Fig. 1 CO2 band at 1.6 m observed on June 17, 2008 by TCCON at Park Falls
(Wisconsin) with solar zenith angle of 22.5.
Fig. 2. Calibration curve of profile retrieved CO2. Red points for using H2O as dry air
standard; Black points for using O2 as dry air standard. Dots for Parkfalls site and
diamonds for Lamont site. O2 correction makes results more consistent from scene
to scene, but introduces a consistent bias.
Fig. 3 (a) The square root of the diagonal in CO2 covariance matrix. (b) The 2-D plot
of the CO2 covariance matrix.
Fig. 4 CO2 profiles measured by aircraft (black) and TES Geos-chem assimilation
(red) at SGP on the same day in 2009. Their best agreements are mostly above 600
hPa in free troposphere.
Fig. 5 The comparison of total column-averaged CO2 from TCCON profile retrievals
to that derived from aircraft. Since most aircraft profiles measure up to 6 km except
three of them go up to 12 km, the integral above the aircraft profile ceiling are
replaced by TCCON a priori on that day. Its error bar is calculated using a priori
covariance above the aircraft ceiling. The green dots are the comparison to those
three aircraft profiles measured up to 12 km. Their uncertainties only from the
assumption in stratosphere and they are better fitted with the solid line.
Fig. 6 The comparison of PBL CO2 estimates with derived aircraft PBL CO2. (a)
Estimates by integrating TCCON a priori from surface up to 600 hPa. (b) Estimates
by TCCON/TES assimilations. The RMS to their own fitted line is reduced from 2.06
ppm for (a) to 1.40 ppm for (b). The improvement of the scattering is mainly at low
CO2 values during summertime when the biosphere is more active other than
wintertime.
Fig. 7 (a) Monthly mean column averages and PBL CO2 in 2009 at Lamont. Flight
column-averaged estimates in black solid line. TCCON column averages in black
dots. Flight PBL estimates in red solid line and TCCON/TES PBL estimates in red
dots. (b) The difference of PBL CO2 and column-averaged CO2 by flight (solid line)
and by TCCON/TES (dots). The agreements to the flight estimated differences are
better.
Unit (ppm)
Day(yyyy
mmdd)
20090108
20090116
20090129
20090204
20090211
20090219
20090221
20090304
20090308
20090314
20090316
20090318
20090329
20090407
20090408
20090420
20090421
20090423
20090517
20090518
20090520
20090526
20090528
20090530
20090604
20090607
20090610
20090612
20090616
20090621
20090623
20090629
20090701
20090706
Without cloud filter
Actual
Bias+5.78
(1 ×
n
(ppm)
𝜎)
0.73
0.31
167
0.58
0.30
171
0.47
0.30
170
0.70
0.26
169
0.93
0.52
132
0.37
1.08
102
0.77
0.41
131
1.36
3.49
24
0.39
0.52
163
0.94
0.99
108
0.14
0.37
157
0.31
1.44
163
0.13
0.88
104
0.24
0.26
98
0.11
0.42
129
-0.58
1.45
93
-0.20
0.29
131
-0.10
0.33
131
-0.08
0.32
130
0.92
0.32
131
0.80
0.58
90
-0.01
0.62
96
0.22
0.30
130
0.41
0.34
130
0.12
0.38
128
-0.91
1.16
3
-0.28
1.63
47
-0.71
1.26
102
-1.21
0.34
129
-0.74
0.28
97
-0.44
0.34
131
0.26
0.36
123
-0.02
0.86
126
1.12
1.56
53
With cloud filter
Actual
Bias+5.71
(1 ×
n
(ppm)
𝜎)
0.68
0.30
161
0.51
0.30
171
0.39
0.30
169
0.63
0.26
169
0.71
0.49
90
0.43
0.38
96
0.71
0.42
130
1.44
N/A
1
0.29
0.39
132
1.02
0.42
102
0.04
0.27
154
0.33
0.44
112
-0.04
0.28
