Permafrost model in coarse-blocky deposits, Dry Andes, Argentina

CARLA TAPIA BALDIS; DARIO TROMBOTTO LIAUDAT

Geographical Research Letters

Universidad de La Rioja

Año: 2018 vol. 46

0211-6820

In this work, we present a statistical permafrost distribution model forcoarse-blocky surfaces in the Central Andes of Argentina. The empiric mathematicalformulation was based on a logistic regression model with logit link. The finalmodel (CBPF) is a combination of two separate occurrence probability models: a)mean annual air temperature-terrain ruggedness model and, b) mean annual airtemperature-potential incoming solar radiation model. The CBPF theprobabilistic regional patterns of permafrost occurrence in coarse-blockysurfaces, as they dominate the landscape in the Central Andes and, they groundthermal properties differs from rocky bedrock. Novelty, we include the completegeomorphological characterization of Bramadero river basin, a high mountainperiglacial area of 250 km2, densely occupied by permafrostfeatures, with each landform as predictive variable for permafrost occurrence. Aregional-extension permafrost distribution model, calibrated with local data, wasachieved. Possible permafrost, in coarse debris, is expected between 4200 to5700 m asl and covers a surface of approximately 1200 km2 in theAndes. Likely permafrost is expected between 4200 to 3400 m asl with a surfaceof 6178 km2 while and unlikely permafrost, occurs between 3400 and3000 m asl with an area of 11060 km2. Moreover, results werecompared with the rock glacier database of Argentina and with the globalpermafrost zonation index (PZI) model.  Permafrostextension over coarse-blocky surfaces was also estimated under Tardiglacialclimatic scenario and surficial patterns of likely degraded permafrost achieved.