Immersive analytics is an emerging field of data exploration and analysis in immersive environments. It is an active research area that explores human-centric approaches to data exploration and analysis based on the spatial arrangement and visualization of data elements in immersive 3D environments. The availability of immersive extended reality systems has increased tremendously recently, but it is still not as widely used as conventional 2D displays. In this dissertation, we described an immersive analysis system for spatiotemporal data and performed several user studies to measure the user performance in the developed system, and laid out design guidelines for an immersive analytics environment. In our first study, we compared the performance of users based on specific visual analytics tasks in an immersive environment and on a conventional 2D display. The approach was realized based on the coordinated multiple-views paradigm. We also designed an embodied interaction for the exploration of spatial time series data. The findings from the first user study showed that the developed system is more efficient in a real immersive environment than using it on a conventional 2D display. One of the important challenges we realized while designing an immersive analytics environment was to find the optimal placement and identification of various visual elements. In our second study, we explored the iterative design of the placement of visual elements and interaction with them based on frames of reference. Our iterative designs explored the impact of the visualization scale for three frames of reference and used the collected user feedback to compare the advantages and limitations of these three frames of reference. In our third study, we described an experiment that quantitatively and qualitatively investigated the use of sonification, i.e., conveying information through nonspeech audio, in an immersive environment that utilized empirical datasets obtained from a multi-dimensional geophysical system. We discovered that using event-based sonification in addition to the visual channel was extremely effective in identifying patterns and relationships in large, complex datasets. Our findings also imply that the inclusion of audio in an immersive analytics system may increase users’ level of confidence when performing analytics tasks like pattern recognition. We outlined the sound design principles for an immersive analytics environment using real-world geospace science datasets and assessed the benefits and drawbacks of using sonification in an immersive analytics setting. / Doctor of Philosophy / When it comes to exploring data, visualization is the norm. We make line charts, scatter plots, bar graphs, or heat maps to look for patterns in data using traditional desktop-based approaches. However, biologically humans are optimized to observe the world in three dimensions. This research is motivated by the idea that representing data in immersive 3D environments can provide a new perspective that may lead to the discovery of previously undetected data patterns. Experiencing the data in three dimensions, engaging multiple senses like sound and sight, and leveraging human embodiment, interaction capabilities, and sense of presence may lead to a unique understanding of the data that is not feasible using traditional visual analytics. In this research, we first compared the data analysis process in a mixed reality system, where real and virtual worlds co-exist, versus doing the same analytical tasks in a desktop-based environment. In our second study, we studied where different charts and data visualizations should be placed based on the scale of the environment, such as table-top versus room-sized. We studied the strengths and limitations of different scales based on the visual and interaction design of the developed system. In our third study, we used a real-world space science dataset to test the liabilities and advantages of using the immersive approach. We also used audio and explored what kinds of audio work for which analytical tasks and laid out design guidelines based on audio. Through this research, we studied how to do data analytics in emerging mixed reality environments and presented results and design guidelines for future developers, designers, and researchers in this field.

