Contribution of L-band SAR to systematic global mangrove monitoring

2014 ◽  
Vol 65 (7) ◽  
pp. 589 ◽  
Author(s):  
Richard Lucas ◽  
Lisa-Maria Rebelo ◽  
Lola Fatoyinbo ◽  
Ake Rosenqvist ◽  
Takuya Itoh ◽  
...  
Keyword(s):  
Policy Development ◽  
Sensor Data ◽  
Global Changes ◽  
Alos Palsar ◽  
Laser Altimeter ◽  
Mangrove Species ◽  
Shuttle Radar Topographic Mission ◽  
International Policies ◽  
The Status ◽  
L Band

Information on the status of and changes in mangroves is required for national and international policy development, implementation and evaluation. To support these requirements, a component of the Japan Aerospace Exploration Agency’s (JAXA) Kyoto and Carbon (K&C) initiative has been to design and develop capability for a Global Mangrove Watch (GMW) that routinely monitors and reports on local to global changes in the extent of mangroves, primarily on the basis of observations by Japanese L-band synthetic aperture radar (SAR). The GMW aims are as follows: (1) to map progression of change within or from existing (e.g. Landsat-derived) global baselines of the extent of mangroves by comparing advanced land-observing satellite 2 (ALOS-2) phased array L-band SAR 2 (PALSAR-2) data from 2014 with that acquired by the Japanese earth resources satellite (JERS-1) SAR (1992–1998) and ALOS PALSAR (2006–2011); (2) to quantify changes in the structure and associated losses and gains of carbon on the basis of canopy height and above-ground biomass (AGB) estimated from the shuttle radar topographic mission (SRTM; acquired 2000), the ice, cloud and land-elevation satellite (ICESAT) geoscience laser altimeter system (GLAS; 2003–2010) and L-band backscatter data; (3) to determine likely losses and gains of tree species diversity through reference to International Union for the Conservation of Nature (IUCN) global thematic layers on the distribution of mangrove species; and (4) to validate maps of changes in the extent of mangroves, primarily through comparison with dense time-series of Landsat sensor data and to use these same data to describe the causes and consequences of change. The paper outlines and justifies the techniques being implemented and the role that the GMW might play in supporting national and international policies that relate specifically to the long-term conservation of mangrove ecosystems and the services they provide to society.

scholarly journals Mapping Woody Volume of Mediterranean Forests by Using SAR and Machine Learning: A Case Study in Central Italy

2021 ◽  
Vol 13 (4) ◽  
pp. 809
Author(s):  
Emanuele Santi ◽  
Marta Chiesi ◽  
Giacomo Fontanelli ◽  
Alessandro Lapini ◽  
Simonetta Paloscia ◽  
...  
Keyword(s):  
Preliminary Investigation ◽  
Central Italy ◽  
Forest Biomass ◽  
Ground Truth ◽  
National Forest Inventory ◽  
Mediterranean Forests ◽  
Alos Palsar ◽  
Laser Altimeter ◽  
Envisat Asar ◽  
L Band

In this paper, multi-frequency synthetic aperture radar (SAR) data at L- and C-bands (ALOS PALSAR and Envisat/ASAR) were used to estimate forest biomass in Tuscany, in Central Italy. The ground measurements of woody volume (WV, in m3/ha), which can be considered as a proxy of forest biomass, were retrieved from the Italian National Forest Inventory (NFI). After a preliminary investigation to assess the sensitivity of backscatter at C- and L-bands to forest biomass, an approach based on an artificial neural network (ANN) was implemented. The ANN was trained using the backscattering coefficient at L-band (ALOS PALSAR, HH and HV polarization) and C-band (Envisat ASAR in HH polarization) as inputs. Spatially distributed WV values for the entire test area were derived by the integration (fusion) of a canopy height map derived from the Ice, Cloud, and Land Elevation Geoscience Laser Altimeter System (ICESat GLAS) and the NFI data, in order to build a significant ground truth dataset for the training stage. The analysis of the backscattering sensitivity to WV showed a moderate correlation at L-band and was almost negligible at C-band. Despite this, the ANN algorithm was able to exploit the synergy of SAR frequencies and polarizations, estimating WV with average Pearson’s correlation coefficient (R) = 0.96 and root mean square error (RMSE) ≃ 39 m3/ha when applied to the test dataset and average R = 0.86 and RMSE ≃ 75 m3/ha when validated on the direct measurements from the NFI. Considering the heterogeneity of the scenario (Mediterranean mixed forests in hilly landscape) and the small amount of available ground measurements with respect to the spatial variability of different plots, the obtained results can be considered satisfactory. Moreover, the successful use of WV from global maps for implementing the algorithm suggests the possibility to apply the algorithm to wider areas or even to global scales.

