Professor Patrick Irwin
Professor of Planetary Physics; Fellow of St Anne's College
About
Professor Patrick Irwin studies the atmospheres of other planets in our solar system, in particular the giant planets and especially the atmospheres of Uranus and Neptune.
His group’s observations are made with interplanetary spacecraft and also ground-based telescopes, observing at infrared wavelengths where the temperature and composition of these planetary atmospheres can be determined though modelling the various radiative transfer processes. These observations are used both to understand how the different planetary atmospheres formed and also to compare the dynamical and chemical processes acting in all planetary atmospheres to gain a better insight into the atmospheric physics of the Earth’s atmosphere.
He is or has been a co-investigator or team member on a number of spacecraft missions, such as Galileo/NIMS, Cassini/CIRS, Venus Express/VIRTIS, Rosetta/VIRTIS and most recently Juice/MAJIS. He is also involved with ground-based observations of the giant planets with telescopes such as IRTF, Gemini and VLT, and space-based telescopes such as HST and JWST.
Professor Irwin is an expert in retrieval theory, the process whereby observations of the spectra of planetary atmospheres are inverted to retrieve the physical properties of the atmosphere being observed. He is the creator of the FORTRAN-based NEMESIS retrieval tool, which has ben used in over 300 scientific publications, and which has led on to a new python-based successor: ArchNEMESIS.
Expertise
- Planetary physics
- Space instrumentation (infrared observations)
- Radiative transfer and inversion of remote sensing atmospheric observations.
- Giant planet atmospheres (Jupiter, Saturn, Uranus and Neptune)
- Terrestrial planet atmospheres (Mars, Venus and Titan)
Selected publications
- The bolometric Bond albedo and energy balance of Uranus (OUP, 2025)
- Clouds and Ammonia in the Atmospheres of Jupiter and Saturn Determined From a Band-Depth Analysis of VLT/MUSE Observations (JGR Planets, 2025)
- Modelling the seasonal cycle of Uranus’s colour and magnitude, and comparison with Neptune (OUP, 2024)
- Latitudinal Variations in Methane Abundance, Aerosol Opacity and Aerosol Scattering Efficiency in Neptune's Atmosphere Determined From VLT/MUSE (JGR Plants, 2023)
- Spectral determination of the colour and vertical structure of dark spots in Neptune’s atmosphere (Nature Astronomy, 2023)
- Hazy Blue Worlds: A Holistic Aerosol Model for Uranus and Neptune, Including Dark Spots (JGR Planets, 2022)
- 2.5D retrieval of atmospheric properties from exoplanet phase curves: application to WASP-43b observations (OUP, 2020)
- Detection of hydrogen sulfide above the clouds in Uranus’s atmosphere (Nature Astronomy, 2018)
- Giant Planets of Our Solar System (2009)