Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Atmosphere of Uranus   Uranus provides a unique laboratory to test our understanding of planetary
atmospheres under extreme conditions. Multi-spectral observations from Voyager,
ground-based observatories, and space telescopes have revealed a delicately
banded atmosphere punctuated by storms, waves, and dark vortices, evolving
slowly under the seasonal influence of Uranus' extreme axial tilt. Condensables
like methane and hydrogen sulphide play a crucial role in shaping circulation,
clouds, and storm phenomena via latent heat release through condensation,
strong equator-to-pole gradients suggestive of equatorial upwelling and polar
subsidence, and through forming stabilising layers that may decouple different
circulation and convective regimes as a function of depth. Weak vertical mixing
and low atmospheric temperatures associated with Uranus' negligible internal
heat means that stratospheric methane photochemistry occurs in a unique
high-pressure regime, decoupled from the influx of external oxygen. The low
homopause also allows for the formation of an extensive ionosphere. Finally,
the atmosphere provides a window on the bulk composition of Uranus - the
ice-to-rock ratio, supersolar elemental and isotopic enrichments inferred from
remote sensing and future \textit{in situ} measurements - providing key
insights into its formation and subsequent migration. This review reveals the
state of our knowledge of the time-variable circulation, composition,
meteorology, chemistry, and clouds on this enigmatic `Ice Giant,' summarising
insights from more than three decades of observations, and highlighting key
questions for the next generation of planetary missions. As a
hydrogen-dominated, intermediate-sized, and chemically-enriched world, Uranus
could be our closest and best example of atmospheric processes on a class of
worlds that may dominate the census of planets beyond our own Solar System.

24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int