Satellite Digital Data Research Articles

Spatial arrangement of social and economic networks among villages in Nang Rong District, Thailand

This paper examines the spatial arrangement of social and economic networks among villages in Nang Rong district, Thailand. We use spatial information from a geographic information system (GIS) for the district to help interpret the patterns of movement of agricultural equipment (large tractors) between villages, of people into villages for temporary labor, and of people to village temples and to elementary and secondary schools within the district. Once social networks have been incorporated into the GIS they can be mapped in relation to geographic features of the district, such as topography, landcover, and locations of roads, rivers, and villages. Not only does geographic information about village locations allow us to properly orient the graphs of these networks, but the resulting visual displays reveal strikingly different spatial arrangements for the five networks. Networks of shared temples and elementary schools link small sets of villages in close geographic proximity whereas tractor hiring, labor movement, and secondary school networks bring together larger sets of villages and span longer distances. Information on landcover from satellite digital data provides insights into the patterns of network ties throughout the district and shows a clear relationship between tractor hiring networks and type of agricultural activity in the district. The spatial analytic capabilities of the GIS also allow us to assess the impact of the administratively defined district boundary on our measured relations and to evaluate whether rivers and perennial streams create barriers to network ties between villages.

Calibration of small-area estimates for map errors in multisource forest inventory

A multisource inventory method has been applied in the Finnish National Forest Inventory (NFI) since 1990.The method utilizes satellite images and digital map data,in addition to field measurements...

Application of environmental models to different hydrological systems

In recent years global problems such as climatic change, acid rain, and water pollution in surface and subsurface environments dominate discussions of world environmental problems. In this paper, the roles of hydrologic processes and hydrogeochemical processes are investigated through development, modification, and application of mathematical models for addressing point and non-point source water quality modelling of receiving waters: surface water, subsurface water and lake water. The paper describes the use of models to simulate the movements of pollutants and water: subsurface water, surface water and lake sediments. A hydrological model was applied to Northeast Pond River watershed to understand climate change effects in the watershed. Four watershed acidification models were applied to compute hydrogen ion, alkalinity and sulphate concentrations from Turkey Lakes watershed, Canada. The computed hydrogen ion was used to estimate acidic events, magnitude of hydrogen ion, and duration using a stochastic model. There exist uncertainties in environmental models due to imperfect knowledge of processes controlling water quality parameters as well as errors in data. Monte Carlo, first order, and inverse method analyses were used to assess uncertainty in models. SUTRA (saturated–unsaturated transport) and SUTRA −1 models were applied to Lambton county, Ontario, Canada to locate groundwater discharge areas for St. Clair River, calculate discharge rates, and hydrogeologic parameters. A sediment contamination model was developed and applied to Great Lakes sediment data to estimate transport parameters by 210Pb data. It was then coupled with fatty acid data and results were compared with observed data. A contaminant transport model was developed and applied to two North American streams to compute stream water concentration. The computed data was compared with observed data using a simple statistical method. A hydrological model was coupled with water quality models and RAISON (regional analysis by intelligent systems on) expert system and applied to Canadian watersheds. Digital satellite data was used to locate groundwater discharge and recharge areas in the watershed. This data is useful as observed data for hydrological modelling and GIS (Geographical Information System) system.

Assessment of waterlogging in Sriram Sagar command area, India, by remote sensing

