Development of a new gas flaring emission data set for southern West Africa
Konrad Deetz and Bernhard Vogel
Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research – Troposphere Research (IMK-TRO), Hermann-von-Helmholtz 1, 76344 Eggenstein-Leopoldshafen
Received: 04 May 2016 – Accepted for review: 22 Jul 2016 – Discussion started: 01 Aug 2016
Abstract. A new gas flaring emission parameterization has been developed which combines remote sensing observations using VIIRS nighttime data with combustion equations. The parameterization has been applied to southern West Africa, including the Niger Delta as a region which is highly exposed to gas flaring. Two two-month datasets for June–July 2014 and 2015 were created. The parameterization delivers emissions of CO, CO2, NO and NO2. A flaring climatology for both time periods has been derived. The uncertainties owing to cloud cover, parameter selection, natural gas composition and the interannual differences are assessed. Largest uncertainties in the emission estimation are linked to the parameter selection. By using remote sensing cloud cover observations, a correction factor for the climatology was established to consider the effect of flares masked by clouds. It can be shown that the flaring emissions in SWA have significantly decreased by 30 % from 2014 to 2015. Existing emission inventories were used for validation. CO2 emissions with the estimated uncertainty in brackets of 8 (12⁄2) Tg y−1 for 2014 and 5 (7⁄1) Tg y−1 for 2015 are derived. The flaring emission estimation within this study for June–July 2014 is in the same order of magnitude compared to existing emission inventories. For the same period in 2015 the emission estimation is one order of magnitude smaller in comparison to existing inventories. The deviations might be attributed to uncertainties in the derived flare gas flow rate, the decreasing trend in gas flaring or inconsistent emission sector definitions. The parameterization source code is available as a package of R scripts.
Deetz, K. and Vogel, B.: Development of a new gas flaring emission data set for southern West Africa, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2016-110, in review, 2016.