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Home > NDACC Goals and Organization > NDACC Protocols > APPENDIX II - Infrared Instruments (FTIRs) > Certification Assessment for NDACC UV/Vis Instrument Intercomparison

Certification Assessment for NDACC UV/Vis Instrument Intercomparison

Observatoire Haute Provence, France 12 - 21 June, 1996

Criteria for type 1 (Trend measurements) certification for NO2 measurements

The UV/Vis appendix gives the NO2 regression analysis accuracy required as -
Residual <= 0.10 x 1016 cm-2, Slope = 1.00 ± 0.05, Intercept <= ± 0.15 x 1016 cm-2.

Criteria for type 2 (Process studies) certification for NO2 measurements

The UV/Vis appendix gives the NO2 ratio accuracy required as -
Standard Deviation <= 0.05, Ratio = 1.00 ± 0.10, Offset <= ± 0.25 x 1016 cm-2.

Type 1 Assessment using Regression (W or S) Analysis

Group & Site

Residual or StdDev

Slope or Ratio

Intercept or Offset

Certification criteria met

Comments

NIWA Global

         Reference Instrument Close to Brem/IASB

Bremen
Ny Alesund

0.037 (W)
0.040 (S)

0.98 (W)
1.00 (S)

0.02 (W)
-0.08 (S)

Yes
Type 1

 Low scatter / Good O3
Close to IASB/NIWA

IASB
Harestua

0.034 (W)
0.041 (S)

1.00 (W)
0.99 (S)

-0.07 (W)
-0.06 (S)

Yes
Type 1

 Low scatter / Good O3
Close to Brem/NIWA

Heidelberg
Kiruna

0.084 (W)
0.108 (S)

0.96 (W)
1.05 (S)

0.04 (W)
-0.09 (S)

Yes
Type 1

 More scatter than
Brem/IASB/NIWA

Type 2 Assessment using Regression (W or S) or Ratio (R) Analysis

CNRS2
Global

 

0.05 (R)

1.01 (W)
0.95 (S)
0.95 (R)

-0.46 (W)
-0.09 (S)

Yes
Type 2

 Low scatter / Good O3

INTA
Tenerife

 

0.05 (R)?

0.95 (W)
0.92 (S)
0.85 (R)?

-0.22 (W)
-0.27 (S)

Yes
Type 2

 Low residual / No O3
→ Processing problem

NILU1
Alomar

 

0.02 (R)

0.84 (W)
0.78 (S)
0.81 (R)

-0.03 (W)
-0.01 (S)

No, but →
(Type 2 ?)

 Low residual / Good O3
→ processing problem

CNR01

 
0.05 (R)

0.96 (S)
0.95 (R)

0.47 (S)

Marginal
Type 2

 No “W” data
Ozone not in spec

Notes:

“W” = Regression results for AM 19 June, processed using common wavelength interval (431 - 454 nm) and Graham & Johnston NO2 and O3 cross sections (Roscoe et al., Table 7).

“S” = Regression results averaged for all mornings using single campaign reference (not given in Roscoe et al.).

“R” = Ratio analysis results averaged for all mornings using daily reference (Roscoe et al., Figure 12).

To correct for Ring effect errors, NO2 results from unpolarised instruments are scaled by 1.035.

 

 

Table 1: Regression analysis set - NO2, AM, Single reference: regression values by day number

SNAM_O.TXT

SNAM_OC.DAT (AES22) SNAM_OD.DAT (BREM1) SNAM_OE.DAT (CNR01)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12       12 0.048 .070 -0.020 12 0.044 0.971 0.267
13 0.358 0.978 0.319 13 0.061 1.092 -0.081 13 0.042 0.945 0.237
14 0.331 1.078 -0.308 14 0.051 1.074 -0.095 14 0.135 0.948 0.123
15 0.200 1.073 -0.043 15 0.031 1.069 -0.084 15 0.050 0.944 0.285
16 0.206 1.011 0.159 16 0.023 1.079 -0.135 16 0.090 0.936 0.268
17       17 0.046 1.061 -0.060 17      
18 0.241 1.072 0.035 18 0.025 1.069 -0.061 18      
19 0.207 1.060 0.048 19 0.028 1.065 -0.078 19 0.038 0.925 0.733
20 0.339 1.037 0.300 20 0.051 1.061 -0.148 20 0.074 0.897 0.835
21       21       21 0.119 0.865 0.980