yes / The importance of real-time processing of solar data especially for space weather applications is increasing continuously. In this paper, we present an automated hybrid computer platform for the short-term prediction of significant solar flares using SOHO/Michelson Doppler Imager images. This platform is called the Automated Solar Activity Prediction tool (ASAP). This system integrates image processing and machine learning to deliver these predictions. A machine learning-based system is designed to analyze years of sunspot and flare data to create associations that can be represented using computer-based learning rules. An imaging-based real-time system that provides automated detection, grouping, and then classification of recent sunspots based on the McIntosh classification is also created and integrated within this system. The properties of the sunspot regions are extracted automatically by the imaging system and processed using the machine learning rules to generate the real-time predictions. Several performance measurement criteria are used and the results are provided in this paper. Also, quadratic score is used to compare the prediction results of ASAP with NOAA Space Weather Prediction Center (SWPC) between 1999 and 2002, and it is shown that ASAP generates more accurate predictions compared to SWPC. / EPSRC

A dual satellite system in a Low Earth Orbit, LEO, would be beneficial to study the electromagnetic occurrences in the magnetosphere and their contributions to the development of the aurora events in the Earth's lower atmosphere. An orbit configuration is sought that would increase the total time that both satellites are inside the auroral oval. Some additional objectives include minimizing the total fuel cost and the average angle between the satellites' radius vectors. This orbit configuration is developed using a series of instantaneous burns applied at each satellite's perigee. An analysis of the optimal solutions generated by a Particle Swarm Optimization method is completed using a cost function with different weights for the time, fuel, and angle terms. Three different scenarios are presented: a single burn case, a double burn case, and a four burn case. The results are calculated using two different orbital mechanics models: an unperturbed two-body simulation and a two-body simulation with added Earth's equatorial bulge effects. It is shown that the added perturbation reduces the total event time in the optimal solutions generated. Specific weights for the cost function are recommended for further studies. / Master of Science

Thesis advisor: Prof. Michael J. Naughton / Thesis advisor: Dr. Cesar E. Valladares / The equatorial and low-latitude ionosphere of the Earth exhibits unique features on its structuring, coupling, and electrodynamics that offer the possibility to forecast the dynamics and fluctuations of ionospheric plasma densities at later times. The scientific understanding and forecasting of ionospheric plasma are necessary for several practical applications, such as for mitigating the adverse effects of space weather on communication, navigation, power grids, space mission, and for various scientific experiments and applications. The daytime equatorial electrojet (EEJ), equatorial ionization anomaly (EIA), as well as nighttime equatorial plasma bubble (EPB) and plasma blobs are the most prominent low-latitude ionospheric phenomena. This dissertation focuses on the multi-diagnostic study of the mechanism, properties, abnormalities, and interrelationships of these phenomena to provide significant contributions to space weather communities from the ground- and space-based measurements. A strong longitudinal, seasonal, day-to-day variability and dependency between EEJ, ExB vertical plasma drift, and total electron content (TEC) in the EIA distribution are seen in the equatorial and low-latitude region. In general, the EEJ strength is stronger in the west coast of South America than in its east coast. The variability of the EEJ in the dayside ionosphere significantly affects the ionospheric electron density variation, dynamics of the peak height of F2-layer, and TEC distributions as the EEJ influences the vertical transport mechanism of the ionospheric plasma. The eastward electric field (EEF) and the neutral wind play a decisive role in controlling the actual configuration of the EIA. The trans-equatorial neutral wind profile calculated using data from the Second-generation, Optimized, Fabry-Perot Doppler Imager (SOFDI) located near the geomagnetic equator and a physics-based numerical model, LLIONS (Low-Latitude IONospheric Sector) give new perspectives on the effects of daytime meridional neutral winds on the consequent evolution of the asymmetry of the equatorial TEC anomalies during the afternoon onwards. The spatial configurations including the strength, shape, amplitude and latitudinal extension of the EIA crests are affected by the EEF associated with the EEJ under undisturbed conditions, whereas the meridional neutral winds play a significant role in the development of their asymmetric structure in the low-latitude ionosphere. Additionally, the SWARM satellite constellation and the ground-based LISN (Low-Latitude Ionospheric Sensor Network) data allow us to resolve the space-time ambiguity of past single-satellite studies and detect the drastic changes that EPBs and plasma blobs undergo on a short time scale. The coordinated quantitative analysis of a plasma density observation shows evidence of the association of plasma blobs with EPBs via an appropriate geomagnetic flux tube. Plasma blobs were initially associated with the EPBs and remained at the equatorial latitude right above the EPBs height, but later were pushed away from geomagnetic equator towards EIA latitudes by the EPB/ depleted flux tubes that grew in volume. Further, there exists a strong correlation between the noontime equatorial electrojet and the GPS-derived TEC distributions during the afternoon time period, caused by vertical E × B drift via the fountain effect. Nevertheless, only a minor correlation likely exists between the peak EEJ and the net postsunset ionospheric scintillation index (S4) greater than 0.2. This study not only searches for a mutual relationship between the midday, afternoon and nighttime ionospheric phenomena but also aims at providing a possible route to improve our space weather forecasting capability by predicting nighttime ionospheric irregularities based on midday measurements at the equatorial and low latitudes. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

