Spatio-temporal analysis of coastal sediment erosion in Cape Town through remote sensing and geoinformation science

Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spatial technologies for multi-dimensional coastline change monitoring. The research presented here intends to showcase the synergy amongst remote sensing techniques by showcasing the use of coastal indicators towards shoreline assessment over the Kommetjie and Milnerton areas along the Cape Town coastline. There has been little progress in coastal studies in the Western Cape that encompass the diverse and dynamic aspects of coastal environments and in particular, sediment movement. Cape Town, in particular; is socioeconomically diverse and spatially segregated, with heavy dependence on its 240km of coastline. It faces sea level rise intensified by real-estate development close to the high-water mark and on reclaimed land. Spectral indices and classification techniques are explored to accommodate the complex bio-optical properties of coastal zones. This allows for the segmentation of land and ocean components to extract shorelines from multispectral Landsat imagery for a long term (1991-2021) shoreline assessment. The DSAS tool used these extracted shorelines to quantify shoreline change and was able to determine an overall averaged erosional rate of 2.56m/yr. for Kommetjie and 2.35m/yr. for Milnerton. Beach elevation modelling was also included to evaluate short term (2016-2021) sediment volumetric changes by applying Differential Interferometry to Sentinel-1 SLC data and the Waterline method through a combination of Sentinel -1 GRD and tide gauge data. The accuracy, validation and correction of these elevation models was conducted at the pixel level by comparison to an in-field RTK GPS survey used to capture the current state of the beaches. The results depict a sediment deficit in Kommetjie whilst accretion is prevalent along the Milnerton coastline. Shoreline propagation and coastal erosion quantification leads to a better understanding of geomorphology, hydrodynamic and land use influences on coastlines. This further informs climate adaptation strategies, urban planning and can support further development of interactive coastal information systems

The potential of multi-sensor satellite data for applications in environmental monitoring with special emphasis on land cover mapping, desertification monitoring and fire detection

Unprecedented pressure on the physical, chemical and biological systems of the Earth results in environment problems locally and globally, therefore the detection and understanding of environmental change based on long-term environmental data is very urgent. In developing countries/regions, because the natural resources are depleted for development while environmental awareness is poor, environment is changing faster. The insufficient environmental investment and sometimes infeasible ground access make the environment information acquisition and update inflexible through standard methods. With the main advantages of global observation, repetitive coverage, multispectral sensing and low-cost implementation, satellite remote sensing technology is a promising tool for monitoring environment, especially in the less developed countries. Multi-sensor satellite images may provide increased interpretation capabilities and more reliable results since data with different characteristics are combined and can achieve improved accuracies, better temporal coverage, and better inference about the environment than could be achieved by the use of a single sensor alone. The objective of this thesis is to demonstrate the capability and technique of the multi-sensor satellite data to monitor the environment in developing countries. Land cover assessment of Salonga national park in the democratic republic of Congo of Africa, desertification monitoring in North China and tropical/boreal wildland fire detection in Indonesia/Siberia were selected as three cases in this study for demonstrating the potential of multi-sensor application to environment monitoring. Chapter 2 demonstrates the combination of Landsat satellite images, Global Position System (GPS) signals, aerial videos and digital photos for assessing the land cover of Salonga national park in Congo. The purpose was to rapidly assess the current status of Salonga national park, especially its vegetation, and investigated the possible human impacts by shifting cultivation, logging and mining. Results show that the forests in the Salonga national park are in very good condition. Most of the area is covered by undisturbed, pristine evergreen lowland and swamp forests. No logging or mining activity could be detected. Chapter 3 demonstrates the one full year time series SPOT VEGETATION with coarse resolution of 1 km and the ASTER images with higher resolution of 15 meters as well as Landsat images for land cover mapping optimised for desertification monitoring in North-China. One point six million km2 were identified as risk areas of desertification. Results show within a satellite based multi-scale monitoring system SPOT VEGETATION imagery can be very useful to detect large scale dynamic environmental changes and desertification processes which then can be analysed in more detail by high resolution imagery and field surveys. Chapter 4 demonstrates the detection of tropical forest fire and boreal forest fire. Firstly, the ENVISAT ASAR backscatter dynamics and ENVISAT full resolution MERIS characteristics of fire scars were investigated in Siberian boreal forest, and results show these two sensors are very useful for fire monitoring and impact assessment. Secondly, the general capability and potential of ENVISAT multi-sensor of MERIS, AATSR, ASAR as well as NOAA-AVHRR and MODIS for tropical forest fire event monitoring and impact assessment in tropical Indonesia were investigated, and results show the capability of ENVISAT to acquire data from different sensors simultaneously or within a short period of time greatly enhances the possibilities to monitor fire occurrence and assess fire impact. Finally, the multi-sensor technology was applied to the disastrous boreal forest fire event of 2003 around East and West Lake Baikal in Siberia, and results show that 202,000 km2 burnt in 2003 within the study area of 1,300,000 km2, which is more than the total burnt area between 1996-2002. 71.4% of the burnt areas were forests, and 11.6% were wetlands or bogs. In total 32.2% of the forest cover has been burnt at least once from 1996 to 2003, 14% of the area has been affected at least twice by fire. These demonstrations show that in spite of the two disadvantages of indirect satellite measurements and the difficulty of detecting the cause of environment change, multi-sensor satellite technology is very useful in environment monitoring. However more studies on multi-sensor data fusion methods are needed for integrating the different satellite data from various sources. The lack of personnel skilled in remote sensing is a severe deficiency in developing countries, so the technology transfer from the developed countries is needed

Earth resources: A continuing bibliography with indexes (issue 60)