Waterlogging is becoming a serious problem in irrigated command areas of India. The study area is the Sriram Sagar command, which is about 120 km north of Hyderabad. An attempt has been made to make an assessment of the waterlogged area and those areas sensitive to waterlogging during the pre and post monsoon periods in the Sriram Sagar command using remorely sensed and field data. Indian Remote Sensing Satellite (IRS-1A-LISS-II) digital data (Computer Compatible Tapes) of 12 April and 6 October 1989, were analysed to assess the areas affected by waterlogging and those areas sensitive to waterlogging. The validation of the IRS-derived waterlogged areas, was done using available water table depth data and other field information. The results obtained from this study indicate that in April and October 1989, areas of some 388 and 540 km2 were waterlogged and about 698 and 802 km2, respectively, were sensitive to waterlogging (where the water table lies between 1 to 2 m, respectively, below the ground surface. It is suggested that periodic assessment of waterlogging, using remotely sensed data, should be carried out in the Sriram Sagar command. The IRS data have been proved to be very succesful for the assessment of waterlogging. Density slicing and principal component analysis are useful techniques in making an assessment of waterlogged areas in irrigated command areas.

An Empirical Model to Predict Widespread Occurrences of Contrails

The increases in total cloud amount documented for large regions during the latter half of the twentieth century have focused attention on the potential contribution from jet condensation trails (contrails). The environmental conditions that favor contrail formation and persistence are not well understood primarily due to the limited number of empirical studies. This study presents an empirical model to predict widespread occurrences of contrails (outbreaks), which was developed from a combination of rawinsonde temperature and GOES water vapor information. Environments containing persisting contrails were first identified on Defense Meteorological Satellite Program satellite imagery for the United States for January and April 1987 and then analyzed in more detail using Advanced Very High Resolution Radiometer (AVHRR) satellite digital data. Adjacent clear and cloudy environments not containing contrails were identified to compare with the conditions favorable for contrail persistence. For this purpose, a predictive logistic model was developed through multiple regression analysis. The model performance was evaluated through goodness-of-fit methods and found to be statistically significant across a range of atmospheric conditions. To further evaluate the model and to demonstrate its application on a real-time basis, predictions of the probability of persisting contrails were made for a case day. Comparisons of the predictions to satellite observations of the existing conditions (using AVHRR data) demonstrate good model performance and suggest the utility of this approach for predicting persisting contrail occurrence. Implementation of this model should allow climate researchers to better quantify the influence of contrails on surface climate and natural cloud formation.

Mapping of crop rotation using multidate Indian Remote Sensing Satellite digital data

Crop rotation is the sequential growth of crops in a year. The feasibility of deriving this information from multi-temporal satellite digital data acquired during different crop seasons in a year is reported herein. Red and NIR bands of the Indian Remote Sensing Satellite (IRS) LISS-I multidate data acquired in different crop seasons resulted in more than 95 percent accuracy of training site pixels. Similar result was also obtained using principal components of multidate data. Inclusion of data acquired during the transitional phase of crop seasons was found to improve classification accuracy. Four-date data acquired between October and March were found to be optimum for deriving such information for West Bengal. The results showed that a rice based single cropping system is the dominant rotation class of the district, while in the irrigation command area of Damodar river, a double cropping system of rice followed by rice and rice followed by potato were the major rotation classes.

Automated mapping of the landslide hazard on the island of Tahiti based on digital satellite data: R. Guillande & 6 others, Mapping Sciences & Remote Sensing, 32(1), 1995, pp 59–70; translated from: Bulletin — Societe Geologique de France, 164(4), 1993, pp 577–583

Automated mapping of the landslide hazard on the island of Tahiti based on digital satellite data: R. Guillande & 6 others, Mapping Sciences & Remote Sensing, 32(1), 1995, pp 59–70; translated from: Bulletin — Societe Geologique de France, 164(4), 1993, pp 577–583

Landsat and SPOT Data Interpretations of Gee-Hydrological Aspects in Wadi Tabalah Area, Kingdom of Saudi Arabia

Remotely sensed digital satellite data play an important role nowadays in geo-hydrological studies, especially when integrated with GIS techniques. Landsat and SPOT imagery were utilized in a lithologically, homogeneous terrain in the middle of the southern Arabian Shield to delineate landclasses, soil temperature, and soil moisture content quantitatively and qualitatively. Four landuse categories (agricultural, urban. uncultivated. uncultivable) were identified from visible and infrared satellite data. Radiance temperature differences were computed for these categories from thermal infrared data and were found to be in good agreement with those predicted from the theoretical functions relating soil moisture to daytime temperature. Results indicate that satellite imagery could be used successfully to predict soil moisture and to assess droughts in the Arabian Shield or any other arid land

