Assessment of NO2 satellite observations for en-route aircraft emissions detection

Abstract

In this work we examine the possibility of using satellite remote sensors for the detection of air traffic emissions produced during the en-route segment of flight in the Upper Troposphere/Lower Stratosphere region (8000–12,000 m). NO2 has been considered as the tracer of aircraft plumes with highest possibility of being successfully detected from space. An analysis of the technical potential of the current orbital sensors capable of measuring NO2 in the proximity of the tropopause has been conducted. In order to estimate an upper bound for the NO2 column related to aircraft emissions, the Canary Islands Corridor has been selected for conducting a simple emission calculation exercise based on real air traffic and operational data, assuming an ideal atmospheric scenario. The results obtained in this approximation have been compared to the actual information retrieved from space sensors. An in-depth inspection of the NO2 column data for two particular areas (Canary Islands Corridor and North Atlantic Flight Corridor) obtained in recent years by SCIAMACHY and OMI has also been carried out. The general conclusions of this viability study are not optimistic. The estimated maximum NO2 column value attributable to aircraft emissions at cruise altitudes were lower than the detection limits associated with SCIAMACHY and OMI for NO2 column measurements. As a result, detecting and quantifying the actual NO2 levels in aircraft corridors by space remote sensing is a very challenging task.