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waternumbers / dynatop

Dynamic TOPMODEL
https://waternumbers.github.io/dynatop/
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Improved initialisation #7

Open waternumbers opened 5 years ago

waternumbers commented 5 years ago

The current initialisation makes is based on a 'constant flux' through the saturated zone. That is the flux from the unsaturated zone q_uz is treated as constant and it is desired that:

  1. The saturate zone be in steady state
  2. The total flux tot he river channels is same as the total flux to the saturated zone.

Ignoring the potential for flow to the surface excess storage results in a least squares problem which is solved for the initial estimate of the redistributive fluxes, and hence (under steady state assumptions) the storage deficit.

it would be useful to allow for a spatial element to the initialisation (e.g. total fluxes to certain groups of channels)

waternumbers commented 4 years ago

As of version 0.11 the recharge figure given is treated as the flux from the unsaturated zone then the saturated zone solved by a single pass from upslope to downslope as if it is in steady state. This partially addresses the issue of initialisation, giving a far more consistent set of states.

One outstanding issue is that the initialisation does not pass excess water back to the surface, so initialisation is best done at low flows which is when the steady state assumption is more likely to be a good approximation.

This issue is left open as a reminder that further improvement is possible