Locking: Snr & Jnr waiting for one another

Solid lines show UMs working, while dotted lines shows them waiting.

Options to avoid/reduce locking

  1. Only pass dynamical core fields (red arrow) on hour
    • Trusts Jnr to evolve fields completely alone for one hour
  2. Early call to UKCA_MAIN1, say at +0 or, for some locking, +15 or +30 mins
    • Chemistry is +30-60 mins old, instead of 15 mins old as before
  3. Share chemistry workload across timesteps for Jnr, so DO_CHEMISTRY every timestep and
    • reduce NTZS and something similar for SPLINSLV2 & SPFULJAC routines, or
    • introduce some convergence criteria