沢田䞉竹内研究室䛷䛿䝸䝰䞊䝖セン䝅ン䜾技術を利用䛧䚸陸域生態系や都市環境䛾評価手法䛾開発を行っ䛶いま䛩䚹こ䜜䛻䛿䚸対象物䛻応䛨た様々䛺セン䝃䛻䜘䜛計測䠄䝰䝙タ䝸ン䜾䠅䛸䚸取得䛧た䝕䞊タ䛛䜙有用䛺情報を抽出䛩䜛た䜑䛾䝰䝕䝹構築䠄䝰䝕䝸ン䜾䠅䛜含ま䜜ま䛩䚹 対象䛸䛧䛶い䜛空間䝇䜿䞊䝹䛿䚸実験室䝺䝧䝹䛛䜙都市䞉地域䝺䝧䝹䚸さ䜙䛻䛿大陸䞉全球䝺䝧䝹ま䛷幅広い䜒䛾䛸䛺っ䛶いま䛩䚹 また䚸高波長分解能䛾ハイパ䞊䝇䝨䜽䝖䝹セン䝃䛻䜘䜛計測や䚸䝺䞊䝄䞊䝇キ䝱䝘䛻䜘䜛計測䚸高解像度航空䝕䝆タ䝹写真䚸可視䞉近赤外䞉熱赤外䛾波長帯を用いた計測䛺䛹対象物䛻応䛨䛶様々䛺波長帯䛾䝕䞊タを利用䛧䛶いま䛩䚹 Ram Avtar 1,2 , R. Suzuki 1 , R. Ishii 1 , H. Kobayashi 1 , S. Nagai 1 , H. Fadaei 1 , R. Hirata 3 , A. B. Suhaili 4 ( 1 E-mail: avtar@jamstec.go.jp) 1 Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), JAPAN 2 United Nations University, Institute for Sustainability and Peace (UNU-ISP), JAPAN 3 Nationals Institute for Environmental Studied (NIES), JAPAN 4 Sarawak Forest Department, Sarawak, MALAYSIA ALOS-PALSAR MULTI-TEMPORAL OBSERVATION FOR DESCRIBING LAND USE AND FOREST COVER CHANGES IN MALAYSIA Abstract: The establishment of plantations in carbon rich peatland of Southeast Asia has shown an increase in the past decade. Use of optical data to monitor changes in peatland forests is difficult because of the high cloudiness in tropical region. Synthetic Aperture Radar (SAR) based remote sensing can potentially be used to monitor changes in such forested landscapes. In this study, we have demonstrated the capability of multi-temporal Fine-Beam Dual (FBD) data of Phased Array L-band Synthetic Aperture Radar (PALSAR) to detect forest cover changes in peatland to other landuse such as oilpalm plantation. Temporal analysis of PALSAR FBD data shows that conversion of peatland forest to oilpalm can be detected by analyzing changes in the value of σ o HH and σ o HV. This is characterized by a high value of σ o HH (-7.89 dB) and σ o HV (-12.13 dB) for areas under peat forests. The value of σ o HV decreased about 2-4 dB due to the conversion of peatland to a plantation area. There is also an increase in the value of σ o HH/σ o HV. Changes in σ o HV is more prominent to identify the peatland conversion than in the σ o HH. STUDY AREA INTRODUCTION Forests play an important role in global carbon cycling as they are potential carbon sinks and sources to the atmospheric CO 2 . Recent reports indicate that deforestation accounts for about 18% of global greenhouse gas emissions, making it the second largest source after fossil fuel (IPCC, 2007). This global deforestation and forest degradation have led to decline in ecosystem services and biodiversity. Peatland forest of Southeast Asia is rich of global biodiversity but recent development activities causes change in landuse pattern such as oilpalm plantation. Optical remote sensing data is often difficult to obtain cloud-free images in tropical regions due to frequent cloud cover. Therefore, use of Synthetic Aperture Radar (SAR) data offers an alternative data source for monitoring deforestation in large and remote areas in tropical region. Longer radar wavelength L-band SAR is better suited to the delineation of forest and forest cover change than other wave-lengths because of its greater penetration through the canopy. The Phased Array Type L-band Synthetic Aperture Radar (PALSAR) data is not subject to cloud interference, making it a more effective data source for monitoring forest and forest cover changes in tropical region. The objective of this study is to monitor the extent and spatial distribution of forest cover and its change in Sarawak, Malaysia. Multi-temporal PALSAR 50m mosaic data acquired from JAXA K&C was also used to monitor changes in the forest cover. STUDY AREA METHODOLOGY 2 0 10 log10( ) 83.0 DN     STUDY AREA RESULTS AND DISCUSSION Expanding plantation areas around Miri, Sarawak revealed by time series images of ALOS/PALSAR Fig. Multi-temporal PALSAR data (a) 04/07/2007, (b) 06/07/2008, (c) 09/07/2009 and (d) 12/07/2010 (a) (b) (d) Surface Volume (Canopy) Double bounce (Ground- trunk, ground- canopy) Volume (Trunk) (c) Fig. Backscattering properties of PALSAR before and after conversion Backscattering properties of peatland Backscattering properties after conversion of peatland to oilpalm PALSAR 50m mosaic 2009 JAXA PALSAR 50m mosaic 2008 JAXA PALSAR 50m mosaic 2007 JAXA Fig. Multi-temporal PALSAR 50m mosaic data (a) 2007, (b) 2008, and (c) 2009 Oilpalm plantation map based on PALSAR 50m mosaic data of JAXA Fig. Oilpalm plantation map of Sarawak Multi-temporal PALSAR data shows the changes in the backscattering properties with the change in objects because of the dependency of SAR data on biophysical parameters. We have selected Regions of Interest (ROIs) in peatland forest and monitored the changes in the σ o HH, HV and HH/HV before and after the conversion of peatland forest to oilpalm plantation. In case of peatland forest the value of σ o HH and HV ranges around -8 and -12 dB respectively and the value of ratio between HH and HV ranges around 4 dB. We have noticed the changes in the value of σ o HH and HV after conversion of peatland forest to oilpalm plantation. The value σ o HV and HH/HV shows significant changes as compared to σ o HH. Based on the temporal changes in the σ o HV and HH/HV, we can easily identify the conversion of peatland forest to oilpalm plantation area. STUDY AREA CONCLUSION Operational monitoring system of forest cover and forest cover change should be an essential tool to contribute towards global climate change issues Multi-temporal PALSAR data is effective to monitor tropical forest cover and forest cover changes PALSAR 50m mosaic data is useful to detect oilpalm plantation area in Sarawak  Combined use of HV and HH/HV backscattering properties is better to identify oilpalm as compared to σ o HH  Oilpalm plantation area map needs to be validated based on in-situ data and existing maps and published papers. Acknowledgement: Authors are also thankful to JAXA for providing PALSAR 50m mosaic data. This study was supported by the Environmental Research and Technology Development Fund (F-1101) of the Ministry of the Environment of Japan. View publication stats View publication stats