In the hot seat: Insolation, ENSO, and vegetation in the african tropics

Sarah J. Ivory, Joellen Russell, Andrew S. Cohen

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


African climate is changing at rates unprecedented in the Late Holocene with profound implications for tropical ecosystems and the global hydrologic cycle. Understanding the specific climate drivers behind tropical ecosystem change is critical for both future and paleomodeling efforts. However, linkages between climate and vegetation in the tropics have been extremely controversial. The Normalized Difference Vegetation Index (NDVI) is a satellite-derived index of vegetation productivity with a high spatial and temporal resolution. Here we use regression analysis to show that NDVI variability in Africa is primarily correlated with the interannual extent of the Intertropical Convergence Zone (ITCZ). Our results indicate that interannual variability of the ITCZ, rather than sea surface temperatures or teleconnections to middle/high latitudes, drives patterns in African vegetation resulting from the effects of insolation anomalies and El Niño-Southern Oscillation (ENSO) events on atmospheric circulation. Global controls on tropical atmospheric circulation allow for spatially coherent reconstruction of interannual vegetation variability throughout Africa on many time scales through regulation of dry season length and moisture convergence, rather than precipitation amount. Key Points Atmospheric variability has a dramatic effect on tropical African vegetation. ITCZ position and intensity result from variations in insolation and ENSO. Growing season vegetation controls are both rainfall and dry season length.

Original languageEnglish (US)
Pages (from-to)1347-1358
Number of pages12
JournalJournal of Geophysical Research: Biogeosciences
Issue number4
StatePublished - Dec 2013


  • ENSO
  • ITCZ
  • NDVI
  • insolation
  • tropical climate
  • vegetation

ASJC Scopus subject areas

  • Soil Science
  • Forestry
  • Water Science and Technology
  • Palaeontology
  • Atmospheric Science
  • Aquatic Science
  • Ecology


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