Recreate river runoff from scratch ACCESS-ESM1.5

Earth System Paleoclimate
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18

Update for anyone interested, e.g. @MartinDix.
I heard back from Charlie Williams (Bristol) and he sent some IDL code for how he reconfigured river runoff in the TRIP scheme. Although I couldn’t use his code directly, I got an idea of what needed to be done. So, I have now adapted my old river runoff algorithm (which I wrote to set up the GFDL model) to reconfigure the TRIP scheme.

I have now created a GitHub repository of the new river runoff procedure I have created. It takes an input Miocene topography at 1x1 deg resolution (same as the TRIP grid), and does the following:

  1. fill_depression.py : Remove land sinks, so that river flowlines always reach the coast, by filling in any sink points. This makes use of a package called richdem that can be installed using conda.
  2. downslope_trip.py : Set direction fields (1-8 for neighbouring grid cells) and coastal runoff points (9), and river sequence accumulation.
  3. river_save.nc : output file containing new river runoff fields.

In river_save.nc, the two outputs for the TRIP scheme are called:

  • route, which specifies the direction fields (field1906), and
  • trip_steps, which defines the sequence (field1905).

I am now testing this new scheme in a Miocene simulation using ACCESS-ESM1.5. So far, it doesn’t crash, but that doesn’t say very much because even the Pre-Industrial scheme doesn’t crash in Miocene topography. I will report back once I have some diagnostics of runoff from the model outputs.

If anyone is interested, or wants to suggest improvements to my TRIP scheme, please feel free to look at the GitHub repo and send me comments.

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