loading page

Assessing Present-Day Atmospheric Control Over the Surface Mass Balance of Patagonian Icefields Through Modeling
  • +1
  • Tomás Carrasco Escaff,
  • Maisa Rojas,
  • Rene Garreaud,
  • Deniz Bozkurt
Tomás Carrasco Escaff
Universidad de Chile

Corresponding Author:[email protected]

Author Profile
Maisa Rojas
University of Chile
Author Profile
Rene Garreaud
University of Chile
Author Profile
Deniz Bozkurt
Universidad de Chile
Author Profile

Abstract

The Patagonian Icefields (Northern Patagonia Icefield and Southern Patagonia Icefield) are the largest ice bodies in the Southern Hemisphere outside Antarctica. Nonetheless, little is known about their main meteorological and glaciological features (mean state, variability and trends) in present climate (last ~30 years). The lack of temporarily and spatially dense observational data in this area has imposed a limitation on the assessment of the atmosphere-cryosphere interaction, a key issue for understanding the past, present and future evolution of these ice bodies and more generally, the southern Andes cryosphere. In this work, we overcome the absence of surface data by modeling the present-day atmospheric surface conditions for southern Andes. We first use a regional climate model (RegCMv4) to dynamically downscale the ERA-Interim reanalysis at 10-km spatial resolution for the period 1980-2015. Then, we statistically downscale its outputs to a 450-m resolution grid. This meteorological forcing is used later as an input for a simplified surface mass balance model. The surface mass balance output is analyzed particularly for spatial and temporal variability as well as trends. This allows us to have a better understanding of the local-scale atmospheric control (i.e., surface temperature, solar radiation and precipitation) over the surface mass balance of Patagonian Icefields. In order to assess the large-scale control over the surface mass balance of Patagonian Icefields, time series of spatially-averaged modeled fields are projected upon main atmospheric fields obtained from ERA-Interim reanalysis. Main results show that years of relatively high (low) surface mass balance are associated with low (high) pressure anomalies near the Bellingshausen Sea, causing an anomalous cyclonic (anticyclonic) circulation that enhances (reduces) the westerlies impinging the Patagonian Icefields which in turn increments (decrements) the surface mass balance. Only weak correlations between the mass balance and the main atmospheric modes of variability (ENSO, PDO, SAM) were found, suggesting little dependency between these modes and the surface mass balance of the Patagonian Icefields.