Analysis of tropical peatland fire risk using drought standardized precipitation index method and TRMM rainfall data

摘要

The area of peatlands in Indonesia is about 20 million hectares or about 10.5% of the total land area of Indonesia, which is spread on the islands of Sumatra, Kalimantan and Papua. Almost every year, these peatlands experience fires in various places. The great fires that occurred in most of Indonesia's peatlands have occurred in 2014 and 2015 which caused severe haze disasters, especially on the islands of Sumatra and Kalimantan, even to neighboring country. The peatland fires continue to recur, which usually occurs in the dry season. In what kind of dryness level that usually peatland fires starting to occur, was analyzed in this study. The analysis was carried out using the drought index of SPI (Standardized Precipitation Index) method and TRMM (Tropical Rainfall Measuring Mission) rainfall data. The study was focused on the Bengkalis Island, which the peatland covered about 90% of the total area of Bengkalis Island. The analysis of SPI was carried out on a half monthly and monthly period for each grid with longitude and latitude size of 0.1° × 0.1°, so that the Bengkalis Island area was divided into 13 grids. TRMM data were downloaded using FileZilla and were analyzed using the Command Prompt application and the GrADS (The Grid Analysis and Display System) application. The values of SPIs were categorized as extremely wet, very wet, moderately wet, Mildly wet, mild wet, moderate drought, severe drought, and extreme drought. The spatial and temporal distribution of SPI were then compared with the historical data of fire events originating from hotspots. This study found that the peatlands start to be high risk against peat fire on meteorological drought index of SPI number of 0.5 with the status of "near normal". The other factors can generate the fire event such as the level of degraded peatland, over-drained peatland, peat thickness, social economic, lack of law enforcement and culture. However, it is important to note that to keep peatlands not burned is always keeping peatlands wet with the application of a good water management system.