scholarly journals TanDEM-X PolarDEM 90 m of Antarctica: Generation and error characterization

2021 ◽  
Author(s):  
Birgit Wessel ◽  
Martin Huber ◽  
Christian Wohlfart ◽  
Adina Bertram ◽  
Nicole Osterkamp ◽  
...  
Keyword(s):  
Ice Cloud ◽  
Amplitude Data ◽  
Open Sea ◽  
Digital Elevation ◽  
X Band ◽  
Error Characterization ◽  
Antarctic Continent ◽  
Absolute Height ◽  
Set Up ◽  
Elevation Model

Abstract. We present the generation and validation of an updated version of the TanDEM-X Digital Elevation Model (DEM) of Antarctica: the TanDEM-X PolarDEM 90 m of Antarctica. Improvements compared to the global TanDEM-X DEM version include filling of gaps with newer acquisitions, interpolating of smaller voids, smoothing of noisy areas and replacing frozen or open sea areas with geoid undulations. For the latter, a new semi-automatic editing approach allowed the delineation of the coastline from DEM and amplitude data. Finally, the DEM was transformed into the cartographic Antarctic Polar Stereographic projection with a homogeneous metric spacing in northing and easting of 90 meters. As X-Band synthetic aperture radar (SAR) penetrates the snow and ice pack by several meters a new concept for absolute height adjustment was set up that relies on areas with stable penetration conditions and on ICESat (Ice, Cloud, and land Elevation Satellite) elevations. After DEM generation and editing, a sophisticated height error characterization of the whole Antarctic continent with ICESat and IceBridge data was carried out and a validation over blue ice achieved a mean vertical height error of just −0.3 m ± 2.5 m standard deviation. The filled and edited Antarctic TanDEM-X PolarDEM 90 m is outstanding due to its accuracy, homogeneity and coverage completeness. It is freely available for scientific purposes and provides a high-resolution dataset as basis for polar research, such as ice velocity, mass balance estimation or ortho-rectification.

scholarly journals TanDEM-X PolarDEM 90 m of Antarctica: generation and error characterization

2021 ◽  
Vol 15 (11) ◽  
pp. 5241-5260
Author(s):  
Birgit Wessel ◽  
Martin Huber ◽  
Christian Wohlfart ◽  
Adina Bertram ◽  
Nicole Osterkamp ◽  
...  
Keyword(s):  
Data Set ◽  
High Resolution Data ◽  
Ice Cloud ◽  
Amplitude Data ◽  
Open Sea ◽  
Digital Elevation ◽  
Error Characterization ◽  
Antarctic Continent ◽  
Set Up ◽  
Elevation Model

Abstract. We present the generation and validation of an updated version of the TanDEM-X digital elevation model (DEM) of Antarctica: the TanDEM-X PolarDEM 90 m of Antarctica. Improvements compared to the global TanDEM-X DEM version comprise filling gaps with newer bistatic synthetic aperture radar (SAR) acquisitions of the TerraSAR-X and TanDEM-X satellites, interpolation of smaller voids, smoothing of noisy areas, and replacement of frozen or open sea areas with geoid undulations. For the latter, a new semi-automatic editing approach allowed for the delineation of the coastline from DEM and amplitude data. Finally, the DEM was transformed into the cartographic Antarctic Polar Stereographic projection with a homogeneous metric spacing in northing and easting of 90 m. As X-band SAR penetrates the snow and ice pack by several meters, a new concept for absolute height adjustment was set up that relies on areas with stable penetration conditions and on ICESat (Ice, Cloud, and land Elevation Satellite) elevations. After DEM generation and editing, a sophisticated height error characterization of the whole Antarctic continent with ICESat data was carried out, and a validation over blue ice achieved a mean vertical height error of just −0.3 m ± 2.5 m standard deviation. The filled and edited Antarctic TanDEM-X PolarDEM 90 m is outstanding due to its accuracy, homogeneity, and coverage completeness. It is freely available for scientific purposes and provides a high-resolution data set as basis for polar research, such as ice velocity, mass balance estimation, or orthorectification.

scholarly journals A NEW HIGH-RESOLUTION ELEVATION MODEL OF GREENLAND DERIVED FROM TANDEM-X

2016 ◽  
Vol III-7 ◽  
pp. 9-16 ◽  
Author(s):  
B. Wessel ◽  
A. Bertram ◽  
A. Gruber ◽  
S. Bemm ◽  
S. Dech
Keyword(s):  
High Resolution ◽  
The Arctic ◽  
Coastal Regions ◽  
Ice Cloud ◽  
Full Coverage ◽  
Ground Control Points ◽  
Digital Elevation ◽  
X Band ◽  
Elevation Model ◽  
Elevation Measurement

