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

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 (XCO2) 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 (XCO2,del), and found that values for XCO(2,del)were on average 1.1 ppm higher than XCO2,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 (Delta XCO2), with significantly lower Delta 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 CO2/year, about 1% of global anthropogenic emissions, which is significantly more than estimated hitherto.