S5P tropical tropospheric ozone product based on convective cloud differential methodKlaus-Peter Heue, Pieter Valks, Diego Loyola, Deutsches Zentrum für Luft- und Raumfahrt (DLR), IMF-ATP, Germany

DLR.de • Chart 1

CCD method

DLR.de • Chart 2

Troposphere<10 km (~280hPa)

Clo

ud to

p he

ight

(R

OC

INN

)Stratospheric V

CD

Above cloud V

CD

~240 DU correctionVC

D

<2 DU

Stratospheric VC

D

~240 DU

total VC

D

~250-280 DU

Tropospheric VC

D

~10-40 DU

convective cloud differential (CCD) method Look for high convective clouds (8.5km< CTH <15km, cldfr>0.8) Column above the cloud is mainly stratospheric

– Correct for column inside the cloud and between CT and 10km– Background region (70°E to 170°E) has low O3 concentrations, low

correction columns– Assume longitudinal constant stratospheric columns

Look for cloud free pixels (cloud cover <10%) Average over 1.25°x 2.5° grid Subtract stratospheric column (convective clouds) from total

column (cloud free)

Tropospheric Ozone

DLR.de • Chart 3

Stratospheric column May 2013

DLR.de • Chart 4

Reference Region

Total Column May 2013

DLR.de • Chart 5

Tropospheric Column May 2013

DLR.de • Chart 6

Comparison to SCIAMACHY tropospheric data

DLR.de • Chart 7

• Zonal means for sondes sometime consist of 1 or 2 stations!

• Offset of 20% added to GOME_CCD data to correct for different altitude ranges:• SCIA 0-16 km• CCD 0-10 km

• VCD =VMR*const*∆P • The ratio of the pressure differences is 1.2 (offset of 20%)

• Difference SCIA-CCD ~2 DU (CCD is lower)

Typical comparison for GOME-2 CCD to sondes• Slight offset ~2 DU• Good agreement with

annual cycle

Comparison to ozone sondes (SHADOZ)

DLR.de • Chart 8

• RAL Profile retrieved on a fixed grid: surface, 450, 170, 100 hpa, …• RAL data scaled to 10 km (280 hPa)• VCD[450-280hpa]=VCD[450-170hpa]/(450-170)*(450-280) • VCDtrop=VCD[p>450]+VCD[450-280]

Comparison to RAL profile retrieval for Sep 2007

DLR.de • Chart 9

CCD GDP 4.8

RAL profile subcolumn below 10 km

CCD minus RAL tropospheric subcolumn: -0.4 ± 3.15

Average difference between CCD and RAL profile

DLR.de • Chart 10

1/1/2007 4/11/2007 7/20/2007 10/28/2007 2/5/2008 5/15/2008 8/23/2008 12/1/2008

-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

Date

Diffe

renc

e in

DU

• The tropospheric ozone CCD algorithm for S5P works• Currently no S5P level-2 test data are available

• Validation by comparing GOME-2 data with other satellite retrievals o For the comparison with SCIAMACHY monthly means a correction term

of +20% was introducesoStill the CCD data were lower than SCIAMACHY (~2 DU) o The sonde data were integrated up to 10 km for the comparison to CCDo The CCD data were higher by ~ 2 DUoGOME-2 data from RAL showed a good agreement until October 2007 o The CCD data are lower compared to RAL

• Comparison with SCIAMACHY gridded data is in progress.

Summary

DLR.de • Chart 11

Extra slides

DLR.de • Chart 12

DLR.de • Chart 13