Transcript pptx
Estuarine Hypoxia Component
of Testbed 2
Marjorie Friedrichs, VIMS, lead
Carl Friedrichs, VIMS, co-lead
Wen Long and Raleigh Hood, UMCES
Malcolm Scully, ODU
FY12 Testbed 2 Kick-off Telecon
Objectives
Compare relative skill of various hydrodynamic
and dissolved oxygen models in reproducing
observations on seasonal time scales in
Chesapeake Bay, by examining:
bottom/surface temperature
bottom/surface salinity
bottom/surface dissolved oxygen
maximum stratification
depth of maximum stratification
hypoxic volume
Provide information to managers such that results
of these analyses could be transitioned to
operational/scenario models
Five Hydrodynamic Models Configured
for the Bay
EFDC
CH3D
Cerco & Wang
USACE
Shen
VIMS
UMCES-ROMS
Li & Li
UMCES
CBOFS (ROMS)
Lanerolle & Xu
NOAA
ChesROMS
Long & Hood
UMCES
Five biological models
• ICM: CBP model; complex biology
• BGC: NPZD-type biogeochemical model
• 1eqn: Simple one equation respiration
(includes SOD)
• 1term-DD: depth-dependent respiration
(not a function of x, y, temperature,
nutrients…)
• 1term: Constant net respiration
Data from 40 CBP stations
= ~40 CBP stations used in
this model-data comparison
mostly 2004
some 2005 results
bottom T, bottom S,
stratification = max dS/dz,
depth of max dS/dz
bottom DO, hypoxic volume
Stratification (max dS/dz; 2004)
bias [psu/m]
unbiased
RMSD
[psu/m]
Stratification is a challenge; CH3D, EFDC reproduce
seasonal/spatial variability best
Sensitivity Experiments
Maximum
Stratification
CH3D, EFDC
ROMS
Stratification is insensitive to grid resolution and changes
in atmospheric forcing
Stratification (max dS/dz; 2004)
bias [psu/m]
unbiased
RMSD
[psu/m]
ROMS with
new TKE
parameter
Adjusting the minimum TKE parameter reduces
the bias in ChesROMS
Hypoxic Volume
bias [km3]
unbiased
RMSD
[km3]
Several simple DO models reproduce seasonal variability
of hypoxic volume about as well as ICM
Hypoxic Volume
bias [km3]
unbiased
RMSD
[km3]
5-model average
does better than any
single model
Overall Progress from Testbed 1
1. Compared 5 different hydrodynamic models
with 5 different DO models (examined 12
different combinations of hydrodynamics+DO
for 2004, subset of these for 2005)
Density stratification at pycnocline is a challenge
Simplest DO models reproduce seasonal variability as
well as most complex models
Multi-model average for hypoxic volume does better than
any single model
Models do much better in our wet year (2005) than our
dry year (2004)
2. Began to examine sensitivity experiments with
individual models
Strong sensitivities to wind, min TKE, advection scheme
Weak sensitivities to river discharge, coastal BC, grid
resolution
Overall Progress from Testbed 1
(cont.)
3. Transitioning information to federal agencies
• Simple DO model incorporated into the research version
of NOAA CSDL’s Chesapeake Bay Operational
Forecast System
• Participated in Eco-Forecasting workshop at NOAA/
NCEP to further hammer out transition steps for
moving to fully operational version of the DO model
• Provided advice to the CBP on future estuarine and
hypoxia modeling strategies, in support of federally
mandated environmental restoration, via a STAC
workshop report
Update on Testbed 1 Deliverables
We are on track to provide all deliverables
as promised by Dec. 31, 2011
Plans for Testbed 2 Year 1
1. Improve modeled density stratification
Examine choice of turbulence closure scheme
and advection scheme
2. Idealized sensitivity experiments with all models
Concentrating on wind, may also include river discharge
3. Additional skill metric
Averaged Discrete Frechet Distance
4. Presentations/publications
Five publications are in preparation
Multiple presentations to managers and
scientific community
“Wish List” for Testbed 2
1. Unstructured Grids
SELFE
FVCOM
2. Potential for < 10 day operational forecasts
Need to examine skill of models in reproducing high
frequency data sets
3. Interannual/Interdecadal skill
We have simulations from 1991-2005 from multiple
models, but we do not yet have the resources to make
these comparisons