Simulated links between deforestation and extreme cold events in South America

David Medvigy, Robert L. Walko, Roni Avissar

Research output: Contribution to journalArticlepeer-review


Many modeling studies have indicated that deforestation will increase the average annual temperature in the Amazon. However, few studies have investigated the potential for deforestation to change the frequency and intensity of extreme events. This problem is addressed here using a variable-resolution GCM. The characteristic length scale (CLS) of the model's grid mesh over South America is 25 km, comparable to that used by limited-area models. For computational efficiency, the CLS increases to 200 km over the rest of the world. It is found that deforestation induces large changes in the frequency of wintertime extreme cold events. Large increases in cold event frequency and intensity occur in the western Amazon and, surprisingly, in parts of southern South America, far from the actual deforested area. One possible mechanism for these remote effects involves changes in the position of the subtropical jet, caused by temperature changes in the Amazon. Increased understanding of these potential changes in extreme events will be important for local agriculture, natural ecosystems, and the human population.

Original languageEnglish (US)
Pages (from-to)3851-3866
Number of pages16
JournalJournal of Climate
Issue number11
StatePublished - Jun 2012


  • Adaptive models
  • Amazon region
  • Atmosphere-land interaction
  • Cold air surges
  • Deforestation

ASJC Scopus subject areas

  • Atmospheric Science


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