ID: 55785
Title: Assessing ground cover at patch and hillslope scale in semi-arid woody vegetation and pasture using fused Quickbird data
Author: Carlos Munoz-Robles, Paul Frazier, Matthew Tighe, Nick Reid, sue V Briggs, Brian Wilson
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Ecohydrology, Image fusion, Inter-patches, Modified intensity-hue-saturation, transform, patches, Australia
Abstract: The amount and distribution of vegetation and ground cover are important factors that influence resource transfer (e.g. runoff, sediment) in patterned semi-arid landscapes. Identifying and describing these features in detail is an essential part of measuring and understanding ecohydrological processes at hillslope scales that can then be applied at broader scales. The aim of this study was to develop a comprehensive methodology to map ground cover using high resolution Quickbird imagery in woody and non-woody (pasture) vegetation. The specific goals were to: (1) investigate the use of several techniques of image fusion, namely principal components analysis (PCA), Brovey transform, modified intensity-hue-saturation (MIHS) and wavelet transform to increase the spatial detail of multispectral Quickbird data ; (2) evaluate the performance of the red and near-infra-red bands (NIR), the difference vegetation index (DVI), and the normalised difference vegetation index (NDVI) in estimating ground cover, and (3) map and assess spatial and temporal changes in ground cover at hillslope scale using the most appropriate method or combination of methods. Estimates of ground cover from the imagery were compared with a subset of observed ground cover estimates to determine map accuracy. The MIHS alogrithm produced images that best preserved spectral and spatial integrity, while the red band fused with the panchromatic band produced the most accurate ground cover maps. The patch size of the ground cover beneath canopies was similar to canopy size, and percent ground cover (mainly litter) increased with canopy size. Ground cover was mapped with relative accuracies of 84% in the woody vegetation and 86% in the pasture. From 2008 to 2009, ground cover increased from 55% to 65% in the woody vegetation and from 40% to 45% in the pasture. These ground cover maps can be used to explore the spatial ecohydrological interactions between areas of different ground cover at hillslope scale with application to management at broader scales.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55784
Title: Crop area mapping in West Africa using landscape stratification of MODIS time series and comparison with existing global land products
Author: Elodie Vintrou, Annie Desbrosse, Agnes Begue, Sibiry Traore, Christian Baron, Danny Lo Seen
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Cultivated area, MODIS time series, stratification, Global land products, Mali
Abstract: In Africa, food security early warning systems use satellite-derived data concerning crop conditions and agricultural production. Such systems can be improved if they are provided with a more reliable estimation of the cultivated area at national scale. This paper evaluates the potential of using time series from the MODerate resolution Imaging Spectroradiometer MOD13Q1 (16-day composite of normalized difference vegetation index at 250m resolution) to extract cultivated areas in the fragmented rural landscapes of Mali. To this end, we first stratified Southern Mali inot 13 rural landscapes based on the spatio-temporal variability of NDVI and textural indices, using an object-oriented classfication scheme.
The accuracy of the resulting map (MODIScrop) and how it compares with existing coarse - resolution global land products (GLC2000 Africa, GLOBCOVER, MODIS V05 and ECOCLIMAP-II), was then assessed against six crop/non-crop maps derived from SPOT 2.5 m resolution images used as references. For crop areal coverage, the MODIScrop cultivated map was successful in assessing the overall cultivated area at five out of the six validation sites (less than 6% of the absolute difference), while in terms of crop spatial distribution, the producer accuracy was between 33.1% and 80.8%. This accuracy was linearly correlated with the mean patch size index calculated on the SPOT crop maps (r2 = 0.8). Using the Pareto boundary as an accuracy assessment method at the study sites, we showed that (i) 20-40% of the classification crop error was due to the spatial resolution of the MODIS sensor (250 m), and that (ii) compared to MODIS V05, which otherwise performed better than the other existing products, MODIScrop generally minimized omission-commission errors. A spatial validation of the different products was carried out using SPOT image classifications as reference. In the corresponding error matrices, the fraction of correctly classified pixels for our product was 70%, compared to 58% for MODIS V05, while it ranged between 40% and 51% for the GLC2000, the ECOCLIMAP-II and the GLOBCOVER.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55783
Title: Understanding the 2007-2008 eruption of Anak Krakatau Volcano by combining remote sensing technique and seismic data
Author: Agustan, Fumiaki Kimata, Yoga Era Pamitro, Hasanuddin Z Abidin
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Krakatau, PALSAR, InSAR, ground deformation, volcano eruption
