Date post: | 16-Jan-2016 |
Category: |
Documents |
Upload: | patrick-golden |
View: | 213 times |
Download: | 0 times |
PrinceWilliamSound
ResurrectionBay
Knight Island Passage
Middleton Island
The physical model is run in three dimensions and the data are used to drive a one – dimensional model at each Seward Line station location. Direct comparisons can then be made between GLOBEC field measurements and the model output. Comparisons here are done for the 2001 field season.
Simulation of the Northern Gulf of Alaska Ecosystem
Kenneth O. Coyle (SFOS, University of Alaska)Al Herman (NOAA, Seattle), Sarah Hinkley (NOAA Seattle)Funding Agency: North Pacific Research Board
Mooring Fluorescence Data GAK5 June 2002 – July 2003
Mooring: gbm3; Depth: 14-15 m; Fluorometer Volts
Time (Month/Year)
Jun/02
Jul/02
Aug/02
Sep/02
Oct/02
Nov/02
Dec/02
Jan/03
Feb/03
Mar/03
Apr/03
May/03
Jun/03
Jul/03
Flu
orom
eter
Vol
ts
0.0
0.5
1.0
1.5
2.0
2.5
Major blooms occur in late April, May or early June with low production in March and early April
Model must reproduce the timing and peaks suggested from mooring fluorescence data.Mooring data from Stabeno (PMEL)
Model Simulation: 2001; GAK6
Time (days)
Mar Apr May Jun Jul Aug Sep Oct
Bio
mas
s (m
g C
m-3
)
0
20
40
60
80
100
Large PhytoplanktonSmall Phytoplankton
Average in upper 50 m
1 3 5 7 9 11 13
July
84
< 2 µm>2-10 µm>10 µm
20
40
60
80
0
0
20
40
60
80
1 3 5 7 9 11 13
<2 µm>2-10 µm>10 µm
May
Seward Line StationsComparison of measured and simulated phytoplankton biomass at station GAK6.Simulated peak biomass occurs in mid April and May with magnitudes similar to field measurement by Lessard (University of Washington).
Field measurements
Primary Production: 204.4 g C m-2 y-1
Time
Mar Apr May Jun Jul Aug Sep
mg
C m
-2 d
-1
0
500
1000
1500
2000
2500
GAK1
Primary Production: 172.2 g C m-2 y-1
Time
Mar Apr May Jun Jul Aug Sep
mg
C m
-2 d
-1
0
500
1000
1500
2000
2500
3000
3500
GAK4
Primary Production: 240.8 g C m-2 y-1
Time
Mar Apr May Jun Jul Aug Sep
mg
C m
-2 d
-1
0
1000
2000
3000
4000
GAK9
Primary Production: 198.8 g C m-2 y-1
Time
Mar Apr May Jun Jul Aug Sep
mg
C m
-2 d
-1
0
500
1000
1500
2000
2500
GAK13
GAK 9 2000-2004 Integrated Productivity
00.5
11.5
22.5
33.5
3 3 4 4 5 5 5 7 7 8 8 10 10 12Month
gC
/m2/
day
GAK 13 2000-2004 Integrated Productivity
0
0.5
1
1.5
2
2.5
3
3 3 3 4 4 5 5 7 7 8 8 10 10 12
Month
gC
/m2/
day
GAK 4 2000-2004 Integrated Productivity
0
1
2
3
4
5
3 3 3 3 3 4 4 4 5 5 5 5 5 7 7 7 7 8 8 8 8 1010101212Month
gC
/m2/
day
GAK 1 2000-2004 Integrated Productivity
0
0.5
1
1.5
2
2.5
3
3 3 3 4 4 5 5 7 7 8 8 10 10 10 12Month
gC
/m2/
day
Simulated and measured primary production for stations GAK 1, 4, 9 and 13. Note that the magnitudes of simulated and measured production are similar but mooring data suggest that production may be more peaked than the simulation indicates. Production measurements by Whitledge and Stockwell (University of Alaska).
