Advanced Study Projects at Leicester

In their fourth year of undergraduate studies, Leicester's Physics and Astronomy students undertake a supervised reading project with an academic supervisor, helping them to develop critical evaluation skills for assessing scientific literature.  As planetary atmospheres is a relatively new discipline for Leicester, I've been offering a range of topics that take the students from Earth-based phenomena to my own work in solar system science.  Some of the projects on offer are listed below.

Climate Oscillations in Earth’s Atmosphere
Our planet’s atmosphere exhibits cycles of activity that operate over annual and multi-year timescales.  Prominent examples include the El Nino Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), the North Atlantic Oscillation (NAO, which helps to modulate the weather patterns over the British Isles), and the Quasi-Biennial Oscillation (QBO) in the equatorial stratosphere.  These atmospheric cycles have only been identified by long-term tracking of meteorological phenomena, such as patterns or rainfall or sea-surface temperatures.  The underlying causes of some of these oscillations remain poorly understood, but there is evidence of connectivity, via teleconnections, between the different cycles.  This project will review the variety of long-term climate cycles, connections to anthropogenic climate change, and implications for cyclic activity on other worlds in our solar system.  You will gain an understanding of the forces influencing UK weather patterns, and the implications for global climate of disruptions to these delicate atmospheric balances.

Suggested Reading:
• El Nino’s Extended Family:  From NASA’s Earth Observatory: https://earthobservatory.nasa.gov/Features/Oscillations/
• NOAA Website on El Nino and El Nina https://www.climate.gov/enso
• North Atlantic Oscillation from UK Met Office: http://www.metoffice.gov.uk/learning/learn-about-the-weather/north-atlantic-oscillation


Alien Skies:  Clouds from Ice Giants to Hot Jupiters
The bewildering variety of planetary environments discovered in the past two decades have provided an extreme test of our understanding of planetary atmospheric chemistry and cloud formation.  Models of planetary clouds are required to explain what the skies might look like on a hot roasting Jupiter, orbiting so close to its star that the temperatures soar to 3000K, and what they might be like on the coldest ice giant like Uranus or Neptune, at a frigid 50K.  This project will introduce you to the physics and chemistry of cloud formation, showing how condensation is influenced by the availability of volatile species and the temperature structure of an atmosphere.  It will take you from familiar clouds of water, to methane raindrops and hazes of iron and titanium.  We’ll conduct a thought experiment for how Jupiter’s cloud structure would change if it migrated inwards, closer and closer to the Sun, and use this to predict what the spectra of exoplanets might look like.

Suggested Reading:
• Fletcher et al., 2014, Exploring the Diversity of Jupiter-Class Planets, https://arxiv.org/abs/1403.4436
• Sanchez-Lavega et al., 2004, Clouds in planetary atmospheres: A useful application of the Clausius-Clapeyron equation, https://www.researchgate.net/publication/243492714
• Marley et al., 2013, Clouds and Hazes in Exoplanet Atmospheres, https://arxiv.org/abs/1301.5627

To the Surface of Europa
The next decade will see two ambitious missions providing new, close-in reconnaissance of Jupiter’s most enigmatic moon, Europa.  Europe’s Jupiter Icy Moons Explorer (JUICE) will conduct two close flybys of Europa, whereas NASA’s Europa Clipper will swing by more than 45 times.  These missions will pave the way for future landings on the surface, and will assess the capability of the Europan surface to host life.  This project will review our current understanding of the surface composition of Europa, its relation to the deep water-ice interior and the action of irradiation of surface materials.  You will look at the evidence for and against different surface acids, sulphates and salts, and their implications for the habitability of the surface.  You will develop an understanding of planetary ice spectroscopy, and the difficulties associated with distinguishing a unique composition from remote planetary measurements.  You will also assess the technological challenges associated with a mission to Jupiter’s moons, both in terms of available power, the harsh radiation environment, and the descent and landing concepts.

Suggested reading:
• JUICE Red Book study report: http://sci.esa.int/juice/54994-juice-definition-study-report/
• Greeley et al., 2004, The Geology of Europa (Chapter 15 of Jupiter. The planet, satellites and magnetosphere), http://adsabs.harvard.edu/abs/2004jpsm.book..329G
• Phillips and Pappalardo, 2014, Europa Clipper Mission Concept, EOS 95, p165-167, http://adsabs.harvard.edu/abs/2014EOSTr..95..165P

Anatomy of a Storm: From Earth to the Giant Planets
Planetary atmospheres serve as global-scale conveyor belts for heat, redistributing energy around the globe and influencing the pattern of weather and seasons.  On the giant planets, thundercloud systems produce lighting 10000x more intense than on Earth, and yet the same physics governs the formation of storm systems on all of the planets in our solar system, albeit under very different environmental conditions.  On Earth and on the giant planets, moist convection driven by the condensation of water (and the release of latent heat) controls this atmospheric heat engine, and shapes the appearance of a planet's atmosphere.  This project will compare and contrast evolving storm systems on terrestrial worlds and giant planets, identifying common processes and key differences between each world.  In particular, you will explore recent planetary-scale events (such as the disappearance and reappearance of Jupiter’s broad dark belts and the eruption of seasonal, globe-encircling storms on Saturn) and the importance of continuous versus triggered convective activity in planetary atmospheres.  You will develop an understanding of how satellite imaging and spectroscopy, either from Earth-orbiting satellites or planetary spaceprobes, contribute to our understanding of storm anatomy, and consider future measurement techniques to explore planetary atmospheric processes.

Suggested reading:
• Introduction to Planetary Atmospheres, Agustin Sanchez-Lavega, CRC Press, 2011.
• Dynamics of Jupiter’s Atmosphere, http://adsabs.harvard.edu/abs/2004jpsm.book..105I
• Cloud Dynamics, Robert Houze, Academic Press, 1993.

Realm of the Giants: Influence of Migration
The formation of the four giant planets shaped the architecture of our entire planetary system, both by providing the bombardment that delivered water and organic materials to our forming planet, and by shielding us from further cataclysmic impacts.  Recent simulations of planetary dynamics suggest that giant planets, once formed in the cold outer solar system beyond the snow line, migrate inwards towards the host star.  You will explore the consequences for such an inward motion, both in terms of the chemical and climatic conditions on the giant planets themselves (e.g., the evaporation of cloud decks) as they evolve the ‘hot Jupiters’, and on the evolution of forming terrestrial worlds.  This will help you to understand the key differences in the atmospheric structure of the four giant planets and, potentially, the hypothesised Planet Nine.  You will also investigate why the inward migration of Jupiter was halted, and outward migration began (the Grand Tack hypothesis), and the implications of this for the evolution of our planetary system.

Suggested reading:
• The Grand Tack Hypothesis, https://en.wikipedia.org/wiki/Grand_tack_hypothesis
• Diversity of Jupiter-Class planets, http://adsabs.harvard.edu/abs/2014arXiv1403.4436F
• Planetary Sciences, de Pater and Lissauer, http://adsabs.harvard.edu/abs/2015plsc.book.....D