Exploring a V-I-S (vegetation-impervious surface-soil) model for urban ecosystem analysis through remote sensing: comparative anatomy for cities†

Abstract Growing interest in urban systems as ecological entities calls for some standards in parameterizing biophysical composition of urban environments. A vegetation-impervious surface-soil ( V-I-S) model is presented as a possible basis for standardization. The V-I-S model may serve as a foundation for characterizing urban/near-urban environments universally, and for comparison of urban morphology within and between cities. Inasmuch as the model may be driven by satellite digital data, it may serve as a global model of urban ecosystem analysis and comparison world-wide. The V-I-S model may prove useful for urban change detection and growth modelling, for environmental impact analysis from urbanization, for energy- and water-related investigations, and for certain dimensions of human ecosystem analysis of the city as well.

Estimation of mercury content in tailings of the gold mine area of Poconé, Mato Grosso, Brazil

As in many other parts of the world, gold is produced in the surface mining region of Poconé, Mato Grosso, Brazil, using mercury. The goal of this investigation was to estimate the amount of mercury in certain tailings and to determine the area of the land that has been contaminated by the gold mining operations. Mercury concentrations from 2 to 495 ng/g (dw) were determined in the tailing materials. It was observed that only isolated sites were acting as central points of contamination. Using digital Landsat satellite data (The-matic Mapper) and aerial photos, the sites degraded by the mining were classified, and their total area was estimated to be 12.3 km(2) in the region of Poconé. It was estimated, that 4.9 km(2) were occupied by the contaminated tailings. The mean height of the pile slags was determined to be 4.5 m. From the experimentally calculated average density of the material in the tailings, 2.01 g/cm(3), the total mercury content in the piles of tailings was estimated to be 1600 ± 350 kg.

Simulating impacts of agricultural policy on nitrogen losses from a watershed in Northern Italy

Thematic maps, statistical data, and field and farm sampling have been merged with digital satellite data to implement simulation models for managing the problems related to agricultural non-point source pollution. This has been done putting the different data sources and techniques into the same Geographical Information System (GIS). The integration of GIS with the environmental impact simulator and economic programming model was utilized for estimating the possible changes in environmental impact caused by the recent Reform in the Common Agriculture Policy (CAP) of the European Union. An economic programming model was built to evaluate land use changes induced by the CAP Reform under different hypotheses of technology adjustment. The entire data set has then been utilized as a geographical data base to run non-point source (NPS) simulation models to estimate the impact on water quality of the agricultural systems located within the study area. Nutrient (nitrogen) concentrations were the environmental indicators chosen to evaluate the impacts on water quality. In this way the system created by the linkage of GIS and simulation model (Spatial Environmental Impact Simulator, SEIS) has become a decision support system, for evaluating the effectiveness of environmental interventions on a regional scale.

Delineation of social forestry plantations under various afforestation programmes using satellite digital data

Digital analysis of IRS 1A LISS-II (23-03-1991) data was used to delineate social forestry plantations in Matar taluka of Kheda district, Gujarat. VAX 11/780 image processing system was used to categorise the various plantations using supervised maximum likelihood classification. The classified output yielded three categories of plantations viz.,Eucalyptus spp.,Acacia spp., and mixed spp. The statistics for all the categories were also generated.

