  The gas giant HD 80606 b has a highly eccentric orbit (e $\sim$ 0.93). The
variation due to the rapid shift of stellar irradiation provides a unique
opportunity to probe the physical and chemical timescales and to study the
interplay between climate dynamics and atmospheric chemistry. In this work, we
present integrated models to study the atmospheric responses and the underlying
physical and chemical mechanisms of HD 80606 b. We first run three-dimensional
general circulation models (GCMs) to establish the atmospheric thermal and
dynamical structures for different atmospheric metallicities and internal heat.
Based on the GCM output, we then adopted a 1D time-dependent photochemical
model to investigate the compositional variation along the eccentric orbit. The
transition of the circulation patterns of HD 80606 b matched the dynamics
regimes in previous works. Our photochemical models show that efficient
vertical mixing leads to deep quench levels of the major carbon and nitrogen
species and the quenching behavior does not change throughout the eccentric
orbit. Instead, photolysis is the main driver of the time-dependent chemistry.
While CH$_4$ dominates over CO through most of the orbits, a transient state of
[CO]/[CH$_4$}] $>$ 1 after periastron is confirmed for all metallicity and
internal heat cases. The upcoming JWST Cycle 1 GO program will be able to track
this real-time CH$_4$--CO conversion and infer the chemical timescale.
Furthermore, sulfur species initiated by sudden heating and photochemical
forcing exhibit both short-term and long-term cycles, opening an interesting
avenue for detecting sulfur on exoplanets.
