Nobuhiro Tomiyama

Glacial lake inventory of Bhutan using ALOS data: methods and preliminary results

Abstarct The Advanced Land Observing Satellite (ALOS) is relatively new. Its optical sensors are capable of making high-resolution digital surface models (DSMs). For the first time, the task of constructing a regional-scale inventory of glacial lakes based on ALOS data has been undertaken. This study presents the data-processing methods and the results of validation and analysis on the ALOS-based glacial lake inventory of Bhutan in the Himalaya. The analysis based on GPS measurements taken at Metatshota lake in the Mangde Chu sub-basin, one of the glacial lakes assessed as presenting a potential flood danger, shows a validation estimate of 9.5 m for the location of the ALOS-based polygon, with a root mean square of 11.7 m. A comparison with digitized data from the International Centre for Integrated Mountain Development (ICIMOD) shows that positioning and evaluation of terrain changes can be significantly improved using ALOS data. Preliminary analysis of the glacial lakes in four sub-basins, Mo Chu, Pho Chu, Mangde Chu and Dangme Chu, reveals that the frequency distribution of lake sizes biases towards smaller lakes. Glacial lakes 0.01–0.05km2 in area account for ~55% of the total number and occupy 13% of the total area. Together our results demonstrate the usefulness of high-resolution ALOS data with accurate DSMs for studying glacial lakes. High priority must be given to continuously improving and updating the glacial lake inventory with high-resolution satellite data.

JAXA High Resolution Land-Use and Land-Cover Map of Japan

Japan Aerospace Exploration Agency creates the “JAXA High Resolution Land-Use and Land-Cover Map (JHR LULC Map)” in Japan. The data was acquired by the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2), onboard the Advanced Land Observation Satellite. Ortho-rectification, atmospheric and slope correction were applied to the AVNIR-2 data. The number of the input data for the classification is 1,876 scenes which were acquired from April 28, 2006 to April 15, 2011. The classification categories are 1) water, 2) urban, 3) paddy, 4) crop, 5) grass, 6) deciduous forest, 7) evergreen forest, 8) bare land, and 9) snow and ice. Pixel spacing of the JHR LULC Map is 0.000278° and 0.000333° for the latitude and longitude, respectively. The temporal classification accuracy was found to be 89.3%, which was calculated using the validated accuracy of the classification multiplied by the surface ratio in each category by the Ministry of Internal Affairs and Communications.

Urban damage detection using decorrelation of SAR interferometric data

We investigate decreasing interferometric correlation of SAR data caused by building damages in urban area. We analyze JERS-1 SAR data pairs straddling the occurrence of the 1995 Hyogoken-nanbu earthquake. The distribution patterns of the pixels which indicated interferometric decorrelation correspond well with the building damaged area reported by the ground survey. The degree of decorrelation shows obvious correlation with the damaged building ratio on the area in each block and measured seismic intensity from strong motion data. The result of this study indicates a fact that the building damage causes the interferometric decorrelation. We also try to extract the urban area damaged by the 2001 Gujrat (western India) earthquake using Radarsat data. For practical use of interferometric decorrelation to detect the urban damage, effect of building type and urban concentration should be examined. These results show the applicability for interferometric analysis of SAR data to urban disaster management.

Development of glacial lake inventory in Bhutan using “Daichi” (ALOS)

The objective of this study is to develop new glacial lake inventory to understand existing condition using the optical imageries of 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 be caused outburst flood when natural dams terminated by moraines are broken, and it represents serious hazard damage in downstream regions. Problems of glacial lake outburst floods (GLOFs) are that anyone does not know when it will occur and how much damage causes by it. To contribute these problems, new glacial lake inventory is currently developing in the Bhutan Himalayan using ALOS imageries. This paper describes procedure of the inventory development including image processing that introduces pan-sharpened and ortho-rectified images by PRISM and AVNIR-2, glacial lakes extraction, and its validation.

The Earthcare Cloud Profiling Radar, its PFM development status (Conference Presentation)

