Transcript Eastern U.S. Continental Shelf Carbon Budget: Modeling

U.S. ECoS
U.S. Eastern Continental Shelf Carbon Budget:
Modeling, Data Assimilation, and Analysis
A project of the NASA Earth System Enterprise
Interdisciplinary Science Program
Ocean Carbon Biogeochemistry Workshop
Woods Hole, MA, July 2006
U.S. ECoS
Science Team
Eileen Hofmann (ODU)
Marjorie Friedrichs (ODU)
Chuck McClain (GSFC)
Sergio Signorini (GSFC)
Antonio Mannino (GSFC)
Cindy Lee (SUNY-SB)
Jay O’Reilly (NOAA)
Dale Haidvogel (RU)
John Wilkin (RU)
Katja Fennel (RU)
Sybil Seitzinger (RU)
Jim Yoder (URI)
Ray Najjar (PSU)
David Pollard (PSU)
project oversight, 1D modeling
1D modeling and data assimilation
project oversight, remote sensing data
satellite data analysis
carbon cycling
carbon cycling
satellite data analysis
circulation modeling
circulation modeling
biogeochemical modeling
food web and nutrient dynamics
food web and nutrient dynamics
oxygen data, climate modeling
climate modeling
U.S. ECoS
Goal: To develop carbon budgets for the U.S. east coast
continental shelf (Mid-Atlantic Bight and South Atlantic Bight)
Research Questions:
1. What are the relative carbon inputs to the MAB and SAB from
terrestrial run-off and in situ biological processes?
2. What is the fate of DOC input to the continental shelf from
estuarine and riverine systems?
3. What are the dominant food web pathways that control carbon
cycling and flux in this region?
4. Are there fundamental differences in the manner in which carbon
is cycled on the continental shelves of the MAB and SAB?
5. Is the carbon cycle of the MAB and SAB sensitive to
climate change?
Outline of Presentation
• Theme 1: Development and implementation of
circulation, biogeochemistry, and carbon cycling models
for the east coast of the U.S.
• Theme 2: Data analysis effort – includes historical in
situ measurements and satellite-derived data
• Theme 3: Limited field measurement effort
• Theme 4: Implementation of data assimilative models
• Theme 5: Interfacing circulation and biogeochemical
models with climate models
Theme 1: Circulation and biogeochemical modeling
Northeast North American shelf model (NENA)
Theme 1: Circulation and biogeochemical modeling
Simulated
Salinity
WOA98
Salinity
10m
August
4m
August 2002
North-south gradients agree, simulations produce mesoscale variability
Wilkin, Haidvogel
Theme 1: Circulation and biogeochemical
modeling
Hindcasts 2002
& onward
Boundary
forcing – cold
bias in HyCOM
solutions
Tides make a
difference:
Georges Bank,
reduced
gradients
Wilkin, Haidvogel
Theme 1: Circulation and biogeochemical modeling
Nitrification
Water column
NH4
NO3
Uptake
Phytoplankton
Grazing
Chlorophyll
Zooplankton
Mortality
Small
detritus
Fennel et al., in
press, GBC
Mineralization
Large
detritus
Nitrification
N2
No DOM yet
NH4
NO3
Denitrification
Sediment
Organic matter
Aerobic mineralization
Theme 1: Circulation and biogeochemical
modeling
DNF: 5.3 TN
4.2 TN
3.3 DIN
0.9 PON
Rivers: 1.8 TN
2.5 DIN
2.9 PON
0.4 TN
Fluxes in 1010 mol N y-1
Fennel et al., in press, GBC
Sources and
sinks of
nitrogen
Role of shelf
denitrification
Theme 1: Circulation and biogeochemical
modeling
Simulated annual air-sea flux of CO2
Explicit inorganic carbon cycling
Positive values indicate uptake by
ocean
Outer Mid-Atlantic Bight continental
shelf is a sink for atmospheric CO2
No net uptake off NJ due to outgassing
during summer from upwelling
Fennel
MAB atmospheric CO2 uptake
estimates
Total
(Mt C yr-1)
Inner Shelf
(0-20 m)
(mol C m-2 yr-1)
Mid-shelf
(20-50 m)
(mol C m-2 yr-1)
Outer Shelf
(50-200 m)
(mol C m-2 yr-1)
DeGrandpre et
al. (2002)
Model
Model w/o DNF
1.0 ± 0.6
0.9
1.62
0.9 ± 0.63
0.38
1.1
1.6 ± 1.28
0.57
1.2
0.7 ± 0.07
0.91
1.2
Theme 2: Satellite and in situ data analyses
Intercomparison of Chlorophyll-a Algorithms: May 14, 2000
OC4v4
Clark
Carder
GSM01
First coastal
intercomparison
Inner shelf
differences
O’Reilly,
Signorini,
McClain
Theme 2: Satellite and in situ data analyses
In situ productivity measurements
Phase good, models differ,
models too high. SAB tough due
to intrusions.