scholarly journals A Structural Classification of Australian Vegetation Using ICESat/GLAS, ALOS PALSAR, and Landsat Sensor Data

2019 ◽  
Vol 11 (2) ◽  
pp. 147 ◽  
Author(s):  
Peter Scarth ◽  
John Armston ◽  
Richard Lucas ◽  
Peter Bunting
Keyword(s):  
National Level ◽  
Airborne Lidar ◽  
Ecosystem Dynamics ◽  
Sensor Data ◽  
Vegetation Density ◽  
Structural Classification ◽  
Alos Palsar ◽  
Laser Altimeter ◽  
Waveform Data ◽  
Vegetation Height

Australia has historically used structural descriptors of height and cover to characterize, differentiate, and map the distribution of woody vegetation across the continent but no national satellite-based structural classification has been available. In this study, we present a new 30-m spatial resolution reference map of Australian forest and woodland structure (height and cover), with this generated by integrating Landsat Thematic Mapper (TM) and Enhanced TM, Advanced Land Observing Satellite (ALOS) Phased Arrayed L-band Synthetic Aperture Radar (PALSAR) and Ice, Cloud, and land Elevation (ICESat),and Geoscience Laser Altimeter System (GLAS) data. ALOS PALSAR and Landsat-derived Foliage Projective Cover (FPC) were used to segment and classify the Australian landscape. Then, from intersecting ICESat waveform data, vertical foliage profiles and height metrics (e.g., 95% percentile height, mean height and the height to maximum vegetation density) were extracted for each of the classes generated. Within each class, and for selected areas, the variability in ICESat profiles was found to be similar with differences between segments of the same class attributed largely to clearance or disturbance events. ICESat metrics and profiles were then assigned to all remaining segments across Australia with the same class allocation. Validation against airborne LiDAR for a range of forest structural types indicated a high degree of correspondence in estimated height measures. On this basis, a map of vegetation height was generated at a national level and was combined with estimates of cover to produce a revised structural classification based on the scheme of the Australian National Vegetation Information System (NVIS). The benefits of integrating the three datasets for segmenting and classifying the landscape and retrieving biophysical attributes was highlighted with this leading the way for future mapping using ALOS-2 PALSAR-2, Landsat/Sentinel-2, Global Ecosystem Dynamics Investigation (GEDI), and ICESat-2 LiDAR data. The ability to map across large areas provides considerable benefits for quantifying carbon dynamics and informing on biodiversity metrics.

scholarly journals Multi-Sensor InSAR Analysis of Progressive Land Subsidence over the Coastal City of Urayasu, Japan

2018 ◽  
Vol 10 (8) ◽  
pp. 1304 ◽  
Author(s):  
Yusupujiang Aimaiti ◽  
Fumio Yamazaki ◽  
Wen Liu
Keyword(s):  
Synthetic Aperture Radar ◽  
Survey Data ◽  
Land Subsidence ◽  
Ground Deformation ◽  
Tohoku Earthquake ◽  
Synthetic Aperture ◽  
Alos Palsar ◽  
The 2011 Tohoku Earthquake ◽  
L Band ◽  
Aperture Radar

