European Facility For Airborne Research May 3, 2024, 20:05
APSOWA
Atmospheric Pollution from Shipping and Oil platforms of West Africa
Scientific project
Characterization of the gaseous and particulate pollutants emitted by shipping and oil and gas extraction platforms off the coast of West Africa.
None
CATOIRE Valery
Infrared laser absorption spectroscopy (ultra-high spectral resolution) applied to balloon and aircraft measurements of trace gases from the free troposphere to the stratosphere.
FA20 - DLR
In the 2000’s, combustion emissions from Africa contributed significantly to worldwide emissions. With their current increase, their contribution should reach 30-50% of the global combustion emissions in the near future (Liousse et al., Environ. Res. Lett. 2014). Furthermore, anthropogenic combustion emissions could be at a similar level as biomass burning emissions around 2030 in Africa, with the anthropogenic emissions from southern West Africa being probably the most important ones of whole Africa. Southern West Africa is indeed experiencing considerable economic and population growth and urbanization, leading to huge atmospheric emissions. These emissions of pollutants (NOx, SO2, VOCs, CH4, CO, CO2, black carbon, organic carbon, etc…) have different origins, such as industrial activities (fossil fuel and mining extraction, etc…), urban traffic, maritime transport, domestic fires, biomass burning (Marais, Jacob, et al., Atmos. Environ. 2014), etc… Observational data specific to this region are scarce, and the existing datasets have not been evaluated, leading to significant uncertainties (Liousse et al., Environ. Res. Lett. 2014). In addition biogenic emissions from the vegetation, the ocean and from soils should play a significant role in the pollution when combined to anthropogenic emissions, leading to a perturbation of the secondary pollutants produced, in particular the ozone level and secondary aerosols formation (Stewart et al., Atmos. Chem. Phys. 2008). Overall southern West Africa represents a complex interplay of natural and anthropogenic emissions with the added complication of the extreme uncertainties associated in both, and the paucity of appropriate modelling studies. The recently selected European FP7 project DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) will assess the impact of these emissions on human and ecosystem health, agricultural productivity, water availability, and energy production. It will quantify the coupling between aerosols and clouds and their impacts on the radiation and energy budgets from the cloud scale to the regional scale of the West African monsoon circulation. For this, DACCIWA will organize a major field campaign in summer 2015, involving three aircrafts (BAe146, ATR42, DLR Falcon20) and a wide range of surface-based instrumentation. These new observational datasets will be used to challenge state-of-the-art weather, climate and atmospheric chemistry models. The goal is to advance the process understanding and the modelling capabilities, including interactions between atmospheric emissions, clouds and the West African monsoon system. Finally the results will guide the development of policies for sustainable development for West Africa and beyond, for other tropical regions. However, limited attention will be paid in DACCIWA to characterizing emissions from the shipping traffic and from oil platforms. Until now this pollution has been mainly evidenced by satellite data such as those from OMI (Ozone Monitoring Instrument) on NASA’s Aura satellite, showing tracks of elevated NO2 levels along the shipping routes of the Gulf of Guinea. Exceptionally high ozone concentrations (up to 300 ppbv) episodes detected by balloon sondes could not be explained by biomass burning and urban pollution alone, but the hypothesis of petrochemical activities has been put forward (Minga et al., Atmos. Chem. Phys. 2010). Our project APSOWA (Atmospheric Pollution from Shipping and Oil platforms of West Africa) will be clustered with DACCIWA, focusing specially on emissions from these activities. So far, only Nigeria has attracted attention since it has Africa’s highest economic and population growth (Marais, Jacob et al., Atmos. Environ. 2014). There are large differences between regional inventories using bottom-up methods and African emissions provided by global inventories, and a general lack of detailed anthropogenic inventories at the continental and regional scales (Liousse et al., Environ. Res. Lett. 2014). Measurements of emission factors (in g of emitted species per kg of dry fuel) as a function of the type of combustion are required in order to build the bottom-up regional inventory, to finally assess the impact of these anthropogenic emissions on climate change and health. Therefore the APSOWA aircraft campaign will consist of flights downwind of individual ships, oil platforms and one harbour (e.g., Accra) in the Gulf of Guinea with the fast-developing countries Ghana, Togo and Benin. The integration of our SPIRIT instrument in the DLR Falcon20 will enable for the first time in-situ fast on-line measurements of essential gaseous pollutants (NO2, CO, CH4). Together with the other Falcon instruments and with the use of modelling tools available in DACCIWA, this will allow the characterization of the nature, importance and geographical extent of this pollution with respect to the other anthropogenic and biogenic emissions. SPIRIT will be integrated in Germany and participate to the whole DACCIWA campaign, enhancing significantly the Falcon instrumentation with mutual benefits for both projects.
Clear sky with wind speed less than 20 m/s in order to perform low altitude (100 m) flights above the ocean.
Usual daytime flight.
Our APSOWA campaign will be clustered with DACCIWA campaign planned in summer 2015. So far, only Nigeria has attracted attention; the goal of APSOWA is to sample pollution west from Nigeria, along the coasts of Benin, Togo and Ghana.There are two maps. One represents the locations of the gas flares stations off the coast of southern West Africa. The other is the geographical area of DACCIWA study, with supersites and radiosonde stations (black markers) and synoptic weather stations (red circles).
3 flights of 3.5 hours each, with meandering patterns in the marine boundary layer downwind of individual ships, oil platforms and one major harbour (e.g. Accra, Ghana).
No.
Trace gases (CH4, CO2, CO, CH4, O3, SO2, NO2, HNO3) and aerosols (sizes, types, concentrations).Meteorological parameters: temperature, relative humidity, horizontal and vertical wind.
Basic instrumentation of the Falcon20: temperature, relative humidity, horizontal and vertical wind, aircraft position, velocity and altitude.Falcon instruments monitoring trace gases (O3, SO2, HNO3, CO2) and aerosols (sizes, types, concentrations) planned for DACCIWA.
The SPIRIT (Spectromètre Infra Rouge In situ Toute altitude) instrument will provide CH4, CO, NO2, and N2O measurements using the well-proven airborne QCLaser spectrometry technique (McQuaid, J., H. Schlager, et al., chap. 3 in “Airborne Measurements: Methods and Instrumentsâ€, M. Wendisch & J.–L. Brenguier ed., EUFAR & Wiley 2013).
1
Surface-based instrumentation from the DACCIWA network and radiosondings with meteorology.
The data are automatically recorded onboard, with on-line quick-look capability. They will be processed in one day, and preliminary results will be presented 24 hours after the flight.
The planning depends only on the DACCIWA campaign planned in June-July 2015.The DACCIWA core group has well received our APSOWA proposition project, as well as the DLR Flight Operations for using the Falcon-20.
Yes
A PhD student funded by Université Orléans will participate in this aircraft campaign, and retrieve and interpret the flight data, as part of her Ph.D thesis.
APSOWA clusters with the existing project DACCIWA supported by EC funding. APSOWA is funded by own resources from the scientific group.Its complementary aim is described in Section 2 above (Description of the experiments).
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