Oerlemans Minimal Model as a Possible Instrument for Describing Mountain Glaciation in Earth System Models

Abstract

The main approaches to mountain glacier simulation were reviewed, and Oerlemans minimal model was chosen as a parameterization core of mountain glaciation in the Earth System models. The proposed model is based on a one-dimensional equation of glacier mass balance. The mass balance components are calculated with the use of a specially developed model of orographic precipitation, an algorithm for correction of incoming solar radiation onto an inclined ice surface, and schemes of calculation of turbulent heat-moisture exchange based on the Monin–Obukhov theory. The model was implemented for the Djankuat glacier (the Central Caucasus), for which a long measurement series is available. The model gives a good reproduction of the dynamics of glacier length over the period 1985–2020 based on measured mass balance values: –13 m/year, which is in practically perfect agreement with the field data. This means that the Oerlemans model can be used in Earth system models. The results of simulation based on the calculated mass balance showed a significant positive trend in ablation at a slight change in accumulation, which is also in agreement with the reality. However, in this case, the values of the annual thawing depth and the glacier contraction are twice as large and those observed in reality. The further development of the model (the inclusion of a snow cover block, the incorporation of debris mantle and mountain–valley circulation) will eliminate these shortcomings.