The Relative Influence of Salinity and Temperature on ...The Relative Influence of Salinity and...

The Relative Influence of Salinity and Temperature on Surface Density Gradient in the Tropical Pacific Ocean

Audrey Hasson, Tony Lee

Ocean Salinity Science and Salinity Remote Sensing Workshop Met Office, Exeter, UK, 26-28 November 2014

2

INTRODUCTION

•  Surface Salinity (SSS) and Temperature (SST) influence surface Density through the Equation of State :

ρ-ρ0=ρref {-α(T-T0)+β(S-S0)}

•  Density gradients in the tropical Pacific are mainly meridional and are associated with baroclinic instabilities

•  Salinity fluctuations can regulate the baroclinic energy transfer (McPhaden et al. 1984, Grodsky et al. 2005, Lee et al., 2014)

•  The new spaceborn SSS datasets give a new capability to enhance our knowledge of the density field and its variability as well as the contribution of SSS and SST

November 27th, 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop

3

DATA SSS :

–  Aquarius/SAC-D level-3 gridded dataset (V3.0 by the Aquarius Project via PO.DAAC) 1º spatial resolution from combined passes averaged over 7 day for August 2011-July 2014

–  SMOS level-3 gridded dataset (v2013 CEC-LOCEAN) ¼º grid every 10 days for January 2010-July 2014

–  ISAS in situ based optimal interpolation, 1º spatial resolution, monthly for 2010-July 2014 (Ifremer)

SST : –  OSTIA level-4 product (V1.0 by the UK Met Office), 0.054º grid at daily

interval from 2006 to present –  Reynolds level-4 product (V2.0 by NCDC/NOAA) ¼º daily from 1981 till

present –  ISAS as for SSS

Currents: –  OSCAR level-4 product (by ESR), 0.33º grid, every 5 days, 1992 to present

All averaged on a 1º grid every 7 days over the Aquarius period November 27th, 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop

4

DATA SSS :

–  Aquarius/SAC-D level-3 gridded dataset (V3.0 by the Aquarius Project via PO.DAAC) 1º spatial resolution from combined passes averaged over 7 day for August 2011-July 2014

–  SMOS level-3 gridded dataset (v2013 CEC-LOCEAN) ¼º grid every 10 days for January 2010-July 2014

–  ISAS in situ based optimal interpolation, 1º spatial resolution, monthly for 2010-July 2014 (Ifremer)

SST : –  OSTIA level-4 product (V1.0 by the UK Met Office), 0.054º grid at daily

interval from 2006 to present –  Reynolds level-4 product (V2.0 by NCDC/NOAA) ¼º daily from 1981 till

present –  ISAS as for SSS

Currents: –  OSCAR level-4 product (by ESR), 0.33º grid, every 5 days, 1992 to present

All averaged on a 1º grid every 7 days over the Aquarius period November 27th, 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop

5

Pacific Ocean Meridional gradient of surface ρ

170oE 170oW 150oW 130oW 110oW 90oW 70oW 50oW 30oW 10oW 10oE

10oS

0o

10oN

(a) Density Mean − Aqua − Ostia

202122232425


10oS

0o

10oN

(b) Density Standard Deviation − Aqua − Ostia

0.350.550.750.951.151.35


10oS

0o

10oN

(c) Density Mean Meridional Gradient − Aqua − Ostia

−2−1.2−0.40.41.22

x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(a) Mean SSS − Aqua

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(b) Mean SSS − Smos

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(c) Mean SSS − Isas

32.9

33.5

34.1

34.7

35.3

35.9

36.5

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(d) Beta SSS Meridional Gradient − Aqua

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(e) Beta SSS Meridional Gradient − Smos

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(f) Beta SSS Meridional Gradient − Isas

−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(a) Mean SST − Ostia

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(b) Mean SST − Rey

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(c) Mean SST − Isas

22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(d) −Alpha SST Meridional Gradient − Ostia

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(e) −Alpha SST Meridional Gradient − Rey

