Periodic Reporting for period 5 - GIANTCLIMES (Giants through Time: Towards a Comprehensive Giant Planet Climatology)
Berichtszeitraum: 2023-04-01 bis 2024-03-31
But these missions offer only fleeting glimpses of these dynamic, ever-changing worlds when compared to their long orbital periods (10 years for Jupiter, 165 years for Neptune). How does the climate, circulation and chemistry of these atmospheres evolve over these large spans of time? What are the natural cycles of climate variability, and how do they differ from world to world? What can the giant planets reveal about the governing forces shaping planetary atmospheres in all their guises?
The aim of GIANTCLIMES was to assemble the first comprehensive climatology of all four giant planets by combining an unprecedented multi-decade archive of ground-based infrared imaging with new spectroscopic observations from space telescopes and visiting spacecraft. This wealth of observational data was studied via a sophisticated suite of spectral analysis software to understand the spatial and temporal variability in the redistribution of energy and material on the four giants. The GIANTCLIMES programme at the University of Leicester consisted of three objectives that hoped to provide something that no single space mission has ever done before: the ability to explore the giants over large spans of time.
1. Climate Cycles on Jupiter: What drives the spectacular transformations of Jupiter’s banded structure and triggers storms? Can these events be predicted? We discovered quasi-regular cycles of activity within Jupiter’s bands and interconnections between the hemispheres that were unexpected, potentially driven by waves emanating from the deep interior, and occasionally disrupted by gargantuan storm eruptions. We constructed a comprehensive climate record (temperature, composition, clouds) over three Jovian years to set the environmental context for Juno’s exploration and JWST’s new observations in 2022-23.
2. Seasons of Saturn: How does the circulation and chemistry of planetary stratospheres change with time as a result of the different conditions on each world? We explored the changing stratosphere of seasonal Saturn using Cassini and JWST observations, combined with four decades of ground-based monitoring to develop a new paradigm for the seasons on giant planets.
3. Ice Giants: How do circulation patterns and climate cycles differ between the Ice and Gas Giants? We combined state-of-the-art observations from space observatories (Spitzer, Herschel, and JWST) with ground-based observations and simulations of their dynamics and chemistry to reveal the climate of these distant worlds like never before, providing the first 3D maps of temperature, composition and circulation within an ice giant atmosphere.
• WP1: Jupiter's Climate: WP1 explored the atmospheric variability of Jupiter over long spans of time, combining data from Earth-based observatories with new observations from NASA’s Juno spacecraft. Using more than three decades of ground-based observations, we identified periodic cycles of atmospheric variability, both in the deep clouds, in the stratosphere, and in tropospheric temperatures. Patterns at widely-separated latitudes appear to be interconnected (suggesting deep origins), and prone to teleconnections by extreme storm events and belt/zone variability. These studies were used as context for Juno’s close-in studies in microwave and infrared light, and for JWST spectroscopic observations of regions of interest in 2022-23. Ultimately, the developing understanding of jovian climate cycles, meteorology, and chemistry have supported our role in the science planning for ESA’s Jupiter Icy Moons Explorer, which launched in 2023.
• WP2: Saturn's Seasonal Stratosphere: Cassini completed its unprecedented exploration of Saturn in 2017, allowing the GIANTCLIMES team to publish new insights into the long-term seasonal variations in Saturn's atmosphere. We supplemented this work using our long-term ground-based infrared campaign, which extends both before and after Cassini's mission, allowing us to track a full seasonal cycle of the giant planet for the first time, and revealing hints of inter-annual variability in Saturn’s seasonal response. These projects culminated with the publication of the first JWST maps of Saturn's northern summer hemisphere in 2022, showing how large-scale circulation patterns completely switch direction over the course of a Saturnian year.
• WP3: Ice Giants: Uranus and Neptune remain the least explored planets in our solar system. GIANTCLIMES enabled the first maps of Uranus' stratosphere and a comprehensive assessment of Neptune's stratosphere over two decades, revealing surprising sub-seasonal variability for the first time. These long-term studies paved the way for the first global maps of the Ice Giant atmospheres from JWST in 2022-23, the most significant new dataset since Voyager.