 

SNAM_OG.DAT (CNRS2) SNAM_OI.DAT (HEID1) SNAM_OK.DAT (IASB)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12 0.157 1.093 -0.011 12 0.158 1.044 -0.027 12 0.033 1.146 -0.110
13 0.044 1.135 -0.235 13 0.085 1.072 -0.007 13 0.034 1.149 -0.087
14 0.235 1.047 -0.016 14 0.119 1.092 -0.026 14 0.059 1.161 -0.082
15 0.061 1.107 -0.066 15 0.119 1.080 -0.091 15 0.026 1.155 -0.094
16 0.043 1.115 -0.041 16 0.096 1.069 0.028 16 0.030 1.168 -0.086
17 0.092 1.108 -0.031 17       17 0.067 1.162 0.003
18 0.069 1.106 -0.061 18 0.062 1.044 -0.001 18 0.035 1.137 -0.024
19 0.166 1.094 -0.111 19 0.068 1.047 -0.036 19 0.035 1.160 -0.042
20 0.058 1.134 -0.172 20 0.070 1.110 -0.240 20 0.027 1.149 -0.052
21 0.395 1.105 -0.111 21 0.196 1.019 -0.388 21 0.065 1.152 -0.037

 

SNAM_OL.DAT (INTA1) SNAM_OM.DAT (NILU1) SNAM_OO.DAT (NIWA1)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12       12 0.061 0.926 0.057 12 0.000 1.000 0.000
13 0.071 1.038 -0.377 13 0.058 0.915 0.147 13 0.000 1.000 0.000
14 0.073 1.041 -0.444 14       14 0.000 1.000 0.000
15 0.041 1.043 -0.239 15       15 0.000 1.000 0.000
16 0.037 1.051 -0.196 16 0.037 0.943 -0.033 16 0.000 1.000 0.000
17 0.033 1.055 -0.148 17 0.071 0.943 -0.002 17 0.000 1.000 0.000
18 0.032 1.052 -0.108 18 0.061 0.935 -0.014 18 0.000 1.000 0.000
19 0.037 1.040 -0.330 19 0.049 0.936 -0.035 19 0.000 1.000 0.000
20 0.057 1.063 -0.268 20 0.048 0.955 -0.082 20 0.000 1.000 0.000
21 0.155 0.966 -0.308 21 0.071 0.943 -0.108 21 0.000 1.000 0.000

 

MERIT_OS.NAM
NO2, AM, Single reference, regression values averaged over all or most days.
X Instrument = NIWA

Y Instr. Days Residual Slope Intercept SZA Min SZA Max
Mean Std Mean Std Mean Std Mean Std Mean Std
AES22  C 7 0.269 0.065 1.04 0.03 0.07 0.20 83.0 0.0 93.0 0.0
BREM1  D 9 0.040 0.013 1.07 0.01 -0.08 0.04 70.0 0.0 93.0 0.0
CNR01  E 8 0.074 0.035 0.93 0.03 0.47 0.31 70.0 0.0 92.8 0.7
CNRS2  G 10 0.132 0.106 1.10 0.02 -0.09 0.07 70.0 0.0 92.8 0.4
HEID1  I 9 0.108 0.043 1.06 0.03 -0.09 0.13 70.0 0.0 92.9 0.3
IASB   K 10 0.041 0.015 1.15 0.01 -0.06 0.03 70.0 0.0 92.8 0.4
INTA   L 9 0.060 0.037 1.04 0.03 -0.27 0.10 70.0 0.0 92.4 0.5
NILU1  M 8 0.057 0.011 0.94 0.01 -0.01 0.08 70.0 0.0 93.0 0.0
NIWA1  O 10 0.000 0.000 1.00 0.00 0.00 0.00 70.0 0.0 93.0 0.0

Processing date: 20 April 1998

 

Table 2: Regression analysis set - O3, AM, Single reference: regression values by day number

