /		profiles of baroclinic velocity /
-          CPIES 		plus barotropic referenced velocity
- 				= absolute velocity profile
- 	   1-D line 		velocity transect, absolute transports
- ________________________________________________________
- Three PIES /		profiles of baroclinic velocity _vector_ /
-           CPIES		plus barotropic velocity _vector_
- 				 = absolute velocity _vector_ profile
-          2-D array		4-D maps of velocity and density structure

## Tight empirical relationships exist between acoustic travel time and Fofonoff Potential and Geopotential Anomaly

- WOCE SR3 examples, in SAF south of Australia

- Mass Transport Streamfunction

- Baroclinic Velocity Streamfunction

## Φ3000 (m2 s-1)

- Φ3000 (m2 s-1)

- View the vertical structure of Specific Volume Anomaly, δ,
- in streamfunction coordinates...

- δ

- When indexed by Φ3000 the
- δ lookup table looks like this...

- WOCE SR3 examples, in SAF south of Australia

- 10-5
- kg/m3

## Φ3000 (m2 s-1)

- Φ3000 (m2 s-1)

- δ

- τ3000 (s)

- When indexed by τ3000 the
- δ lookup table looks like this...

- View the vertical structure of Specific Volume Anomaly, δ,
- in streamfunction coordinates...

- When indexed by Φ3000 the
- δ lookup table looks like this...

- 10-5
- kg/m3

## Two IESs:  Profiles of baroclinic velocity

**Notes:**
Note: IES estimate is the average between instruments while the current meter is a point measurement.  This accounts for a significant portion of the rms difference.

## Eastward baroclinic transports crossing WOCE SR3

- Solid – CTDs (S. Rintoul)
- Dashed – IES method

- Transports relative to 3000 dbar

## Three IESs, 2-D array:  		profiles of BC velocity vector 

- SYNOP moored Current Meter measurements and IES’s

- stack of velocities
- from
- Current Meters =>

- stack of velocities from
- <= IESs
-  (65 km
-   spacing)

- Three IESs, 2-D array:  		profiles of BC velocity vector

- ... differences can be entirely attributed to
- point sampling *vs.* lateral-average sampling differences

## A CPIES mapping array determines 

- A CPIES mapping array determines
- the velocity field as the sum of a
- baroclinic profile plus barotropic
- reference velocity

- The BC velocities are aligned in a single direction
- (called ‘equivalent barotropic’);
- adding a BT component can cause turning.

## Mesoscale array of PIESs and deep CMs: Abyssal cyclones develop under steep upper-jet troughs

- Maps show three fields
**Pressure field anomaly at 3500 m**  *I**n** **c**o**l**o**r*
**Depth of the 12°C isotherm** contoured –––  at 200 m intervals
**Velocity vectors at 3500 m**

- Tick marks: 50 km intervals

## Mesoscale array of PIESs and deep CMs: Abyssal cyclones develop under steep upper-jet troughs

- Mesoscale array of PIESs and deep CMs: Abyssal cyclones develop under steep upper-jet troughs

## PIES with deep current reference, e.g., CPIES capabilities

1-D transects provide absolute velocity and transport estimates
Cost-effective for high horizontal spatial resolution 
Geostrophic velocities are laterally integrated (intrinsically)
High temporal sampling for extended time periods (up to 5 years) 

2-D arrays of CPIESs can provide velocity structure
With mesoscale spatial and temporal resolution
Well-resolved maps allow for dynamical diagnoses & case-studies

- 1-D transects provide absolute velocity and transport estimates
- Cost-effective for high horizontal spatial resolution
- Geostrophic velocities are laterally integrated (intrinsically)
- High temporal sampling for extended time periods (up to 5 years)
- 2-D arrays of CPIESs can provide velocity structure
- With mesoscale spatial and temporal resolution
- Well-resolved maps allow for dynamical diagnoses & case-studies

- Summary

## End of planned presentation
Some extra slides follow

- Some extra slides follow

## IES-estimated temperatures agree with measured temperatures

- In the Sub-Antarctic Front south of Australia

-  Measured
- temperatures

- IES-estimated
-  temperatures

## Sort hydrographic data by _index 

- Sort hydrographic data by _index

- Choose reference _index

- Assemble regional
- hydrographic data set

- ... examples from Gulf of Mexico

- τ

-  T
- (oC)

## Fit cubic splines to data

- τ

-  T
- (oC)

## Final GEM field – a lookup table

- τ

-  T
- (oC)

## Final GEM field – a lookup table

- τ

-  T
- (oC)

## Three PIES and a deep CM yield profiles of absolute velocity vectors

- MMS / SAIC - Gulf of Mexico moorings

**Notes:**
If the IESs are in a triangle or square in a 2-D array, both north and east components of geostrophic velocity may be estimated as a function of depth.  
This plot from our SYNOP experiment compares directly measured currents at 100, 200, 400, 700, and 1000m relative to 3500m on a current meter mooring against currents simultaneously estimated at these same depths from a surrounding array of IESs.  The agreement was good, with the main differences again due to the difference of point sampling vs lateral-averaging.  In the weaker currents at the 1000m depth some other processes are evident, which represent a deviation from perfect estimation of currents by IES-GEM techniques.  

## IES-estimated currents agree with measured currents

- In the Sub-Antarctic Front south of Australia

- Dotted – Measured
-  currents
- Solid – IES-estimated
- currents

## A CPIES mapping array determines 

- A CPIES mapping array determines
- the velocity field as the sum of a
- baroclinic profile plus barotropic
- reference velocity

- The BC velocities are aligned in a single direction
- (called ‘equivalent barotropic’);
- adding a BT component can cause turning.

## Mapping and case studies, cont’dsteep meander loop, deep eddy field, and RAFOS tracks

**Tick marks: 50 km apart**

- Mapping and case studies, cont’dsteep meander loop, deep eddy field, and RAFOS tracks