El Niño/Southern Oscillation
• Major climatic perturbation on the planet
• Coupled atmosphere ocean process
• Key is the western tropical Pacific
– Ascending branch of the Walker circulation
– Potential energy for Kelvin wave pulse
• www.pmel.noaa.gov/tao/elnino/nino-home.html
Coupled Walker/Ocean
Circulation
El Niño Conditions
Relation of
Sea Level
with SOI
Statistical relationship
with SOI
Coastal signals seen
in CA Current
Ted Strub [OSU]
San Francisco Sea Level
CA Current Effects
San Francisco Sea Level
Kelvin Wave Pulse
Kelvin wave pulse
Ted Strub [OSU]
Santa Barbara Channel - PnB
Santa Barbara Channel
Primary Production
hn
CO2
NUTS
O2
Phytoplankton
Plants
Light, carbon & nutrients make plants & O2
Santa Barbara Channel
Santa Barbara Channel
Santa Barbara Channel Annual
Means – Oct/Oct
Year
SST
(oC)
SSS
(psu)
SSNO3
(mM)
SSChl
(mg m-3)
T(50m)
(oC)
NO3(50m)
(oC)
Wind
Speed
(m s-1)
SCR
discharge
(Mm3/y)
1996 to
1997
15.30
(2.00)
33.62
(0.09)
1.81
(2.30)
2.01
(1.68)
11.48
(0.78)
13.24
(3.93)
7.12
(2.69)
85.00
(466.72)
1997 to
1998
17.35
(5.45)
33.42
(0.20)
0.80
(1.39)
1.05
(1.16)
13.59
(2.35)
7.53
(6.87)
5.99
(2.06)
940.07
(3958.98)
1998 to
1999
14.91
(2.76)
33.5
(0.15)
2.21
(2.76)
2.13
(2.22)
11.18
(1.32)
12.21
(4.48)
7.77
(1.43)
16.30
(51.77)
1999 to
2000
15.36
(1.85)
33.66
(0.12)
1.52
(1.46)
2.74
(2.89)
11.36
(0.97)
11.17
(5.86)
6.70
(2.84)
801.16
(3550.45)
2000 to
2001
15.37
(2.33)
33.58
(0.13)
0.79
(1.07)
1.70
(2.08)
11.24
(0.87)
11.14
(5.23)
6.1
(2.23)
298.68
(1975.85)
Total
15.63
(2.46)
33.58
(0.15)
1.42
(1.97)
1.94
(2.20)
11.71
(1.56)
11.14
(5.51)
6.7
(2.32)
435.09
(2597.87)
97/98 ENSO in SB Channel
• Deep thermocline & high SST
– Limits nitrate supply & chlorophyll biomass
– Chl & nitrate are much lower during ESNO
• Forcings change
– Wind speeds (West channel buoy) are lower
– Santa Clara River discharges are >> normal
Ocean Color 97/98 ENSO
Kahru & Mitchell [2000; GRL]
More low Chl regions
during ENSO
Fewer occurrences of low
SST during ENSO
Comparisons with the 82-83
ENSO
97/98 ENSO in Central CA
• Biological processes are much lower
• Winds are roughly the same
• Upwelling still happens
– but it is less “useful” water upwelling
El Niño & CA Current
• Kelvin wave pulse propagates north
– Propagates 40,000 km in 6 months (2-3 m/s)
• Depresses thermocline & raises SST
– Thermocline is depressed 30 to 70 m
• Winds are not affected in some places not others
• Role of thermocline depth is critical
– reduced nutrient supply and lower chlorophyll
El Niño & Global NPP
El Niño &
Global NPP
El Niño &
Global NPP
El Niño & NPP
• Global primary production rates are a
funtion of thermal stratification
• Strong relationship with Multi-ENSO Index
(MEI)
– MEI is like the SOI
• Global NPP is related to ENSO
Ecosystem Regime Shifts - PDO
• Climate oscillators besides ENSO
– Pacific decadal oscillation - PDO
• Ecosystem effects of “regime shifts”
– 1977 (have we flipped back??)
– Food web & fishery responses
Pacific Decadal Oscillation
Warm
http://jisao.washington.edu/pdo/
Cool
Pacific Decadal Oscillation
Southern Oscillation Index
• SOI = Tahiti - Darwin air pressure D’s
• Low SOI = El Niño conditions
Pacific Decadal Oscillation
PDO vs. ENSO
Pacific Decadal Oscillation
Warm
Cool
http://tao.atmos.washington.edu/pdo/
Southern Oscillation Index
• SOI = Tahiti - Darwin air pressure D’s
• Low SOI = El Niño conditions
Pacific Decadal Oscillation
ENSO
Pacific Decadal Oscillation
Pink
Salmon
Chum
Coho
Sockeye
Chinook
PDO and Salmon Yields
September 1972 (National Fisherman 1972)
"Bristol Bay [Alaska] salmon run a disaster."
"Gillnetters in the Lower Columbia [Washington and
Oregon] received an unexpected bonus when the largest
run of spring chinook since counting began in 1938
entered the river."
1995 Yearbook (Pacific Fishing 1995)
"Alaska set a new record for its salmon harvest in 1994,
breaking the record set the year before."
"Columbia [Washington and Oregon] spring chinook
fishery shut down; west coast troll coho fishing banned."