SOAM_K.TXT

SOAM_KD.DAT (BREM1) SOAM_KE.DAT (CNR01) SOAM_KG.DAT (CNRS2)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12 0.069 0.971 0.285 12 0.317 0.828 12.850 12 0.134 0.956 0.432
13 0.109 0.976 0.266 13 0.282 0.789 11.981 13 0.105 0.926 0.591
14 0.069 0.974 0.177 14 0.217 0.806 13.008 14 0.085 0.981 0.411
15 0.107 0.979 0.099 15 0.529 0.786 12.911 15 0.080 0.953 0.391
16 0.079 0.963 0.097 16 0.755 0.727 11.798 16 0.129 0.945 0.377
17 0.086 0.956 0.060 17 0.037 9.726 6.794 17 0.124 0.934 0.419
18 0.075 0.980 0.043 18       18 0.111 0.956 0.381
19 0.092 0.969 0.113 19 0.265 0.776 6.818 19 0.109 0.948 0.438
20 0.065 0.988 0.074 20 0.574 0.664 6.814 20 0.171 0.969 0.285
21       21 0.843 0.862 7.480 21 0.318 1.043 0.002

 

SOAM_KI.DAT (HEID1) SOAM_KK.DAT (IASB) SOAM_KL.DAT (INTA1)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12 0.101 1.043 0.060 12 0.000 1.000 0.000 12      
13 0.113 1.032 0.245 13 0.000 1.000 0.000 13      
14 0.114 1.008 0.268 14 0.000 1.000 0.000 14      
15 0.096 1.038 0.093 15 0.000 1.000 0.000 15      
16 0.117 1.024 0.214 16 0.000 1.000 0.000 16      
17       17 0.000 1.000 0.000 17      
18 0.080 1.035 0.173 18 0.000 1.000 0.000 18      
19 0.093 1.019 0.211 19 0.000 1.000 0.000 19      
20 0.111 1.030 0.226 20 0.000 1.000 0.000 20      
21 0.138 1.055 0.335 21 0.000 1.000 0.000 21      

 

SOAM_KM.DAT (NILU1) SOAM_KO.DAT (NIWA1)
Day Res-Err Slope Intercept Day Res-Err Slope Intercept
12 0.134 0.967 0.104 12 0.155 1.012 -0.172
13 0.134 0.975 -0.136 13 0.111 1.019 -0.208
14       14 0.086 1.002 -0.209
15       15 0.093 1.014 -0.195
16 0.092 0.950 0.093 16 0.069 0.988 0.041
17 0.140 0.957 0.031 17 0.063 0.990 0.017
18 0.104 0.980 -0.095 18 0.077 1.015 -0.033
19 0.086 0.955 -0.084 19 0.081 0.998 -0.032
20 0.123 0.978 -0.228 20 0.100 1.017 -0.037
21 0.106 0.970 -0.096 21 0.064 1.002 0.036

 

MERIT_KS.OAM
O3, AM, Single reference, regression values averaged over all or most days.
X Instrument = IASB

(Y) Days Residual Slope Intercept SZA Min SZA Max
Mean Std Mean Std Mean Std Mean Std Mean Std
BREM1  D 9 0.083 0.015 0.97 0.01 0.13 0.08 50.0 0.0 92.9 0.3
CNR01  E 9 0.424 0.251 1.77 2.81 10.05 2.78 50.0 0.0 88.9 9.9
CNRS1  G 10 0.137 0.065 0.96 0.03 0.37 0.14 50.0 0.0 92.7 0.5
HEID1  I 9 0.107 0.016 1.03 0.01 0.20 0.08 50.0 0.0 92.7 0.5
IASB   K 10 0.000 0.000 1.00 0.00 0.00 0.00 50.0 0.0 92.8 0.4
INTA1  L                      
NILU1  M 8 0.115 0.019 0.97 0.01 -0.05 0.11 50.0 0.0 92.8 0.4
NIWA1  O 10 0.090 0.026 1.01 0.01 -0.08 0.10 50.0 0.0 92.8 0.4

Processing date:18 February 1998

 

Table 7: NO2 regression results for the morning of 19 June using the single campaign reference, with common analysis wavelength interval (431 - 454 nm), with solar zenith angles >= 70°, and with Graham and Johnston cross sections for NO2 and O3. The reference instrument is NIWA.

Instrument Residual Error
(1016 molec cm-2)		 Slope
(dimensionless)		 Intercept
(1016molec cm-2)
Aber .251 .79 .43
AES7 1.530 .91 .67
Brem .037 .98 .02
CNRS2 .226 1.01 -.46
Heidv .084 .96 .04
IASB .034 1.00 -.07
INTA .072 .95 -.22
NILU1 .041 .84 -.03
NILU2 .545 1.18 -1.85

PVJ:OHPCERT3.DOC:26/11/98
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