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characteristics of electromagnetic radiation in remote sensing

Wavelength is usually represented by the Greek letter lambda (λ). High-pitched sounds have short wavelengths and high frequencies. Understanding the characteristics of electromagnetic radiation in terms of their wavelength and frequency is crucial to understanding the information to be extracted from remote sensing data. Frequency is normally measured in hertz (Hz), equivalent to one cycle per second, and various multiples of hertz. Optical remote sensing devices operate in the visible, near infrared, middle infrared and short wave infrared portion of the electromagnetic spectrum. Hospitals use imaging technology, including CAT scans, magnetic resonance imaging (3-D imaging of soft tissue), and x-rays for examining our bodies. The sun provides the initial energy source for much of the remote sensing of the Earth surface. As a train or race car advances towards us, our ears tend to hear progressively lower sounds or frequencies (shorter wavelengths) until it reaches us, the original frequency of the object when it is broadside, then even lower frequencies as it moves further away. Sensors detect and measure electromagnetic energy in different portions of the spectrum. Both have the same amplitude at the same time. This involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials, by which they may be … Low sounds are the opposite. %PDF-1.5 %���� Electromagnetic Radiation. The wavelength and frequency are the two important characteristics of this electromagnetic radiation. The answer is ... Answer 1: The most obvious source of electromagnetic energy and radiation is the sun. Principles of remote sensing Detection and discrimination of objects or surface features means detecting and recording of radiant energy reflected or emitted by objects or surface material. The measurement of this radiation takes place in what are known as spectral bands. Remote sensing provides a synoptic view that carries a continuous record of the environment that is consistent. Wavelength and frequency are inversely related, meaning as one increases the other decreases. Both these fields travel at the speed of light (c). In addition, the use of drones is emerging due to the high-resolution data that can be collected in a short time for real-time monitoring. Remote sensing makes it possible to collect data of dangerous or inaccessible areas. This same principle (applied to light) is used by astronomers to see how quickly stars are moving away from us (the Red shift). The wavelength is the length of one wave cycle, which can be measured as the distance between successive wave crests. h�b```a``�a�``0abf@ afV�,�7 ������AS��ܙ�g,dH����|Ό��{=TMD�+���}K����ÆC?V�Dĭ���>&��9���֏w$�..H�ؒ������h�� ���������V�V� �Ѐ� ˜AP9�. Different Two characteristics of electromagnetic radiation are particularly important for understanding remote sensing. Summary Remote sensing is the measurement and recording of the electromagnetic radiation emanating from the earth’s environment by sensors mounted on a platform at a vantage point above the earth’s surface. Wavelength is usually represented by the Greek letter lambda (λ). The vital concepts of spatial resolution and detection are explained using the eye as an example of remote sensing system. This energy is in the form of electromagnetic radiation. The relationship between wavelength and frequency is described by the following formula: c = λ x ν c = Speed of Light (… If you have studied an engineering or physical science discipline, much of this may be familiar to you. Express your answer in micrometres(μm). We have to understand clearly these two properties in this context. The first chapter of the book summarizes the fundamental characteristics of electromagnetic radiation and the interactions of radiation with matter that are the basis of remote sensing. The sensor is merely a passive observer collecting electromagnetic radiation. electromagnetic radiation). h�bbd```b``��`� ,rLւH�V����"�����@���* �q=#�� �D�����0 .= 0 The electromagnetic spectrum is the term used to describe to entire range of all possible frequencies of electromagnetic radiation. You will not receive a reply. Active sensors, provide their own source of energy to illuminate the objects they observe. Print. All matters reflect, emit or radiate a range of electromagnetic energy, depending upon the material characteristics. However, later … 7. Remote sensing is the part of geospatial technologies that deals with the detection of electromagnetic radiation to determine characteristics without direct contact. There are other types of light which are invisible to us...but more about that later. These sensors measure land and sea surface temperature, vegetation properties, cloud and aerosol properties, and other physical properties. These are the wavelength and frequency. 