High-Resolution Image

South America, southern Africa and the Indonesian archipelago represent the three major areas of tropical biomass burning and smoke production. Using MODIS-derived monthly mean Level 3 data, the figure shows a 8 year time series of the aerosol optical depth (AOD) for each of the three regions (right). All three regions show maximum AOD during the July - October season, with southern Africa concentrated in the early part of that period and Indonesia towards the end of the period. The panels on the left compare monthly mean AOD in September and October, 2006 and 2007 for all three tropical biomass burning areas.

As reported in Koren et al. (2007) and shown in the Image of the Week September 23, 2007, mean AOD levels in South America increase from 2000 to 2005, then drop significantly in 2006. The reversal of this trend was attributed to a combination of changes in cultural practices and the onset of a early rainy season. However, we see that in 2007, smoke in South America was again at high levels, higher than any other year in the MODIS record. In contrast, 2006 was a significant burning year in Indonesia, while 2007 had relatively little smoke. Interannual variability in biomass burning in Indonesia is linked directly to ENSO cycles, with 2002, 2004 and 2006 all identified as El Nino years.

Koren, I., L. A. Remer, and K. Longo, 2007: Reversal of trend of biomass burning in the Amazon. Geophys. Res. Lett.,34, L20404, doi:10.1029/2007GL031530.

(Submitted by Lorraine Remer)