progress on the unification of the so 2 retrieval for gome-2a/b and omi
DESCRIPTION
Progress on the unification of the SO 2 retrieval for GOME-2A/B and OMI. C. Hörmann, S. Beirle, K. Mies and T. Wagner First German S5P Verification Meeting Bremen November 28 and 29, 2013. Unification of SO 2 DOAS retrieval. - PowerPoint PPT PresentationTRANSCRIPT
Progress on the unification of the SO2 retrieval for GOME-2A/B and OMI
C. Hörmann, S. Beirle, K. Mies and T. Wagner
First German S5P Verification Meeting BremenNovember 28 and 29, 2013
Unification of SO2 DOAS retrieval
- Same DOAS fit properties for all 3 instruments (GOME-2A, GOME-2B, OMI):
- Fit range: 312.1-324 nm
- Used absorption cross sections: SO2 223K (Bogumil et al.) O3 223K (Bogumil et al.)
O3 223K * λ additional O3 cross sections to correct O3 223K ^ 2 for AMF wavelength dependence (Pukite
et al., 2011)
Ring Inverse reference (straylight correction)
- Calibration via single reference spectrum for GOME-2A/B, individual referencespectra for each OMI detector raw
New SO2 DOAS retrieval for OMI
Daily de-striping by subtraction of detector raw dependent offset from Pacific reference sector(red orbit stripes on April 1 due to „OMI Zoom Mode“ individual calibration needed?!?)
Daily data: OMI SO2 VCD (geo.)
lat. dependent offset still visible
eruption of Piton de la Fournaise
Substraction of latitudinal dependent offset (calculated for each grid row, i.e. 0.1°)
offset corrected
Daily data: OMI SO2 VCD (geo.)
Comparison to GOME-2A SO2 VCD (geo.)
Good agreement, only small differences because of different overpass time
GOME-2AOMI
Mean latitudinal SO2 VCD(without latitudinal offset correction)
Latitude [°N]
Mea
n SO
2 VCD
GOME-2AOMI
Mean latitudinal SO2 VCD(latitudinal offset corrected)
Latitude [°N]
Mea
n SO
2 VCD
Monthly mean: OMI SO2 VCD (geo.)
offset corrected
lat. dependent offset again visible
interference with topography and bright surfaces
ice edge
visible
Comparison to GOME-2A SO2 VCD (geo.)
Very good agreement Less interference with topography because of pixel size?
less interference with topography
GOME-2AOMI
Latitude [°N]
Mea
n SO
2 VCD
Mean latitudinal SO2 VCD(without latitudinal offset correction)
GOME-2AOMI
Latitude [°N]
Mea
n SO
2 VCD
Mean latitudinal SO2 VCD(latitudinal offset corrected)
GOME-2A vs. OMI (monthly mean)
Good agreement between GOME-2A and OMI for monthly mean Best correlation for Norilsk region probably because of fairly constant emissions
Popocatépetl/Mexico City Nyiamuragira Norilsk (volcanic/anthropogenic) (volcanic) (anthropogenic)
1:1 slope 1:1 slope 1:1 slope
Comparison of GOME-2A vs. GOME-2B
data format problem (contact R. Lang)
GOME-2A data quality decreased due to degradation (σ2013 ≈ 2 ∙ σ2007) due to narrow swath, global coverage after ≈ 4.5 days
good agreement (almost same overpass time) GOME-2B data blurred compared to GOME-2A (larger pixel size)
GOME-2B SO2 VCD
GOME-2AGOME-2B
Latitude [°N]
Mea
n SO
2 VCD
Mean latitudinal SO2 VCD(without latitudinal offset correction)
strong latitudinal offset (unknown origin)
GOME-2AGOME-2B
Latitude [°N]
Mea
n SO
2 VCD
Mean latitudinal SO2 VCD(latitudinal offset corrected)
Very good agreement after latitudinal offset
correction
GOME-2A vs. GOME-2B (monthly mean)
Good agreement between GOME-2A and GOME-2B for monthly mean Large scatter visible in GOME-2A data
Popocatépetl/Mexico City Nyiamuragira Nevado del Ruiz (volcanic/anthropogenic) (volcanic) (volcanic)
1:1 slope 1:1 slope 1:1 slope
Plans for the near future
1) Further improving SO2 fit ( especially GOME-2A/B)
2) Comparison of timeseries/annual maps (e.g. China, Norilsk…)
3) Evaluation of SCIAMACHY data
4) Implementation of SO2 DOAS fit at larger wavelengths for OMI+ combination approach + intercomparison GOME-2A/B/OMI
5) Analysis and comparison of test data (CAMELOT)