William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth...
Transcript of William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth...
![Page 1: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/1.jpg)
Rain-Induced Ocean Surface Salinity Gradients:Can they tell us anything about near surface physics?
William Asher, Andrew Jessup, Ruth Branch, and Dan ClarkApplied Physics LaboratoryUniversity of Washington
Seattle, Washington
NASA Aquarius Program: Grant NNX09AU73G
![Page 2: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/2.jpg)
Why are salinity gradients at the ocean surface important?
Mis-match between SMOS/Aquarius with respect to measurement depths
ARGO float salinity profile
Microwave penetration depth
Grodsky and Carton, 2012
![Page 3: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/3.jpg)
How do salinity gradients form?
Measure S as a function of U, R etc.
![Page 4: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/4.jpg)
Can their presence be predicted from surface meteorological measurements?
Predict S from remote measurements of U, R etc.
![Page 5: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/5.jpg)
Measuring salinity gradients: The Surface Salinity Profiler (SSP)
Towed from shipFollows surface at tow speeds of 2 m/sRides outboard of wakeInstruments mounted on rigid keel
Instrumented with:0.05 m Seabird 49 CTD
0.20 m Seabird 49 CTD1.00 m Seabird 49 CTD
2.00 m Seabird 19 CTD
![Page 6: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/6.jpg)
Measuring salinity gradients in the equatorial Pacific Ocean using the SSP
SSP deployed from the R/V Kilo Moana
Cruise conducted December 6-16, 2011
Sailed from Apia, Western Samoa to Honolulu, Hawaii
Deployed the SSP a total of eight times
Sampled 3 rain events
![Page 7: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/7.jpg)
SSP Observation of Rain, Equatorial PacificR/V Kilo Moana, December 13, 2011 12.07 N, 160.9 W
![Page 8: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/8.jpg)
SSP Observation of Rain, Equatorial Pacific
![Page 9: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/9.jpg)
Salinity profiles and gradients
![Page 10: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/10.jpg)
Gradient at 0.12 m Gradient at 0.12 m
Salinity Gradient vs. rain rate and accumulationS
(psu
/m)
![Page 11: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/11.jpg)
Salinity gradients as a function of wind speed
![Page 12: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/12.jpg)
Is there dynamical information in the gradients?
2
Z40
Z
,z
tAS z t S et
Assume simple 1-d diffusion
Vertical eddy diffusivity, z
31 32 33 34 35 36Salinity (psu)
2
1.6
1.2
0.8
0.4
0
Dep
th (m
)
t1 t2 t3 t4
![Page 13: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/13.jpg)
Dep
th (m
)
Is there dynamical information in the gradients?
![Page 14: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/14.jpg)
Eddy diffusivity vs. wind speed
![Page 15: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/15.jpg)
10-4 10-3 10-2 10-1
N2 -2
10-6
10-5
10-4
10-3
10-2
2-1
KM-11Law et al.
Eddy diffusivity vs. buoyancy frequency
![Page 16: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/16.jpg)
Conclusions
1. Rain generates measurable near-surface (top 0.5 m) salinity gradients that can form at wind speeds up to 10 m/s
2. The magnitude of the gradient is related to total rain amount and the stability and mixing in the near surface
3. These gradients are large enough (in terms of S) to affect Aquarius
4. Extend over large enough areas to affect satellite measurements
![Page 17: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/17.jpg)
![Page 18: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/18.jpg)
The Surface Salinity Profiler (SSP) in tow from the R/V Thomas G. Thompson
Wake
SSP
![Page 19: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/19.jpg)
The underway salinity gradient instrument package on the R/V Thomas G. Thompson
![Page 20: William Asher, Andrew Jessup, Ruth Branch, and Dan Clark ... · William Asher, Andrew Jessup, Ruth Branch, and Dan Clark Applied Physics Laboratory University of Washington Seattle,](https://reader034.fdocuments.us/reader034/viewer/2022052320/5f0fa9c07e708231d4454601/html5/thumbnails/20.jpg)
Underway salinity measurements: R/V T. G. Thomson