The inner magnetosphere modeling is an important component of the magnetosphere simulation frameworks with significant implications for space weather and a. principle methodology to understand the magnetospheric response to changes in the solar wind. The thesis shows our efforts in constructing and validating the contemporary Rice Convection Model (RCM) code and its interface as a next-generation code to predict electric fields, field-aligned currents, and energetic particle fluxes in the inner magnetosphere and subauroral ionosphere during geomagnetic disturbed times. The RCM was used to simulate the geomagnetic storms with fixed boundary conditions of time-dependent Tsyganenko-Mukai boundary conditions. This work shows the results of two extremely- strong storm events with significant interchange motion. The ring current injection predicted by the RCM is shown to be overestimated, consistent with the previous results of overestimating particle fluxes by the RCM. This effect is magnified here since the southward component of interplanetary magnetic field is very strong reaching about 50 nT. Time-dependent Borovsky's boundary condition is implemented and used to alleviate the huge pressure and get better tendency of ring current energy calculated by the Dessler-Parker-Sckopke relation. This work also describes a new module of generalized Knight's relation to compute the parallel potential drops from the calculated field-aligned currents through Vasyliunas equation. It gives different ionospheric conductance and plasma drift signatures particularly around the midnight. The inclusion of parallel electric fields will replace the treatments of energy flux in the substorm simulations since that the Hardy normalization cannot perform the desired function during the substorm expansion phase and the energy flux floor gives arbitrary enhanced the precipitating energy flux and ionospheric conductances at high latitude especially for the westward clectrojet around the midnight. Since the original Knight's relation gives too large field-aligned potential drop, the modified Knight's relation is applied and implemented successfully into the RCM. Therefore, the RCM is capable of real time event simulation including strong geomagnetic storms and magnetospheric substorms, although full validation of model predictions with typical observations remains to be done.

This work serves to present the background, approach, and selected results for the initial master thesis and prototyping phase of Open Space, a joint visualization software development project by National Aeronautics and Space Administration (NASA), Linköping University (LiU) and the American Museum of Natural History (AMNH). The thesis report provides a theoretical introduction to heliophysics, modeling of space weather events, volumetric rendering, and an understanding of how these relate in the bigger scope of Open Space. A set of visualization tools that are currently used at NASA and AMNH are presented and discussed. These tools are used to visualize global heliosphere models, both for scientific studies and for public presentations, and are mainly making use of geometric rendering techniques. The paper will, in detail, describe a new approach to visualize the science models with volumetric rendering to better represent the volumetric structure of the data. Custom processors have been developed for the open source volumetric rendering engine Voreen, to load and visualize science models provided by the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center (GSFC). Selected parts of the code are presented by C++ code examples. To best represent models that are defined in non-Cartesian space, a new approach to volumetric rendering is presented and discussed. Compared to the traditional approach of transforming such models to Cartesian space, this new approach performs no such model transformations, and thus minimizes the amount of empty voxels and introduces less interpolation artifacts. Final results are presented as rendered images and are discussed from a scientific visualization perspective, taking into account the physics representation, potential rendering artifacts, and the rendering performance.

Machine-learning algorithms are applied to explore the relation between significant flares and their associated CMEs. The NGDC flares catalogue and the SOHO/LASCO CME catalogue are processed to associate X and M-class flares with CMEs based on timing information. Automated systems are created to process and associate years of flare and CME data, which are later arranged in numerical-training vectors and fed to machine-learning algorithms to extract the embedded knowledge and provide learning rules that can be used for the automated prediction of CMEs. Properties representing the intensity, flare duration, and duration of decline and duration of growth are extracted from all the associated (A) and not-associated (NA) flares and converted to a numerical format that is suitable for machine-learning use. The machine-learning algorithms Cascade Correlation Neural Networks (CCNN) and Support Vector Machines (SVM) are used and compared in our work. The machine-learning systems predict, from the input of a flare¿s properties, if the flare is likely to initiate a CME. Intensive experiments using Jack-knife techniques are carried out and the relationships between flare properties and CMEs are investigated using the results. The predictive performance of SVM and CCNN is analysed and recommendations for enhancing the performance are provided. / EPSRC

