SEAMEO BIOTROP presented Aslan, PhD, the Centre’s Research Manager, in its 1^st 2020 online Quarterly Public Seminar, held on 29 June 2020, to talk about his team’s research study in 2019 on the urgency of peatland mapping and analysis studies in Indonesia using active and passive satellite imagery method in supporting low carbon development. A total of 96 participants from various Indonesian research and education institutions as well as private companies and non-government organizations joined this online activity.

At this seminar, Dr Aslan said that forest protection and peatland restoration are among five main policies of the Indonesian Government pertaining to low carbon development planning (PPRK), because the amount of carbon stored in the soil of peatland ecosystems is estimated to be 10 times greater than that stored above the soil surface. The carbon stored in the peatlands must be kept relatively stable and not be emitted into the atmosphere to prevent global warming.

He continued, based on the 2015 National Determined Contribution (NDC) document, written in the Paris Agreement, the Government of Indonesia has set a target of reducing Greenhouse Gas (GHG) emissions, which is 29% unconditionally (on its own) and 41% conditionally (with adequate international support) in 2030.

To support this policy, Dr Aslan and his team carried out research activities to ensure the availability of accurate basic information related to the latest map of peatland distribution in Indonesia as a basis for national low carbon policy making. He utilized remote sensing technology from active and passive satellite imagery method, including geostatistical modeling, and used input of more than 20 thousand validated peatland field observations from various sources. Through the MaxEnt geostatistical modeling approach, four scenarios of peatland distribution throughout Indonesia were produced.

Dr Aslan explained that mapping using active and passive satellite imagery method has three advantages. First, it produces a map of peatland distribution that can combine the advantages possessed by active and passive satellite images. Indonesia as a tropical country is strongly influenced by cloud cover which greatly affects the accuracy of mapping peatland distribution in Indonesia. In this context, the use of active satellite imagery method, which is based on radar waves, is a solution for peatland mapping activities in the tropics that are often disrupted by cloud cover because radar sensors have the ability to penetrate clouds.

Second, the map of peatland distribution produced has a more detailed scale, which is 1:100,000 (much better in terms of accuracy) compared to the 1:250,000 reference map issued by the Centre for Agricultural Land Resources (BBSDLP) of the Indonesian Ministry of Agriculture. As an illustration, based on data released by BBSLDP (2011), no peatland cover was found in Sulawesi Island, but the results of this study showed the opposite. The existence of peatland in Sulawesi Island has been verified from field observation data (ground truth), active and passive satellite data monitoring, as well as from media news about peatland fires in Southeast Sulawesi Province in 2019.

Third, the map of peatland distribution is generated using a systematic and efficient approach because it is derived from geostatistics modeling of Big Data Analysis and compilation of active and passive satellite data using Google Earth Engine technology. On the other hand, the map of peatland distribution issued by BBSLDP (2011) was produced using the peatland distribution boundary mapping method which might be biased because it uses a visual interpretation mapping technique having limitations and requires expertise and highly experienced operators to recognize the characteristics of the satellite image hue and peat soil covered by vegetation in the field.

From the results of this study, Dr Aslan said that the latest spatial data and information on peatlands in Indonesia on a scale of 1: 100,000 is available in the form of geodatabases and printed maps. In addition, a web-based interactive map (GIS web) of peatlands in Indonesia can be accessed in https://gambut.netlify.com/. The method used in this study can also be applied by other parties with minimum supervision and unbiased results. Nevertheless, he said, the map of peatland distribution resulting from this study was still a probable presence of peatlands because it was produced based on a geostatistical modeling approach. Therefore, it is necessary to carry out a further thorough and systematic field validation and verification of the results.

Dr Aslan is a professional researcher and philanthropist with a strong background in spatial planning, remote sensing, geographic information systems (GIS) and natural resource management. He earned a PhD degree in Environmental Science from Indiana University, USA, in 2017 and an MS degree in Civil and Environmental Engineering from University of Missouri, USA, in 2009.