Natural Phenomena

Relative spectral reflectance is an illumination invarient image feature that is related to many ecological phenomena that are difficult to measure, such as plant CO2 uptake. We describe a procedure to estimate the relative spectral reflectance of known subject using ...

Realistic simulation of natural phenomena such as clouds is one of the most challenging problems facing computer graphics. The complexity of cloud formation, dynamics and light interaction makes real time cloud rendering a difficult task. In addition, traditional computer graphics methods involve high amounts of memory and computing resources, which currently limits their realism and speed. We propose an efficient and computationally inexpensive phenomenological approach for modelling and rendering cumulus clouds, by drawing on several approaches that we combine and extend. This paper focuses on the modelling of the cloud’s shape, rendering and sky model but is does not deal with the animation of the cloud.

In a world in growing turbulence, complexity and uncertainty, where crisis is becoming the norm rather than the exception, resilience is increasingly seen as a critical feature that reflects the capacity of a system to absorb disturbance and reorganize without collapsing. Resilient systems are more adaptable to change, are more able to learn and are less vulnerable to disturbance and

The intellectual achievements of ancient India lay scattered across several fields of study texts ranging from the Vedas and the Upanishads to a whole range of scriptural scientific and artistic sources. In ancient India, the development of knowledge in scientific disciplines like Astronomy, arithmetic, algebra, medicine, chemistry, biology were the results of meticulously accurate observations of natural phenomena. The contribution of ancient India in this field was not well documented but it is known to many prominent astronomers and physicists in the world. India stood in the highest position in the Vedic period. The objective of the study is to search the enrichment in Astronomy in ancient India. This study is a descriptive type of research based on secondary data gathered from ancient books, epics like Upanishad, Srimad Bhagavad Gita, articles, websites and web-based journals.

What's interesting about The Strait of Gibraltar?

The strange natural phenomenon of two non-mixed seas in the Strait of Gibraltar has invited amazement at the same time get the world's attention.

The fact is there is two water flowing, met but not mixed and separated.

The Strait of Gibraltar separates the continent of Africa and Europe, precisely between the countries of Morocco and Spain.

In the strait there are meetings of two different types of seas. The difference will be very clearly visible from the color of the sea. There is even a line that separates the two, and the unique water from both sides of the ocean is not mixed with each other.

Jan van Eyck’s depiction of nature and natural phenomena is without equal. It is true that some of his contemporaries excelled in painting particular facets of nature to such a degree that they actually surpassed him in fidelity: Pisanello (c. 1395–c. 1455) and his studies of birds, for example. Yet none came close to matching the comprehensive scope or precision of Van Eyck’s observation of the natural world. His hard-to-fathom realism has already been discussed in numerous studies, both en passant and in detail. I will limit myself in this essay to the scientific accuracy of the painter’s representation of nature and natural phenomena. The picture presented here is inevitably incomplete, for apart from the fact that Van Eyck’s oeuvre offers an inexhaustible wealth of detail, we need to realize that it has not survived intact. Karel van Mander (1548–1606) noted that he painted ‘from life’ (nae t’leven) and that it took him a great deal of time to paint his landscapes. And we know from Bartolomeo Fazio, for example, that the Lomellini Triptych contained an elaborate background landscape, even though the painting has disappeared without trace. Bearing in mind that our knowledge is fragmentary, this essay aims to draw a summary sketch of Van Eyck’s vision of nature, based on a combined scientific and art-historical analysis of specific natural phenomena. ‘Vision’ is intended here in both the literal sense of his observational powers and, insofar as possible, metaphorically too: how does nature fit into the way he conceived his art? Did Jan van Eyck view the world with different eyes from many of his colleagues? His acute observation of rocks, clouds, the moon and the silhouettes of birds in flight is unprecedented; for the most part, these are facets of nature to which painters before Van Eyck paid little heed, and that were not studied or painted in such detail by his contemporaries either. All the same, his powers of observation were not boundless, and this too will be highlighted as a corrective to his otherwise undisputed genius. Van Eyck’s paintings were not, moreover, mirrors of reality, or at least only partially so: they drew on a realism suffused with pictorial strategies. This is a fragmentary realism, manipulated and laden with symbolism.8 Van Eyck adjusted his observation of nature to his painterly vision of it, both consciously and unconsciously, and also to some extent out of necessity or pragmatism, given that it is plainly not possible to study and paint the entire natural world in extenso.