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-08-14T14:56:36Z No. of bitstreams: 1 DANIELLE CAGLIARI DE LIMA – DISSERTAÇÃO (PPGMET) 2017.pdf: 3778584 bytes, checksum: 74013e9f2e77f7e02dbb6be83101aaf0 (MD5) / Made available in DSpace on 2018-08-14T14:56:36Z (GMT). No. of bitstreams: 1 DANIELLE CAGLIARI DE LIMA – DISSERTAÇÃO (PPGMET) 2017.pdf: 3778584 bytes, checksum: 74013e9f2e77f7e02dbb6be83101aaf0 (MD5) Previous issue date: 2017-08-29 / Capes / Estudos recentes mostram que o ciclo solar influencia os sistemas meteorológicos estratosféricos e troposféricos, proporcionando assim um novo quadro conceitual que reconsidera a evidência da influência solar no clima. Portanto, a principal proposta desse trabalho é investigar os possíveis efeitos dos ciclos solares nas anomalias da Temperatura da Superfície do Mar (ATSM). Para tanto, utilizou-se dados do número de manchas solares (NMS), proveniente do Royal Observatory of Belgium, de ATSM das áreas dos Niños 1+2, 3, 3.4 e 4, no Pacífico, e das áreas do Atlântico Tropical Norte e Sul, obtidos nos sites do CPC/NCEP/NOAA e do ESRL/NOAA, respectivamente, e de Oscilação Decenal do Pacífico (ODP), do ESRL/NOAA, todos dados mensais no período de dezembro/1949 a janeiro/2017. Objetivando filtrar as oscilações de escala intrasazonal, foi realizada a média móvel de três meses, com valor centrado no mês intermediário para todas as séries. Empregou-se o método dos quantis para classificar os períodos frios, neutros e quentes de cada área, considerando os 25% menores valores como períodos frios, os 25% intermediários como neutros e os 25% superiores como quente. Foram calculadas as médias e os desvios padrões do NMS para cada período e realizado o teste t de Student para comparar estas médias. Dessa forma verificou-se que, nos períodos de máximos do NMS, as ATSM no Pacífico e Atlântico Norte tendem para as condições neutras e as do Atlântico Sul para as frias. Para se verificar detalhes da relação entre as séries de ATSM e NMS, aplicou-se a análise espectral de transformadas Ondaletas Contínuas, Cruzadas e de Coerências, tendo como base a Ondaleta de Morlet. Os resultados demostraram haver influências dos ciclos solares de Hale (256 meses), de Schwabe (128 meses) e do seu segundo harmônico (64 meses) no comportamento das ATSM. Também foi observado que as ATSM nos oceanos Pacífico e Atlântico respondem de forma diferente ao forçante solar. Concluiu-se que os efeitos dos ciclos solares sobre as ATSM se dá de forma não linear, pois ocorreram mudanças de fases entre as séries ao longo do tempo. Quanto à diferença de resposta das ATSM do Pacífico e do Atlântico, ao forçante solar, acredita-se que seja devido à Anomalia Geomagnética do Hemisfério Sul e a fenômenos atmosféricos associados, mas não houve estudos contundentes a esse respeito, tanto que se sugerem pesquisas sobre a influência dos ciclos solares na circulação atmosférica, principalmente, para a região do Atlântico Sul. / Recent studies show that the solar cycle influences stratospheric and tropospheric meteorological systems, thus providing a new conceptual framework that reconsiders the evidence of solar influence on climate. Therefore, the main proposal of this work is to investigate the possible effects of solar cycles on Sea Surface Temperature Anomalies (SSTA). In order to do so, we used data of sunspot number (SN) from the Royal Observatory of Belgium, SST anomalies in the areas of Niños 1 + 2, 3, 3.4 and 4 in the Pacific, and North Atlantic and South Atlantic, in the Atlantic, obtained from the CPC/NCEP/NOAA and ESRL/NOAA sites, respectively, and Pacific Decadal Oscillation (PDO), from the ESRL/NOAA, all monthly data during the period of December/1949 to January/2017. A three-month moving average filter was applied on all series to remove the intraseasonal oscillations. The quantile method was used to classify the cold, neutral and warm periods of each area, considering the 25% lower values as cold periods, the 25% intermediate as neutral and the 25% higher as warm. The means and standard deviations of the SN were calculated for each period and Student's t-test was performed to compare these means. It was verified that, in periods of SN maxima, the SSTA in the Pacific and North Atlantic tended to neutral conditions and those from the South Atlantic to the cold. In order to verify details of the relation into the series of SSTA and SN, the spectral analysis of the Continuous Wavelet Transform, Cross-Wavelet Transform and Wavelet Coherence was used, based on Morlet wavelet. The results showed that there were influences of solar cycles of Hale (256 months), Schwabe (128 months) and its second harmonic (64 months) in the behavior of SSTA. It has also been observed that the SSTA in the Pacific and Atlantic oceans respond differently to the solar forcing. It was concluded that the solar cycles effects on SSTA occur in a non-linear way, as there were phase changes between the series over time. As for the difference in the response of the Pacific and Atlantic SSTA to the solar forcing, it is believed to be due to the Southern Hemisphere Geomagnetic Anomaly and associated atmospheric phenomena, but there have been no conclusive studies on this matter, so much so that researches are suggested on the influence of solar cycles on the atmospheric circulation, most importantly for the South Atlantic region.

