Medhavy Thankappan

Mr. Medhavy Thankappan

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2012 in Remote Sensing of Environment
Verified
Journal Article
Closed access
FLFuqin Li
Fuqin Li
DJDavid L. Jupp
David L. Jupp
MTMedhavy Thankappan
Medhavy Thankappan
LLLeo Lymburner
Leo Lymburner
NMNorman Mueller
Norman Mueller
AHAlex Held
Alex Held

2 March 2015 in International Journal of Digital Earth
Verified
Journal Article
Open access
ALAdam Lewis
Adam Lewis
LLLeo Lymburner
Leo Lymburner
MPMatthew B. J. Purss
Matthew B. J. Purss
BBBrendan Brooke
Brendan Brooke
BEBen Evans
Ben Evans
LWLesley Wyborn
Lesley Wyborn
The effort and cost required to convert satellite Earth Observation (EO) data into meaningful geophysical variables has prevented the systematic analysis of all available observations. To overcome these problems, we utilise an integrated High Performance Computing and Data environment to rapidly process, restructure and analyse the Australian Landsat data archive. In this approach, the EO data are assigned to a common grid framework that spans the full geospatial and temporal extent of the observations – the EO Data Cube. This approach is pixel-based and incorporates geometric and spectral calibration and quality assurance of each Earth surface reflectance measurement. We demonstrate the utility of the approach with rapid time-series mapping of surface water across the entire Australian continent using 27 years of continuous, 25 m resolution observations. Our preliminary analysis of the Landsat archive shows how the EO Data Cube can effectively liberate high-resolution EO data from their complex sensor-specific data structures and revolutionise our ability to measure environmental change.

1 September 2009 in Remote Sensing of Environment
Verified
Journal Article
Closed access
MWMagnus Wettle
Magnus Wettle
PDPaul J. Daniel
Paul J. Daniel
GLGraham A. Logan
Graham A. Logan
MTMedhavy Thankappan
Medhavy Thankappan

15 July 2019 in Data
Verified
Journal Article
Open access
PDF file
CTCatherine Ticehurst
Catherine Ticehurst
ZZZheng-Shu Zhou
Zheng-Shu Zhou
LALehmann Eric A.
Lehmann Eric A.
FYFang Yuan
Fang Yuan
MTMedhavy Thankappan
Medhavy Thankappan
MPMatt Paget
Matt Paget
A research alliance between the Commonwealth Scientific and Industrial Research Organization and Geoscience Australia was established in relation to Digital Earth Australia, to develop a Synthetic Aperture Radar (SAR)-enabled Data Cube capability for Australia. This project has been developing SAR analysis ready data (ARD) products, including normalized radar backscatter (gamma nought, γ0), eigenvector-based dual-polarization decomposition and interferometric coherence, all generated from the European Space Agency (ESA) Sentinel-1 interferometric wide swath mode data available on the Copernicus Australasia Regional Data Hub. These are produced using the open source ESA SNAP toolbox. The processing workflows are described, along with a comparison of the γ0 backscatter and interferometric coherence ARD produced using SNAP and the proprietary software GAMMA. This comparison also evaluates the effects on γ0 backscatter due to variations related to: Near- and far-range look angles; SNAP’s default Shuttle Radar Topography Mission (SRTM) DEM and a refined Australia-wide DEM; as well as terrain. The agreement between SNAP and GAMMA is generally good, but also presents some systematic geometric and radiometric differences. The difference between SNAP’s default SRTM DEM and the refined DEM showed a small geometric shift along the radar view direction. The systematic geometric and radiometric issues detected can however be expected to have negligible effects on analysis, provided products from the two processors and two DEMs are used separately and not mixed within the same analysis. The results lead to the conclusion that the SNAP toolbox is suitable for producing the Sentinel-1 ARD products.

1 May 2006 in International Journal of Remote Sensing
Verified
Journal Article
Closed access
AJA. T. Jones
A. T. Jones
MTMedhavy Thankappan
Medhavy Thankappan
GLG. A. Logan
G. A. Logan
JKJ. M. Kennard
J. M. Kennard
CSC. J. Smith
C. J. Smith
GLG. M. Lawrence
G. M. Lawrence
Annular‐ to crescent‐shaped low backscatter SAR slicks over carbonate reefs and shoals in the Timor Sea that exhibit ‘feathering’, and within the coral spawning period for the region, are interpreted to be caused by a coral spawn event. This represents the first time that such an event has been interpreted through satellite remote sensing. Additionally, ocean current data and detailed swath bathymetry of the sea floor to the south‐east of the coral spawn slicks suggest that elongate repeating slicks in this area are related to current flow over submarine channels. Assessment of these slicks in association with ancillary data, such as bathymetry, current velocities, weather, and timing of SAR acquisition allow a more robust interpretation of their origins. Through differentiating coral spawn and bathymetric slicks from oil and other biological slicks in shallow carbonate systems, such as the Timor Sea, petroleum and environmental assessments for these areas can be improved.

1 July 2013
Verified
Conference Paper
Closed access
MGMatthew Garthwaite
Matthew Garthwaite
MTMedhavy Thankappan
Medhavy Thankappan
MWM. L. Williams
M. L. Williams
SNS. Nancarrow
S. Nancarrow
AHA. Hislop
A. Hislop
JDJ. Dawson
J. Dawson
Geoscience Australia is implementing the geospatial component of the Australian Geophysical Observing System (AGOS). AGOS infrastructure will include a network of radar corner reflectors, in addition to a geodetic ground mark network for monitoring ground deformation in Australia. In this paper we describe the design of radar corner reflectors for deformation studies and calibration of Synthetic Aperture Radar (SAR) sensors. Through a prototyping campaign in 2013 we will seek a single reflector design that can be used for deformation and calibration studies using X- and C-band SAR sensors. Prototyping will involve precise determination of reflector radar cross section at an outdoor radar test range and a temporary field deployment in the Canberra region during which X- and C-band data acquisitions will be made from orbiting SAR satellites. We also outline plans to deploy corner reflectors in the Surat Basin of Queensland to monitor ground deformation induced by coal seam gas (CSG) extraction.