Abstract: One of the most violent volcanic eruption in recorded history is the Krakatau eruption on August 27, 1883. This caldera-forming eruption destroyed two thirds of the Krakatau volcanic island in the Sunda Strait resulting in the remaining three small islands later known as the Krakatau complex. From 1927 to 1929, eruptions in the center of Krakatau complex have produced a new volcano named Anak Krakatau, which continuously builds its body through eruptions until now. One eruption event took place between 2007 and 2008 with several eruptions that lasted in total from the end of October 2007 to August 2008. Eruptions were characterized by Strombolian activity with ash columns 1 km high, as well as pyroclastic and lava flows. We monitored the ground deformation of Anak Krakatau Volcano by interfering PALSAR data from June 2007 to February 2009. The result of InSAR technique shows a complex pattern of ground deformation. Inflation up to 4 cm, together with subsidence around the crater, was measured for almost three months before the eruption with a volume increase of approximately 1 x 106 m3. After the eruption, the southwest side of the volcanic cone subsided by 18 cm, whereas the northeast side of the cone uplifted 12 cm in almost two years. The observed ground deformation after the eruption can be explained by 4 m of tensile opening along a dipping rectangular tensile dislocation buried in an elastic half-space, approximately 400m below sea level.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55782
Title: Identifying transit corridors for elephant using a long time-series
Author: Claudia Pittiglio, Andrew K Skidmore, Hein A M J van Gils, Herbert H T Prins
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Species distribution, transit corridor, Kernel density, path analysis, l9ogistic regression, long-term aerial survey
Abstract: The role of corridors in mitigating the effects of landscape fragmentation on biodiversity is controversial. Recent studies have highlighted the need for new approaches in corridor design usign long-term datasets. We present a method to identify transit corridors for elephant at a population scale over a large area and an extended period of time using long-term aerial surveys. We investigated environmental and anthropogenic factors directly and indirectly related to the wet versus dry season distribution of elephant and its transit corridors. Four environmental variables predicted the presence of elephant at the landscape scale in both seasons: distance from permanent water, protected areas and settlements and vegetation structure. Path analysis revealed that altitude and monthly average NDVI, and distance from temporary water had a significant indirect effect on elephant distribution at local scale in dry and wet seasons respectively. Five transit corridors connectign Tarangire National Park and the northern as well as south-eastern wet season dispersal areas were identified and matched the wildlife migration routes described in the 1960s. The corridors are stable over the decades, providing landscape connectivity for elephant. Our approach yielded insights how advanced spatial analysis can be integrated with biological data available from long-term datasets to identify actual transit corridors and predictors of species distribution.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55781
Title: An assessment on the use of Terra ASTER L3A data in landslide susceptibility mapping
Author: H A Nefeslioglu, B T San, C Gokceoglu, T Y Duman
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Terra ASTER L3A data, DEM, topographic attributes, Landslide susceptibility, kelemen catchment area (Western Black Sea region Turkey)
Abstract: The main purpose of the present study is to evaluate the potential use of Terra ASTER data-the L3A DEM and its derivatives in landslide susceptibility mapping. For the purpose, an appropriate application site from the Western Black Sea region of Turkey - the Kelemen catchment area was selected. During the analyses, a two-stage comparative evaluation was carried out. In the first stage, the differences between the DEMs obtained from Terra ASTER L3A data and the conventional topographic data; and their first and second derivatives were investigated. Subsequently, different susceptibility maps were produced by using the DEMs and the topographic attributes obtained from both source of data in addition to the spectral information acquired from satellite sensor. According to the results of the comparative evaluations, a strong correlation between Terra ASTER L3A DEM and the conventional topographic data was obtained. However, depending on the increment of the degree of the derivative, an evident decrease in the spatial correlations was observed. On the contrary, the final model performance, prediction capacity, and the spatial performance statistics for the landslide susceptibility maps produced by using both source of data were found as very high and close to each other.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55780
Title: Water-poverty relationships in the coastal town of Mbour (Senegal): Relevance of GIS for decision support
Author: Nene Makoya Toure, Alioune Kane, Jean Francois Noel, Vincent Turmine, Valentine Nedeff, Gabriel Lazar
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Fresh water, sustainable development, coastline, poverty, GIS
Abstract: Coastal area is always a zone with complex problems. Due to the attraction they exert, are facing many social problems. Therefore, a coastal city is usually a city with problems. Its extension, caused by the influx of people from different backgrounds, creates an increased demand for services. One of the problems frequently encountered, especially in Senegal, is access to water. The problem of access to water is poorly treated, without beig correlated with the urban evolution, i.e. with increasing population and demand growth. The water resource is facing numerous complications such as the lack of integrated management, integration issues at the governance level, where the local factor is often forgotten.