1 mm - 1 m The shortest wavelengths in this range have properties similar to thermal infrared region. • EMR is a dynamic form of energy. Scientists say that the Earth itself vibrates at a very low frequency, making a sound far below the human hearing range. The shorter the wavelength, the higher the frequency. In particular, microwave remote sensing uses electromagnetic radiation with a wavelength between 1 cm and 1 m (commonly referred to as microwaves) as a measurement tool. Electromagnetic radiation spans a large spectrum of wavelengths starting from very short wavelengths, γ-ray (10 10 m) to long radio waves (10 6 m). Passive remote sensing systemsmeasure existing radiation such as the reflected solar radiation from the earth’s surface. Some Earth surface Electric and magnetic fields obey the properties of superposition so that a field due to any particular particle or time-varying electric or magnetic field will contribute to the fields present in the same space due to other cau… The wavelength is the length of one wave cycle, which can be measured as the distance between successive wave crests. Lesson 4 Sensors Characteristics. Fundamentals of Remote Sensing 1.2 Electromagnetic Radiation As was noted in the previous section, the first requirement for remote sensing is to have an energy source to illuminate the target (unless the sensed energy is being emitted by the target). An active sensor emits radiation in the direction of the target to be investigated. The shorter the wavelength, the higher the frequency or the longer the wavelength, the lower the frequency. Assume the speed of light to be 3x108 m/s. The remote sensing device that we humans use to detect radiation from the sun is our eyes. Most sensors record the EMR in this range, e.g., bands of IRS P6 LISS IV sensor are in optical range of EMR. This is appropriate because EMR often displays wavelike characteristics; e.g., interference. Remote sensing systems are divided into two groups based on separate technical solutions. Sensor is an electronic circuit which can record the electromagnetic radiation incident upon it. Understanding the characteristics of electromagnetic radiation in terms of their wavelength and frequency is crucial to understanding the information to be extracted from remote sensing data. active and passive. These are the wavelength and frequency. Wavelength is usually represented by the Greek letter lambda (&lambda). 4.1 Remote Sensing Sensors. In remote sensing, we are most interested in measuring the radiation reflected from targets. Electromagnetic radiation consists of an electrical field(E) which varies in magnitude in a direction perpendicular to the direction in which the radiation is traveling, and a magnetic field (M) oriented at right angles to the electrical field. All electromagnetic radiation has fundamental properties and behaves in predictable ways according to the basics of wave theory. Remote sensing instruments are of two primary types—. �3�A�A���I�K���|������3���zH�. These are the wavelength and frequency. Electromagnetic radiation is a form of energy emitted by all matter above absolute zero temperature (0 Kelvin or -273° Celsius). Both these fields travel at the speed of light (c). These are the wavelength and frequency. In remote sensing, it is the measurement of electromagnetic radiation reflected or emitted from an object, is the used to identify the target and to infer its properties. Answer 2: Using the equation for the relationship between wavelength and frequency, let's calculate the wavelength of radiation of a frequency of 500,000 GHz. The first requirement for remote sensing is an energy source which can illuminate a target. Two characteristics of electromagnetic radiation are particularly important for understanding remote sensing. Electromagnetic Radiation Source of Remote Sensing data. The wavelength is the length of one wave cycle, which can be measured as the distance between successive wave crests. Most passive systems used by remote sensing applications operate in the visible, infrared, thermal infrared, and microwave portions of the electromagnetic spectrum. Yes, they can be considered remote sensors - and very good ones - as they detect the visible light from the sun, which allows us to see. ...you can use an oscilloscope, a special electronic device which displays waves similar to the electromagnetic radiation waves you have seen here, to look at the wavelength and frequency patterns of your voice. For most purposes, the ultraviolet or UV portion of the spectrum has the shortest wavelengths which are practical for remote sensing. X-rays, ultraviolet rays, visible light, infrared light, heat, microwaves, and radio and television waves are all examples of electromagnetic energy. Remote Sensing is a set of multidisciplinary techniques and methodologies that aim at obtaining information about the environment through “remote” measurements. Remote sensing involves the measurement of energy in many parts of the electromagnetic (EM) spectrum. • The whole range of EMR is called spectrum. Microwave Region This is the longest wavelength used in remote sensing. • The foundation of remote sensing technology is based on the measurement and interpretation of the patterns of EMR. Passive remote sensing refers to the sensing of electromagnetic waves that did not originate from the satellite or instrument itself. Characteristics as Wave motion: EMR can be considered as a transverse wave with an electric field and a magnetic field, located at right angles to each other. Section 1.2 Electromagnetic Radiation These are all examples of non-intrusive remote sensing methods. %%EOF The goal of this article is to provide an introduction to the basics of satellite remote sensing with a special focus on the principles, characteristics, analysis, and applications of remote sensing data acquired in different parts of the electromagnetic spectrum.

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