In earthquake-prone areas, identifying patterns of ground deformation is important before they become latent risk factors. As one of the severely damaged areas due to the 2011 Tohoku earthquake in Japan, Urayasu City in Chiba Prefecture has been suffering from land subsidence as a part of its land was built by a massive land-fill project. To investigate the long-term land deformation patterns in Urayasu City, three sets of synthetic aperture radar (SAR) data acquired during 1993–2006 from European Remote Sensing satellites (ERS-1/-2 (C-band)), during 2006–2010 from the Phased Array L-band Synthetic Aperture Radar onboard the Advanced Land Observation Satellite (ALOS PALSAR (L-band)) and from 2014–2017 from the ALOS-2 PALSAR-2 (L-band) were processed by using multitemporal interferometric SAR (InSAR) techniques. Leveling survey data were also used to verify the accuracy of the InSAR-derived results. The results from the ERS-1/-2, ALOS PALSAR and ALOS-2 PALSAR-2 data processing showed continuing subsidence in several reclaimed areas of Urayasu City due to the integrated effects of numerous natural and anthropogenic processes. The maximum subsidence rate of the period from 1993 to 2006 was approximately 27 mm/year, while the periods from 2006 to 2010 and from 2014 to 2017 were approximately 30 and 18 mm/year, respectively. The quantitative validation results of the InSAR-derived deformation trend during the three observation periods are consistent with the leveling survey data measured from 1993 to 2017. Our results further demonstrate the advantages of InSAR measurements as an alternative to ground-based measurements for land subsidence monitoring in coastal reclaimed areas.

scholarly journals The Potential Scattering Model for Oil Palm Phenology Based on Spaceborne X-, C-, and L-Band Polarimetric SAR Imaging

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Soni Darmawan ◽  
Ita Carolita ◽  
Rika Hernawati ◽  
Dede Dirgahayu ◽  
Agustan ◽  
...  
Keyword(s):  
Nonlinear Model ◽  
Oil Palm ◽  
Potential Scattering ◽  
Radiometric Calibration ◽  
Polarimetric Radar ◽  
Polarimetric Sar ◽  
Alos Palsar ◽  
Scattering Model ◽  
Sar Imaging ◽  
L Band

Information about oil palm phenology is required for oil palm plantation management, but using spaceborne polarimetric radar imagery remains challenging. However, spaceborne polarimetric radar on X-, C-, and L-band is promising on structure vegetation and cloud area. This study investigates the scattering model of oil palm phenology based on spaceborne X-, C-, and L-band polarimetric Synthetic Aperture Radar (SAR) imaging. The X-, C-, and L-band polarimetric SAR are derived from spaceborne of TerraSAR-X, Sentinel-1A, and ALOS PALSAR 2. Study area is located in oil palm plantations, Asahan District, North Sumatra, Indonesia. The methodology includes data collection, preprocessing, radiometric calibration, speckle filtering, terrain correction, extraction of scattering value, and development of scattering model of oil palm phenology. The results showed different scattering characteristics for the X-, C-, and L-band polarimetric SAR of oil palm for age and found the potential of the scattering model for oil palm phenology based on the X-band on HH polarization that showed a nonlinear model with R 2 = 0.65 . The C-band on VH and VV polarization showed a nonlinear model with R 2 = 0.56 and R 2 = 0.89 . The L-band on HV and HH polarization showed a logarithmic model with R 2 = 0.50 and R 2 = 0.51 . In this case, the most potential of the scattering model of oil palm phenology based on R 2 is using C-band on VV polarization. However, the scattering model based on X-, C-, and L-band is potentially to be used and applied to identify the phenology of oil palm in Indonesia, which is the main parameter in yield estimation. For the future phenology model needs to improve accuracy by integrating multisensors, including different wavelengths on optical and microwave sensors and more in situ data.

scholarly journals Population status of Heritiera fomes Buch.-Ham., a threatened species from Mahanadi Mangrove Wetland, India

2021 ◽  
Vol 13 (12) ◽  
pp. 19791-19798
Author(s):  
Sudam Charan Sahu ◽  
Manas Ranjan Mohanta ◽  
N.H. Ravindranath
Keyword(s):  
Natural Populations ◽  
P Value ◽  
Population Status ◽  
Mangrove Species ◽  
Sea Levels ◽  
Excoecaria Agallocha ◽  
Mangrove Wetland ◽  
Heritiera Fomes ◽  
The Status ◽  
Rising Sea Levels

