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Working Group 4 Coastal Biogeochemistry Forum, June 23-25, 2004. K. Lindsay, G. McKinley, C. Nevison, K. Plattner, R. Seifert Can coastal ecosystems be represented in global models?
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Working Group 4Coastal Biogeochemistry Forum, June 23-25, 2004 • K. Lindsay, G. McKinley, C. Nevison, K. Plattner, R. Seifert • Can coastal ecosystems be represented in global models? • a. How many different types of coastal zones need representation (temperature / topography / phytoplankton types)? • b. What processes do we need to capture / understand how well? • c. Can these processes be parameterized / resolved in models?
Global Ocean Models SST, U 0.3 m/s MOM4 0.6o-3o x 3o MOM4 3.75o x 4.5o
Regional Oceanic Modeling System (ROMS) • 3-dimensional circulation model • U.S. West Coast configuration (28oN - 48oN; 1000 km offshore) • Several models with varying horizontal resolution (20km, 15km and 5km) • Partially to fully eddy-resolving • 20 vertical layers (sigma-coordinates) • Climatological forcing (Levitus T,S; COADS) • Coupled to an NPDZ ecosystem model including a formulation of the carbon cycle
UCLA ROMS: US West Coast Configuration - Level 0 (15 km) - Level 1 (5 km) 15km 5km
Surface Chl-a: ROMS 15km vs. 5 kmAnnual Mean Pt. Arena Pt. Arena San Francisco San Francisco Monterey Bay Monterey Bay ROMS 15 km ROMS 5 km Chl-a (mg m-3)
Surface Chl-a: ROMS 15 km vs. 5 kmSnapshot May 21 ROMS 15 km ROMS 5 km Chl-a (mg m-3)
Can ROMS be Applied to Non-Upwelling Coastal Ecosystems?What Changes are Needed to NPDZ Model?
Alternatives to Prognostic Numerical Models? In some cases, simpler diagnostic or correlative models may also be useful Bakun Upwelling Index Coastal N2O Emissions c) Coastal CO Production
Upwelling Estimated from QSCAT Wind Data Nevison et al., 2004
Upwelling Along Global Eastern Boundaries Estimated from Satellite Winds annual average upwelling rate (m/s) Nevison et al., 2004
N2O and O2 are Strongly Anticorrelated in Ocean Depth ProfilesData from Butler et al., 1988
Sharp Increase Observed in Surface DN2O near Coast Nevison et al., 2004
Coastal N2O Sources estimated from Satellite Winds and subsurface Oxygen Climatologyvalues are DN2O (nM) Nevison et al., 2004
Carbon Monoxide Produced by Photodissociation of Colored Dissolved Organic Matter (CDOM)(SeaWiFS 1997-1999)
Spectrally Resolved Calculation:CO Production = ∫l F *AQY * (1-e-A) dl Zafiriou et al., 2003
BGC-Ecosystem Model in ROMS • NPDZ-type ecosystem model incl. C and O2 cycles • Tuned to upwelling conditions applying literature values • Initial and boundary conditions: • T, S: Levitus (monthly) • NO3: World Ocean Atlas (seasonal) • NH4, Phyto, Zoo, Det (Large/Small), CaCO3: const. (arbitr.) • DIC: - Surface: based on pCO2 climatology (Takahashi et al., 2002) • - Layers with seasonal variations of T: Interpolation of DIC based on seasonal T variations • - Deep ocean: NOAA/GLODAP climatology (annual) • ALK: - Surface: NTA/T relationship(Millero et al., 1998) • - Layers with seasonal variations of T:Interpolation of NTA based on seasonal T variations • - Deep ocean: NOAA/GLODAP climatology (annual) - All layers: Computation of Alk from NTA and S
Eddy Kinetic Energy increases largely withfiner model resolution- mean and mesoscale variability in the CCS Surface EKE (cm2 s-2) 5 km 10 km 20 km Time (years) (Marchesiello et al., JPO 2003)