Anthropogenic CO₂ emissions assessment of Nile Delta using XCO₂ and SIF data from OCO-2 satellite

Abstract

We estimate CO 2 emissions from the Nile Delta region of Egypt, using over five years of column-averaged CO 2 dry air mole fraction (XCO 2 ) data from the NASA's OCO-2 satellite. The Nile Delta has significant anthropogenic emissions of CO 2 from urban areas and irrigated farming. It is surrounded by the Sahara desert and the Mediterranean Sea, minimizing the confounding influence of CO 2 sources in surrounding areas. We compiled the observed spatial and temporal variations of XCO 2 in the Nile Delta region (XCO 2,del ), and found that values for XCO 2,del were on average 1.1 ppm higher than XCO 2,des (mean XCO 2 in desert area). We modelled the expected enhancements of XCO 2 over the Nile Delta based on two global CO 2 emission inventories, EDGAR and ODIAC. Modelled XCO 2 enhancements were much lower, indicating underestimation of CO 2 emissions in the Nile Delta region by mean factors of 4.5 and 3.4 for EDGAR and ODIAC, respectively. Furthermore, we captured a seasonal pattern of XCO 2 enhancement (XCO 2 ), with significantly lower XCO 2 during the summer agriculture season in comparison to other seasons. Additionally, we used solar-induced fluorescence (SIF) measurement from OCO-2 to understand how the CO 2 emissions are related to agricultural activities. Finally, we estimated an average emission of CO 2 from the Nile Delta from 2014-2019 of 470 Mt CO 2 /year, about 1% of global anthropogenic emissions, which is significantly more than estimated hitherto.