Heritiera fomes Buch.-Ham. is assessed as an endangered mangrove species by IUCN, and information on population status is lacking. The present study assesses the status of H. fomes in Mahanadi Mangrove Wetland on the east coast of India. Three forest blocks were selected and sampled for this study. Among these, the mean girth at breast height (GBH) of H. fomes was the highest in Hetamundia (HD) forest block. GBH of H. fomes was inversely proportional to the cumulative disturbance index (R2= 0.7244, p value <0.005). The relative density was maximum for H. fomes (56%) at Bhitarkharnasi (BK), and for Excoecaria agallocha at Hetamundia (HD; 35%) & Kansaridia (KD; 54%), respectively. Excoecaria agallocha is a dominant species possibly impacting natural populations of H. fomes. Climate change and rising sea levels may also negatively affect the existence of this species. Therefore, appropriate strategies should be taken for conservation of this globally threatened mangrove species prior to its extinction.

scholarly journals INSAR COHERENCE AND POLARIMETRIC PARAMETERS BASED CHARACTERIZATION OF FLOODED AREA – CASE STUDY OF A NATURAL WORLD HERITAGE SITE KAZIRANGA NATIONAL PARK

2018 ◽  
Vol IV-5 ◽  
pp. 265-272
Author(s):  
A. S. Dini Das ◽  
S. Kumar ◽  
A. Babu ◽  
P. K. Thakur
Keyword(s):  
National Park ◽  
World Heritage ◽  
Natural World ◽  
World Heritage Site ◽  
Alos Palsar ◽  
Kaziranga National Park ◽  
Heritage Site ◽  
L Band ◽  
Flooded Area

<p><strong>Abstract.</strong> Flood is a major threat to one of the UNESCO world heritage site of India-The Kaziranga National Park. Every year during the monsoon several hundreds of animals which include globally threatened species like single-horned Indian Rhinoceros of Kaziranga lose their lives due to the flood. The Synthetic Aperture Radar (SAR) can be used to monitoring the flood than the optical remote sensors because of their capability of all-weather and time-independent operability. The microwave L band is most suitable for the flood studies because of its higher penetration capability even through the vegetation. In this study, the advantages of SAR polarimetry and Interferometry of multi-temporal L band dual-pol data of ALOS PALSAR 2 were used to characterize the flooded area and also to monitor the flood extent. The H/ A/ Alpha decomposition gives a better characterization of the flooded area. The separability analysis is done with a different combination of decomposition parameters and the parameters having high-class separability between water and non-water areas are selected. Polarimetric classification using Random forest classifier is done on these selected decomposition parameters to classify the study into water and non-water areas. The classified images of different months before, during and after the flood time is used to quantitatively estimate the flood extent and for time series analysis. The Interferometric SAR coherence images along with the backscatter images are used to generate the RGB composites which also gives times series information on the flood impact.</p>

scholarly journals Socio-economic burden of pulmonary hypertension: relevance of assessment in Russia and the world

2020 ◽  
Vol 92 (3) ◽  
pp. 125-131
Author(s):  
V. D. Zakiev ◽  
A. D. Gvozdeva ◽  
T. V. Martynyuk
Keyword(s):  
Pulmonary Hypertension ◽  
Economic Burden ◽  
Policy Development ◽  
Premature Death ◽  
Legal Regulation ◽  
Regional Budget ◽  
The World ◽  
The Status ◽  
Life Threatening ◽  
Drug Provision

Pulmonary hypertension (PH) is a progressive disease which is characterized with the increase of pulmonary artery pressure and pulmonary vascular resistance. Such condition leads to right ventricular heart failure and premature death of patients. Pulmonary arterial hypertension (PAH) has the status of an orphan disease. However in Russia only idiopathic PH is included in the list of 24 life-threatening and chronic progressive rare diseases, while other forms of PH are not in it. Inclusion in this list guarantees drug provision for patients at the expense of the regional budget, while patients with other forms of PH can rely on free medication only if they have a disability. The lack of criteria for revising this list as well as the imperfection of legal regulation in the field of drug support for orphan diseases leads to high disability, a significant decrease in the duration and quality of life of patients with PH. As part of a multicriteria approach, a clinical and economic analysis of the disease burden can be one of the tools for policy development and decision-making on the distribution of funding in the healthcare. The article provides a review of the economic burden of various forms of PH in the world.