In this paper we present for the first time the new digital elevation model (DEM) for Greenland produced by the TanDEM-X (TerraSAR add-on for digital elevation measurement) mission. The new, full coverage DEM of Greenland has a resolution of 0.4 arc seconds corresponding to 12 m. It is composed of more than 7.000 interferometric synthetic aperture radar (InSAR) DEM scenes. X-Band SAR penetrates the snow and ice pack by several meters depending on the structures within the snow, the acquisition parameters, and the dielectricity constant of the medium. Hence, the resulting SAR measurements do not represent the surface but the elevation of the mean phase center of the backscattered signal. Special adaptations on the nominal TanDEM-X DEM generation are conducted to maintain these characteristics and not to raise or even deform the DEM to surface reference data. For the block adjustment, only on the outer coastal regions ICESat (Ice, Cloud, and land Elevation Satellite) elevations as ground control points (GCPs) are used where mostly rock and surface scattering predominates. Comparisons with ICESat data and snow facies are performed. In the inner ice and snow pack, the final X-Band InSAR DEM of Greenland lies up to 10 m below the ICESat measurements. At the outer coastal regions it corresponds well with the GCPs. The resulting DEM is outstanding due to its resolution, accuracy and full coverage. It provides a high resolution dataset as basis for research on climate change in the arctic.

scholarly journals A NEW HIGH-RESOLUTION ELEVATION MODEL OF GREENLAND DERIVED FROM TANDEM-X

2016 ◽  
Vol III-7 ◽  
pp. 9-16 ◽  
Author(s):  
B. Wessel ◽  
A. Bertram ◽  
A. Gruber ◽  
S. Bemm ◽  
S. Dech
Keyword(s):  
High Resolution ◽  
The Arctic ◽  
Coastal Regions ◽  
Ice Cloud ◽  
Full Coverage ◽  
Ground Control Points ◽  
Digital Elevation ◽  
X Band ◽  
Elevation Model ◽  
Elevation Measurement

In this paper we present for the first time the new digital elevation model (DEM) for Greenland produced by the TanDEM-X (TerraSAR add-on for digital elevation measurement) mission. The new, full coverage DEM of Greenland has a resolution of 0.4 arc seconds corresponding to 12 m. It is composed of more than 7.000 interferometric synthetic aperture radar (InSAR) DEM scenes. X-Band SAR penetrates the snow and ice pack by several meters depending on the structures within the snow, the acquisition parameters, and the dielectricity constant of the medium. Hence, the resulting SAR measurements do not represent the surface but the elevation of the mean phase center of the backscattered signal. Special adaptations on the nominal TanDEM-X DEM generation are conducted to maintain these characteristics and not to raise or even deform the DEM to surface reference data. For the block adjustment, only on the outer coastal regions ICESat (Ice, Cloud, and land Elevation Satellite) elevations as ground control points (GCPs) are used where mostly rock and surface scattering predominates. Comparisons with ICESat data and snow facies are performed. In the inner ice and snow pack, the final X-Band InSAR DEM of Greenland lies up to 10 m below the ICESat measurements. At the outer coastal regions it corresponds well with the GCPs. The resulting DEM is outstanding due to its resolution, accuracy and full coverage. It provides a high resolution dataset as basis for research on climate change in the arctic.

scholarly journals Validation of SRTM X Band DEM over Himalayan Mountain

2014 ◽  
Vol XL-4 ◽  
pp. 71-74 ◽  
Author(s):  
R. D. Gupta ◽  
M. K. Singh ◽  
S. Snehmani ◽  
A. Ganju
Keyword(s):  
High Resolution ◽  
Accuracy Assessment ◽  
Mountainous Regions ◽  
Digital Elevation ◽  
X Band ◽  
Global Positioning ◽  
Himalayan Mountain ◽  
Elevation Model ◽  
First Time ◽  
The Himalaya

