Top-down quantification of methane emissions from the oil, gas and waste sectors on the Arabian Peninsula using helicopter-borne observations

Methane (CH4) emissions from the oil and gas (O&G) sector remain highly uncertain on the Arabian Peninsula, despite the region’s major contribution to global hydrocarbon production and increasing mitigation commitments. As the second most important greenhouse gas after carbon dioxide (CO2), CH4 is a key target of global climate initiatives due to its higher short-term global warming potential, enabling faster climate benefits from mitigation. In this context, UNEP’s International Methane Emissions Observatory (IMEO) aims to improve the accuracy of emission data from the oil and gas, waste, and coal sectors through targeted measurement studies to support mitigation activities.In autumn 2023, airborne observations of CH4 emissions from the O&G and waste sectors were performed for the first time on the Arabian Peninsula, namely in Oman, using the helicopter-towed probe HELiPOD. Equipped with instrumentation measuring the three-dimensional wind vector and in situ CH4 (Picarro G2401-m and LI-7700), repeated upwind and downwind measurements were conducted at varying horizontal distances (~1–5 km) and altitudes (~35–3000 m) to capture inflow conditions and the horizontal and vertical dispersion of CH4 plumes. Co-located mobile ground-based CH4 measurements complemented the airborne probing, with both datasets combined within a mass-balance approach to quantify emissions.Depending on the surveyed O&G emission source (point or clustered), calculated CH4 emission rates span a wide range from