Hi all,
I am Bartholome, a practicum student working with Katrin Meissner on the deoxygenation of the oceans.
I have to clarify the river routing on the ACCESS-ESM model.
Is the surface runoff instantaneous in this model?
If not, how long does it take for a rain drop to travel for example down the Nile to the Mediterranean Sea?
Thank you in advance, Bart
@bduboc I believe the river routing is instantaneous in all ACCESS coupled models. But I’m tagging some people who know better so they can correct me if I’m wrong. @inh599 @MartinDix @Jhan
@bduboc @clairecarouge @MartinDix @Jhan
I believe that ESM uses the TRIP river routing model - in which case there is a delay between runoff and river outflow to the ocean.
The relevant literature (from comments in JULES code) is Oki et al, 1999, J.Met.Soc.Japan, 77, 235-255. In effect the model specifies a river grid (which is different to atmospheric grid cell), each cell has a river storage, a river length, river meander and a connecting river network. Storage evolves over time depending on inflow (from the upstream network and runoff) and a decay timescale which gets applied to the existing storage. The decay time scale depends on the length and meander (and river routing time step - which is 1 day from memory)
The net result is that it would be very difficult to state how long a particular drop of water takes to pass down any river system.
All runoff (surface and subsurface) passes into the river network instantaneously during that atmospheric time step (20 minutes) - this is accumulated in time to match the river model’s time step.