The present research study assesses the accuracy of the SRTM X band DEM with respect to high accuracy photogrammetric Digital Elevation Model (DEM) for parts of the Himalaya. The high resolution DEM was generated for Manali and nearby areas using digital aerial photogrammetric survey data of 40 cm Ground Sampling Distance (GSD) captured through airborne ADS80 pushbroom camera for the first time in Indian Himalayan context. This high resolution DEM was evaluated with Differential Global Positioning System (DGPS) points for accuracy assessment. The ADS80-DEM gave root mean square error (RMSE) of ~<1m and linear error of 1.60 m at 90 % confidence (LE 90) when compared with the DGPS points. The overall RMSE in vertical accuracy was 73.36 m while LE 90 was 75.20 m with regard to ADS80 DEM. It is observed that the accuracy achieved for part of Himalayan region is far less as compared to the values officially claimed. Thus, SRTM X band DEM should be used with due care in mountainous regions of Himalaya.

scholarly journals ICESAT VALIDATION OF TANDEM-X I-DEMS OVER THE UK

2016 ◽  
Vol XLI-B4 ◽  
pp. 129-136 ◽  
Author(s):  
L. Feng ◽  
J.-P. Muller
Keyword(s):  
Slope Aspect ◽  
Surface Slope ◽  
Grid Spacing ◽  
Digital Elevation ◽  
X Band ◽  
Elevation Data ◽  
Vertical Accuracy ◽  
Elevation Model ◽  
The Uk ◽  
Interferometric Sar

From the latest TanDEM-X mission (bistatic X-Band interferometric SAR), globally consistent Digital Elevation Model (DEM) will be available from 2017, but their accuracy has not yet been fully characterised. This paper presents the methods and implementation of statistical procedures for the validation of the vertical accuracy of TanDEM-X iDEMs at grid-spacing of approximately 12.5&thinsp;m, 30&thinsp;m and 90&thinsp;m based on processed ICESat data over the UK in order to assess their potential extrapolation across the globe. The accuracy of the TanDEM-X iDEM in UK was obtained as follows: against ICESat GLA14 elevation data, TanDEM-X iDEM has &minus;0.028±3.654&thinsp;m over England and Wales and 0.316&thinsp;±&thinsp;5.286&thinsp;m over Scotland for 12&thinsp;m, &minus;0.073&thinsp;±&thinsp;6.575&thinsp;m for 30&thinsp;m, and 0.0225&thinsp;±&thinsp;9.251&thinsp;m at 90&thinsp;m. Moreover, 90&thinsp;% of all results at the three resolutions of TanDEM-X iDEM data (with a linear error at 90&thinsp;% confidence level) are below 16.2&thinsp;m. These validation results also indicate that derivative topographic parameters (slope, aspect and relief) have a strong effect on the vertical accuracy of the TanDEM-X iDEMs. In high-relief and large slope terrain, large errors and data voids are frequent, and their location is strongly influenced by topography, whilst in the low- to medium-relief and low slope sites, errors are smaller. ICESat derived elevations are heavily influenced by surface slope within the 70&thinsp;m footprint as well as there being slope dependent errors in the TanDEM-X iDEMs.

scholarly journals VALIDATION OF "AW3D" GLOBAL DSM GENERATED FROM ALOS PRISM

2016 ◽  
Vol III-4 ◽  
pp. 25-31 ◽  
Author(s):  
Junichi Takaku ◽  
Takeo Tadono ◽  
Ken Tsutsui ◽  
Mayumi Ichikawa
Keyword(s):  
Ice Cloud ◽  
Ground Control Points ◽  
Digital Elevation ◽  
The Status ◽  
Stereoscopic Observation ◽  
Data Coverage ◽  
Elevation Model ◽  
Image Archives ◽  
Global Datasets ◽  
Global Data

Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), one of onboard sensors carried by Advanced Land Observing Satellite (ALOS), was designed to generate worldwide topographic data with its optical stereoscopic observation. It has an exclusive ability to perform a triplet stereo observation which views forward, nadir, and backward along the satellite track in 2.5 m ground resolution, and collected its derived images all over the world during the mission life of the satellite from 2006 through 2011. A new project, which generates global elevation datasets with the image archives, was started in 2014. The data is processed in unprecedented 5 m grid spacing utilizing the original triplet stereo images in 2.5 m resolution. As the number of processed data is growing steadily so that the global land areas are almost covered, a trend of global data qualities became apparent. This paper reports on up-to-date results of the validations for the accuracy of data products as well as the status of data coverage in global areas. The accuracies and error characteristics of datasets are analyzed by the comparison with existing global datasets such as Ice, Cloud, and land Elevation Satellite (ICESat) data, as well as ground control points (GCPs) and the reference Digital Elevation Model (DEM) derived from the airborne Light Detection and Ranging (LiDAR).

scholarly journals Sub-Canopy Topography Estimation from TanDEM-X DEM by Fusing ALOS-2 PARSAR-2 InSAR Coherence and GEDI Data

