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-====== General_report ======
-= RBCC-E Arosa 2008 Calibration Summary  =
-<br>
-===== Reference comparison:  =====
-Brewer #017 and #185 were present at the campaign, calibration of both brewers differs in 0.5%. Brewer #017 shows temperature dependence during the campaign, but if we use the temperature coefficients calculated with the data collected during the campaign this difference vanishes. As most of single brewers, Brewer#017 shows a stray light issue, underestimating ozone at high ozone slant path (ozone x air mass).
-<br> During the return to Izaña, Brewer#185 suffered a shock. As a result of this, the slit mask position resulted altered, so we can't guarantee that the instrument was the same before and after the campaign. However, after realignment of the slit mask the instrument recovers the previous constants so we have some confidence that the instrument did not change. In any case we are pretty sure that the instrument did not change during the trip to Arosa.
-<br> {{wiki:Figure001.png}}
-**Figure 1: Reference Comparison Brewer #017 (IOS) vs Brewer #185 (RBCC-E), with the original configuration (red dotted line) and after adjustment on #017 of the temperature coefficients (dashed line).**
-<br>
-<br>
-===== Introduction  =====
-We divide the calibration into three steps: Instrumental, wavelength calibration and ETC transfer. Briefly, from the known formula of the ozone calculation <br> <math>{O_3} = {{F - ETC} \over {\alpha \,m}}</math>&nbsp; (1,1)
-where F is Rayleigh corrected double ratios, <span class="texhtml">α</span> is the ozone absorption coefficient, m is the ozone airmass and ETC is the extraterrestrial constant.
-*Instrumental calibration includes all the parameters that affect the measured counts (F): Dead Time, Temperature coefficients and Attenuation of the Filter.
-<math>F = \sum\limits_{i = 1}^4 {{w_i}} {F_i}\left( {DT,TC,AT} \right)</math>(1.2)
-*Wavelength calibration determines the ozone absorption coefficient (<span class="texhtml">α</span>).
-<math>\alpha  = \sum\limits_{i = 1}^4 {{w_i}\alpha ({\lambda _i})}</math>(1.3)
-*ETC transfer is performed by comparison with the reference. Changes in instrumental and wavelength calibration affect the final ETC.
-For each instrument we consider if maintenance works were made or not. The instrument can have modifications during maintenance works, so we divide the period of the campaign into three periods: initial blind days to check the status of the instrument, days for maintenance and finally the final days to set the new calibration. For the instruments without maintenance the time periods are the same (Table 1).
-<br>
-{| style="border-spacing: 0pt;"
-|+ Table 1&nbsp;: Calibration Periods
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Instrument
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Cal days
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Blind days
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Final days
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 17
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 40
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 203-212
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-206
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 206-212
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 64
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 205-210
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 205-207
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 205-207
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 72
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 203-212
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 208-212
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 201-205,208-212
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 156
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-212
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-206
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 208-212
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 163
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 204-209
-|}
-<br>
-===== Standard Lamp analysis  =====
-The way to monitor the calibration is by mean of Standard Lamp test. In particular the ratio R6 is a measure of ozone but using the internal standard lamp as a light source. In the analysis of the campaign we look at the SL ratios to check the instrument stability. Comparing the SL Ratios with the original configuration and the final one is a good tool to check the possible change on the instrumental calibration of the instrument (Figure 2).
-{{wiki:FiguraSL.png}}
-**Figure 2: Evolution of the SL values respect reference values using the initial configuration (upper plot) and final one (lower plot)**
-The calibration provides a R6 reference value, usually the value recorded during the calibration. Previous reference values and new ones with the observed values are shown in Table 2.
-<br>
-{| style="border-spacing: 0pt;"
-|+ Table 2&nbsp;: R6 reference values and mean values during the campaign with the initial and final configuration.
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Brewer
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | R6 reference
-Original
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Mean R6
-Original
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | R6 reference
-Final
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Mean R6
-Final
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 17
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2090
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2091
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2100
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2101
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 40
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1730
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1721
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1717
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1717
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 64
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1675
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1671
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1670
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1671
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 72
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1930
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1920
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1920
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1919
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 156
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 430
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 446
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 435
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 435
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 163
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 200
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 202
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 188
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 188
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 185
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 312
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 312
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 312
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 313
-|}
-**Table 2&nbsp;: R6 reference values and mean values during the campaign with the initial and final configuration.**
-<br> A difference of more than five units from the reference value normally indicates the need of SL correction. Looking at the SL data we can conclude Arosa brewers 040,072,156 and probably 163 need standard lamp correction for the analysis of ozone when using the original configuration; whereas for the final configuration no SL correction is needed for any instrument. (Figure 4)
-<br> {{wiki:FigureSL c.png}}
-**Figure 3: SL R6 differences between observations and reference values. Difference between initial and final configuration is also showed**
-<br> We can also consider that a change of more than 5 units on SL value, between the original and final instrument calibration,is a major change in instrument configuration. So modifications on the instrumental calibration (F) of brewers #017, #156 and #163 will produce a significative change in the ETC calibration.