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN

(f) −Alpha SST Meridional Gradient − Isas

−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

•  When looking in the density space, SSS and SST meridional gradients are of the same magnitude


Contributions of SSS (Aquarius v3) and SST (OSTIA)

6


SSS dominates density where we observe strong regional gradients : •  in the upwelling zones •  near the ITCZ and SPCZ •  around the great estuaries (Amazon, Congo, Niger)


10oS

0o

10oN


202122232425


10oS

0o

10oN


0.350.550.750.951.151.35


10oS

0o

10oN


−2−1.2−0.40.41.22

x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


32.9

33.5

34.1

34.7

35.3

35.9

36.5

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

•  When looking in the density space, SSS and SST meridional gradients are of the same magnitude

•  SSS and SST both contribute around the equator




10oS

0o

10oN


202122232425


10oS

0o

10oN


0.350.550.750.951.151.35


10oS

0o

10oN


−2−1.2−0.40.41.22

x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


32.9

33.5

34.1

34.7

35.3

35.9

36.5

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

7


β ∂S/∂y is much larger than –α ∂T/∂y at the equator


β*dS/dy -α*dT/dy 1ºN -1.3 -1.4

Equator -0.8 -0.1 1ºS -0.3 0.8

*10-6


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN

15ºN(a) Beta .* dSSS/dy

−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN

15ºN(b) − Alpha .* dSST/dy

−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN

15ºN(c) dDensity/dy

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN

15ºN(d) STD Beta .* SSS

Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN

15ºN(e) STD Alpha .* SST

Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN

15ºN(f) STD Density

Aqua Ostia

Smos Rey

Isas Isas

Profiles over 220 − 261ºE

−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.3 0.4 0.5 0.6 0.7 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


8

Comparison of SSS and SST products Pacific Ocean Meridional gradient of surface ρ


All SSS and SST products show consistent meridional profiles

SSS •  All SSS products show

relative maxima at the same latitudes

•  ISAS SSS fronts are weaker •  SMOS fronts are stronger

SST •  All SST product show similar

amplitude in the maxima •  ISAS SST maxima are shifted

poleward and less narrow

9

Contributions of SSS (Aquarius v3) and SST (OSTIA) Variability of ρ in the 14-50d band

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(a) STD Density (14−50d filtered) − Aqua − Ostia

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(b) STD SSS (14−50d filtered) − Aqua

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(c) STD SST (14−50d filtered) − Ostia

0.03

0.09

0.15

0.21

0.27

0.33

0.05 0.1 0.15 0.2 0.25 0.310ºS

5ºS

0

5ºN

10ºN

15ºN(c) STD TIW (14−50d) Density

0.02 0.04 0.06 0.08 0.110ºS

5ºS

0

5ºN

10ºN

15ºN(b) STD (50−80d) Density

0.1 0.2 0.3 0.4 0.5 0.610ºS

5ºS

0

5ºN

10ºN

15ºN(a) STD (< 365d) Density

•  In the Pacific Ocean, strongest variability found with 3ºN off the equator and around 7.5ºN

•  Contribution of SSS in the 2 zones •  Contribution of SST only near equator


Pacific Atlantic

10

Contributions of SSS (Aquarius v3) and SST (OSTIA) Variability of ρ in the 14-50d band

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(a) STD Density (14−50d filtered) − Aqua − Ostia

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(b) STD SSS (14−50d filtered) − Aqua

170oE 150oW 110oW 70oW 30oW 10oE

10oS

0o

10oN

(c) STD SST (14−50d filtered) − Ostia

0.03

0.09

0.15

0.21

0.27

0.33

0.05 0.1 0.15 0.2 0.25 0.310ºS

5ºS

0

5ºN

10ºN

15ºN(c) STD TIW (14−50d) Density

0.02 0.04 0.06 0.08 0.110ºS

5ºS

0

5ºN

10ºN

15ºN(b) STD (50−80d) Density

0.1 0.2 0.3 0.4 0.5 0.610ºS

5ºS

0

5ºN

10ºN

15ºN(a) STD (< 365d) Density

•  In the Pacific Ocean, strongest variability found with 3ºN off the equator and around 7.5ºN