scholarly journals Women’s entrepreneurship policy: a 13 nation cross-country comparison

2017 ◽  
Vol 9 (3) ◽  
pp. 206-228 ◽  
Author(s):  
Colette Henry ◽  
Barbara Orser ◽  
Susan Coleman ◽  
Lene Foss
Keyword(s):  
Policy Development ◽  
Methodological Approach ◽  
Future Research ◽  
Entrepreneurship Policy ◽  
Policy Makers ◽  
Content Type ◽  
Policy Practice ◽  
Women’S Entrepreneurship ◽  
The Status ◽  
Women's Entrepreneurship

Purpose Government attention to women’s entrepreneurship has increased in the past two decades; however, there are few cross-cultural studies to inform policy development. This paper aims to draw on gender and institutional theory to report on the status of female-focused small and medium-sized enterprises/entrepreneurship policies and to ask how – and to what extent – do women’s entrepreneurship policies differ among countries? Design/methodology/approach A common methodological approach is used to identify gaps in the policy-practice nexus. Findings The study highlights countries where policy is weak but practice is strong, and vice versa. Research limitations/implications The study’s data were restricted to policy documents and observations of practices and initiatives on the ground. Practical implications The findings have implications for policy makers in respect of support for women’s entrepreneurship. Recommendations for future research are advanced. Originality/value The paper contributes to extant knowledge and understanding about entrepreneurship policy, specifically in relation to women’s entrepreneurship. It is also one of the few studies to use a common methodological approach to explore and compare women’s entrepreneurship policies in 13 countries.

The potential of using Sentinel-1 and ALOS PALSAR-2 data for characterizing West Siberian lake ice backscatter anomalies

2021 ◽  
Author(s):  
Georg Pointner ◽  
Annett Bartsch
Keyword(s):  
Thick Layer ◽  
Arctic Lakes ◽  
The Arctic ◽  
Late Winter ◽  
Alos Palsar ◽  
Lake Ice ◽  
In Situ Data ◽  
L Band ◽  
Ice Regime ◽  
Sar Imagery

&lt;p&gt;Millions of lakes and ponds occupy large areas of the Arctic discontinuous and continuous permafrost zones. During most of the year, the surfaces of these lakes remain covered by a thick layer of ice. Synthetic Aperture Radar (SAR) data have shown to be useful for studying the ice on Arctic lakes, especially for monitoring lake ice phenology and the grounding state of the ice (ice frozen to the lakebed versus floating lake ice). Significant backscatter is often observed from the floating ice regime in C-band due to scattering on a rough ice-water interface.&lt;/p&gt;&lt;p&gt;Recent research has revealed features of anomalously low backscatter in Sentinel-1 C-band SAR imagery on some of the West Siberian lakes that likely belong to the floating ice regime. These anomalies are characterized by prominent shapes and sizes and seem to expand throughout late winter and/or spring. It is currently assumed that some of these features are related to strong emissions of natural gas (methane from hydrocarbon reservoirs), making it important to assess their origin in detail and understand the associated mechanisms. However, in-situ data are still missing.&lt;/p&gt;&lt;p&gt;Here, we assess the potential of the combined use of C-band Sentinel-1 (freely available) and L-band ALOS PALSAR-2 data&amp;#160; (available through JAXA PI agreement #3068002) to study the backscatter anomalies. We highlight the differences between observed backscatter from the two sensors with respect to different surface types (ground-fast lake ice, floating lake ice and anomalies) and investigate backscatter differences between frozen and melting conditions. Further, polarimetric classification is performed on L-band PALSAR-2 imagery, which reveals differences in scattering mechanisms between anomalies and floating lake ice.&lt;/p&gt;

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