dimes: diapycnal and isopycnal mixing experiment in the southern
TRANSCRIPT
![Page 1: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/1.jpg)
DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean
• A US+UK experiment • Diapycnal diffusion and isopycnal dispersion and eddy fluxes • Improve eddy parameteriza>ons in models of the MOC for climate variability
WHOI
FSU
SIO
UW/APL
UEA
BAS
NOC Southampton
SAMS (Scotland) Read all about it: http://dimes.ucsd.edu/
![Page 2: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/2.jpg)
Why K? Dominant momentum balances:
V = net meridional volume flux, τo = wind stress η = layer thickness, p = pressure, pb = bottom pressure
Surface -fV1 = τo
-fV2 = η'1p'1x - η'2p'2x
-fV3 = - hpbx “blocked” layer
ρ1
ρ2
ρ3
…adapted from Olbers
Side view of the ACC
zonally open
τo
![Page 3: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/3.jpg)
Why K? Dominant momentum balances:
V = net meridional volume flux, τo = wind stress η = layer thickness, p = pressure, pb = bottom pressure
Surface -fV1 = τo
-fV2 = η'1p'1x - η'2p'2x ≈ K dq/dy
-fV3 = - hpbx
zonally open
“blocked” layer
ρ1
ρ2
ρ3
…adapted from Olbers
Side view of the ACC τo
![Page 4: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/4.jpg)
![Page 5: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/5.jpg)
DIMES Overview
X X
UK2.5
![Page 6: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/6.jpg)
The tracer
• Trifluoromethyl-‐sulphur-‐pentafluoride.
• Inert, non-‐toxic. • 1 milligram is detectable in a cubic kilometer of seawater, by gas chromatography with electron capture detec>on.
CF3SF5
Ledwell Watson
![Page 7: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/7.jpg)
R/V Revelle, 5 Jan to 1 Mar 2009
US1 Cruise Track and Deployments
Sound sources
Tracer release
CTD surveys Float deployments
SoSo large blue Solo small blue Rafos black CTD red
![Page 8: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/8.jpg)
Injec>on patch on P18 Sec>on
![Page 9: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/9.jpg)
Mean Concentra>on versus Depth (using mean density vs depth from CTD)
![Page 10: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/10.jpg)
Tracer Simula>on 22 Feb 2010
Now wait a year… …but follow the evolution of the tracer with altimetry
X
![Page 11: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/11.jpg)
Cruise Track R/V Thompson 15 Jan–5 Mar 2010
US2
![Page 12: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/12.jpg)
Tracer Transects Column Integral
Horizontal structure
![Page 13: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/13.jpg)
Ini>al & 12-‐month profiles
kz = 0.13 cm2/s
Vertical structure
![Page 14: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/14.jpg)
Sco>a Sea
![Page 15: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/15.jpg)
RRS James Cook UK2 Dec 2010 – Jan 2011
![Page 16: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/16.jpg)
JC054 Sta>ons
2 years later
![Page 17: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/17.jpg)
Average Profiles
0 500 1000 1500 2000 2500 3000 3500 4000 4500 -1800
-1700
-1600
-1500
-1400
-1300
West of DP
East of DP
US2
Normalized Concentration
DP kz ~ 1 cm2/s
![Page 18: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/18.jpg)
DIMES Floats
• 11 sound sources for acous>c array • ~ 150 Argos and Iridium Rafos floats
![Page 19: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/19.jpg)
R/V Revelle, 5 Jan to 1 Mar 2009
US1 Cruise Track and Deployments
Sound sources
Tracer release
CTD stations (red) Float deployments in triplets
SoSo large blue Solo small blue Rafos black CTD red
![Page 20: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/20.jpg)
Neutral Density Sec>on at 105 W Deployment on 2 isopycnal surfaces
X
![Page 21: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/21.jpg)
DIMES Floats as of Sept 2011
US1 1
US1 2US1 3
US1 4
US1 5
US1 6UK1 1
UK1 2UK1 3
UK1 4
110oW 100oW 90oW 80oW 70oW 60oW 50oW
65oS
60oS
55oS
50oS
Dimes Trajectories (43) Orsi fronts
![Page 22: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/22.jpg)
Drake Passage Fronts and Floats
SOSE mean speed AVISO 7 yr mean speed + real floats + bathymetry
![Page 23: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/23.jpg)
100oW
90oW 80oW 70oW
60oW
60o S
55o S
50o S
1000 2000 3000 4000 5000 6000Depth (m)
Tracer-‐Float Spreading
All stations Deep float surfacings
![Page 24: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/24.jpg)
60 50 40 30 20 10 0 10 200
1
2
3
4
5
6
7
SSH(cm)
Num
ber o
f Par
ticle
s
Starting DF
100 80 60 40 20 0 20 400
1
2
3
4
5
6
SSH(cm)
Num
ber o
f Par
ticle
s
Ending DF
PDFs
Kdiff = σ2/2Δt = (400km)2/4yrs ≈ 1200 m2/s Also, d<X2>/dt ~ 1000m2/s and dKSSH/dz <0
−120 −100 −80 −60 −40 −20 0 20 40 600
100
200
300
400
500
600
700
800
900
1000
1100
SSH (cm)
Column Integral (pmol/m2) & Floats
Year 2
Tracer: blue Floats: green
![Page 25: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/25.jpg)
Ver>cal Structure
Klocker et al; Speer et al.
i-----------------------------I
![Page 26: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/26.jpg)
Ver>cal Structure
Klocker et al
1000 K 0
![Page 27: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/27.jpg)
Conclusions 1. Deep isopycnal mixing in the ACC is
-‐ about 1200 m2/s (uncertain>es TBD) -‐ associated with f/H -‐ weaker away from topography?
2. DIMES float trajectories will provide direct but limited
diffusivity es>mates and other quan>>es, state es>mates necessary
3. Need to observe ver>cal structure of mixing to discriminate
theories 4. Flow spligng and merging: braided jets
![Page 28: DIMES: Diapycnal and Isopycnal Mixing Experiment in the Southern](https://reader031.vdocuments.net/reader031/viewer/2022030323/58a2c33c1a28ab90398bb072/html5/thumbnails/28.jpg)