The town of Mbour, object of our study, does not come out of that lot, being an attractive coastal city, from an African country. This indicates the need for an integrated management oriented from local to a global basis and not vice versa. The study presented in this paper indicates that a large proportion of the population has not access to a verified drinking water system and uses water from wells or standpipes. Half of the surveyed population (50%) has no access to a water supply system. The water poverty map of the town overlaps with that of the general poverty excepting few neighborhoods. This means that even areas that are not affected by poverty have a very low or poor access to water, which so far remains the perverse effect of the reform of teh Senegalese water sector in 1995.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55779
Title: Hyperspectral remote sensing of evaporate minerals and associated sediments in Lake Magadi area, Kenya
Author: Gayantha R L Kodikara, Tsehaie Woldai, Frank J A van Ruitenbeek, Zack Kuria, Freek van der Meer, Keith D Shepherd, G J van Hummel
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Hyperion, Lake Magadi, MTMF, surface mineral mapping, Magadiite, kenyaite
Abstract: Pleistocene to present evaporitic lacustrine sediments in Lake Magadi, East African Rift Valley, Kenya were studied and mapped using spectral remote sensing methods. This approach incorporated surface mineral mapping using space-borne hyperspectral Hyperion imagery together with laboratory analysis, including visible, near-infrared diffuse reflectance spectroscopy (VNIR) measurements and X-ray diffraction for selected rock and soil samples of the study area. The spectral signatures of Magadiite and Kenyaite, which have not been previously reported, were established and the spectral signatures of trona, chert series, volcanic tuff and the High Magadi bed were also analyzed.
Image processing techniques, MNF (Minimum Noise Fraction) and MTMF (Mixture Tuned Matched Filtering) using a stratified approach Iimage analysis with and without the lake area), were used to enhance the mapping of evaporates. High Magadi beds, chert series and vocanic tuff were identified from the Hyperion image with an overall mapping accuracy of 84.3%. Even though, the spatial distribution of evaporites and sediments in Lake Magadi area change in response to climate variations, the mineralogy of this area has not been mapped recently. The results of this study shows that usefulness of the hyperspectral remote sensing to map the surface geology of this kind of environment and to locate promising sites for industrial open-pit trona mining in a qualitative and quantitative manner.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55778
Title: Spatio-temporal pattern analysis of land use/cover change trajectories in Xihe watershed
Author: Dongchuan Wang, Jianhua Gong, Liding Chen, Lihui Zhang, Yiquan Song, Yujuan Yue
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Change trajectories, Land use/cover change, Landscape metrics, RCI, Slope, Aspect, River line
Abstract: Human-induced land use/cover change has been considered to be one of the most important parts of global environmental changes. In loess hilly and gully regions, to prevent soil loss and achieve better ecological environments, soil conservation measures have been taken during the past decades. The main objective of this study is to quantify the spatio-temporal variability of land use/cover change spatial patterns and make preliminary estimation of the role of human activity in the environmental change in Xihe watershed, Gansu Province, China. To achieve this objective, the methodology was developed in two different aspects, that is. (1) analysis of change patterns by binary image of change trajectories overlaid with different natural geographic factors, in which Relative Change Intensity (RCI) metric was established and used to make comparisons, and (2) analysis based on pattern metrics of main trajectories in the study area. Multi-source and multi-temporal Remote Sensing (RS) images (including Landsat ETM+ (30 June 2001), SPOT imagery (21 November 2003 and 5 May 2008) and CBERS02 CCD (5 June 2006) were used due to the constraints of the availability of remotely sensed data. First, they were used to extract land use/cover types of each time node by object-oriented classification method. Classification results were then utilized in the trajectory of land use/cover changes through the given four time nodes. Trajectories at every pixel were acquired to trace the history of land use/cover change for every location in the study area. Landscape metrics of trajectories were then analyzed to detect the change characteristics in time and space through the given time series. Analysis showed that most land use/cover changes were caused by human activities, most of which, under the direction of local government, had mainly led to virtuous change on the ecological environments. While, on the contrary, about one quarter of human- induced changes were vicious ones. Analyis through overlaying binary image of change trajectories with natural factors can efficiently show the spatio-temporal distribution characteristics of land use/cover change patterns. It is found that in the study area RCi of land use/cover changes is related to the distance to the river line. And there is a certain correlation between RCI and slope grades. However, no obvious correlation exists between RCI and aspect grades.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55777
