Correlation of drought and fire hotspots by using Standardized Precipitation Index (SPI) from TRMM Rainfall Data from 2015 to 2019 at Central Kalimantan, Indonesia

摘要

Kalimantan is a region in Borneo Island in Indonesia that holds a massive tropical forest with 36.5 million ha, which covers 30,2% of the national forest area. More importantly, the tropical forest in Kalimantan is mostly covered by peatlands at risk of forest fires. Historical data showed that most of the fire events happened in Central Kalimantan. According to the Indonesian Ministry of Environment and Forestry, around 22,35% of burned forest areas in Indonesia during 2015 forest fire cases happened in Central Kalimantan. While in the 2019 Indonesian forest fires, around 19,26% of burned forest areas also happened in Central Kalimantan. One of the leading causes of forest fires is the dryness of peatland that the lower part of it is incredibly prone to be a source of the fire. This heat source, called fire alerts, can be seen using thermal-based infrared sensors from satellite imagery. Long dry season with a low rainfall rate was suspected as the main cause of many fire alerts in the lower part of peatland. We retrieved and processed rainfall data from Tropical Rainfall Measuring Mission (TRMM) as an input to calculate the dryness classification using Standardized Precipitation Index (SPI), as well as fire alerts data from VIIRS (Visible Infrared Imaging Radiometer Suite) satellite imagery during 2015 - 2019. This research aims to analyze the relationship between the dryness peatland condition and the intensity of fire alerts by generating a correlation graph between drought on a long dry season and fire alerts generated from VIIRS. Forest fires are very susceptible to occur at the SPI drought index showing a number ＜-1 with the classification "quite dry."