•  Contribution of SSS in the 2 zones •  Contribution of SST only near equator


Pacific Atlantic

11

From SSS (Aquarius v3) and SST (OSTIA)

Sources of variability in the 14-50d band

–  Baroclinic instabilities via the 50d low passed (LF) meridional density gradient (a) –  Barotropic instabilities via the LF meridional gradient of zonal current (b) –  Freshwater fluxes via Precipitation standard deviation (c)

•  Tropical Instability Waves (TIWs) which extract energy through: –  Baroclinic conversion between the background available potential

energy and the perturbation potential energy (PPE) –  Barotropic conversion between the background kinetic energy

and the perturbation kinetic energy –  We neglect the Kelvin-Helmholtz conversion (daily and shorter

fluctuations)

•  Freshwater fluxes mainly in the ITCZ and SPCZ


12



−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN

15ºN(a) Mean LF Density Gradient

−1 −0.5 0 0.5 1x 10−6

10ºS

5ºS

0

5ºN

10ºN

15ºN(b) Mean LF dy/du

0 2 4 6 8 1010ºS

5ºS

0

5ºN

10ºN

15ºN(c) P std deviation

Pacific Atlantic


To give an idea on where sources of variability are important: 3 proxies


Baroclinic proxy Barotropic proxy Freshwater f. proxy

13





−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


−1 −0.5 0 0.5 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 2 4 6 8 1010ºS

5ºS

0

5ºN

10ºN




Pacific Atlantic

5.5ºN -

7.5ºN

14



−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


−1 −0.5 0 0.5 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 2 4 6 8 1010ºS

5ºS

0

5ºN

10ºN






Pacific Atlantic

2.5ºN -

4.5ºN

15



−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


−1 −0.5 0 0.5 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 2 4 6 8 1010ºS

5ºS

0

5ºN

10ºN






Pacific Atlantic

0.5ºS -

1.5ºN

16



−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


−1 −0.5 0 0.5 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 2 4 6 8 1010ºS

5ºS

0

5ºN

10ºN



Baroclinic proxy

The recent SSS datasets give a new insight to the Baroclinic Energy conversion between the background available potential energy and the TIW induced Perturbation Potential Energy (PPE)

17


Indication of Baroclinic conversion of energy

–  High correlation in SST as found by Shelton et al. (2000) over 1998-99 –  High correlation in SSS as well

Shows the relation between the 14-50d variability and the low frequency meridional gradient, reflecting baroclinic energy transfer between the TIW and background field

SST SSS

Between 0.5ºS and 1.5ºN


R2=0.71 R2=0.75

LP Mean SST gradient LP Mean SSS gradient

14-5

0d S

ST

std

14-5

0d S

SS

std

Pacific Atlantic

November 27th, 2014 Ocean Salinity Science and Salinity Remote Sensing Workshop 18

ρ’2 as a proxy for the PPE and baroclinic conversion rate Contribution of S and T to density variance


10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN

(b) Mean Rho(SSS)’^2


10oS

0o

10oN

(c) Mean Rho(T)’^2


10oS

0o

10oN

(d) Mean −2*Beta*SSS’*Alpha*SST’


10oS

0o

10oN

(e) Mean Mean Rho(SSS)’^2 −2*Beta*SSS’*Alpha*SST’’

0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

Perturbation Potential Energy (PPE) :


10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

PPE is linked to Baroclinic conversion if no transfer from Kinetic to Potential Energy

!′! = !! !"′ ! + −!"′ ! − 2!"#′!′ !




10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

Perturbation Potential Energy (PPE) Is proportional to :


10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

Direct contribution of SSS

Direct contribution of SST

Contribution of the SSS and SST covariance

!′! = !! !"′ ! + −!"′ ! − 2!"#′!′ !




