Publications
| Title: | Spaceborne Radar Monitoring of Forest Fires and Forest Cover Change - A case study in Kalimantan |  |
| Authors: | Sugardiman, R.A. | |
| Year: | 2007 | |
| Inside: | Tropenbos Kalimantan Series | |
| Publishing Country: | The Netherlands | |
| Abstract: | Spaceborne Radar Monitoring of Forest Fires and Forest Cover Change. A case study in Kalimantan. PhD thesis, Wageningen University, Wageningen, The Netherlands, 190p. The devastation of tropical rainforests has been proven to have a significant effect on global climate change. The future sustainability of these forests has subsequently become a major concern for the international community. As a result, the Indonesian Ministry of Forestry (MOF) is eager to carry out forest inventory activities and to generate information related to forestry resources . Advanced spaceborne radar techniques exist as a highly promising tool for monitoring forests. This technique is complementary with existing spaceborne optical imagery which is often impeded by excessive cloud cover. Radar provides reliable information on a regular basis and has been applied to various types of applications e.g. forest classification. The approach presented in this thesis includes three main elements. Firstly, multi-temporal classification of spaceborne Synthetic Aperture Radar (SAR) data using Iterated Conditional Modes is proposed as a rapid step for Maximum Likelihood classification in order to circumvent the more time-consuming step of image segmentation. Secondly, slope correction is used for dealing with steep slopes that have considerable geometric distortion. Thirdly, textural analysis has been applied to derive additional information layers in multi-temporal classification from fine structures in the radar images (Figures 2-1 and 2-10). The study focuses on three test site areas i.e. Sungai Wain test site area, the Gunung Meratus test site area and the NASA AirSAR PacRim-II test site area (Figures 3-1 and 3-9). This area has experienced long drought periods associated with the El Niño Southern Oscillation (ENSO) phenomenon. For this study, the severe ENSO event of 1997 - 1998 is of particular interest. Forest fires occur almost every year in this test site area; however, each event is specific in intensity and extent (Figure 4-16). A longer time series of radar images accounts for every event observation made (Table 3-6 and Figure 3-10). The results show high accuracy ranging from 85.2 % to 98.8 % for almost all land cover types (Table 4-5). Slope correction has a positive effect but does not appear to have very high accuracy. It is shown that the induced slope correction is around 1 dB while values up to 10 dB were expected. The resolution of the digital elevation model is an important factor for the correction of relief in spaceborne SAR data. When the resolution is too coarse, i.e. spatial features of slope correction are coarser than the actual structures, the pattern of relief will be flattened out (Figures 4-12 and 5-4). Utilization of textural features yields a significant improvement of overall classification accuracy, which increases from 36.5 % to 48.5 % (Tables 4-20 and 4-21). The approach developed for the Gunung Meratus has broad application potential. It would seem to be sufficiently mature for it to be applied to other areas; for example, the Mawas and Sebangau peat swamp forest area (Figures 4-25 and 4-26). This method of radar monitoring system may have the potential to become the core system for 'fast illegal logging response' within the Indonesian MOF. The implementation of the SAR monitoring for the Indonesian MOF is accelerating the ongoing decentralization policy. Recommendations are offered here to the Indonesian MOF, particularly for enhancing the capability of local authorities to provide fast, accurate, and reliable information on forest condition (Sections 5.5 and 5.6). This capability will help ensure that Indonesia's remaining tropical rainforest will be managed sustainably. | |
| ISBN: | 978-90-5113-087-4 | |
| ISSN: | 1566-6522 | |
| Tropenbos: | Yes | |
| Downloadable: | Yes | |
| Possible to order: | No | |
| Price: | € 0 | |
| Language: | EN |