-<br> The temperature range of the instruments during the campaign was very high (from 10Âº to 40Âº). The behaviour of the instruments against temperature is plotted on figure 4. The calculated slopes of the regression lines are summarized in table 4.
-<br>
-{| style="border-spacing: 0pt;"
-|+ Table 3: Temperature dependence R6 units/Cº
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <br>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | IOS#017
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ARO#040
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | POL#064
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ARO#072
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ARO#156
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | WRC#163
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | IZO#185
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Initial
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | -0.39
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.26
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.10
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | -0.09
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.45
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.77
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.1
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Final
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.01
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.06
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.10
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | -0.06
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | -0.18
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.08
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.1
-|}
-**Table 3: Temperature dependence R6 units/Cº**
-<br> {{wiki:FigureSLtemp.png}}
-**Figure 4&nbsp;: Temperature dependence of the instruments during the campaign, original configuration (blue) and final configuration (green).**
-**<br>**
-<br> For all the instruments we have the initial calibration and the final one, which can be the same. In some instruments you can also find a third calibration which is a suggested one for the period before the campaign. Most of the data of calibration are on ICF files with some remarkable exceptions like SL reference value.
-<br>
-<br>
-===== Wavelength calibration.  =====
-==== Introduction  ====
-(Cal-step, dispersion slpines vs cuadratic, ozone lines....)
-==== Analysis  ====
-Analysis of 2007 and 2008 dispersion tests was made for all the instruments participating in Arosa 2008 Intercomparison Campaign. Main results are summarized in Table 4. During the maintenance, the cal-step of brewers from Arosa (#064, #072 and #156) were adjusted and for #072 the Hg reference line was also changed. For this brewer, comparison of Ozone absorption coefficients before and after the maintenance is not direct and we use the absolute steps from the micrometer to perform the comparison.
-The wavelength is determined by the step motor that controls the dispersion grating. The resolution achieved in one step is about 0.3% in ozone absorption coefficient, which results in a 0.3% in total ozone. We consider this precision of the brewer in wavelength to decide if we change or not the ozone dispersion coefficient. If the change is plus/minus one step we consider the same results and donâ€™t change the value, and if the change is greater than 2 steps the change is performed.
-<br>
-{| style="border-spacing: 0pt;"
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Brewer
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Î± orig
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 2007
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Î± final
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 2008
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | observations
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | IOS#017
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3380
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3395
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3380
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | <br>
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | No Changes
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | IOS#040
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3400
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3403
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3384
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3331
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Calc-Step
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | POL#064
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3423
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3425
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3423
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3428
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | No Changes
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ARO#072
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3434
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3422
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3397
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3397
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Calc-Step/HG
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ARO#156
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3467
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3425
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3409
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3409
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Calc-Step/HG
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | WRC#163
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3394
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3406
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3414
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | 0.3414
-| style="border-width: 0.018cm 0.018cm medium; border-style: solid solid none; border-color: rgb(0, 0, 0) rgb(0, 0, 0) -moz-use-text-color; padding: 0cm 0.191cm;" | Y
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | IZO#185
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.3422
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.3416
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.3422
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 0.3425
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | No Changes
-|}
-**Table 4: Summary of the wavelength calibration: ozone absorption coefficient Î± for the initial calibration and final calibration ,the calculated values for the dispersion performed in 2007 and 2008 and in the last column, reason of the changes of the wavelength calibration.**
-<br> There are two remarkable cases:
-#Brewer #040, for which the dispersion test performed in 2007 agree with the configuration value but is quite different compared with the value calculated in 2008 (1.5&nbsp;%); considering the long history of the instrument we decide to maintain the 2007 value updated to the new cal-step position.
-#Brewer #156, for which the ozone absorption coefficient in use is in disagreement (1.2&nbsp;%) with the dispersions performed in 2007 and 2008. This produces a slope, when comparing the ozone of this brewer with both references vs. ozone slant path (Figure 5 and Figure 6) results in overestimation in low ozone slant path and underestimation in higher.
