Comparison of Digital Elevation Models for the designing water reservoirs: a case study Pskom water reservoir

This study investigates the accuracy of various DEMs (SRTM DEM, ASTER GDEM, and ALOS PALSAR DEM) for the area of the designing Pskom water reservoir (recommended to construction in Pskom River, in Tashkent region. DEMs are compared for the study area using the Global Mapper application and selection Ground Control Points (GCP). The RMSE we calculate is the most easily interpreted statistic as the square root of the mean square error because it has the same units as the quantity drawn on the vertical axis. Results show that SRTM based measurements of ground control points (GCPs) exhibit RMSE of 15.72 m while ASTER DEM based measurements exhibits and RMSE of 18.47 m, ALOS PALSAR exhibit RMSE of 14.02 m for the Water reservoir located in the plain. There are AOS PALSAR outperforms SRTM and ASTER DEM in detecting vertical accuracy. Based on the capabilities of the Global Mapper program, we can build the longitudinal profile of the approximate location where the dam can be built in each DEM and compare. The results obtained show that the dam height is 187 m at ALOS PALSAR DEM, 168 m at ASTER GDEM, and 175 m at SRTM. The study found that using ALOS PALSAR data in the design of the proposed Pskom Reservoir for construction leads to a more accurate result. Comparing the DEMs data shows that there is more difference between the vertical accuracy; the horizontal accuracy level is almost the same. The results were obtained using ALOS PALSAR data in determining the storage volume (W=479368568 m3) and area (F=8.31 sq., km) of the water reservoir

Mapping of clear-cuts in Swedish forest using satellite images acquired by the radar sensor ALOS PALSAR

This study presents results for observing forest changes in Sweden using multi-temporal L-band satellite data and is a part of the JAXA’s ALOS Kyoto and Carbon Initiative. An extensive dataset of images acquired by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) is investigated for clear-cut detection in boreal forests in northern Sweden (Lat. 64°14’ N, Long. 19°50’ E). Strong forest/non-forest contrast and temporal consistency were found for the Fine Beam Dual HV-polarized backscatter during unfrozen conditions. Thus, a simple thresholding algorithm that exploits the temporal consistency of pair-wise HV-backscatter measurements has been developed for detection of clear-felled areas. When applied to an image pair acquired during favorable weather conditions, the detection algorithm identified 76% of the clear-cut pixels within a reference layer, with zero erroneously detected pixels. With further refinement, the developed methodology can be an option to present operational alternatives for clear-cut detection

Aplicación del método magnetotelúrico (MT) en la caracterización de reservorios geotérmicos

Se realizaron inversiones unidimensionales (1D) y bidimensionales (2D) de datos magnetotelúricos para revelar la estructura de resistividad del subsuelo del volcán Paka en la zona central del Rift de Kenia. Cuarenta y ocho datos de sondeos magnetotelúricos que abarcan cuatro perfiles de investigación se invirtieron utilizando el esquema de inversión de Occam. El resultado justo debajo del volcán Paka muestra una capa superficial de unos 300 metros con una alta resistividad (>100Ω.m), seguida de una capa de baja resistividad (100Ω.m) posiblemente causada por minerales resistentes a altas temperaturas (230° C) clorita y epidot

Estimación de biomasa forestal mediante el uso de imágenes radar.

