NUMERICAL MODELING OF TROPICAL GLACIER RESPONSE TO CLIMATE CHANGES AT NEVADO HUAGURUNCHO IN THE CENTRAL PERUVIAN ANDES

Glaciers in the tropics are highly sensitive indicators of climate change, and records of past glacier activity are among the most valuable archives of climate variability and forcings in this region. However, ambiguities over how tropical glaciers respond to specific elements of climate impede efforts to use glacier fluctuations as paleoclimate proxies. Numerical models offer a means to assess glacier dynamics that is difficult to accomplish using data alone. This project focuses on modeling tropical glacier responses to past, present, and future climate changes at Nevado Huaguruncho (10°14’S, 76°03’W), one of the few presently glaciated summits in the Eastern Cordillera of the central Peruvian Andes. The glacial history of Nevado Huaguruncho was recently reconstructed using cosmogenic ¹⁰Be exposure dating of moraines and multiproxy analyses of radiocarbon-dated lake sediments. Here, we build on this earlier work by applying a surface energy mass-balance model and coupling this with an ice dynamics model driven by the simulated energy balance outputs. The coupled energy mass-balance and ice dynamics model will be used replicate the present-day glacier extent in Jaico Valley using temperature and precipitation solutions informed by glacier sensitivity experiments in the southern Peruvian Andes. We will then alter temperature and precipitation in the model to constrain an array of plausible climate conditions that sustain ice at the local last glacial maximum extent. Subsequent experiments will test the local glacier response to increased atmospheric temperatures in the tropics based on projections of future warming. The modeling of climate controls at Nevado Huaguruncho will contribute to a regional synthesis of the influences of climate change on glacier responses in central Peru.