The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is joint mission between Europe and Japan for the launch year of 2018. Mission objective is to improve scientific understanding of cloud-aerosol-radiation interactions that is one of the biggest uncertain factors for numerical climate and weather predictions. The EarthCARE spacecraft equips four instruments such as an ultra violet lidar (ATLID), a cloud profiling radar (CPR), a broadband radiometer (BBR), and a multi-spectral imager (MSI) and perform complete synergy observation to observe aerosols, clouds and their interactions simultaneously from the orbit. Japan Aerospace Exploration Agency (JAXA) is responsible for development of the CPR in this EarthCARE mission and the CPR will be the first space-borne W-band Doppler radar. The CPR is defined with minimum radar sensitivity of -35dBz (6dB better than current space-borne cloud radar, i.e. CloudSat, NASA), radiometric accuracy of 2.7 dB, and Doppler velocity measurement accuracy of less than 1.3 m/s. These specifications require highly accurate pointing technique in orbit and high power source with large antenna dish. JAXA and National Institute of Information and Communications Technology (NICT) have been jointly developed this CPR to meet these strict requirements so far and then achieved the development such as new CFRP flex-core structure, long life extended interaction klystron, low loss quasi optical feed technique, and so on. Through these development successes, CPR development phase has been progressed to critical design phase. In addition, new ground calibration technique is also being progressed for launch of EarthCARE/CPR. The unique feature of EarthCARE CPR is vertical Doppler velocity measurement capability. Vertical Doppler velocity measurement is very attractive function from the science point of view, because vertical motions of cloud particles are related with cloud microphysics and dynamics. However, from engineering point of view, Doppler measurement from satellite is quite challenging Technology. In order to maintain and ensure the CPR performance, several types of calibration data will be obtained by CPR. Overall performance of CPR is checked by Active Radar Calibrator (ARC) equipped on the ground (CPR in External Calibration mode). ARC is used to check the CPR transmitter performance (ARC in receiver mode) and receiver performance (ARC in transmitter mode) as well as overall performance (ARC in transponder mode with delay to avoid the contamination with ground echo). In Japan, the instrument industrial Critical Design Review of the CPR was completed in 2013 and it was also complemented by an Interface and Mission aspects CPR CDR, involving ESA and the EarthCARE Prime, that was completed successfully in 2015. The CPR Proto-Flight Model is currently being tested with almost completion of Proto-Flight Model integration. After handed-over to ESA planned for the beginning of 2017, the CPR will be installed onto the EarthCARE satellite with the other instruments. After that the CPR will be tested, transported to Guiana Space Center in Kourou, French Guiana and launched by a Soyuz launcher in 2018. This presentation will show the summary of the latest CPR design and CPR PFM testing status.

EarthCARE/CPR design results and PFM dvelopment status

Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) is a Japanese-European collaborative earth observation satellite mission aimed to deepen understanding of the interaction process between clouds and aerosols and their effects on the Earth’s radiation. The outcome of this mission is expected to improve the accuracy of global climate change prediction. As one of instruments for EarthCARE, the Cloud Profiling Radar (CPR) is the world’s first space-borne Doppler cloud radar jointly developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). In Japan, the critical design review of the CPR has been completed in 2013, and CPR proto-flight model was manufactured and integrated until summer in 2015. Finally, the proto-flight test have been just started. This paper describes the design results and current status of CPR proto-flight test.

Comparison of Atmospheric Phase Delay on ALOS PALSAR Interferogram and Cloud Distribution Pattern on Simultaneously Observed AVNIR-2 Images

Tropospheric artifact is a serious problem for detecting crustal deformation using differential synthetic aperture radar intereferometry (DInSAR) technique. Advanced Land Observing Satellite (ALOS) has capability for simultaneous observation between synthetic aperture radar, PALSAR and optical sensor, AVNIR-2. We compared ALOS PALSAR interferogram with simultaneously observed AVNIR-2 images. Nominal spatial resolution of AVNIR-2 is sufficient for valuation of PALSAR interferogram. Terra/Aqua MODIS images are compared with PALSAR interferogram and cloud top heights is estimated. Test site is Miyagi prefecture where one of the most active seismic zone in Japanese islands. AVNIR-2 images show the two types of clouds pattern that causes interferometric phase delay. The first is lee wave cloud which shows the presence of gravity waves. The second is thick cloud as cumulus which is formed by condensation of water vapor. An interferogram show combination of phase delays in a couple of data. Simultaneously observed AVNIR-2 image is possible to use for evaluation of PALSAR interferometric fringe patterns.

A relationship between tsunami disaster along west coast of Sumatra and land elevation analyzed with Landsat/ETM+ and SRTM data

Among the tsunami disaster area in December 26, 2005, the northwest coast of Sumatra was suffered with heavy damage along 250 km length. Though the degree of damage depends upon various reasons, this work focuses on clarifying the relationship between disaster and elevation. Landsat/ETM+ data are available in handicapped condition with SLC problem. Nevertheless, it serves to investigation of the affected area. SRTM data of the NASAs Space Shuttle Endeavor in February 2000 offers us a reliable data of land elevation at an interval of 90 meters. Affected area is interpreted on Landsat-5/TM also with the SRTM elevation data. Affected area can be seen in brown and coincides with the elevation less than 9 meters on the true color composite of Landsat/TM or on the RGB:543 composite. In addition to this, tsunami run-up height and intrusion distance, land subsidence, and land uplift are measured.

Land surface observation using multi-polarization ENVISAT ASAR data

Multi-polarized space borne SAR data can be used to detect changes in land cover. The ENVISAT ASAR has the ability to acquire images using two polarizations simultaneously. This paper discusses the capability of detecting land surface characteristics using ENVISAT ASAR dual polarization data. The applicability of image mode and alternative polarization mode data are investigated, and backscattering coefficients for images with different polarizations are compared. Optical images and GIS data are used as reference data. Two types of land cover in Japan are examined: forest on an active volcano (Miyakejima, a volcanic island that erupted in 2000), and an urban area (central Tokyo). Differences were evident between bare land and forest areas in the HH and HV polarized data sets. City street patterns exhibit differences in backscattering characteristics between like- and crosspolarized SAR images: cross-polarization backscattering is increased for streets that are inclined to the radar irradiation direction