Mathematical formulation of the problem Selection of well suited days during MADCAT Available supporting data sets Results, interpretation & outlook Assessing the need for a O4 scaling factor for MAX-DOAS measurements during the MAD-CAT campaign in Maing Germany, Summer 2013 T. Wagner, J. Remmers, R.Shaiganfar, J. Lampel, Y. Wang, S. Beirle, S. Dörner Max-Planck-Institute for Chemistry, Mainz, Germany
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Assessing the need for a O4 scaling factor for MAX -DOAS ...joseba.mpch-mainz.mpg.de/pdf_dateien/TWAGNER_EGU_O4...Mathematical formulation of the problem Selection of well suited days
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Mathematical formulation of the problem
Selection of well suited days during MADCAT
Available supporting data sets
Results, interpretation & outlook
Assessing the need for a O4 scaling factor for MAX-DOAS measurements during the MAD-CAT
campaign in Maing Germany, Summer 2013
T. Wagner, J. Remmers, R.Shaiganfar, J. Lampel, Y. Wang, S. Beirle, S. Dörner
Max-Planck-Institute for Chemistry, Mainz, Germany
measuredAMFVCDSCD
VCD
measured optical depth (of the O4 aborption at 360 nm) O4 aborption cross section SCD slant column density of O4 VCD vertical column density of O4 AMF Air mass factor
Are measurements and simulations in agreement for well defined situations, or is a scaling factor needed?
simulatedmeasured AMFAMF?
Are measurements and simulations in agreement for well defined situations, or is a scaling factor needed?
measuredAMFVCDSCD
VCD
measured optical depth (of the O4 aborption at 360 nm) O4 aborption cross section SCD slant column density of O4 VCD vertical column density of O4 AMF Air mass factor
simulatedmeasured AMFAMF?
Spectral analysis
T & p profiles
Different data sets, temperature dependence
Radiative transfer simulations
Two selected days
Clear days during MADCAT
Available data sets
Spectroscopy
MAX-DOAS measurements (4 azimuth directions)
Different O4 cross sections, including temperature dependence
AMF calculations & O4 VCD calculations
Ceilometer backscatter profiles (above 150m)
AOD from AERONET sun photometer
Surface measurements of pm2.5 and pm10
Temperature and pressure profiles from ECMWF
Surface measurements of temperature, pressure, rel. humidity
Standard O4 analysis at 360 nm
-wavelength range: 352 – 387 nm (two O4 bands)-Fraunhofer reference spectrum (FRS): 08.07., 10:05:35, SZA: 32.37°, elevation angle: 90°-calibration: using NDSC high resolution solar spectrum -cross sections:-O3, Bogumil et al., 223K-NO2 Vandaele, 298K-BrO, Fleischmann, 223K-O4, Thalmann, 293K-Ring 1-Ring 2 (Ring 1 -4)-polynomial of 5th order-intensity offset (second order polynomial)-measured spectrum is allowed to shift (versus FRS and cross sections)
Standard O4 analysis at 360 nm
Fit result for north-east direction, 08.07.2013, 11:21:54, elevation angle: 6°, SZA: 27.6°
Results for different spectral ranges
Fit result for north-east direction, 08.07.2013, 11:21:54, elevation angle: 6°, SZA: 27.6°
352-387nm:
O4 bands at 360nm and 380 nm
345-377nm:
O4 band at 360nm
335-377nm:
O4 bands at 340nm and 360nm
Influence of the wavelength range:Two other wavelength ranges are tested:-345-377nm: only the O4 band at 360nm-335-377nm: two O4 bands at 340nm and 360nm
Influence of the wavelength range:Two other wavelength ranges are tested:-345-377nm: only the O4 band at 360nm-335-377nm: two O4 bands at 340nm and 360nm
Influence of the wavelength range:Two other wavelength ranges are tested:-345-377nm: only the O4 band at 360nm-335-377nm: two O4 bands at 340nm and 360nm
Comparison of profiles without (blue) and with (magenta) extinction correction. Both profile versions are scaled to the same total AOD determined from the sun photometer.
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03:00 07:00 11:00 15:00 19:00Time (08.07.2015)
O4
AM
F (1
°)
elev_3elev_3elev_3
07:00 - 11:0004:00 - 07:0011:00 - 19:00
RTM results (AMF for 1° elevation, north-east direction)
Influence of time of day (T, p, O4, aerosol profiles)
08.07.2013
RTM results (AMF for 1° elevation, north-east direction)
Influence of extrapolation of aerosol profile below 180m
On the morning of 18.06 RTM results are higher than measured O4 dSCDs
What is the reason?
O4 AMF
O4 DAMF
Aerosol concentration measured by in situ instruments
In the morning of 18.06. high aerosol load was found close to the surface
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3:00 7:00 11:00 15:00 19:00Time
pm2.
5 [µ
g/m
³]
blue: 18.06.red: 08.07.
ZitadelleParcusstrasseWI Ringkirche
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3:00 7:00 11:00 15:00 19:00Time
pm 1
0 [µ
g/m
³]
blue: 18.06.red: 08.07.
ParcusstrasseZitadelleMombachWI Schierst.WI Sued
Modified aerosol extinction profile for morning of 18.06. 2013
The values below 180m are set to three times the values of the profile with linear extrapolation below 180m. The total AOD is changed from 0.38 (average value) to 0.41 (close to maximum during that period).
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Ext
inct
ion
[1/k
m]
slope_180_240m
double slope_180_240m
const
three times extinction_AOD041
RTM results (AMF for 1° elevation, north-east direction)
-measured O4 AMFs (and dAMFs) on 08.07.2013 are by about 20% larger than simulated ones (on 18.06. differences are smaller)-RTM uncertainties or choice of cross sections and fit settings can not explain these differences
-for the selected days the calculation of the O4 VCD is very accurate (but changes of the O4 VCD are > 10% during the MADCAT period due to pressure and temperature variations)-temperature dependence of O4 cross section is large (30% change of O4 dSCD for 100K temperature difference), but can not explain the observed differences on the selected days.
-the need for scaling factor remains unexplained
-all steps should be repeated by other participants (using also measurements from other instruments)
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