The work of Luciano Floridi lies at the interface of philosophy, information science and technology, and ethics, an intersection whose existence and significance he was one of the first to establish. His closely related concepts of a philosophy of information (PI), informational structural realism, information logic (IL), and information ethics (IE) provide a new ontological perspective from which moral concerns

Compuesto de tres capítulos, recopila de manera sencilla información sobre el efecto climático en Colombia del ENOS, sus efectos socioeconómicos directos e indirectos y sectoriales y las actividades de gestión de riesgo de desastres ejercidas a través de las entidades del SNGRD, resumiendo las fortalezas y vulnerabilidades de las acciones de gestión del riesgo de desastres actuales en Colombia. Uno de los mayores impactos del diagnóstico es que permita generar información pertinente y entendible para las entidades nacionales tomadoras de decisiones y para el público en general que favorezcan la gestión de riesgo en Colombia de manera más eficiente.

The stratigraphically important Tawaghat - Jipti Route corridor along Kali River Valley in Pithoragarh district of Uttaranchal State is characterized by formidable physical features. The lofty hill ranges, steep valleys, cliffs, gorges and huge accumulation of scree and debris mass owe their origin to complex physical, geologic and tectonic processes. Being a part of the active Himalayan orogenic belt, the natural hazards viz. landslides and earthquakes forms an integral part of the study area. In the investigated area, landslides are by far the most significant natural hazard in terms of damage caused to lives and properties. Landslides in the study area are triggered both due to natural phenomena (high rainfall, seismicity) and anthropogenic activities (road development and deforestation). Commonly observed slope failures include block slide, debris slide and earth creep. The presented study aims to develop a methodology that could produce a hazard map over a large area with higher degree of accuracy in a GIS environment; incorporating utility of information theory in landslide hazard zonation. In all, 37 variables are identified as conditioning and triggering factors and accordingly probabilistic prediction map is prepared by this method. On the basis of histogram distribution, the polygon elements are classified into five hazard classes viz. very low (Ij <= -0.02), Low (-0.02 < Ij < 0.103) moderate (0.10 <Ij <0.23), high (0.23 < Ij < 0.40) and very high (Ij > 0.40) landslide hazard prone zones. Further, this probabilistic prediction map is compared with the actual landslide map generated from recent satellite data (IRS ID LISS-III+PAN, December 2002) for the accuracy of prediction. The generated hazard maps agree with the observed landslide incidences. Thus, this adopted approach effectively proves its efficacy in deriving a reliable landslide hazard zonation.

This paper sets out to examine some of Riemann&#39;s papers and notes left byhim, in the light of the &quot;philosophical&quot; standpoint expounded in his writings on Naturphilosophie. There is some evidence that manyof Riemann&#39;s works, including his Habilitationsvortrag of 1854 on the foundations of geometry, may have sprung from his attempts to find a unified explanation for natural phenomena, on

Timely and accurate change detection of Earth's surface features is extremely important for understanding relationships and interactions between human and natural phenomena in order to promote better decision making. Remote sensing data are primary sources extensively used for change detection in recent decades. Many change detection techniques have been developed. This paper summarizes and reviews these techniques. Previous literature has shown that image differencing, principal component analysis and post-classification comparison are the most common methods used for change detection. In recent years, spectral mixture analysis, artificial neural networks and integration of geographical information system and remote sensing data have become important techniques for change detection applications. Different change detection algorithms have their own merits and no single approach is optimal and applicable to all cases. In practice, different algorithms are often compared to find the best change detection results for a specific application. Research of change detection techniques is still an active topic and new techniques are needed to effectively use the increasingly diverse and complex remotely sensed data available or projected to be soon available from satellite and airborne sensors. This paper is a comprehensive exploration of all the major change detection approaches implemented as found in the literature. Abbreviations used in this paper 6S second simulation of the satellite signal in the solar spectrumANN artificial neural networksASTER Advanced Spaceborne Thermal Emission and Reflection RadiometerAVHRR Advanced Very High Resolution RadiometerAVIRIS Airborne Visible/Infrared Imaging SpectrometerCVA change vector analysisEM expectation–maximization algorithmERS-1 Earth Resource Satellite-1ETM+ Enhanced Thematic Mapper Plus, Landsat 7 satellite imageGIS Geographical Information SystemGS Gramm–Schmidt transformationJ-M distance Jeffries–Matusita distanceKT Kauth–Thomas transformation or tasselled cap transformationLSMA linear spectral mixture analysisLULC land use and land coverMODIS Moderate Resolution Imaging SpectroradiometerMSAVI Modified Soil Adjusted Vegetation IndexMSS Landsat Multi-Spectral Scanner imageNDMI Normalized Difference Moisture IndexNDVI Normalized Difference Vegetation IndexNOAA National Oceanic and Atmospheric AdministrationPCA principal component analysisRGB red, green and blue colour compositeRTB ratio of tree biomass to total aboveground biomassSAR synthetic aperture radarSAVI Soil Adjusted Vegetation IndexSPOT HRV Satellite Probatoire d'Observation de la Terre (SPOT) high resolution visible imageTM Thematic MapperVI Vegetation Index