Glacier_ice tracer in UBCWM model

[ktsuruta]

I would like to trace the contribution of glacier ice melt to outflow in a Raven simulation of the Allouette using the Tutorial 3 UBCWM setup. However, my methodology is producing an all zero pollutograph. My tracer setup is as follows:

:Transport GLACIER_ICE
:FixedConcentration GLACIER_ICE GLACIER_ICE 1.0
:FixedConcentration GLACIER_ICE SHALLOW_GW 0.0
:FixedConcentration GLACIER_ICE DEEP_GW 0.0

Any ideas as to what is causing the zero pollutograph? Could it relate to the negative sign of water within the glacier_ice storage compartment? The concentration csv has non-zero Total Mass and Cumlative Loading entries.

Thanks for the help,
Kai

[jrcraig]

The negative storage is likely the culprit. Easy solution (I hope) - initialize the GLACIER_ICE storage in the .rvc file to 100,000 mm (100m) for all HRUs with glaciers.

[ktsuruta]

That did the trick. Thanks, James.

I thought a bit about the tracer setup and am now not sure the shallow_gw and deep_gw components should have a fixed concentration of zero. The decision was based on the example tracers in Tutorial 3. What is the reason shallow_gw and deep_gw had fixed zero concentration in the SNOWMELT and GLACIER transport setup? If I want to know the total impact of glacier ice on outflow, should I remove the last two :FixedConcentration commands?

[rchlumsk]

Hi Kai

I believe the reason for the shallow and deep groundwater components being tagged as zero was to track only the snowmelt runoff directly, with the logic that snowmelt which enters the groundwater system is no longer 'meltwater' but groundwater. If you wish to account for all of the water from the glacier, not just melt and effectively runoff, it would make sense to remove those last two commands which effectively scrub the glacier consideration from that water.