Development and Validation of New Glacial Lake Inventory in the Bhutan Himalayas Using ALOS ‘ DAICHI ’

This study aims to develop and validate a new glacial lake inventory in order to gain an understanding of existing conditions. This is being done using optical imageries acquired by the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) onboard the Advanced Land Observing Satellite (ALOS, nicknamed ‘Daichi’). Glacial lakes can cause outburst floods when natural dams break, and they represent a serious hazard to downstream regions. A major challenge associated with glacial lake outburst floods (GLOFs) is the inability to predict when they will occur or how much damage they will cause. In order to mitigate GLOF hazard risks, a new glacial lake inventory of the Bhutan Himalayas using ALOS imageries is currently being developed, combining PRISM and AVNIR-2 results in imaging with a fine spatial resolution of 2.5 m and multi-spectral precise geolocation. In addition, PRISM can derive precise digital terrain information, i.e., digital surface model (DSM) using its along-track stereo capabilities. We describe the methodology used in the development of the ALOS-based glacial lake inventory, including image processing procedures, glacial lake extraction, accuracy assessments of the generated PRISM DSM for the entire country of Bhutan, and validation of the inventory.