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Xiao-Hai Yan1, Young-Heon Jo1, Feili Li1
and Tim Liu2
June 9, 20101 Center for Remote Sensing, University of Delaware2 M/S 300-323, 4800 Oak Grove Dr. Jet Propulsion Laboratory, Pasadena, CA 91109
Characteristic Features of DOC in the Labrador Sea based on Multi-Sensor
Measurements
AMOC
DOC Studies in LSLabrador Sea Group (1998)- Labrador Sea Deep Convection
ExperimentMarshal and Shott (1998)- Open ocean deep convection:
Observations, theory and modelsYashayaev and Loder (2009)-Enhanced production of Labrador
Sea Water in 2008Vage et al.(2009)- Return of DOC to subpolar NAO in winter 2007-
2008Lozier (2009)-Overturning assumptions based on NAORemote Sensing?Fischer et al. (1999)-DOC using SAR (?)Hermann et al. (2009)-Monitoring DOC from space
(Mediterranean Sea)How Good is RS for DOC observations?
4
(Yan et al.,JPO, 2006)
MethodologyMethodology• Integrated Multi-Sensor Data AnalysisIntegrated Multi-Sensor Data Analysis
• WhereWhere
1( , , , , ) [ ( , , , , ) ( , , , , )]
1[ ( , , , ) ( , , , )]
K
Total Total
K
UL UL Total UL
T S W X t T S W X t T S W X tK
T W X t T W X tK
]),,(1
),,([
]),,(1
),,([
K
WW
K
TTUL
tXWK
tXW
tXTK
tXT
)(,,0
0
400
0
400
curlgf
gSdzTdz WST
04/18/235
NAUCW: North Atlantic Upper Cold Water 2.5 - 5 °C
NABCW: North Atlantic Bottom Cold Water 0 - 2.5 °C
Where is DOC in LS?When does it occur?Can we observe/monitor it?
How much does water sink?How much contribution to the AMOC……
Chanut et al., 2008
Vertical structures of DOC from floats measurements
Weak and strong DOC events?
Yashayaev and Loder (2009)
Strategy to detect DOC events using RS
Two proxies for detecting DOCLST and SST differences and winds’ directionSteric heights and steric ratios
Fisher et al., 1999
Brunt-Vaisala (Buoyancy) frequency from a Float
How long it takes to reach 1800m depth?
Can SSHA contain DOC signals?
Satellite observations for weak and strong DOC events
Weak DOC events Strong DOC events
SSHA
LST and SST
Winds
Temperature comparisons over land and sea
Monthly temperature for Jan and FebWeekly temperature for Jan and FebWeekly temperature from 2006 to 2008
Steric height and its ratio (Sr)for Proxy II
0
0
dz
dz
Z
S
Z
T
T
Sr
S
T
S
Where, α and β are the thermal and the salt expansion coefficients, respectively.
Preliminary Conclusion•Difficult to detect precondition of DOC, but possible to monitoring DOC after convection.
• Two proxies are useful to monitor changes in water column of DOC and non-DOC sites.
•Temperature proxy for DOC shows that low SST requires LST threshold at -3C between Green Land and West of Baffin Sea . Steric height ratio proxy shows ~ 8 times larger for strong DOC than weak DOC.
• Subsurface temperature can be estimated from SSHA and provide information for AMOC & DOC analyses.
•Caution is required in analyzing with satellite data since there are still other similar signatures.
•EEMD can be used to decompose different spatial scales.