Supervisors: David Armstrong and Matteo Brogi

This project will explore the potential of spectroscopic astronomical observations for monitoring of greenhouse gases in the Earth’s atmosphere.

Spectra of astrophysical targets contain the imprint of the Earth, in the form of absorption and emission lines from atoms and molecules in the atmosphere. In particular the signatures of carbon dioxide and methane are highly significant, gases which are the primary anthropogenic drivers of climate change. In astronomy much effort is placed in removing this ‘contamination’, known as tellurics, but these could be ideal data for study of the Earth’s atmosphere.

This project has two key goals:

1. Using astronomical spectra for Earth atmosphere monitoring, discovering what type and quality of data is suitable and what molecules can be routinely detected with what precision. If successful we aim to feed this knowledge into global climate models by collaborating with the Met Office.

2. Using the resulting improved modelling of Earth telluric contamination to better understand the astrophysical targets, including exoplanet atmospheres.

If successful this will be a novel methodology for greenhouse gas measurements, complementary to existing ground and space-based facilities.

Context

Climate change driven by greenhouse gases has had measurable effects on biodiversity, land, ecosystems and human activity. Understanding the sources and sinks of greenhouse gases, both anthropogenic and natural, is key to planning and implementing evidence-driven responses to future climate change. Determining the global budget, concentration and flux of such gases is a complex modelling effort driven by a range of observations. Given the complexity of the problem, even the substantial dataflow available is sparse in some aspects.

Greenhouse gas monitoring currently occurs through a combination of ground-based stations and earth-orbit satellites, such as ESA’s Sentinel-5P. Space-based remote sensing complements the ground network through global coverage with improved spatial resolution. Satellite data can probe the atmosphere away from the surface (‘column’ measurements), but most satellite measurements rely on reflected sunlight and so only occur during the day; regular observations of the atmosphere away from the surface are rare at night. Astronomical observations not only tend to happen at global black-spots, but of course at night.

As such the nightly observation of hundreds of astrophysical targets represents a huge, and so far unused potential source of data for modelling the Earth's climate.