-<br>
-<br>
-===== ETC calibration  =====
-==== Initial calibration  ====
-The purpose of initial calibration is to check the calibration of the instrument before the maintenance works as well as evaluate the current calibration performance and if the Standard Lamp traces properly the changes. For this analysis we use the blind-days data with the configuration and the SL reference values provided by the operators. The ozone percentage ratio against the reference vs ozone slant column are shown on Figure 5&nbsp;: Ozone percentage difference of the instruments against RBCC-E referenceFigure 5 ( RBCC-E reference) and Figure 6 (IOS reference). The effect of stray light on IOS reference is clear from this plot.
-{{wiki:Blind185.png}}
-**Figure 5&nbsp;: Ozone percentage difference of the instruments against RBCC-E reference**
-<br>{{wiki:Blind017.png}}
-**Figure 6&nbsp;: Ozone percentage difference of the instruments against IOS reference**
-<br> In order to evaluate if the SL tracks the calibration we perform a calculation of the ETC for the blind period. The ETC is obtained by comparison with reference brewer **IZO#185** using simultaneous measurements during the blind period (two measurements are considered simultaneous if the time difference is less than three minutes). Measurements with airmass difference greater than 3% were removed from the analysis. From the ozone formula (1,1) we can derive the ETC calculation<br>
-<br> <span class="texhtml">//E**'T**'C// = //F// − //O//<sub>3//r**'e**'f//</sub>α * //m//</span>(1.5)
-<br> Corrected counts (F) and airmass factor (m) are known, and&nbsp; ozone absorption coefficient&nbsp;<span class="texhtml">α</span> can be computed from the wavelength calibration, so using the simultaneous ozone data from the reference instrument,&nbsp; ETC can be derived.
-<br>ETC depends of the value of ozone absorption coefficient. For all the brewers we use the initial configuration value with the exception of Brewer #156 for which we use the calculated values (see previous section). Only for&nbsp; brewer #040 the SL tracks the change observed in ETC, in other words the application of the SL correction only improves the comparison in this particular brewer (Table 5 ). We have to take into account that all the brewers were previously calibrated against #017, this comparison is in preparation.
-<br>
-{| style="border-spacing: 0pt;"
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <br>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>R6 Ref</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>R6 Obs.</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>ETC</center> <center>init</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>ETC</center> <center>sugg</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>R6r-R6obs - (ETC-ETC sugg)</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>17</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2090</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2091</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>3310</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>3298</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-13</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>40</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1730</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1721</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2960</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2947</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-4</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>64</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1675</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1671</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2850</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>2835</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-11</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>72</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1930</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1920</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>3170</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>3170</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>10</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>156</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>430</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>446</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1740</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1741</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-15</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>163</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>200</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>202</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1439</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1435</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-6</center>
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>185</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>312</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>312</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>1574</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-</center>
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | <center>-</center>
-|}
-**Table 5&nbsp;: Summary of ETC and SL correction for the blind days. Values around +/-5 five on the last columns indicate that SL tracks the ETC detected change.**
-<br>
-==== Ozone comparison: Final calibration  ====
-The calibration uses the final days observations with the method described on previous section. Table 6 summarizes the changes and Figure 7 the ratios against the reference. The difference between single brewers and double brewers is clear with an underestimation about .5% for #074 and #072 and 1% for <nowiki>#017 and #040 at </nowiki>1k DU (osc).
-<br> {{wiki:Final185.png?600}}
-**Figure 7&nbsp;: Ozone Percentage difference between the instruments final calibration**
-<br>
-{| style="border-spacing: 0pt;"
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Brewer
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | ETC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Î‘ *(10000)
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | R6 reference
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 17
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3310
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3380
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2100
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 40
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2960
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3384
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1717
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 64
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 2835
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3423
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1670
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 72
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3185
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3397
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1920
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 156
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1750
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3409
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 435
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 163
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1405
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3414
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 188
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 185
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 1574
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 3422
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 312
-|}
-**Table 7: Final Calibration Summary**
-<br>
-{| style="border-spacing: 0pt;"
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Brewer
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Instrument calibration
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | wavelength
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Etc transfer
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 17
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | TC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 40
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | TC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y (Calc-Step)
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 64
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 72
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | NC (ND)
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y (Calc-Step/HG)
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 156
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | DT/TC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y (Calc-Step)
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y
-|-
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | 163
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | TC
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y
-| style="border: 0.018cm solid rgb(0, 0, 0); padding: 0cm 0.191cm;" | Y
-|}
-**Table 6: Summary of changes during calibration (NC no change, TC Temperature Coef, DT (Dead Time), HG change hg test line)**
-<br>

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