Modeling and Data Assimilation in Support of ACE

Watson GreggNASA/GSFC/Global Modeling and Assimilation Office

NASA

Supporting data and publications: Google gmao, click Research, thenOcean Biology Modeling (http://gmao.gsfc.nasa.gov/research/oceanbiology)

RadiativeModel

(OASIM)

CirculationModel

(Poseidon)

BiogeochemicalProcesses Model

Winds SST

Layer DepthsIOP

Ed(λ)

Es(λ)

Sea Ice

NASA Ocean Biogeochemical Model (NOBM)Winds, ozone, relative humidity, pressure, precip. water, clouds (cover, τc),

aerosols (τa, ωa, asym)

Dust (Fe)

Advection-diffusion

Temperature, Layer Depths

Ed(λ)

Es(λ)

Chlorophyll, Phytoplankton GroupsPrimary ProductionNutrientsDOC, DIC, pCO2, FCO2

Spectral Irradiance/Radiance

Outputs:

Global model grid: domain: 84S to 72N1.25 lon., 2/3 lat.14 layers

atm pCO2

Diatoms

Biogeochemical Processes Model Ecosystem Component

Chloro-phytes

Cyano-bacteria

Cocco-lithophores

Si

NO3

NH4

Herbivores

N/CDetritus

Fe

SilicaDetritus

PhytoplanktonNutrients

IronDetritus

N/CDetritus

Herbivores

Phyto-plankton

DissolvedOrganicCarbon

Dissolved InorganicCarbon

pCO2(water)

pCO2(air)

Winds,Surface pressure

Biogeochemical Processes Model Carbon Component

Validation

Variable Global Difference % Correlation over Basins

Nitrate 18.9% 0.905 P<0.05Ammonia Not tested Not testedSilica 5.4% 0.952 P<0.05Dissolved Iron 45% 0.933 P<0.05Diatoms 15.5% 0.850 P<0.05Chlorophytes -16.2% 0.020 NSCyanobacteria 7.9% 0.970 P<0.05Coccolithophores -2.6% 0.700 P<0.05Total Chlorophyll vs In situ -17.1% 0.787 P<0.05 vs SeaWiFS -8.0% 0.618 P<0.05 vs Aqua 1.1% 0.469 NSHerbivores Not tested Not testedDetritus Not tested Not testedDiss. Inorganic Carbon 0.1% 0.972 P<0.05pCO2 0.0% 0.765 P<0.05Air-sea carbon flux 3.1% 0.741 P<0.05

Ozone

Molecules, aerosols

OxygenWater vaporCO2

air

sea

Ed

Es

(1 - )

EdEs

(1 - )EdEsEu

Ed, Es Ed, Es

LwN

Total Surface Irradiance (direct+diffuse; spectrally integrated; clear/cloudy): bias=1.6 W m-2 (0.8%)RMS=20.1 W m-2 (11%)r=0.89 (P<0.05)

OASIM

Surface Clear Sky Spectral Irradiance (PAR wavelengths):RMS=6.6%Integrated PAR:RMS=5.1%

450 475 500 600 625 650 675

a(λ), bb(λ)

525 550 575 700350 375 400 425

Chlorophyll components:diatomschlorophytescyanobacteriacoccolithophores

CDOM

water

aw(λ), bbw(λ)

aCDOM(λ)

ap(λ), bbp(λ)

OASIM Upwelling Irradiance(Forward Model)

detritus

ad(λ),

bbd(λ)

OASIM In-water Radiative Model

mW

cm

-2 u

m-1 s

r-1

Modeling Water-Leaving Radiances (with assimilated chlorophyll) Tropical

Rivers(CDOM)

Cocco-lithophores

Data Assimilation

In ocean biology, Two Classes:Variational (e.g., adjoint, 4DVar)Sequential (e.g., Kalman Filter)

We use Sequential Methodologies,Conditional Relaxation Analysis MethodEnsemble Kalman Filter

Routinely assimilating SeaWiFS and Aqua Chlorophyll Data

Bias Uncertainty NSeaWiFS -1.3% 32.7% 2086Free-run Model -1.4% 61.8% 4465Assimilation Model 0.1% 33.4% 4465

vs.In SituData

mg

m-3

Potential Support for ACE

Pre-Launch Observing Simulation System Experiments (OSSE’s)GMAO signaturePreviously done for SeaWiFS

e.g., orbit selection, sampling strategy (targeted sampling), band selection, potential algorithm effectiveness, variousaspects of instrument design

Development of a globally representative, dynamic simulated data set

Post-Launch Data Assimilation:

Reasonableness of derived products in the context of an interdependent set of variables

Removal of Sampling Biases caused by clouds, aerosols, low light, others