76
0.17
0.26
98
0.01
0.40
121
-0.56
0.44
69
-0.28
0.29
130
-0.18
0.30
122
-0.15
0.32
130
0.85
0.32
131
0.63
0.50
75
-0.08
0.36
86
0.15
0.30
130
0.34
0.34
130
0.05
0.38
128
-0.41
N/A
1
-0.73
1.27
27
-0.91
0.35
72
-1.28
0.34
128
-0.81
0.28
95
-0.52
0.32
129
0.21
0.32
118
-0.19
0.46
119
0.95
0.33
43
Expected
𝒅𝒂𝒚
𝒉𝒓
𝜎(𝛿𝑋𝑪𝑶
) 𝜎(𝛿𝑋𝑪𝑶
)
𝟐
𝟐
0.27
0.33
0.34
0.33
0.33
0.33
0.34
0.32
0.32
0.33
0.32
0.32
0.33
0.33
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.31
0.32
0.32
0.31
0.31
0.31
0.31
0.31
0.32
0.79
0.81
0.84
0.81
0.82
0.83
0.84
0.75
0.78
0.80
0.76
0.76
0.79
0.79
0.76
0.78
0.77
0.74
0.77
0.75
0.74
0.75
0.75
0.73
0.75
0.71
0.73
0.73
0.71
0.71
0.70
0.71
0.72
0.73
20090715
20090731
20090802
20090803
20090822
20090823
20090901
20091019
20091101
20091102
20091103
20091111
20091122
20091218
20091220
20091227
-2.16
0.45
0.39
-2.04
0.22
-0.59
1.13
-2.02
-0.33
-0.55
-0.82
-0.69
-0.27
-0.08
0.48
0.17
1.49
0.36
0.29
0.31
1.24
0.38
0.70
N/A
0.36
0.33
0.35
1.25
0.52
0.47
0.38
0.66
4
127
131
130
7
130
103
1
130
131
131
89
82
127
101
10
-0.92
0.37
0.32
-0.35
0.06
-0.66
1.04
-2.07
-0.40
-0.62
-0.89
-0.69
-0.30
-0.15
0.41
0.42
N/A
0.34
0.29
0.33
1.05
0.38
0.66
N/A
0.36
0.33
0.35
0.63
0.39
0.47
0.38
1.18
Mean
0.00
0.67
108
0.00
0.39
RMS
0.78
1
125
131
130
3
130
102
1
130
131
131
67
68
127
101
3
10
0
0.31
0.32
0.31
0.31
0.32
0.31
0.32
0.32
0.32
0.32
0.32
0.32
0.32
0.33
0.33
0.34
0.70
0.73
0.72
0.70
0.73
0.72
0.73
0.74
0.75
0.76
0.77
0.77
0.78
0.82
0.79
0.84
0.32
0.78
0.67
Table 1. Lists of bias error and its standard deviation (1 × 𝜎) of TCCON profile
retrieved column averages within 4-hr time window of each flight measurement.
The expected uncertainties from measurement error covariance and the sum of
measurement error covariance and systematic error covariance are also listed in the
last two columns. To remove the unclear sky spectra measurements, we dismiss the
retrievals when the parameter ‘fvis’ (fractional variation in solar intensity) is
greater than 0.05, which suggests the cloud coverage during the spectra
measurement. By applying the cloud filter, the consistency between the imperial
error estimates and expected error estimates is improved. The columns for ‘𝑁’ are
the total numbers of retrievals within 4-hr time window. They are reduced after
applying the cloud filter. When 𝑁 is below 50, the statistics is not sufficient. The pink
cells are the cases that either the 1 × 𝜎 is beyond 1 ppm, which is not consistent
with the estimates by the measurement error covariance or 𝑁 is below 50. The
yellow cells are the cases that the 1 × 𝜎 is between 0.5 and 1 ppm, which are barely
agree with the expected estimates. The green cells are the cases that after applying
the cloud filter, the consistency is reached. It is noticed that for those cases
remaining inconsistent are because the values of 𝑁 is below 50.
Unit (ppm)
Total column averages
PBL column averages;
Combining two data set;
[Total column amount – free
troposphere column amount
(above 600 hPa)]
TCCON
TCCON prior
TCCON – TES/GEOS-Chem
TCCON – TCCON prior
TCCON prior – TES/GEOSChem
Accuracy Precision
-5.71
0.67
1.04
1.50
0.32
-0.96
1.24
Table 2. Accuracy and precision comparisons.
1.40
2.26
3.65