September 1915 (Pacific Fisherman 1915)
"Never before have the Bristol Bay [Alaska] salmon
packers returned to port after the season's operations so
early."
"The spring [chinook salmon] fishing season on the
Columbia River [Washington and Oregon] closed at
noon on August 25, and proved to be one of the best for
some years."
1939 Yearbook (Pacific Fisherman 1939)
"The Bristol Bay [Alaska] Red [sockeye salmon] run was
regarded as the greatest in history."
"The [May, June and July chinook] catch this year is one
of the lowest in the history of the Columbia [Washington
and Oregon]."
PDO and Fish Yields
PDO
and …
Mantua et al…
Pacific Decadal Oscillation
PDO
and …
salmon stock
1947 step 1977 step
western Alaska sockeye -37.2% +242.2%
central Alaska sockeye
-33.3% +220.4%
central Alaska pink
southeast Alaska pink
-38.3%
-64.4%
+251.9%
+208.7%
TABLE 3: Percent change in mean catches of four
Alaskan salmon stocks following major PDO sign
changes in 1947 and 1977.
PDO
and …
Salmon and the PDO
• Two Hypotheses for signal
–First feeding of smolts entering ocean &
PDO_altered primary production
– Streamflow alterations drive salmon habitat
availability
• Consensus is the first feeding…
PDO
and …
Bristol Bay Salmon Stocks
• Studied / Modeled
Extensively
• Study concluded
Biocomplexity preserved
by setting regional
guidelines– not just
protecting economically
viable stock
• BUT- where does PDO fit
in?
The largest harvest of sockeye salmon in the world occurs in the Bristol Bay area of
southwestern Alaska where 10 million to more than 30 million sockeye salmon may be
caught each year during a short, intensive fishery lasting only a few weeks.
Freshwater Life: Half of the Cycle
Sockeye: “Simply put, the adults spawn
at a date that, given the average
thermal regime, will allow the embryos
to complete embryonic development
and emerge in time to feed on aquatic
insects and zooplankton the following
spring”
Hilborn et. al. 2003
Bristol Bay Hydrology & PDO
• Above average mean
annual discharge
warm-PDO
• Below average mean
annual discharge
cool-PDO
• In general, high
streamflow =
favorable
reproductive
conditions
Bristol Bay Catch History
Dominant location
varies
PDO-flux influences
general
productivity?
Stock spawning
ground,
adaptations
influence success
of individual runs
PDO-related
population change
not evident in
1920’s to 1940’s?
Bristol Bay Stock History
Increase in recruits
= higher survival
rates
• Regional
Stock have
variety of
adaptations
to mean
hydrologic
& ecologic
conditions
Number of recruits per spawner: Total # adult salmon returning from a spawning
year divided by # fish spawned in that brood year
Pacific Decadal Oscillation
Salmon and the PDO
PDO
Spawners passing
Bonneville Dam
Hatchery returns
PREDICTIONS?
• Spring Chinook
returns correlated
with a “food chain”
indicator of ocean
conditions, with a
two year lag
400
y = 15.5 + 353.0 X
300
p = 0.045, R
2
= 0.26
200
1997/98 El Niño
100
0
-100
-200
past Bonneville Dam two years later
Anomaly of counts of adult spring Chinook
-300
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
Cold Water Copepod Biomass Anomaly
Regression curve shown excludes
the very high survival years of 1970 and 1973
•
12
1970
R 2 = 0.75
p = 0.0002
10
1969
1973
8
1971
6
4
1972
Ocean Entry
2005
OPI Coho Survival
2
0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
Northern Copepod Biomass Anomaly
0.6
0.8
Columbia River coho
returns correlated
with the same indicator
but with one year lag
A working mechanistic
hypothesis: source
waters. . .
“Cool”
Phase
 Transport of cold
water, phytoplankton
and boreal zooplankton
into the NCC from Gulf
of Alaska
“Warm”
 Transport of warm
water, phytoplankton
and sub-tropical
zooplankton into NCC
from offshore and from
the south
Phase
Salmon and the PDO
• Two Hypotheses for signal
–First feeding of smolts entering ocean &
PDO_altered primary production
– Streamflow alterations drive salmon habitat
availability
• Consensus is the first feeding…
Predicting
CA/OR Coho
& Chinook
Runs for
2012/2013
http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm
Predicting
CA/OR Coho
& Chinook
Runs for
2012/2013
Predicting
CA/OR Coho
& Chinook
Runs for
2012/2013
Predicting CA/OR Coho & Chinook Runs
for 2011/2012
Pacific Decadal Oscillation
PDO from Tree Rings
Used tree rings from Jeffrey
Pine & Douglas Fir
Biondi, Gershunov & Cayan, 2001 North Pacific Decadal Climate
Variability Since AD 1661. Journal of Climate, 14, 5-10.
PDO from
Tree Rings
Pacific Decadal Oscillation
Pacific Decadal Oscillation
Pacific Decadal Oscillation
• Decadal scale variations in patterns over Pacific
• Warm phase
– Alaska moist, salmon up (freshwater habitat is good)
– Oregon/Washington dry, salmon down
– Patterns throughout Pacific basin
• Cool phase opposite
• Fisheries response (time scales match)