Table 1.
Annual ENSO index, dry season precipitation, and other parameters affecting fire emissions for Borneo and optimized emission estimates for Borneo, Sumatra, other regions, and all regions combined
| Year | ENSO index* (−) | Borneo |
Sumatra: |
Other regions: |
Whole region: |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Dry season precipitation†‡ (mm month−1) | Forest clearing rate‡ (% yr−1) | Distance to canals§ (km) | Persistent fire fraction¶ (−) | Bottom-up fire emissions‖ (Tg C yr−1) | Optimized emissions estimate‖** (Tg C yr−1) | optimized emissions estimate‖** (Tg C yr−1) | optimized emissions estimate‖** (Tg C yr−1) | optimized emissions estimate‖** (Tg C yr−1) | ||
| 2000 | −0.21 | 145 | 0.24 | NA | 0.39 | 8 ± 2 | 7 ± 3 | 35 ± 29 | 4 ± 2 | 47 ± 29 |
| 2001 | 0.07 | 87 | 1.20 | 0.79 | 0.52 | 27 ± 8 | 27 ± 12 | 23 ± 19 | 3 ± 1 | 53 ± 22 |
| 2002 | 0.73 | 42 | 1.59 | 1.14 | 0.59 | 123 ± 35 | 123 ± 56 | 46 ± 37 | 15 ± 7 | 185 ± 67 |
| 2003 | 0.25 | 98 | 0.73 | 1.03 | 0.51 | 28 ± 8 | 27 ± 12 | 38 ± 30 | 2 ± 1 | 67 ± 33 |
| 2004 | 0.54 | 65 | 0.73 | 1.22 | 0.54 | 66 ± 19 | 66 ± 30 | 47 ± 38 | 7 ± 3 | 120 ± 49 |
| 2005 | 0.35 | 101 | 1.54 | 0.98 | 0.54 | 32 ± 9 | 31 ± 14 | 88 ± 71 | 3 ± 2 | 123 ± 72 |
| 2006 | 0.75 | 36 | 3.47 | 1.48 | 0.61 | 234 ± 66 | 236 ± 106 | 63 ± 50 | 3 ± 1 | 303 ± 118 |
| Mean | 0.35 | 82 | 1.36 | 1.11 | 0.53 | 74 ± 21 | 74 ± 33 | 49 ± 39 | 5 ± 2 | 128 ± 51 |
*Dry season (June–October) multivariate ENSO index (MEI, http://www.cdc.noaa.gov/people/klaus.wolter/MEI/mei.html).
†Mean monthly precipitation during the 3 consecutive months with lowest rainfall, based on TRMM precipitation.
‡For Borneo south of 1°S, the region most heavily impacted by ENSO drought. This part of the island had an area of 19 Mha.
§Mean distance to drainage, either canals or rivers, of MODIS active fire observations for a region corresponding to Landsat scene path 118 row 062 in southern Borneo (Fig. S1).
¶Fraction of total detected fires that were detected during more than one satellite overpass in the same 1-km grid cell during the dry season, indicating high fuel loads such as fires associated with forest loss or peat burning that burn for longer periods in the same place (27).
‖Uncertainties represent 1 sigma range.
**Based on the anomaly optimization (see Materials and Methods) and the mean of the bottom-up model.