An Operational System for Generating Cloud Drift Winds in the Australian Region and Their Impact on Numerical Weather Prediction

The Australian Bureau of Meteorology has, since June 1992, produced cloud drift wind data for operational use. These data are used in the analysis cycle of the local operational numerical weather prediction system. This paper describes the methodology used for automatically producing cloud drift winds and also for their application to numerical weather analysis and prediction. Local processing of Geostationary Meteorological Satellite digital infrared data into cloud motion vectors has provided several advantages. It ensures timely availability of the data in the Australian National Meteorological Centre for the operational Regional Assimilation and Prediction (RASP) system. It allows quality control and, in particular, height assignment to be closely tied to the RASP system, which is consistent with the long-term requirement for the processing of these remotely sensed data to be done as part of the assimilation system. Importantly, use of the data has resulted in consistent improvements both in forecasts from the RASP system over the Australian region in real-time trials over several months and in forecasts over the Southern Hemisphere in a two-month trial with the Bureau of Meteorology Research Centre Global Spectral Model.

Chlorophyll Measurements in the Presence of Suspended Sediment Using Broad Band Spectral Sensors Aboard Satellites

ABSTRACT Concentrations of chlorophyll-a in waters with high average annual concentrations of suspended sediment were measured in three lakes and compared with broad band Landsat MSS satellite digital data for 104 dates between December 1976 and August 1988. Concentrations of chlorophyll-a ranged from 0.3 to 211 mg·m−3 for 452 measurements. Concentrations of suspended sediment ranged from 1 to 867 mg·l−1 in the same samples. In general, chlorophyll-a concentrations were inversely related to suspended sediment concentrations. Radiance and reflectance calculated from the four MSS bands increased as a function of increasing concentrations of suspended sediment. Radiance and reflectance were inversely related to the concentration of chlorophyll-a, but the relationships were not statistically significant. This study indicated that the measurement of chlorophyll-a with broad band (100 nanometer) MSS data in waters dominated by suspended sediments is not effective since the detection of the increased absorption or reflectance of radiation due to chlorophyll-a is masked by the spectral reflectance due to suspended sediments. In order to quantitatively determine chlorophyll by remote sensing in systems dominated by suspended sediment high spectral resolution information (10 to 15 nm band widths) at approximately 675 and 705 nanometers (nm) will be required.

Evaluation of model back trajectories of the Kuwait oil fires smoke plume using digital satellite data

This study evaluates the accuracy of the National Weather Service Medium Range Forecast (MRF) global model outputs in simulating the transport and dispersion of the Kuwait oil fire smoke plume. A technique was developed to analyze NOAA polar orbiting satellite imagery to obtain horizontal smoke plume positions. The plume heights were obtained by combining the satellite analysis with back trajectory results. Backward trajectories were computed using both coarse and fine resolution MRF wind fields. The average of the absolute value of relative trajectory error ([R.T.E.]) for the late summer period (24 July–15 September 1991) was about 10° o of the travel distance when using the fine grid trajectories with the optimum plume centroid height and 14° o when using the coarse grid model output. The absolute R.T.E. for the optimum plume height runs was half of the R.T.E. for the constant starting height run ([R.T.E.] = 0.21). This difference indicates the importance of proper specification of plume centroid height when using high resolution meteorological data for transport studies. Use of the standard coarse grid MRF wind fields to drive the transport model was shown to lead to large errors near the source due to the poor horizontal and vertical resolution.

Remote sensing of the impact of reindeer grazing on vegetation in northern Fennoscandia using SPOT XS data

Digital image analysis and SPOT XS satellite data recorded on 1 August 1991 were used to monitor vegetation in the border region between Enontekio municipality, Finland, and Kautokeino municipality, Norway. A supervised classification on the red wave length channel was undertaken using training areas for maximum likelihood classifier to produce seven spectral land cover classes. The classification revealed great differences in vegetation between Finland and Norway. The largest difference was the lack of Cladinalichens on the Finnish side of the border. The area on the Finnish side is used for grazing all year round, while the area on the Norwegian side is a winter range only. According to official data for the local reindeer population, the average annual grazing pressure (head/area/time) is higher on the Norwegian side of the reindeer fence. The Finnish grazing practice is believed to have a detrimental impact on the vegetation, and has lead to pasture land degradation.