Satellite productivity measurements
O’Reilly
Annual PP, mean and
ratio to mean
O’Reilly
Max:min
annual
PP
(19982005)
O’Reilly
Theme 2: Satellite and in situ data analyses
SAB variability
Analyses of forcing
functions and
chlorophyll (response),
1998-2005
Top- size of North
Atlantic Subtropical
gyre (chl-based)
Middle- Cape Fear
River discharge
Bottom- Chlorophyll
Signorini, McClain
Theme 2: Satellite and in situ data analyses
Analyses of
forcing functions
and response at 3
sites
Sea surface height
anomaly (green) and
NASG size (blue)
May reflect seasonal
migration of Gulf
Stream front—
offshore in spring,
onshore in fall
Signorini, McClain
SST trend
Chl trend
O’Reilly
Theme 2: Satellite and in situ data analyses
Analyses of World
Ocean Database
for study region:
focus on MLD and
dissolved O2.
Siewert, Najjar
Theme 2: Satellite and in situ data analyses
MLD based on
ΔT = 0.2°C
Siewert, Najjar
Theme 2: Satellite and in situ data analyses
MAB outer shelf annual cycles of the oxygen anomaly
0-30 m
30-60 m
60-100 m
Siewert, Najjar
Theme 2: Satellite and in situ data analyses
MAB Sea-to-air oxygen flux
Outer Shelf
Slope
Mid-Shelf
Inner Shelf
Siewert, Najjar
Themes 1 and 2: Modeling and satellite analyses
Fennel, Wilkin, O’Reilly, Signorini,
McClain
Themes 1 and 2: Modeling and satellite analyses
Model-data
comparisons
 Model
crashes in
summer
(no tides)
Fennel, Wilkin,
O’Reilly
Themes 1 and 2: Modeling and satellite
analyses
Fennel,
Wilkin,
O’Reilly
Themes 1 and 2: Modeling and satellite analyses
Satellite-derived
primary production (PP)
using VGPM2
VGPM2 applied to
NENA-simulated fields
Modeled PP
using NENA
Fennel, Wilkin, O’Reilly
Themes 1 and 2: Modeling and satellite
analyses
Model-data
comparison
Wilkin, O’Reilly
Theme 3: Field measurements
Chesapeake Bay and adjacent coastal waters – ODU monthly
cruises and NASA NIP (Mannino)
• ODU cruises - one day, 8 hour
cruise, 4 stations
• NIP – grid of stations, 3-4 day
cruises
• Carbon, nutrients, chl a,
pigments, absorb., …
• Estimate fluxes - model
• Algorithm development
ARCHIVED SAMPLES
2002 to present
Theme 3: Field measurements
DOC (µM C)
40
From cruises in Southern
MAB, including lower
Chesapeake Bay.
80
120
160
0
10
Spring conditions well mixed
except where influenced by
rivers.
