tropomi's co retrieval code for the sentinel 5 precursor...
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TROPOMI's CO retrieval code for the Sentinel 5 Precursor mission tested on 10 years of SCIAMACHY's 2.3 μm measurementsTobias Borsdorff, Joost aan de Brugh, Paul Tol, Ilse Aben, Jochen Landgraf
Netherlands Institute for Space Research (SRON)
Spectral mean signal relative to 11 Jan. 2003.
SCIAMACHY’s daily sun measurements
The need for a reflectance retrieval
R=μ
0
π ⋅I Earth
I Sun
S i(t)=α(t)βi(t)S i(t0)+ϵi(t)
The need for a reflectance retrieval
(grey, e.g. gloudemans et al.,2008)
A wider CO retrieval window
Signal to noise of SCIAMACHY spectra
Mean (2003-2012)
Radiometric offset correction
F (x ,a)=F (x)+∑i=0
n=3
a(i ) p i(λ)
Sahara
Australia
Error of clear sky retrievals
Error of cloud contaminated retrievals
CAK[1]
Borsdorff, T., Hasekamp, O. P., Wassmann, A., and Landgraf, J.: Insights into Tikhonov regularization: application to trace gas column retrieval and the efficient calculation of total column averaging kernels, Atmos. Meas. Tech., 7, 523-535, doi:10.5194/amt-7-523-2014, 2014.
Validation: SCIAMACHY vs. NDACC/IRWG
NDACC (pink)SCIAMACHY (black)
47.42N
67.84N
Validation: SCIAMACHY vs. TCCON
TCCON (blue)SCIAMACHY (black)
45.95N
-12.43S
Validation: bias (SCIAMACHY - FTIR)
Data usage: spatial resolution
Mean (2003-2012)
cylindrical equal area projection (nlat=180, nlon=360)
Data usage: temporal resolution
30-day medians
TROPOMI: single overpass over china
CO column [1018 molec cm-2]
Summary and conclusions
● TROPOMI CO retrieval code performs good on real data:
– good agreement with TCCON (0.1 ± 7.5 ppb).
– bias with NDACC/IRWG (-8.9 ± 8.3 ppb)
– good agreement with TM5 over Africa
● Next: TROPOMI cloud retrieval with SCIAMACHY spectra
● Now available: full mission SCIAMACHY CO dataset
(cloud free scenes over land)
Image: ESA
© Astrium
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