Transcript Evaluating Skill in Ocean Model Parameterizations: Taylor Diagrams

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)
T ~ -1oC
T ~ -4.5oC
Loop Current
Shedding front
T ~ -0.5oC
Warm core eddy
Cluster-averaged
temperature profiles
ageostrophic
velocity
(cm s-1)
ageostrophic
KE
(cm2 s-2)
vertical
shear
(s-2)
Richardson
number
Taylor
Taylor diagram
f
R


E
Taylor, K., 2001: JGR, 106, D7, 7183-7192
Diagrams:
Taylor Diagram
– Skill Score
Taylor diagram
S-isolines:
0.1 intervals, grey shading
S  [0.6,0.7]
S  [0.9,1.0]

Taylor, K., 2001: JGR, 106, D7, 7183-7192
MOTIVATION:
Northern Cyclone
Southern Cyclone
Ivan (2004) over the
GOM SSH (cm)
from HYCOM (from
Halliwell et al.,
MWR, 2008).
SST Analyses
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 OML
GOM4: 31 layers, 3-5m in OML
Vertical mixing
KPP
GOM5: MY
GOM6: GISS
CD
Donelan
GOM7: Powell
GOM8: Large and Pond
GOM9: 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
TMI and KPP SST Comparisons
Pre Ivan SST
Post-Ivan SST
Pre-Post Ivan
ΔSST
Observed/Simulated
Current Response at
M9 (1.5 Rmax)
from 7 Experiments
Halliwell 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)
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.
Goal: To observe and improve our understanding of the LC response to the nearsurface 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.
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……