Andes Mountains

The Role of Mountains

  • Andes Mountains

    Mountains represent approximately 24% of the land surface of the Earth and play a vital role in sustaining ecosystems and humanity especially in the tropics where population is high.

  • Precipitation is the critical freshwater input to the hydrologic system in mountain regions of the world and has a fundamental influence on mountain glaciers and ecosystems.
  • Precipitation is the primary parameter preserved in ice cores obtained from mountain glaciers and ice caps.

Photo Credit: Patience Perry

Rapid Deglaciation in the Andes Mountains

  • Precipitation phase (rain vs. snow), timing, frequency, and amount control surface albedo in mountain environments, whereas cloud cover associated with precipitation events reduces solar radiation, together resulting in a major influence on climate.
  • As such, precipitation variability is an important influence on glacier mass balance in the tropical Andes.

Precipitation in the Tropical Andes Mountains

  • Precipitation is particularly significant in the Centrall Andes Mountains of southern Peru and Bolivia, influencing glacier mass balance and surface albedo a region where glacier meltwater is critical for buffering water supplies during the dry season.
  • It is widely recognized that precipitation serves as the primary influence on oxygen stable isotope ratios (δ18O) preserved in tropical ice cores. Precipitation provides the critical freshwater inputs to hydrologic resources (e.g., irrigation, hydroelectricity, water reservoirs) and is a major influence on ecosystems and agriculture.
  • Scientific understanding of tropical Andean precipitation processes and occurrence remains quite low, leading to considerable uncertainty in precipitation-glacier-hydroclimate interactions, paleoclimatic reconstructions, and projections of future climate scenarios. Such shortcomings derive from: inadequate or non-existent surface and upper-air observational networks in the region, lack of basic and applied atmospheric research in the region, the interaction of multiscale atmospheric processes in areas of significant topographic relief, and limited educational and outreach resources focused on precipitation and atmospheric science in general in the tropical Andes.

Tropical Andean Precipitation Research Challenges

Research equipment, Andes Mountains

Previous investigations of tropical Andean precipitation are limited and focused primarily on:

  • Large-scale atmospheric circulation on seasonal (wet vs. dry) and inter-annual timescales
  • Precipitation-climate-glacier interactions in the inner and outer tropics
  • Atmospheric influences on δ18O values recorded in precipitation in the context of paleoclimatic interpretation. Other than a few investigations focused on the Andean Altiplano and the intermontane valleys of Ecuador, research on the physical processes associated with tropical Andean precipitation is largely non-existent, which is surprising given the significant role precipitation processes play in influencing other aspects of the hydroclimate and ecosystems across the region.

Photo Credit: Tracie Seimon


This material is based upon work supported by the National Science Foundation under Grant Number AGS-1347179. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.