This bibliography lists 485 reports, articles, and other documents introduced into the NASA scientific and technical information system between October 1 and December 31, 1988. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, oceanography and marine resources, hydrology and water management, data processing and distribution systems, and instrumentation and sensors

Aeronautics and space report of the President, 1982 activities

Achievements of the space program are summerized in the area of communication, Earth resources, environment, space sciences, transportation, aeronautics, and space energy. Space program activities of the various deprtments and agencies of the Federal Government are discussed in relation to the agencies' goals and policies. Records of U.S. and world spacecraft launchings, successful U.S. launches for 1982, U.S. launched applications and scientific satellites and space probes since 1975, U.S. and Soviet manned spaceflights since 1961, data on U.S. space launch vehicles, and budget summaries are provided. The national space policy and the aeronautical research and technology policy statements are included

Passively Estimating Index of Refraction for Specular Reflectors Using Polarimetric Hyperspectral Imaging

As off-nadir viewing platforms becoming increasingly prevalent in remote sensing, material classification and ID techniques robust to changing viewing geometries must be developed. Traditionally, either reflectivity or emissivity are used for classification, but these quantities vary with viewing angle. Instead, estimating index of refraction may be advantageous as it is invariant with respect to viewing geometry. This work focuses on estimating index of refraction from LWIR (875-1250 wavenumbers) polarimetric hyperspectral radiance measurements

Simulation de l'humidité du sol-température de brillance à partir des données in situ dans le cadre de la validation des produits SMOS, site test Valencia Anchor Station

Lancée en novembre 2009, l'objectif principal de la mission SMOS (Soil Moisture and Ocean Salinity) est de fournir une cartographie globale de l'humidité du sol avec une précision supérieure à 0.04 m3/m3 et avec une résolution spatiale comprise entre 35 km au nadir et 55 km (43 km en moyenne) en utilisant la radiométrie en bande L (1.4 GHz). La résolution spatiale des satellites tels que SMOS induit de nombreuses questions scientifiques qui nécessite un minimum de mesures de terrain représentatives de la zone vue par le capteur. C'est dans cette optique que la validation des données SMOS nécessite l'acquisition de nombreuses mesures sur une vaste zone. Dans ce sens, le site VAS (Valencia Anchor Station), défini par l'université de Valence (Espagne) en décembre 2001, a pour objectif principal de caractériser une surface dédiée à l'étalonnage et la validation des missions satellites d'observation de la terre. Dans le contexte de la validation des produits SMOS au-dessus des terres émergées, l'objectif principal de cette thèse est la génération de "Match-ups" sur la zone VAS (équivalente à un pixel SMOS), qui sont à comparer avec les données réelles SMOS. Les Match-ups sont des températures de brillance micro-ondes passives simulées en utilisant les variables et les caractéristiques de surface de la zone VAS. Ainsi, pour modéliser l'humidité du sol et la température de brillance associée, nous avons couplé un modèle SVAT (Soil-Vegetation-Atmosphere-Transfer) avec un modèle de transfert radiatif. Les processus hydrologiques sont simulés avec le modèle ISBA (Interactions between Soil Biosphere Atmosphere), alors que l'émission micro-ondes est simulée avec le modèle L-MEB (L-band Microwave Emission of the Biosphere) qui est utilisé dans l'algorithme d'inversion des humidités de surface à partir des données SMOS.Launched in November 2009, the main goal of the SMOS (Soil Moisture and Ocean Salinity) mission is to map global fields of surface soil moisture with an accuracy better than 0.04 m3/m3 land with a spatial resolution ranging from 35 km at nadir up to 55 km (43 km average) using L-band (1.4 GHz) radiometry. The large pixel size of satellite missions such as SMOS, introduces a number of scientific questions that requires a minimum of field measurements representative of the area seen by the sensor. Thus, the validation of SMOS data requires the maintenance of long term measurements over large areas. This is the role of Valencia Anchor Station (VAS), established by the University of Valencia in December 2001, whose principal objective is to characterize an area dedicated to the calibration and validation of Earth Observation missions. In the context of the validation of the SMOS products over land, the main objective of this thesis consists in accurately generating the Match-ups over the VAS area (equivalent to a SMOS pixel) to be compared with the SMOS real data. The Match-ups are defined as simulated passive microwave brightness temperatures using the surface variables as well as the characteristics of the VAS area. A coupled SVAT (Soil-Vegetation-Atmosphere-Transfer) - radiative transfer model was developed for modelling the soil moisture and the resulting microwave emissions. The hydrological processes are simulated with a SVAT model named ISBA (Interactions between Soil Biosphere Atmosphere), while the microwave emission is simulated using the L-MEB (L-band Microwave Emission of the Biosphere) model upon which the SMOS Level 2 processor is based

Water Resources Management and Modeling

Hydrology is the science that deals with the processes governing the depletion and replenishment of water resources of the earth's land areas. The purpose of this book is to put together recent developments on hydrology and water resources engineering. First section covers surface water modeling and second section deals with groundwater modeling. The aim of this book is to focus attention on the management of surface water and groundwater resources. Meeting the challenges and the impact of climate change on water resources is also discussed in the book. Most chapters give insights into the interpretation of field information, development of models, the use of computational models based on analytical and numerical techniques, assessment of model performance and the use of these models for predictive purposes. It is written for the practicing professionals and students, mathematical modelers, hydrogeologists and water resources specialists

International VLBI Service for Geodesy and Astrometry 2014 Annual Report

IVS is an international collaboration of organizations which operate or support Very Long Baseline Interferometry (VLBI) components. The goals are: 1. To provide a service to support geodetic, geophysical and astrometric research and operational activities. 2. To promote research and development activities in all aspects of the geodetic and astrometric VLBI technique. 3. To interact with the community of users of VLBI products and to integrate VLBI into a global Earth observing system