Model Simulation: 2001; GAK6
Time (days)
Mar Apr May Jun Jul Aug Sep Oct
Bio
mas
s (m
g C
m-3
)
0
20
40
60
80
100
Large MicrozooplanktonSmall Microzooplankton
Average in upper 50 m
1 3 5 7 9 11 130
20
40
60
80
100
July
HnanoHdinoCiliates
1 3 5 7 9 11 130
10
20
30
40
50
60
AugustHnanoHdinoCiliates
Seward Line Stations
Comparison of measured and simulated microzooplankton biomass at station GAK6. Magnitudes of simulated and measured biomass are similar. Field data from Lessard (University of Washington)
Field Data
N. plumchrus & N. flemingeri
Month
Mar Apr May Jun Jul Aug Sep Oct
Mea
n ca
rbon
bio
mas
s (m
g m
-3)
0
10
20
30
40
50
19971998199920002001200220032004
Calanoida
Month
Mar Apr May Jun Jul Aug Sep Oct
Mea
n ca
rbon
bio
mas
s (m
g m
-3)
0
20
40
60
80
100
120
19971998199920002001200220032004
Model Simulation: 2001; Gak6
Time (days)
Mar Apr May Jun Jul Aug Sep Oct
Bio
mas
s (m
g C
m-3
)
0
10
20
30
40
50
60
Neocalanus spp.
Small Copepods
Average in upper 100 m
Field Data
Comparison of measured and simulated mesozooplankton biomass at station GAK6. Total zooplankton biomass (top panel, field data) is similar to simulation. Neocalanus biomass in simulation is high for 2001
Model Simulation: 2001; Gak6
Time (days)
Mar Apr May Jun Jul Aug Sep Oct
PA
R (
E m
-2 d
-1)
0
20
40
60
80
100
PAR Fraction = 0.5PAR Fraction = 0.7Ship Time vs Surface Light
Photosynthetically active radiation (PAR) in the model was similar to values measured at the ship’s mast head during cruises, but the range of measured values was substantially greater than simulated values.
Conclusions:The model as currently parameterized was
capable of reproducing broad scale patterns of nutrient concentration, primary production, and biomass of phytoplankton, microzooplankton and mesozooplankton on the northern Gulf of Alaska shelf for 2001.
Remaining Tasks:1)Get the physical model to run with tides.2)Run the model on the 3 km Gulf of Alaska
grid for 2001, 2002, 2003, 2005 and 2006.
Major question: Can the model reproduce the interannual
variability observed in the field data?
The ecosystem model is embedded in a 3-dimensional physical circulation model (ROMS) to link climate forcing to the ecosystem response.
11 Component ModelSlide by G. Gibson
Iron
ROMS
Model and Site Description
SeaWiFS Satellite Chlorophyll May 13 2001Simulated primary production (g C m-2 y-1)
Comparison of simulated primary production and satellite chlorophyll image. Note the elevated primary production and chlorophyll concentration to the west of the Seward Line (arrows) suggesting the model can reproduce physical mechanisms affecting distribution of production on the shelf.
Distribution of Production
Phytoplankton Biomass and Production
Seasonal Zooplankton Biomass
0 50 100 150 200
D istance (km )
-100
-80
-60
-40
-20
0
De
pth
(m
)
N itra te (m M m-3
)
0.01.32.63.85.16.47.79.010.211.512.814.115.316.617.919.220.521.723.024.325.6
0 50 100 150 200
D istance (km )Am m onium (m M m
-3 )
0.00.20.30.50.60.80.91.11.21.41.51.71.82.02.12.32.42.62.72.93.0
0 50 100 150 200
D istance (km )
-100
-80
-60
-40
-20
0
De
pth
(m
)
N itra te (m M m-3
)
0246810121416182022242628303234363840
0 50 100 150 200
D istance (km )Am m onium (m M m
-3 )
00.10.20.30.40.50.60.70.80.911.11.21.31.41.51.61.71.81.92
Simulated
Measured
July 2001
Simulated and measured nitrate and ammonium on Seward Line. The simulation can reproduce the vertical distribution and approximate magnitude of field measurement. Nutrient data from Whitledge (University of Alaska).
Simulated surface nitrate (mM m-3), July 10
The model was capable of producing the high nitrate concentrations above the seasonal thermocline in the Alaska gyre and nitrate exhaustion typical of the shelf during summer.
Seasonal and Geographic Nutrient Distribution
Photosynthetically Active Radiation
Conclusions and Perspectives
Phytoplankton Biomass