Interannual variations in vegetation activities and climate variability caused by ENSO in tropical rainforests
Abstract:Interannual variations in terrestrial carbon cycle over tropical rainforests affect the global carbon cycle. Terrestrial ecosystem models show the interannual relationship between climate changes due to El Niño-Southern Oscillation (ENSO) and net primary production over tropical rainforests. However, we need an independent analysis using satellite-based vegetation index and climate parameters. In the present study, we extracted the ENSO-related interannual variations from time-series in Normalized Difference Vegetation Index (NDVI) and climate data from 1981 to 2000, and analysed their relevance. We detected relationships among NDVI, ENSO, and climate parameters from long-term data with negative NDVI-ENSO, NDVI-temperature, and positive NDVI-precipitation relations. These correlations suggest that interannual variability in vegetation activities over tropical rainforests could be extracted from NDVI time-series despite noise components in NDVI data, and that interannual changes in precipitation and temperature caused by ENSO play a more important role in vegetation activities over tropical rainforests than in incoming surface solar radiation.
Document Type: Research Article
Affiliations: 1: Division of Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan 2: San Jose State University and NASA Ames Research Center, Moffett'Field, CA, 94035
Publication date: January 1, 2007