Table 1. LETKF parameters.
Horizontal localization scale (number of grids):
7
vertical localization scale (m):
2000
Covariance inflation parameter (%):
21 (10.5, 42)
Observation error of SSHA (m):
0.2 (0.1 & 0.05)
Observation error of T (0C):
1.0
Time interval of LETKF (day):
2
ensemble members:
20
Table 2. The LETKF Experiments and the OI experiment.
LETKF runnum
obs data used
012
SSHA (>500m)+MCSST+parm_infl (42%)
013
SSHA (>500m)+MCSST+parm_infl (10.5%)
014
SSHA(>500m) +MCSST+LC(uv, err = 0.05 m/s)
015
SSHA(>500m)+MCSST +parm_infl (21%)
016
SSHA(>500m) +MCSST+LC(uv, err = 0.1 m/s)
OI
SSHA(>500m)+MCSST
Table 3. The comparison between the model output and Loop Current moorings. The vector
correlations, skills, mean and standard deviation ratios are averaged over depth, 90 days, and 9
moorings (a, b, & c) for different experiments.
V. Corr
Skill
mean
std
run
R
Θ
u
v
speed ratio
αm-αo
ratio
OI
0.41
29o
0.63
0.79
0.56
-10o
0.88
012
0.47
23o
0.88
0.95
0.91
22o
0.80
013
0.47
31o
0.87
0.94
0.92
4o
0.90
014
0.41
20o
0.82
0.87
0.69
13o
0.72
015
0.49
19o
0.88
0.95
0.91
9o
0.74
016
0.46
16o
0.89
0.86
0.70
18o
0.77
Table 4 The comparison between the model output and Loop Current mooring d. The vector correlations,
skills, mean and standard deviation ratios are averaged over depth, 54 days, and 8 moorings (d) for
different experiments.
skill
run
R
mean
std
θ
u
v
speed ratio αm-αo
ratio
0.51
53o
0.36 0.70
0.85
-14o
0.94
012 0.68
72o
0.27 0.69
0.87
-6o
0.92
013 0.66
72o
0.29 0.76
0.96
-12o
0.98
014 0.53
62o
0.31 0.70
0.74
-16o
0.67
015 0.59
92o
0.31 0.75
0.79
-2o
0.69
016 0.53 91 o 0.31 0.65
0.67
45 o
0.70
OI
Fig.1 Model domain and bathymetry in the Gulf of Mexico. The red grids represent the locations for the
MCSST, and the blue grids are the locations for AVISO satellite SSHA used in the LETKF. The white
triangles indicate the locations of Loop Current moorings a, b, & c, the yellow triangles indicate the
locations of Loop Current moorings d, and the green dots are the NDBC ADCP locations in the northern
Gulf. The yellow cross denotes the oil spill location. Grey contours are 200m and 2000m isobaths.
Fig2. Daily-averaged SSH (colors in m), surface currents (squiggly black lines) and wind stress vectors
(blue) shown every 6 days for the OI experiment (see Table 2) . White contour=AVISO SSH=0 and grey
contour=200m isobath.
Fig. 3 Daily-averaged SSH (colors in m), surface currents (squiggly black lines) and wind stress vectors
(blue) shown every 6 days for the LETKF experiment (see Table 2) . White contour=AVISO SSH=0 and
grey contour=200m isobath.
Fig.4 Comparison between AVISO and modeled SSHA. Top: spatial correlation coefficient between the 6
experiments and AVISO SSHA’s in the region north of 23oN and west of 84oW, and over water region
deeper than 500 m in the Gulf of Mexico for time period 04/22-07/21 in 2010; and bottom: the
corresponding RMS error for the same region. In each case, the 90-day means are also shown. See Table
2 for experiment names.
Fig.5 Variance ellipses and the corresponding mean velocity vector at z=-100m from moorings (blue,
mooring a, b, &c) and model experiments (red ) for the entire 90 days. Left panel: OI; right panel:
LETKF015.
Fig.6 The same as the Fig. 5, except that z=-500m
Fig. 7 The 90-day averaged vector correlation, correlation coefficient (R, left) and angle (θ, right), over
moorings a, b, & c in the vertical. See Table 2 for experiment details.
Fig. 8 Observed and model (see Table 2) mean velocity vectors (left) and principle axis standard
deviation ellipses (right) displayed as a function of depth at the mooring b2 (its location see Fig.1); the
period of analysis is 90 days from April, 22 to July, 21 in 2010. Note that the scale in the lower left panel
is five times larger than the others.
Fig. 9 Variance ellipses and the corresponding mean velocity vector from moorings (blue, mooring d
near bottom ) and model experiments (red ) for the entire 90 days. See Table 2 for experiment details.
Fig.10 Vector correlation (R: top panel; θ: bottom panel) of model and three ADCP currents (green dots in
Fig. 1) at 500 m.
Fig. 11 Variance ellipses and the corresponding mean velocity vector at z=-500m from ADCP (blue) and
model experiments (red ) from May, 1 to Jul, 21. Left panel: OI; right panel: LETKF012.