Title: Spectral mixture analysis to assess post-fire vegetation regeneration using Landsat Thematic Mapper imagery: Accounting for soil brightness variation
Author: S Veraverbeke, B Somers, I Gitas, T Katagis, A Polychronaki, R Goossens
Editor: Alfred Stein
Year: 2012
Publisher: Elsevier, Vol 14, Issue 1, February 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Fire, vegetation recovery, Landsat Thematic Mapper, Spectral mixture analysis, MESMA, segmentation
Abstract: Post-fire vegetation cover is a crucial parameter in rangeland management. This study aims to assess the post-fire vegetation recovery 3 years after the large 2007 Pelophonnese (Greece) wildfires. Post-fire recovery landscapes typically are mixed vegetation-substrate environments which makes spectral mixture analysis (SMA) a very effective tool to derive fractional vegetation cover maps. Using a combination of field and simulation techniques this study aimed to account for the impact of background brightness variability on SMA model performance. The field data consisted out of a spectral library of in situ measured reflectance signals of vegetation and substrate and 78 line transect plots. In addition, a Landsat Thematic Mapper (TM) scene was employed in the study. A simple SMA, in which each constituting terrain feature is represented by its mean spectral signature, a multiple endmember SMA (MESMA) and a segmented SMA, which accounts for soil brightness variations by forcing the substrate endmember choice based on ancillary data (lithological map), were applied. In the study area two main spectrally different lithological units were present: relatively bright limestone and relatively dark flysch (sand-siltstone). Although the simple SMA model resulted in reasonable regression fits for the flysch and limestones subsets separately (coefficient of determination R2 of respectively 0.67 and 0.72 between field and TM data), the performance of the regression model on the pooled dataset was considerably weaker (R2 = 0.65). More over, the regression lines significantly diverged among the different subsets leading to systematic over-or underestimations of the vegetative fraction depending on the substrate type. MESMA did not solve the endmember variability issue. The MESMA model did not manage to select the proper substrate spectrum on a reliable basis due to the lack fo shape differences between the flysch and limestone spectra. The segmented SMA model which accounts for soil brightness variations minimized the variability problems. Compared to the simple SMA and MESMA models, the segmented SMA resulted in a higher overall correlation (R2 = 0.70), its regression slope and intercept were more similar among the different substrate types and its resulting regression lines more closely resembled the expected one-one line. This paper demonstrates the improvement of a segment approach in accounting for soil brightness variations in estimating vegetative cover using SMA. However, further research is required to evaluate the model ' s performance for other soil types, with other image data and at different post-frve timings.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55776
Title: Performance of the tsunami forecast system for the Indian Ocean
Author: T Srinivasa Kumar, Shailesh Nayak, Patanjali Kumar, R B S Yadav, Ajay Kumar, M V Sunanda, E Uma Devi and S S C Shenoi
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: Bottom pressure recorders, Indian Tsunami Early Warning System, tidal stations, tsunami modelling and bulletins
Abstract: The Indian Tsunami Early Warning System (ITEWS) at the Indian National Centre for Ocean Information Services, Hyderabad, is responsible for issuing tsunami bulletins in India. The tsunami centre operates on a 24 x 7 basis and monitors seismological stations, bottom pressure recorders and tidal stations throughout the Indian Ocean to evaluate potentially tsunamigenic earthquakes and disseminating tsunami bulletins. The end-to-end capabilities of this warning system have been well proven during all the tsunamigenic earthquakes that occurred since September 2007. Comparison of the earthquake parameters estimated by ITEWS with other international seismological agencies suggests that the system is performing well and has achieved the target set up by the Inter-governmental Oceanographic Commission.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55775
