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

Ankit Shekhar,Shrutilipi Bhattacharjee,Johannes C Paetzold,Xinxu Zhao,Veronika Ruisinger,Florian Dietrich,Jia Chen,Steven C Wofsy

doi:10.1088/1748-9326/ab9cfe

Ankit Shekhar, Shrutilipi Bhattacharjee + Show 6 more

Open Access

https://doi.org/10.1088/1748-9326/ab9cfe

Copy DOI

Abstract

We estimate CO2 emissions from the Nile Delta region of Egypt, using over five years of column-averaged CO2 dry air mole fraction (XCO2) data from the NASA’s OCO-2 satellite. The Nile Delta has significant anthropogenic emissions of CO2 from urban areas and irrigated farming. It is surrounded by the Sahara desert and the Mediterranean Sea, minimizing the confounding influence of CO2 sources in surrounding areas. We compiled the observed spatial and temporal variations of XCO2 in the Nile Delta region (XCO2,del), and found that values for XCO2,del were on average 1.1 ppm higher than XCO2,des (mean XCO2 in desert area). We modelled the expected enhancements of XCO2 over the Nile Delta based on two global CO2 emission inventories, EDGAR and ODIAC. Modelled XCO2 enhancements were much lower, indicating underestimation of CO2 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 XCO2 enhancement (ΔXCO2), with significantly lower ΔXCO2 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 CO2 emissions are related to agricultural activities. Finally, we estimated an average emission of CO2 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.

Highlights

Our planet Earth has witnessed about 40% increase in atmospheric CO2 concentrations since the preindustrial age
On average higher solar-induced fluorescence (SIF) values correlated with higher XCO2, which might not be expected for forest, but because of all the fossil fuel and soil CO2 emissions associated with the farming and irrigation in the Nile Delta
Our study assesses CO2 emissions from the Nile Delta, which is characterized by anthropogenic activities such as agriculture and urbanization, using the OCO-2 satellite observations of atmospheric CO2 concentrations

Summary

Introduction

Our planet Earth has witnessed about 40% increase in atmospheric CO2 concentrations since the preindustrial age. Most global estimates of CO2 emissions are provided by state-of-the-art emissions inventories which employ ‘bottom-up’ methods to quantify emissions, using human activity data and emission factors (Oda and Maksyutov 2011, Janssens–Maenhout et al 2019, Peylin et al 2013, Boden et al 2017, Oda et al 2018) as per the directions of IPCC (Intergovernmental Panel on Climate Change). These models have not been extensively tested for intensively farmed areas, like river deltas. These discrepancies can result in ∼40% to ∼100% uncertainty in emission estimations at the country and the local scales, respectively (Peylin et al 2013, Wang et al 2013)

Methods

Results

Conclusion