Remote sensing of the impact of reindeer grazing on vegetation in northern Fennoscandia using SPOT XS data

Digital image analysis and SPOT XS satellite data recorded on 1 August 1991 were used to monitor vegetation in the border region between Enontekio municipality, Finland, and Kautokeino municipality, Norway. A supervised classification on the red wave length channel was undertaken using training areas for maximum likelihood classifier to produce seven spectral land cover classes. The classification revealed great differences in vegetation between Finland and Norway. The largest difference was the lack of Cladinalichens on the Finnish side of the border. The area on the Finnish side is used for grazing all year round, while the area on the Norwegian side is a winter range only. According to official data for the local reindeer population, the average annual grazing pressure (head/area/time) is higher on the Norwegian side of the reindeer fence. The Finnish grazing practice is believed to have a detrimental impact on the vegetation, and has lead to pasture land degradation.

Using spot satellite data to map impervious cover for urban runoff predictions

Environment planners are constantly seeking rapid, accurate, and cost‐effective techniques to determine land cover information associated with water quality and quantity during runoff events in urban watersheds. Traditionally, this is accomplished with field surveys, aerial photographs, and/or generalized published maps. These techniques can be time consuming and labor intensive. In this study, SPOT, 10 meter‐panchromatic, satellite digital data were used to classify and map impervious cover in an urban watershed in Dallas, Texas (USA). Using the image‐derived impervious cover map and a hydrologic runoff equation, urban storm water volumes were predicted for 1990 and 1991 with an 85% accuracy when compared to actual runoff data obtained from a U.S. Geological Survey (U.S.G.S) stream gauge station.

Mapping of satellite derived surface albedo on the Mitdluagkat Glacier, Eastern Greenland, using a digital elevation model and SPOT HRV data

Jacobsen, Anne, Allan R. Carstensen & John Kamper: Mapping of satellite derived surface albedo on the Mitdluagkat Glacier, Eastern Greenland, using a digital elevation model and SPOT HRV data. Geografisk Tidsskrift 93:6–18. Copenhagen 1993. An approach for obtaining reflectance factors and surface albedo on a glaciated surface in a high relief environment combining a digital elevation model and SPOT HRV satellite data is presented. The methodology has been applied on the Mitdluagkat Glacier, Ammassalik, Eastern Greenland. Correction of reflectance factors with respect to solar incidence angle permits classification of different glacial metamorphic fades favourably compared with published data on field measurements from other glaciated regions. Development of surface albedo on reflectance factors corrected for solar incidence angle enables spatial analysis of the glaciated surface thus providing mapping of local climate induced surface features and the spatial distribution of ablation and accumulation zones on the Mitdluagkat Glacier.

Digitally processed satellite data as a tool in detecting potential groundwater flow systems

Recent hydrologic research provides support for the regional groundwater flow systems concept. The fundamental unit of such a concept is a vertical section in which three groundwater regions are distinguished, namely: recharge, transition, and discharge regions. Simulation of regional groundwater flow models has been devised using this concept. This paper presents an investigation into the use of digital satellite data as a tool in identifying the potential of groundwater flow system areas. Digital radiance data collected by LANDSAT over Big Creek and Big Otter Creek basins in southern Ontario, Canada, have been utilized to delineate the principal groundwater regimes according to the proximity of the water table to the surface, i.e. discharge, recharge, and transition areas. During the spring, the modulating influence of ground water on the near-surface temperature enables such a classification to be performed using only the near-infrared energy band of the satellite. Such classification is directly comparable with thermal data collected by aircraft overflights of the watersheds. During the summer months, however, the presence of phreatophytic vegetation throughout the watershed requires that the visible energy band data be used in conjunction with the near-infrared data to effect such a classification scheme. The location of such groundwater flow systems provides valuable input to the hydrological modeling, the selection of sites for solid waste disposal and non-point-source modeling.