Title: Investigation of biodegradable and biocompatible castor oil poly (mannitol-citric-sebacate) polyester as a drug carrier
Author: P S Sathiskumar, Sunita Chopra and Giridhar Madras
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: Biodegradable, biocompatibility, castor oil polyesters, drug-delivery
Abstract: Castor oil-based poly (mannitol-citric sebacate) was synthesized by simple,catalyst-free melt condensation process using monomers having potential to be metabolized in vivo. The polymer was characterized using various techniques and the tensile and hydration properties of the polymers were also determined. The biocompatibility of the polymer was tested using human foreskin fibroblasts cells. The in vitro degradation studies show that the time for complete degradation of the polymer was more than 21 days. The usage of castor oil polyester as a drug carrier was analysed by doping the polymer with 5-fluorouracil model drug and release rate was studied by varying the percentage loading of drugs and the pH of the PBS solution medium. The cumulative drug-release profiles exhibited a biphasic release with an initial burst release and cumulative 100% release within 42 h. To understand the role of the polymer as a drug carrier in the release behaviour, drug-release studies were conducted with another drug, isoniazid. The release behaviour of isoniazid drug from the same polymer matrix followed an nth order kinetic model and 100% cumulative release was achieved after 12 days. The variation in the release behaviour for two model drugs from the same polymer matrix suggests a strong interaction between the polymer and the drug molecule.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55774
Title: Trend analysis of rainfall and temperature data for India
Author: Sharad K Jain and Vijay Kumar
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: Climate change, rainfall, trend, river basin, seasonal analysis, temperature data
Abstract: This article aims to review studies pertaining to trends in rainfall, rainy days and temperature over India. Sen ' s non-parameteric estimator of slope has been frequently used to estimate the magnitude of trend, whose statistical significance was assessed by the Mann-Kendall test. Spatial units for trend analysis vary from station data to sub-division to sub-basin/river basins. There are differences in the results of the various studies. There are differences in the results of the various studies, and a clear and consistent picture of rainfall trend has not emerged. Although the different units (sub-basins or sub-divisions) may have a non-zero slope value, few values are statistically significant. In a study on basin-wise trend analysis, 15 basins had decreasing tend in annual rainfall; only one basin showed significant decreasing trend at 95% confidence level. Among six basins showing increasing trend, oen basin showed significant positive trend. Most of the basins had the same direction of trend in rainfall and rainy days at the annual and seasonal scale.
Regarding trends in temperature, the mean maximum temperature series showed a rising trend at most of the stations; it showed a falling trend at some stations. The mean minimum temperature showed a rising as well as a falling trend. At most of the stations in the south, central and western parts of India a rising trend was found. Some stations located in the north and northeastern Idnia showed a falling trend in annual mean temperature. Most of the data used in trend analysis pertained to the stations located in urban areas and these areas are sort of heat islands. This article also highlights the need of a network of baseline stations for climatic studies.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55773
Title: A simple technique to estimate linear body measurements of elephants
Author: S Wijeyamohan, V Sivakumar, Bruce Read, Dennis Schmitt, S Krishnakumar, Charles Santiapillai
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: None
Abstract: None
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55772
Title: Five-armed body fossil from the Ediacaran Jodhpur Sandstone, Marwar Supergroup, Western Rajasthan, India: a possible precursor of phylum Echinodermata
Author: S Kumar, D K Srivastava, S Ahmad
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: None
Abstract: None
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55771
Title: Anomalous concentration of REE-Th-U in microclinite-pyroxenite-albitite in Ajmer and Nagaur districts, Rajasthan
Author: A Muthamilselvan, P K Panchal, A V Jeyagopal, L K Nanda, P B Maithani
Editor: P Balaram
Year: 2012
Publisher: Current Science Association, Vol 102, No1, 10 January 2012
Source: Centre for Ecological Sciences
Reference: None
Subject: Current Science
Keywords: None
Abstract: None
Location: 241
Literature cited 1: None
Literature cited 2: None