Post on 19-Jan-2016
description
transcript
Spatial Indices of Upwelling
1) Coastal Topography
Premise
• Average spatial patterns of coastal ocean processes are strongly influenced by topography and bathymetry
How to quantify coastal topography?
‘Coastal Anomaly’
Broitman and Kinlan 2006 MEPS, In press
Bays Headlands
(Embayments)
0
-1.0
+1.0
(Headlands)
Norm
alized residual from sm
oothed coast
COASTAL STRUCTURE
Alo
ng
-co
ast
Dis
tan
ce (
km)
Scale of Smoothing (km)
Smoothing Scale=1000 km
COASTAL STRUCTURE
Smoothing Scale=50 km
COASTAL STRUCTURE
S. Africa WNAChile
Coastal Topographic IndexCoastal Topographic Index
• Easily calculated• Data readily available• Arbitrarily high
resolution• Can index processes
at multiple scales
• Indirect index; index of upwelling or any other process depends on nature of coupling
• Not dynamic (no time component)
• Oversimplified?
ConsPros
SST
Spatial Indices of Upwelling
2) SST-derived indices
time
longitude
lati
tude
Coastal SST
Latitudinal mean at each pixel
Topographic Index and dSST Spatial Series
C) Topo vs. Δ SST C) Topo vs. Δ SST
Correlation between Topo and dSST indices
Correlation with Bakun Regional Index
Ecosystem Structure
Spatial patterns of kelp and phytoplankton
Biomass
Areal cover
chl-a vs. kelp
Spatial Cross-Correlations
A) Topo vs. kelpA) Topo vs. kelp
B) Topo vs. chl-aB) Topo vs. chl-a
C) Topo vs. Δ SST C) Topo vs. Δ SST
Spatial Cross-Correlations
Jones et al 1988, Cont Shelf Res
Approximately the same characteristic scaleApproximately the same characteristic scale
Alongcoast scales: Variogram Analysis
Variable Nugget (SE) Sill (SE) Range (SE) (km)
Kelp 0.35 (0.09) 0.65 (0.09) 188 (100)
Chl-a 0.13 (0.08) 0.87 (0.08) 178 (34)
ΔSST† 0.008 (0.007) 0.992 (0.007) 151 (18)
Coast Anomaly 0.04 (0.03) 0.96 (0.03) 161 (40)
Alongcoast scales: Variogram Analysis
Onshore Community Patterns
South Africa58 sites along 2000 km of coast
WNA73 sites
along 6000 km of coast
Chile26 sites
1000 km of coast
100 200 300 400 500 600 700 800 900
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
xcorr: Urchin GSI vs. Topographic Index
smoothing scale for topographic index (km)
corr
ela
tion
co
eff.
What scale of coastal features matter to the What scale of coastal features matter to the process you’re interested in?process you’re interested in?
Correlation between variable of interest and topographic index at each smoothing scale
-25 -20 -15 -10 -5 0 5 10 15 20 25
-0.2
0
0.2
0.4
0.6
Along-coast Lag Distance (km)
Cro
ss-C
orre
lati
onScale of pattern is just part of the questionScale of pattern is just part of the question
Peak @ 15 km in the poleward direction
Correlations with Coastal Anomaly – South AfricaCorrelations with Coastal Anomaly – South Africa
Correlation with Coastal Anomaly – MusselsCorrelation with Coastal Anomaly – Mussels
CHILE SOUTH AFRICA
Chile – Upwelling-Recruitment Dynamics Seen in Bare Space?
Coastal Topography and Physical ForcingCoastal Topography and Physical Forcing
CHILE SOUTH AFRICA
Correlation with Coastal Anomaly: MusselsCorrelation with Coastal Anomaly: Mussels
CHILE SOUTH AFRICA
Correlation with Coastal Anomaly: Trophic GrpsCorrelation with Coastal Anomaly: Trophic Grps
CHILE SOUTH AFRICA
Long-term Average Recruitment vs. Topography at 21 Coastal Sites
Green=Chthamalus
Black=Balanus
Balanus
r2=0.84, p<0.0001
Multiple regression with:
Topo10km, Topo150km, Coastal Coordinate (linear latitudinal trend)
Other processes correlated with topography
Aside… Hierarchical Bayesian Modeling for Data Integration & Complex Hypothesis Testing
Santa Barbara
Offshore Ocean Nearshore Ocean
Site 3
Site 4
Site 2
Site 1
Offshore
Larval
Pool
Santa Barbara
Offshore Ocean Nearshore Ocean
Recruitment
Offshore
Larval
Pool
Sea Temp (SST)
ChlorophyllA
Current
Current
Current
Current
Recruitment
Recruitment
Recruitment
16 points in time, each describing previous month
0, 1, m2
Rit~Poisson(FtHitei)
k,S
Likelihood:
Parameters:
Priors:N(0,10-3)
vague
Data: SSTt-TS GitRit
IG(10-3,10-3)vagueN(0,10-3)
vague
Links: Ft = k + S TS*SSTt-TS Logit(Hit)= 0+1Git+g
g ~N(0,m2)
i~N(0,2)
IG(2,10)informative
2
TS=0
2
i = space index , t = time index
OffshoreLarval Pool
OnshoreDelivery
Combine theseto get Recruitment
Chl , gate+errror, Gamma
SST , gate+errror, Gamma
SST , gate+errror,
Poisson
SST , gate+errror,
Poisson, site effects