An Investigation into Contrail Observability from Different Satellite Platforms

Abstract

Contrails are line-shaped ice clouds that can form behind aircraft engines and, under certain cold and moist conditions, spread into contrail cirrus that persists for several hours. By adding to the existing cloud cover, contrails can act to either cool or warm, with the latter, on average, being dominant, resulting in an overall warming effect. Although the effective radiative forcing from contrails is inferred to be of the same order of magnitude as that caused by aviation’s CO₂ emissions, large uncertainties remain around specific radiative forcing estimates. Observational studies of contrails, either to support climate impact assessments or operational contrail avoidance strategies, face trade-offs between spatial and temporal resolution. Many recent publications have relied on data from geostationary satellites accepting lower input data resolution in exchange for higher temporal resolution and greater spatial coverage. Limitations of the observability of contrails in the resulting images have not been sufficiently investigated and need to be assessed and quantified. This study aims to leverage the higher spatial resolution of VIIRS satellite imagery to identify potential limitations on contrail observability in lower-resolution GOES ABI imagery. We generate a dataset of human-identified contrails visible in false-color thermal infrared imagery from both GOES ABI and VIIRS for twelve scenes over the contiguous US. Based on this dataset, we investigate the number, cover, and appearance of the observed contrails. We find that GOES ABI does not resolve 80% of all contrails that can be identified in VIIRS imagery and only shows half of the total observed contrail length. Finally, incorporating an existing contrail-flight matching algorithm by Barbosa, we show that VIIRS tends to resolve more younger contrails than GOES ABI. The findings from this study help to bound the validity of current contrail simulations and modeling outputs that estimate contrail cover and occurrence.