evaluating skill in ocean model parameterizations: taylor diagrams
DESCRIPTION
Evaluating Skill in Ocean Model Parameterizations: Taylor Diagrams. Lynn (Nick) Shay and G. Halliwell MPO, RSMAS, Univ. of Miami PhOD, AOML, NOAA http://isotherm.rsmas.miami.edu/~nick HFIP Observations and Modeling Teams. T’is the Season……. - PowerPoint PPT PresentationTRANSCRIPT
Evaluating Skill in Ocean Model Parameterizations: Taylor Diagrams
Lynn (Nick) Shay and G. Halliwell MPO, RSMAS, Univ. of Miami
PhOD, AOML, NOAA http://isotherm.rsmas.miami.edu/~nick
HFIP Observations and Modeling Teams
T’is the Season…….
Ivan’s Track and Intensity Relative to OHC (left) NRL SEED Mooring Locations in Northern Gulf of Mexico Relative
to Bottom Depth (Right) (Teague et al., JPO, 2007).
14 ADCP moorings- Focus here in Array 9.
Ocean Structure Gulf Versus East Pacific
Strong vertical temperature, salinity and density gradients at base of OML in EPAC…
Implications for mixing…and ocean (SST) cooling.
N~20 cph
Differentiated cooling in the LC system (Jaimes and Shay, MWR, 2009)Differentiated cooling in the LC system (Jaimes and Shay, MWR, 2009)
Loop Current Shedding front
Warm core eddy
T ~ -1oC
T ~ -4.5oC
T ~ -0.5oC
ageostrophicvelocity(cm s-1)
ageostrophicKE
(cm2 s-2)
verticalshear(s-2)
Richardson number
Cluster-averaged temperature profiles
R
f
E
Taylor diagram Taylor Diagrams:
Taylor, K., 2001: JGR, 106, D7, 7183-7192
Taylor diagram Taylor Diagram – Skill Score
S [0.6,0.7]
S [0.9,1.0]
S-isolines: 0.1 intervals, grey shading
Taylor, K., 2001: JGR, 106, D7, 7183-7192
MOTIVATION:
Ivan (2004) over the GOM SSH (cm) from HYCOM (from Halliwell et al., MWR, 2008).
SST Analyses
Northern Cyclone
Southern Cyclone
HYbrid Coordinate Ocean Model (HYCOM)Hurricane Ivan Simulations 10 Sept-6 Oct 04
Configuration:• 0.04° Mercator grid, Gulf of Mexico domain• No data assimilation performed
Initial and boundary conditions from U.S. Navy HYCOM ocean nowcast-forecast system:•Data assimilative ocean nowcast•Navy Coupled Ocean Data Assimilation (NCODA) assimilation
Atmospheric Forcing:•Navy 27 km COAMPS atmospheric model•Vector wind blended with higher resolution fields from HWIND •Wind stress for HWIND calculated using Donelan cd
Hurricane Ivan Modeling Experiment Summary
Model Attribute Baseline Experiment GOM1 Alternate Experiments
Horizontal resolution 0.04° Mercator GOM2: 0.08° Mercator
Vertical resolution 26 layers, 4-8m in OML GOM3: 21 layers, 7.5-15m in OMLGOM4: 31 layers, 3-5m in OML
Vertical mixing KPP GOM5: MYGOM6: GISS
CD Donelan GOM7: PowellGOM8: Large and PondGOM9: Large and Pond (capped)GOM10: Shay and Jacob
CEL, CES COARE3.0 algorithm GOM11: Kara et al.
Atmospheric forcing 27-km COAMPS+H*WIND GOM12: 27-km COAMPS only
Outer model NCODA GoM hindcast GOM13: Free GOM simulation
Ocean Dynamics 3-D Ocean Physics GOM14:1-D Column Models
RMS SST (oC) Differences
Pre Ivan SST
Post-Ivan SST
Pre-Post Ivan ΔSST
TMI and KPP SST Comparisons
Observed/Simulated Current Response at M9 (1.5 Rmax)from 7 ExperimentsHalliwell et al., MWR, (2009)
Below cd using ocean response as a tracer in Shay and Jacob (2006)
Current Time Series Comparisons @ 1.5 Rmax
U (east-west) V (north-south)
Taylor Diag., simulations vs. baseline:
SST;
v Current at M9 (1.5Rmax).
(Halliwell et al., MWR, 2009)
Taylor Diag., simulations vs. observations:
SST;
v Current at M9 (1.5Rmax).
(Halliwell et al., MWR, 2009)
Regression XBT Transect: East Pacific Ocean
XBT Transect-East Pacific
Equivalent OHC and Juliette (2001)
Track and Intensity of TC’s Gustav and Ike Versus AXBTs relative to OHC and 26oC Isotherm Depth.
Gustav : 191 AXBTs 111 GPS Drifters Floats
Ike : 216 AXBTs 111 GPS Drifters Floats
(Shay et al. 2009)
NOAA WP-3D Profiling over MMS Moorings
(Collaboration with AOML HRD, AOC, TPC, NCEP)
Goal: To observe and improve our understanding of the LC response to the near-surface wind structure during TC passages. Specific objectives are:
1. Determine the oceanic response of the LC to TC forcing; and, 2. Influence of the LC response on the atmospheric boundary layer and intensity.
Deliverables include:
V, T, S profiles to 1000 m @ 2-m resolution.
Surface winds (SFMR, GPS) provided by HRD.
Atmospheric profiles of V, T and RH @ 5-m resolution.
Progress and Blueprint For Future
Ivan a clear example of negative feedback (wake cooling/mixing induced by strong winds and Cold Core Ring) as opposed to positive feedback over the Loop Current and Warm Core Rings.
Taylor Diagrams collapse Standard Deviation, Correlation Indices and RMS Differences into one representation relative to an observation of current, temperatures, winds, humidities, variance etc to assess model performance.
Estimate skill by combining standard deviations and correlations.
In Ivan case, 14 sets of model simulations were made differing in only one aspect at a time. Approach shows sensitivity and allows us to isolate physics (Even a 1-D versus 3-D Ocean!)
Applying same approach to OHC variability in assessing uncertainties in satellite retrievals using in situ data as truth.
Field programs to acquire 3-D data……