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7304
Author(s):  
Pengyuan Tan ◽  
Jianjun Zhu ◽  
Haiqiang Fu ◽  
Changcheng Wang ◽  
Zhiwei Liu ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Main Idea ◽  
Coherent Scattering ◽  
Ecosystem Dynamics ◽  
Forest Height ◽  
Digital Elevation ◽  
X Band ◽  
Dem Accuracy ◽  
Study Sites ◽  
Elevation Model

This paper develops a framework for extracting sub-canopy topography from the TanDEM-X digital elevation model (DEM) by fusing ALOS-2 PARSAR-2 interferometric synthetic aperture radar (InSAR) coherence and Global Ecosystem Dynamics Investigation (GEDI) data. The main idea of this method is to estimate the forest height signals caused by the limited penetration of the X-band into the canopy from the TanDEM-X DEM. To achieve this goal, a spaceborne repeat-pass InSAR coherent scattering model is first used to estimate the forest height by the ALOS-2 PARSAR-2 InSAR coherence (APIC), taking the GEDI canopy height as the reference. Then, a linear regression model of the TanDEM-X DEM Vegetation Bias (TDVB) depending on the forest height and the fraction of vegetation cover (FVC) is established and used to estimate the sub-canopy topography. The proposed method was validated by the data of the Amazon rainforest and a boreal forest in Canada. The results showed that the proposed method extracted the sub-canopy topography at the study sites in the tropical forest and boreal forest with the root mean square error of 4.0 m and 6.33 m, respectively, and improved the TanDEM-X DEM accuracy by 75.7% and 39.7%, respectively.

scholarly journals High-Resolution Elevation Model of Lop Nur Playa Derived from TanDEM-X

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yuyang Geng ◽  
Yun Shao ◽  
Tingting Zhang ◽  
Huaze Gong ◽  
Lan Yang
Keyword(s):  
High Resolution ◽  
Least Square ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Relative Height ◽  
Laser Altimeter ◽  
Ice Cloud ◽  
Digital Elevation ◽  
Lop Nur ◽  
Elevation Model

In this paper, a digital elevation model (DEM) was produced for Lop Nur playa produced with the data from TanDEM-X mission. The spatial resolution is 10 m. It covers an area of 38,000 km2 for orthometric height from 785 m to 900 m above sea level, which is composed of 42 interferometric synthetic aperture radar (InSAR) scenes. A least-square adjustment approach was used to reduce the systematic errors in each DEM scene. The DEM produced was validated with data from other sensors including Ice, Cloud, and land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) and aerial Structure-from-Motion (SfM) DEM. The results show that global elevation root mean square error to GLAS is 0.57 m, and the relative height error to SfM DEM in complicated terrain is 3 m. The excellent height reliability of TanDEM InSAR DEM in Lop region was proved in this paper. A reliable high-resolution basic topographic dataset for researches of Lop Nur was provided.

scholarly journals TANDEM-X MISSION STATUS, PRODUCTS AND PERSPECTIVES

2018 ◽  
Vol XLII-1 ◽  
pp. 45-49 ◽  
Author(s):  
J. Böer ◽  
C. Wecklich ◽  
M. Bachmann ◽  
S. Buckreuss ◽  
P. Rizzoli ◽  
...  
Keyword(s):  
Formation Flying ◽  
Remote Sensing Data ◽  
Radar Data ◽  
The Earth ◽  
Digital Elevation ◽  
Commercial Market ◽  
Absolute Height ◽  
Data Coverage ◽  
Land Surfaces ◽  
Elevation Model

<p><strong>Abstract.</strong> TanDEM-X is an innovative single-pass interferometric radar mission, which is comprised of two formation flying satellites. The TerraSAR-X (TSX) satellite was launched on June 15th 2007, and its almost identically constructed twin satellite TanDEM-X (TDX) was launched on 21st of June 2010. Together they supply high-quality radar data in order to serve two main mission goals: Scientific observation of the Earth and provision of remote sensing data for the commercial market (TerraSAR-X mission), and the generation of a global digital elevation model (DEM) of the Earth’s surface (TanDEM-X mission). Between December 2010 and early 2015, radar data of all land surfaces has been acquired and as of September 2016 the final TanDEM-X DEM dataset has been available. This paper provides a final quality assessment of the TanDEM-X global DEM products with respect to the relative and absolute height accuracy and data coverage both at the global and geocell level. In addition, an overview on current mission status is given and new DEM products, which are currently in the scope of the TanDEM-X mission, are described.</p>

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