Orientador: Paulo de Oliveira Camargo / Banca: João Francisco Galera Monico / Banca: Edvaldo Simões da Fonseca Junior / Banca: Cláudia Pereira Krueger / Banca: Moisés Ferreira Costa / Resumo: O erro devido à ionosfera nas observáveis GNSS (Global Navigation Satellite System) é diretamente proporcional à densidade de elétrons presente na ionosfera e inversamente proporcional a frequência do sinal. Da mesma forma que no posicionamento por ponto, os resultados obtidos no posicionamento relativo são afetados pelo efeito sistemático da ionosfera, que é uma das maiores fontes de erro no posicionamento com GNSS. Mesmo considerando que parte dos erros devido à ionosfera é cancelada na dupla diferenciação, a ionosfera pode causar fortes impactos no posicionamento relativo. O problema principal neste método de posicionamento é a variação espacial na densidade de elétrons, que pode ocorrer em função de vários fatores, tais como hora local, variação sazonal, localização do usuário, ciclo solar e atividade geomagnética. Dependendo das condições do clima espacial, que é controlado pelo Sol, a atividade geomagnética pode ser alterada de forma significativa, dando origem a uma tempestade geomagnética. Nesta pesquisa foram avaliados os efeitos da ionosfera no posicionamento relativo, com observações GNSS da fase da onda portadora (L1), nas regiões ionosféricas de latitude média e alta e na região equatorial. Nas duas primeiras regiões foram analisados os efeitos da ionosfera em períodos de irregularidades, decorrentes de tempestades geomagnéticas. Na região equatorial, que engloba o Brasil, foram analisados os efeitos da ionosfera em função da variação diária e sazonal. No processamento dos dados GNSS foi utilizado o GPSeq, que processa os dados na forma recursiva e fornece os Resíduos Preditos da Dupla Diferença da Fase (RPDDF) ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The error caused by ionosphere on GNSS (Global Navigation Satellite System) is directly proportional to the density of electrons from ionosphere and inversely proportional to the frequency squared of the signal GNSS. As in the case of point positioning, results in relative positioning are affected by systematic effect from ionosphere, which is one of major error sources in the GNSS positioning. Although some errors caused by ionosphere are canceled in double difference, strong impacts may be caused by ionosphere on the relative positioning. In this positioning the main problem is the spatial variation in electron density that can occur due local time, seasonal variation, user location, solar cycle, geomagnetic activity, etc. Depending on the conditions of space weather, in which is controlled by the Sun, the geomagnetic activity can be changed inducing geomagnetic storms. In this research the effects from ionosphere has been evaluated in GNSS relative positioning using L1 carrier phase observations, at the three regions of the ionosphere: middle and high latitudes and equatorial region. In regions of middle and high latitudes have been analyzed the effects from ionosphere in irregularities periods, caused by geomagnetic storms. In the equatorial region, including Brazil, have been analyzed the effects from ionosphere according daily and seasonal variation. In the processing GNSS data has been used GPSeq software. This software processes the data in a recursive form and provides the Predicted Residual of Carrier Phase Double Difference (PRCPDD) ... (Complete abstract click electronic access below) / Doutor