La importancia de la Biomasa a nivel mundial, ha llevado a que más de 130 países celebren el protocolo de Kioto sobre el cambio climático dictaminando como objetivo la reducción de las emisiones de seis gases de efecto invernadero y tres gases industriales fluorados, así como la incorporación de la fijación del CO2 como un objetivo dentro de los criterios de gestión de bosques. Entre las metodologías no destructivas para estimación de biomasa, aquí desarrolladas se describen tres técnicas que varios autores han propuesto para calcular los valores de biomasa y carbono, tal como el uso de ecuaciones alométricas por medio de la medición de variables dasométricas como el DAP, la aplicación de la teoría de huecos (v.g. DHP, TRAC), y la obtención de biomasa mediante información radar. Las imágenes radar proporcionan una clara ventaja al poder ser adquiridas en cualquier momento del día e independientemente de las condiciones climatológicas. Se han adquirido dos imágenes de sensores diferentes, tal como ALOSPALSAR que trabaja en la banda L y RADARSAT-2 que trabaja en la banda C, se aplica la metodología descrita por Saatchi et al. (2007), desarrollando los algoritmos semiempíricos propuestos para la estimación de biomasa del fuste (Ws) y biomasa de la copa (Wc), obteniendo los coeficientes a partir de información adquirida en campo. ABSTRACT The importance of biomass worldwide has led to more than 130 countries to celebrate the Kyoto Protocol, aimed at reducing emissions of six greenhouse gases and three fluorinated industrial gases, and the incorporation of the fixation of CO2 as an objective within forest management criteria. Among the non-destructive methods for estimating biomass, three techniques were developed. These have been described by some authors, as the use of allometric equations by measuring forest variables such as the DAP, the application of the Gap Theory (e.g. DHP, TRAC), as well as deriving biomass by radar information. The radar images provide a clear advantage since they can be gathered at any time of the day regardless of the weather conditions. For this purpose, two radar products have acquired from different sensors, such as ALOSPALSAR operating on L frequency band and RADARSAT-2 operating on C frequency band. The methodology applied in this work is described in Saatchi et al. (2007), that develop semiempirical algorithms for estimating stem biomass (Ws) and crown biomass (Wc). The corresponding coefficients are determined by means of regression procedures using field information derived from allometric and radiation measurements

ALOS PALSAR Products Verification

ALOS, an enhanced successor of the Japanese Earth Resources Satellite 1 (JERS-1), was launched from JAXA’s Tanegashima Space Center in January 2006. ALOS operates from a sun-synchronous orbit at 691 km, with a 46-day recurrence cycle carrying a payload of three remote sensing instruments: the Panchromatic Remote Sensing Instrument for Stereo Mapping (PRISM) , the Advanced Visible and Near-Infrared Radiometer type 2 (AVNIR-2) and the polarimetric Phased Array L-band Synthetic Aperture Radar (PALSAR). The PALSAR sensor has the capacity to operate with a wide range of off-nadir angles and resolutions in a single-, dual-, and quad-pol mode. An important contribution to the ALOS mission is the verification of PALSAR products to be distributed by the European ADEN node using the PALSAR processor developed by JAXA. Under contract to ESA/ESRIN the Microwaves and Radar Institute at the German Aerospace Center (DLR) Oberpfaffenhofen and its partners BAE Systems Advanced Technology Centre and CREASO GmbH developed a quality assessment tool (CALIX) for the verification of standard ALOS PALSAR products and also provided support for the verification for the ALOS PALSAR data quality. In addition, a set of corner reflectors and transponders have been deployed at the DLR test site Oberpfaffenhofen throughout the whole commissioning phase to allow an accurate measure of the basic product quality parameters. The quality assessment features of the CALIX software include a product reader, antenna pattern estimation, point target analysis, distributed target analysis, geometric analysis and polarimetric analysis. Results obtained with CALIX on a set of products acquired over the DLR test site will be presented in this paper. Since PALSAR is the first fully polarimetric spaceborne L-band sensor, propagation effects are important new issues to be addressed. The main challenge is to assess the influence of the ionosphere on the polarisation. Different approaches for estimating the Faraday rotation angle have been applied and the results are here compared

ALOS PALSAR Products Verification - Verification Plan

This document contains the plan for the verification campaign and the verification procedures for ALOS PALSAR products

ALOS PALSAR Products Verification - Measurement Report

This document contains a brief report about the measurements carried out during the ALOS PALSAR verification campaign

ALOS PALSAR Products Verification - CAL/VAL Report

This document reports the analysis of various ALOS PALSAR products using the CALIX quality control tool and results from the verification campaign

ALOS PALSAR Products Verification - CALIX Software User Guide

This document describes how to use the software CALIX, the External Calibration IDL project. CALIX performs all algorithmic steps necessary for absolute radiometric calibration and geometric calibration

ALOS PALSAR Products Verification - CALIX Software User Guide

This document describes how to use the software CALIX, the External Calibration IDL project. CALIX performs all algorithmic steps necessary for absolute radiometric calibration and geometric calibration