A method for monitoring hydrological conditions beneath herbaceous wetlands using multi-temporal ALOS PALSAR coherence data

2015 ◽  
Vol 6 (8) ◽  
pp. 618-627 ◽  
Author(s):  
Meimei Zhang ◽  
Zhen Li ◽  
Bangsen Tian ◽  
Jianmin Zhou ◽  
Jiangyuan Zeng
Author(s):  
M. Zhang ◽  
Z. Li ◽  
B. Tian ◽  
J. Zhou ◽  
J. Zeng

Reed marshes, the world’s most widespread type of wetland vegetation, are undergoing major changes as a result of climate changes and human activities. The presence or absence of water in reed marshes has a significant impact on the whole ecosystem and remains a key indicator to identify the effective area of a wetland and help estimate the degree of degeneration. Past studies have demonstrated the use of interferometric synthetic aperture radar (InSAR) to map water-level changes for flooded reeds. However, the identification of the different hydrological states of reed marshes is often poorly understood. The analysis given in this paper shows that L-band interferometric coherence is very sensitive to the water surface conditions beneath reed marshes and so can be used as classifier. A method based on a statistical analysis of the coherence distributions for wet and dry reeds using InSAR pairs was, therefore, investigated in this study. The experimental results were validated by in-situ data and showed very good agreement. This is the first time that information about the water cover under herbaceous wetlands has been derived using interferometric coherence values. This method can also effectively and easily be applied to monitor the hydrological conditions beneath other herbaceous wetlands.


Author(s):  
Pertiwi Jaya Ni Made ◽  
Fusanori Miura ◽  
A. Besse Rimba

A large-scale earthquake and tsunami affect thousands of people and cause serious damages worldwide every year. Quick observation of the disaster damage is extremely important for planning effective rescue operations. In the past, acquiring damage information was limited to only field surveys or using aerial photographs. In the last decade, space-borne images were used in many disaster researches, such as tsunami damage detection. In this study, SAR data of ALOS/PALSAR satellite images were used to estimate tsunami damage in the form of inundation areas in Talcahuano, the area near the epicentre of the 2010 Chile earthquake. The image processing consisted of three stages, i.e. pre-processing, analysis processing, and post-processing. It was conducted using multi-temporal images before and after the disaster. In the analysis processing, inundation areas were extracted through the masking processing. It consisted of water masking using a high-resolution optical image of ALOS/AVNIR-2 and elevation masking which built upon the inundation height using DEM image of ASTER-GDEM. The area result was 8.77 Km<sup>2</sup>. It showed a good result and corresponded to the inundation map of Talcahuano. Future study in another area is needed in order to strengthen the estimation processing method.


Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 156 ◽  
Author(s):  
Noorlaila Hayati ◽  
Wolfgang Niemeier ◽  
Vera Sadarviana

Landslides are one of the natural hazards that occur annually in Indonesia. A continuous geodetic observation in the landslide prone area is essential to support the precautionary measures. Because of its hilly topography, torrential rainfall and landslide history, the Ciloto district in Indonesia has been affected by ground deformation for an extended period of time. The purpose of our study is to detect significant movement and quantify the kinematics of its motion using the Interferometric synthetic aperture radar (InSAR) time series analysis and multi-band SAR images. We utilized the small baseline SDFP technique for processing multi-temporal SAR data, comprising ERS1/2 (1998–1999), ALOS PALSAR (2007–2009), and Sentinel-1 (2014–2018). Based on the detected deformation signal in the Ciloto area, the displacement rates are categorized as very slow movements. Two active main landslide zones; the Puncak Pass and the Puncak Highway area, which show the trend of slow movement progressively increasing or descreasing, were detected. The integration of the velocity rate between InSAR results and ground observations (e.g., terrestrial and GPS) was conducted at the Puncak Highway area from the temporal perspective. Using the polynomial model, we estimated that the area had cumulatively displaced up to −42 cm for 25 years and the type of movements varied from single compound to multiple rotational and compound.


2015 ◽  
Vol 77 (2) ◽  
pp. 959-985 ◽  
Author(s):  
Fajar Yulianto ◽  
Parwati Sofan ◽  
Any Zubaidah ◽  
Kusumaning Ayu Dyah Sukowati ◽  
Junita Monika Pasaribu ◽  
...  

Author(s):  
K. Miyaoka ◽  
M. Maki ◽  
J. Susaki ◽  
K. Homma ◽  
K. Yoshida ◽  
...  
Keyword(s):  

2015 ◽  
Vol 166 ◽  
pp. 138-153 ◽  
Author(s):  
Mikhail Urbazaev ◽  
Christian Thiel ◽  
Renaud Mathieu ◽  
Laven Naidoo ◽  
Shaun R. Levick ◽  
...  

Author(s):  
Pertiwi Jaya Ni Made ◽  
Fusanori Miura ◽  
A. Besse Rimba

A large-scale earthquake and tsunami affect thousands of people and cause serious damages worldwide every year. Quick observation of the disaster damage is extremely important for planning effective rescue operations. In the past, acquiring damage information was limited to only field surveys or using aerial photographs. In the last decade, space-borne images were used in many disaster researches, such as tsunami damage detection. In this study, SAR data of ALOS/PALSAR satellite images were used to estimate tsunami damage in the form of inundation areas in Talcahuano, the area near the epicentre of the 2010 Chile earthquake. The image processing consisted of three stages, i.e. pre-processing, analysis processing, and post-processing. It was conducted using multi-temporal images before and after the disaster. In the analysis processing, inundation areas were extracted through the masking processing. It consisted of water masking using a high-resolution optical image of ALOS/AVNIR-2 and elevation masking which built upon the inundation height using DEM image of ASTER-GDEM. The area result was 8.77 Km<sup>2</sup>. It showed a good result and corresponded to the inundation map of Talcahuano. Future study in another area is needed in order to strengthen the estimation processing method.


2020 ◽  
Vol 12 (2) ◽  
pp. 299 ◽  
Author(s):  
Yanan Du ◽  
Guangcai Feng ◽  
Lin Liu ◽  
Haiqiang Fu ◽  
Xing Peng ◽  
...  

Coastal areas are usually densely populated, economically developed, ecologically dense, and subject to a phenomenon that is becoming increasingly serious, land subsidence. Land subsidence can accelerate the increase in relative sea level, lead to a series of potential hazards, and threaten the stability of the ecological environment and human lives. In this paper, we adopted two commonly used multi-temporal interferometric synthetic aperture radar (MTInSAR) techniques, Small baseline subset (SBAS) and Temporarily coherent point (TCP) InSAR, to monitor the land subsidence along the entire coastline of Guangdong Province. The long-wavelength L-band ALOS/PALSAR-1 dataset collected from 2007 to 2011 is used to generate the average deformation velocity and deformation time series. Linear subsidence rates over 150 mm/yr are observed in the Chaoshan Plain. The spatiotemporal characteristics are analyzed and then compared with land use and geology to infer potential causes of the land subsidence. The results show that (1) subsidence with notable rates (>20 mm/yr) mainly occurs in areas of aquaculture, followed by urban, agricultural, and forest areas, with percentages of 40.8%, 37.1%, 21.5%, and 0.6%, respectively; (2) subsidence is mainly concentrated in the compressible Holocene deposits, and clearly associated with the thickness of the deposits; and (3) groundwater exploitation for aquaculture and agricultural use outside city areas is probably the main cause of subsidence along these coastal areas.


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