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O litoral cearense convive hoje com um dos maiores ensamentos litorÃneos brasileiro, isso ocorre porque, nas Ãltimas dÃcadas, a ocupaÃÃo das Ãreas litorÃneas para o turismo e habitaÃÃo tem se intensificado gradativamente. AtravÃs do estudo das dunas do municÃpio de Aquiraz pretendeu-se apreender a dinÃmica presente nesse setor litorÃneo e obter apÃs uma anÃlise detalhada um diagnostico ambiental, o qual propiciou a elaboraÃÃo de propostas de gestÃo para toda Ãrea estudada. Mas, a principal finalidade da pesquisa foi compreender a estrutura e funcionamento das dunas de maneira integrada. E entender como essas unidades naturais se comportam e interagem dentro do sistema litorÃneo. A Ãrea em que se desenvolvem as avaliaÃÃes situa-se no setor leste costeiro desse municÃpio e o campo de duna presente nesse setor sÃo umas das maiores expressÃes espaciais desse tipo de feiÃÃes no litoral nordestino brasileiro. A compreensÃo dos processos pretÃritos e presentes que contribuÃram na formaÃÃo dessas dunas, a identificaÃÃo das suas diferentes tipologias, a classificaÃÃo de acordo com o seu estado dinÃmico e individualizaÃÃo das suas geraÃÃes foi o nosso principal objetivo. A pesquisa encontra-se alicerÃado na Teoria GeossitÃmica e dentro dos procedimentos tÃcnicos e metodolÃgicos aplicados buscou-se a anÃlise espaÃo-temporal atravÃs da interpretaÃÃo de produtos cartogrÃficos de diferentes perÃodos, em uma faixa tempo de quase cinqÃenta anos. Diante do contexto a revisÃo bibliogrÃfica, anÃlise cartogrÃfica e etapa de campo foram cruciais para um maior conhecimento da Ãrea e para a concretizaÃÃo do trabalho. De acordo com os critÃrios adotados foram identificadas duas geraÃÃes de dunas e vÃrios tipos de morfologia, alÃm de alguns setores com formas de uso e ocupaÃÃo indevidas que estÃo provocando a degradaÃÃo das dunas e alterando a dinÃmica natural da Ãrea. Entretanto, o trecho estudado tem a maior parte das suas dunas ainda conservadas, em virtude de grande partes delas estarem sob proteÃÃo da LegislaÃÃo Federal. Ao final foi evidenciada a necessidade da implantaÃÃo de medidas de manejo ambiental capazes de minimizar os impactos ambientais nos trechos com ocupaÃÃes e de monitoramento, para que os setores de dunas mais conservados, nÃo se transformem em futuras de Ãreas de degradaÃÃo ambiental. / Ceara coast possesses one of the largest occupations of the coast Brazilian coast, this happens because, in the last decades, the occupation of the coastal areas for the tourism and house has if intensified gradually. Thr ough the study of the dunes of the municipal district of Aquiraz it intended to apprehend the present dynamics in that coastal areas and to obtain after a detailed analysis an environmental diagnose, which propitiated the elaboration of management proposals for every studied area. But, the main purpose of the research was to understand the structure and operation of the dunes in an integrated way. And to understand about those natural units behaves and they interact inside of the coastal system. The area that if was developed the evaluations locates in the coastal east of that municipal district and the field of present dune in that section are some of the largest space expressions of that type of features in the coast Brazilian Northeast. The understanding of the past and present processes that contributed in the formation of those dunes, the identification of their different typologies, the classification in agreement with their dynamic state and individualization of their generations was our main objective. The research is based in the Geosystem theory and inside of the technical and methodological procedures applied the analysis in a space of time was looked for through the interpretation of cartographic products of different periods, almost fifty year old. Before the context the bibliographical rev ision, cartographic analysis and field stage were crucial for a larger knowledge of the area and for the materialization of the research. In agreement with the adopted criteria they were identified in two generations of dunes and several morphology types, besides some areas with use and occupation forms that are provoking the degradation of the dunes and altering the natural dynamics of the area. However, the studied area has most of their dunes conserved still, because great parts of them to be under protection of the Federal Legislation. At the end the need of the implantation of environmental measures handling was evidenced capable to minimize the environmental impacts in the areas with occupations and of accompaniment, so that the dunes more conserved, don't change in the future in areas of environmental degrad ation.