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Module smb_oggm

Module smb_oggm implements the monthly temperature index model calibrated on geodetic mass balance (MB) data (Hugonnet, 2021) by OGGM. The yearly surface mass balance is computed with:

\[SMB = \frac{\rho_w}{\rho_i} \sum_{i=1}^{12} \left( P_i^{sol} - d_f \max \{ T_i - T_{melt}, 0 \} \right),\]

where \(P_i^{sol}\) is the monthly solid precipitation, \(T_i\) is the monthly temperature, and \(T_{melt}\) is the air temperature above which ice melt is assumed to occur (parameter temp_melt). The parameter \(d_f\) is the melt factor (parameter melt_f), and \(\frac{\rho_w}{\rho_i}\) is the ratio of water to ice density. Solid precipitation \(P_i^{sol}\) is computed from precipitation and temperature such that it equals precipitation when the temperature is lower than a certain threshold (parameter temp_all_solid), zero above another threshold (parameter temp_all_liq), with a linear transition between the two. Module oggm_shop provides all calibrated parameters [1].

Contributors: Guillaume Jouvet, Fabien Maussion

Reference: Maussion, Fabien, et al. "The open global glacier model (OGGM) v1. 1." Geoscientific Model Development 12.3 (2019): 909-931.

Config Structure

smb_oggm:
  update_freq: 1
  ice_density: 910.0
  wat_density: 1000.0
  melt_enhancer: 1

Parameters

Name Type Units Description Default Value
update_freq float y Update the mass balance each X years 1
ice_density float kg m^{-3} Density of ice for conversion of SMB into ice equivalent 910.0
wat_density float kg m^{-3} Density of water 1000.0
melt_enhancer float dimless Melt enhancer factor 1