Depth (m)
30 Mar – 1 Apr cruise 
20
Bay Mouth
30
Plume 3
CLT
Outer Shelf
40
Outer Shelf
Slope
Mannino
50
Theme 3: DOC & CDOM field measurements
250
From cruises in
Southern MAB,
including lower
Chesapeake Bay.
200
DOC (µM)
Seasonal algorithms
needed. Offset due to
net community
production of DOC
and bleaching from
spring to summer.
y = 97x + 75
R2 = 0.92
y = 101x + 49
R2 = 0.96
150
y = 89x + 48
R2 = 0.98
100
Fall '04 - Spring '05
50
July, Aug & Sept '05
Nov '05
0
0.0
Mannino
0.5
1.0
aCDOM(355) (m -1)
1.5
2.0
Themes 2 & 3: Satellite and field measurements
Aqua-MODIS-based CDOM*
Mannino
*Based on in situ aCDOM and in situ reflectance ratios
Themes 2 & 3: Satellite and field measurements
Aqua-MODIS-based DOC (mM)
Mannino
Theme 4: Biogeochemical data assimilation
Developed a 1-D data assimilative ‘Modeling Testbed’
This framework includes:
mixing, advection, diffusion, attenuation, sinking subroutines
This framework requires:
forcing fields: T, MLD, PAR, w, Kv
boundary and initial conditions
ecosystem model subroutine
adjoint of ecosystem model subroutine
biogeochemical data for evaluation/assimilation
This framework will be used to:
Perform parameter sensitivity/optimization analyses
Test new parameterizations and formulations
Compare multiple models at a single site
Compare model performance at various sites
Theme 4: Biogeochemical data assimilation
Comparison of simulated nitrate from 1D and 3D models at a
site on MAB continental shelf
3D
1D
Friedrichs
5m
55 m
115 m
Theme 4: Biogeochemical data assimilation
Identical Twin Numerical Experiments - Use SeaWiFS and in situ data
Chl2C_m
PhyIS
PhyMR
Vp0
ZooGR
CoagR
Sremin
7 (of 18) parameters can be independently estimated
Friedrichs
DOM modeling
Jean-Noel Druon
1-D MAB results
Theme 5: Climate Modeling
How will coastal regions respond to climate change,
and what are the feedbacks on the carbon cycle?
Force the circulation/biogeochemical model with climate
change scenarios:
Present day scenario: 1980-2000
100 years later scenario: 2080-2100
Using RegCM3
Theme 5: Climate Modeling
Winter
Summer
Simulated
precipitation
Observed
precipitation
Pollard, Najjar
Theme 5: Climate Modeling
Six-hourly precipitation fields from a 10-year
simulation using present conditions
Pollard, Najjar
Summary
U.S. ECoS Goal: To develop carbon budgets for the U.S.
east coast continental shelf waters
• Circulation model shows observed features for SSS, SST.
More evaluation (e.g., MLD) needed. Tides, BCs make a
difference.
• Biogeochemical model captures chl variability. Chl too low
in gyre. More tracer evaluation needed (e.g., oxygen)
• Denitrification significantly influences air-sea carbon flux in
model. MAB air-sea flux agrees with observations.
• Satellite productivity algorithms give MAB results close to
observed. Issues in SAB.
• Interannual variability and long-term trends in chl, PP, SST.
Summary
U.S. ECoS Goal: To develop carbon budgets for the U.S.
east coast continental shelf waters
• Riverine & gyre influences on chl seen in SAB.
• Field data have allowed development of CDOM and DOC
products for MAB
• Model and satellite productivity issues need resolution.
• 1D models and data allow parameters for 3D models to be
constrained.
• DOM poised to be included in 3D model.
• Regional climate model set up and ready for climate
change runs
Summary
U.S. ECoS Goal: To develop carbon budgets for the U.S.
east coast continental shelf waters
• No component can do this by itself—
synthesis approach
• Requires modeling effort coupled with
satellite and in situ data analysis
• Ongoing effort—observationalists and
modelers working together