10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046



10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

Direct contribution of SST

Direct and indirect contribution of SSS



Omitting SSS to the PPE computation lead to an underestimation of •  72% in the entire domain •  66% in the northern edge

of the CT •  84% in the ITCZ consistent with Grodsky et al. (2005) and Lee et al. (2014) findings in the Atlantic Ocean.


10oS

0o

10oN

(a) Mean Rho’^2


10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN



10oS

0o

10oN


0.006

0.011

0.016

0.021

0.026

0.031

0.036

0.041

0.046

!′! = !! !"′ ! + −!"′ ! − 2!"#′!′ !


22

CONCLUSIONS

•  Satellite measurements of SSS has enabled the studies of the relative contribution of SST and SSS on the mean meridional density gradient as well as the TIW-related density variability on basin scale.

•  Salinity has a substantial effect on meridional gradient

and thus TIW-related baroclinic energy conversion, both in the Pacific and the Atlantic.

•  All SSS and SST products are consistent. Spaceborn data captures sharp gradients and variability not seen in gridded observations.


Date Goes Here Name of presentation or other info goes here 24

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


32.9

33.5

34.1

34.7

35.3

35.9

36.5

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


22.8

23.8

24.8

25.8

26.8

27.8

28.8

170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


170oE 150oW 110oW 70oW 30oW 10oE 10oS

0o 10oN


−2

−1.6

−1.2

−0.8

−0.4

0

0.4

0.8

1.2

1.6

2x 10−6


10oS

0o

10oN


202122232425


10oS

0o

10oN


0.350.550.750.951.151.35


10oS

0o

10oN


−2−1.2−0.40.41.22

x 10−6

−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.2 0.4 0.6 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−2 −1 0 1x 10−6

10ºS

5ºS

0

5ºN

10ºN


−4 −2 0 2x 10−6

10ºS

5ºS

0

5ºN

10ºN


0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Aqua

Smos

Isas

0 0.1 0.2 0.3 0.4 0.510ºS

5ºS

0

5ºN

10ºN


Ostia

Rey

Isas

0.2 0.4 0.6 0.810ºS

5ºS

0

5ºN

10ºN


Aqua Ostia

Smos Rey

Isas Isas




Baroclinic conversion of energy

−2 0 2

x 10−6

0

0.05

0.1

0.15

0.2

0.25

mean LF SST gradient

std T

IW S

ST

−2 0 2

x 10−6

0

0.05

0.1

0.15

0.2

0.25

mean LF SSS gradient

std T

IW S

SS

4.5ºS

2.5ºS

0.5ºS

1.5ºN

3.5ºN

5.5ºN

7.5ºN

9.5ºN

10.5ºN

Pacific (blue) and Atlantic Oceans (red) between −5.5−11.5ºN

(a) (b)

Pacific Atlantic

Oct11 Jan12 Apr12 Jul12 Oct12 Jan13 Apr13 Jul13 Oct13 Jan14 Apr140

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018


0.005

0.01

0.015

0.02

0.025

0.03

0.035

(Rho’)2 (Beta*SSS’)2 (−Alpha*SST’)2 −2*Beta*SSS’*Alpha*SST’

110ºW − 0.5ºN

15.5ºW − 0.5ºN


Contribution of SSS and SST Seasonality of the baroclinic conversion rate


0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018


0.005

0.01

0.015

0.02

0.025

0.03

0.035

(Rho’)2 (Beta*SSS’)2 (−Alpha*SST’)2 −2*Beta*SSS’*Alpha*SST’

110ºW − 0.5ºN

15.5ºW − 0.5ºN

27

Contribution of SSS and SST Seasonality of the baroclinic conversion rate

Seasonal cycle in the proxy for PPE Maximum from July to January – consistent with TIW activity cycle Contribution from SST following the cycle Contribution from SSS has a strong interannual variability


The Relative Influence of Salinity and Temperature on ...The Relative Influence of Salinity and...

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