first analysis of the nares strait ct-string data

First Analysis of theNares Strait CT-String

DataBerit Rabe

&Helen

Johnson

xo

• 6/8 CT-moorings recovered (each with 4 SBE37)• 2 missing ones are assumed to be lost, no signal• KS03: pressure sensor at 200dbar no data,but additional pressure sensor at 80dbar• All other ones: complete 3-year record

109m

SBE37 Mooring Design:

• Depth of instruments: 30m, 80m, 130m, 200m

• Pressure sensors at upper and lower instrument

• Flexible, made for bending due to icebergs

First evaluation of pressure data:Example: Pressure data KS05 upper instrumentRed: original dataBlue: 5 day low-pass filtered dataYellow: meanGreen: standard deviation

Time [days since 01/01/2003]

Pressure [dbar]

• Mean and standard deviation for low-pass filtered data• Higher variability at 30m than at 200m as expected• If pressure difference higher than 0.5dbar before and after deployment exponential fit was used

KS01 KS03 KS05 KS07 KS09 KS13

mean 36.78

40.25

38.81

45.67

53.90

43.41

std 4.02 5.74 5.36 8.09 5.73 5.04

mean 197.56

-------

200.05

201.24

216.34

202.75

std 0.79 -------

0.58 1.15 0.47 0.16

• TS diagrams for KS01 and KS13 upper instruments as a function of depth.

KS01

KS13

• Upper level: seasonal cycle, lowest salinity in summer

• Deepening of isohalines towards Ellesmere Island at 80 and 130dbar

3 year salinity time series

• Obvious seasonal variability, vertical instrument excursion and transient events...

• Was winter 2003 anomalous?

3 year temperature time series

KS01

KS03

KS05

KS07

KS09

KS13

Mean S for each depth bin (when instrument is there!)

Upper

2

3

Lower

*

x

Salinity Profiles

KS01

KS03

KS05

KS07

KS09

KS13

Mean T for each depth bin (when instrument is there!)

Upper

2

3

Lower

*

x

Temperature Profiles

KS01 - CTD 2003

KS03

KS05

KS07

KS09

KS13 - CTD 2003

- CTD 2006 (dashed)

Two tidal cycles....

Upper

2

3

Lower

*

x

Salinity - Julian Day 220, with 2003 and 2006 CTD profiles

KS01 - CTD 2003

KS03

KS05

KS07

KS09

KS13 - CTD 2003

- CTD 2006 (dashed)

Two tidal cycles....

Upper

2

3

Lower

*

x

Temperature - Julian Day 220, with 2003 and 2006 CTD profiles

What next?!

• Remaining calibration issues.

• Plot some sections - “snapshots” in time and mean picture in any given season.

• Look at particular events (and their signature in ADCP and IPS data too).

• Quantify changes in baroclinic transport on various timescales (and examine their causes).

• Lots lots more.....!