ICOS Science Conference 2020, Session 17

1. High quality trace gas measurements in the Marine Boundary Layer on
Ships of Opportunity (SOOP)
“Ringo Task 3.2”
Gregor Rehder, Marc F. Delmotte, Michael Glockzin, Lynn Hazan, Armin Jordan, Victor Kazan, Syrine
Nouicer, Michel Ramonet, and Tobias Steinhoff
gregor-rehder@io-warnemuende.de

2. BACKGROUND AND RATIONALE
- A fleet of SOOP lines hosting automated seawater pCO2
measurements provides backbone for global pCO2
integration (e.g. SOCAT)
- Most SOOP lines maintain atm. measurements (~every
6-8 h) in the MBL
- Use of atm. measurements mostly limited to QC
purposes, or local ASE calculations
- Atm. data from SOOPs have so far not been regularly
quality controlled or transferred into products
- Yet, if quality was sufficient, SOOP lines could
provide atm. CO2 and other GHG concentrations at
locations difficult to reach, on platforms which are
maintained anyhow
- Data with “exotic” spatiotemporal resolution
from Wanninkhof et al., 2019
from Steinhoff et al., 2019

3. RINGO TASK 3.2.
Improving atmospheric measurements on Ships
Of Opportunity (SOOP)
Overarching Questions:
- Can we provide data matching ICOS ATC criteria
from SOOPs, using the same technology?
- How far can we improve sporadic atm.
measurements using existing pCO2 setups?
- Would these data improve eg. inverse modelling
products?
- Could data be handled by the ATC?
THREE COMLEMENTARY LINES
SOOP TAVASTLAND (IOW)
Baltic (Lübeck – Kemi)
- easy to access,
- surrounded by ICOS atm. station network
- aim for „easy to move“-unit
- covering continental to Arctic air masses
SOOP COLIBRI (LSCE)
Europe – French Guiana
- undersampled equatorial Atlantic
- extreme range of external conditions
SOOP ATLANTIC SAIL (GEOMAR)
English Channel – Westwards
- attempt to use instrumentation also used for water
measurements
- cost optimization
(MPI JENA, CAL, and ICOS ERIC)
Consulting during construction phase, provision of flask
sampler, provision of calibration gases, assessment of
added value through inverse modelling runs

4. Current status
• Severe delays due to instrument availability,
ship liaison issues, and lately ship access due
to Covid 19
• Yet we are getting there
• Glimpse on results with strong focus on SOOP
COLIBRI
International Activity
- Recognition of the potential of SOOP-hosted MBL
measurements in Ocean Obs 2019 Community
paper (Wanninkhof et al., 2019)
- Proof of concept underway using data from the UK
Carribean Line (UExeter, UEA, UEdingburgh)
against GEOS-Chem atmospheric chemistry
transport model

5. North Atlantic Line (SOOP
ATLANTIC SAIL, GEOMAR)
•Installation of suite of calibration gases
and target gas ranging from 373 to 448
ppm (provided by ICOS CAL
• Air filtering system and add. drying step
• Parallel run of LICOR 7000 (classical
infrared) and new LICOR 7815 (OF-CEAS)
Results and Importance
- Tests suggest repeatability of better 0.01
ppm at tav = 10 seconds for the LI 7815
- Add. tests on long-term drift needed
- Required modifications on the GO system due
to internal pump of the sensor
- Integration in GO system internationally on the
way; likely to become standard set-up

6. Picarro pump
Picarro Analyser
Multi-positions
Valve Safeguard hard disk
UPS
o Air inlet
o CRDS analyser (CO2, CH4, CO, H2O - Picarro G2401)
o Calibration and quality control compressed air cylinders (4) provided by the central
calibration centre from ICOS-RI connected to a multi-position valve
o GPS set up to recover real time positioning of the vessel and absolute time stamp
o Power supply to preserve the equipment in case of power shut-down
o 4G router used for data transfer during the time the vessel stays in a harbor
GPS
Air inlet line and GPS cable
Installation on SOOP COLIBRI
Inlet

7. Data
• Regular Target Measurements March-
Sept. 2019 with biases lower than 0.05
ppm for CO2 and 0.5 ppb for CH4
• Achievable data quality matches ATC
standards
• Data stream from moving platform was
implemented
• Different treatment in harbor, coastal, and
open ocean settings by automated data
selection (based on position information)

8. Data
• Regular Target Measurements March-Sept
2019 with biases lower than 0.05 ppm for
CO2 and 0.5 ppb for CH4
• Achievable data quality matches ATC
standards
• Data stream from moving platform was
implemented
• Different treatment in harbor, coastal, and
open ocean settings by automated data
selection (based on position information)
• Spike detection implemented (after El
Yazidi et al. 2018); CO contamination as
contamination proxy
Concentration differences
with and without spikes
CO Spikes are found in hours for 27% in harbour, 9% in
European coasts and 6% during transtalantic passsages
Tableau3.1 : Valeurs moyennes de l’écartentre lesmesures CO2, CH4 et CO avant et après l’éliminatio
pics de CO
Port Europe Atlantique
CO2 (ppm) 1.2 0.7 0.5
CH4 (ppb) 3.3 0.15 -0.002
CO (ppb) 1.4 0.6 0.7
Mean differences of hourly means with and
without spikes

9. So far 5 round trips Europe > Guyana > Europe,
each one lasting about 1 month

10. Strong correlations
betweens the 3 species
North/South gradient:
increase of CO and CH4 at
high latitudes, and
decrease of CO2
(biospheric uptake)
CO & CO2 higher near
Amazonia, maybe due to
the strong fire activity in
Aug. 2019
Short term variability
explained by synoptic
transport of air masses.
Aug-Sept 2019

11. Comparison of CO2 and CH4 with
CAMS forecasts
• Systematic offset of CO2 and CH4
concentrations. These offset are already
well known and documented in reports
based on ICOS and TCCON
observations
• Most synoptic variabilities are very well
represented in location and amplitude
• The signals from Amazonia (CO2
increase, CH4 decrease) are
underestimated
Aug-Sept 2019

12. NEXT STEPS
• Final assembly of instrumentation on board
SOOP Tavastland (all components on ship, but
assembly only with one person during the 6h
harbor window on Fridays)
• Analysis of the first months of atm.
measurements using “just” short atm. data
from a pCO2 system equipped with a LI 7815
(SOOP ATLANTIC SAIL)
• Assessment of these data by ATC
• Analysis of improvement for e.g
inverse modelling products

13. High quality trace gas measurements in the Marine Boundary Layer on
Ships of Opportunity (SOOP)
“Ringo Task 3.2”
Gregor Rehder, Marc F. Delmotte, Michael Glockzin, Lynn Hazan, Armin Jordan, Victor Kazan, Syrine
Nouicer, Michel Ramonet, and Tobias Steinhoff
gregor-rehder@io-warnemuende.de
Thank you
Questions?