What Remote Sensing is.

Active and Passive Remote Sensing.

How Remote Sensing works?

Spatial / Spectral / Temporal resolution.

Which instruments are used.

Applications of Remote Sensing. Gamma Rays X Rays Ultraviolet Waves Infrared Waves Micro Waves Radio Waves

NASA’S Satellites and their Latest Mission.

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Remote sensing is the collection and interpretation of information about the earth from far away. Information from space, the air and ships (taking measurements from the ocean depth) significantly aids our understanding of the Earth. Remote sensing is essential to accurately model the environment and map the earth for use in Geography Information Systems (GIS).

What Remote Sensing is What Remote Sensing is

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Active Systems: The sensor creates and emits its own energy, which is then detected and measured as it is reflected from objects. An example is radar.Passive Systems: Sensors detect and measure electromagnetic energy (energy from the sun) as it is reflected or reradiated from the Earth’s surface

Active and Passive Remote Sensing Active and Passive Remote Sensing

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All remote sensing systems such as satellites are dependent on energy. Energy comes in many forms, yet most traditional remote sensing systems measure wavelengths from within the electromagnetic spectrum.

How does Remote Sensing Work? How does Remote Sensing Work?

Humans can only see a small portion of the electromagnetic spectrum called visible light.

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Resolution Resolution

Spatial Resolution: a term that refers to the number of pixels utilized in the construction of digital images. Images with a higher spatial resolution are composed of a greater number of pixels than those with a lower resolution.

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Spectral Resolution: a term that refers to the width of the wavelength intervals measured in the electromagnetic spectrum. Remote sensors can collect data in the visible part of the spectrum (to provide images such as aerial photographs).Other sensors may collect data in the invisible sector like infrared and ultraviolet.

Temporal Resolution: also known as a repeat cycle or orbital cycle, describes the frequency with which images are collected from the same area. Temporal resolution may be continuous, several times a day, daily or once every few days

Instruments used in Remote Sensing Instruments used in Remote Sensing

Satellite images can be produced from a range of different sensors found on the remote sensing system, each used for different purposes.

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Applications of Remote Sensing. Applications of Remote Sensing.

Conventional radar is mostly associated with aerial traffic control, early warning, and certain large scale meteorological data. Doppler radar is used by local law enforcements’ monitoring of speed limits and in enhanced meteorological collection such as wind speed and direction within weather systems in addition to precipitation location and intensity.K

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Laser and radar altimeters on satellites have provided a wide range of data. By measuring the bulges of water caused by gravity, they map features on the seafloor to a resolution of a mile or so. By measuring the height and wavelength of ocean waves, the altimeters measure wind speeds and direction, and surface ocean currents and directions.

Remote sensing has enabled mapping, studying, monitoring and management of various resources like agriculture, forestry, geology, water, ocean etc. It has further enabled monitoring of environment and thereby helping in conservation. In the last four decades it has grown as a major tool for collecting information on almost every aspect on the earth. With the availability of very high spatial resolution satellites in the recent years, the applications have multiplied. 

Applications of Remote Sensing. Applications of Remote Sensing. K

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(Light Detection and Ranging: LIDAR) is well known in examples of weapon ranging, laser illuminated homing of projectiles. LIDAR is used to detect and measure the concentration of various chemicals in the atmosphere, while airborne LIDAR can be used to measure heights of objects and features on the ground more accurately than with radar technology. Vegetation remote sensing is a principal application of LIDAR.

Gamma Rays Gamma Rays

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Gamma Rays refers to electromagnetic radiation with a very high frequency. Gamma rays are created by radioactive decay. Scientists use Gamma rays (A Gamma Ray Spectrometer) to determine what makes up the surface soils of Mars.

X Rays X Rays

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X Rays refers to electromagnetic waves with a very short wavelength. Beams of X Rays are fired at substances to see what elements they contain. (E.g. They are used to determine the elements contained in rocks on Mars.) X rays can determine temperature, since temperature determines the wavelength of the radiation emitted by an object. The hotter the object, the shorter the wavelength.

Ultraviolet Waves Ultraviolet Waves

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Ultraviolet Radiation is found in sunlight and causes sunburn. Ozone (O3) protects us from the sun’s ultraviolet radiation. Ozone monitoring instruments in satellites monitor the amount of Ozone in the atmosphere.

Visible Light Waves Visible Light Waves

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Scientists can learn the composition of an atmosphere by considering how atmospheric particles scatter light. Nitrogen and Oxygen are just the right size to scatter the wavelength of blue light.

Infrared Waves Infrared Waves

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Long wave infrared radiation emitted by the earth is responsible for heating the atmosphere. Infrared cameras can penetrate regions with dense gas / dust particles. NASA’s Spitzer telescope was able to locate23 000 planet forming discs in the Orion Nebula by sensing the infrared glow of their warm dust. Our TV remotes use infrared light.

Microwaves Microwaves

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Microwaves are used in Doppler radar, which is used for short-term weather forecasting. Medium band microwaves can penetrate dust, smoke and clouds to reveal the earth’s surface. Satellite microwave measurements reveal the arctic sea ice cover every day even where clouds exist.

Radio Waves Radio Waves

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Many of the greatest astronomical discoveries have been made using radio waves (Pulsars, Plasma clouds and Quasars). Astronomical objects with magnetic fields usually produce radio waves (such as our sun). NASA’S Stereo satellite is able to monitor bursts of radio waves from the sun’s corona.

credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

NASA SATELLITE FLEET Satellites Satellites

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credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

NASA SATELLITE FLEET NASA Satellites NASA Satellites

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credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

NASA SATELLITE FLEET Landsat Landsat

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The instruments on the Landsat satellites have acquired millions of images.

The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional, planning, surveillance and education, and can be viewed through the USGS 'EarthExplorer' website.

Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters; the temporal resolution is 16 days.[2]

credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

NASA SATELLITE FLEET Recording data: Landsat Recording data: Landsat

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credit: NASA/Goddard Space Flight Center Scientific Visualization Studio

NASA SATELLITE FLEET Cloudsat Cloudsat

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Tropical Rainfall Measuring Mission (TRMM)Tropical Rainfall Measuring Mission (TRMM)

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NASA’S TERRA Satellite NASA’S TERRA Satellite

Orbiting Carbon Observatory: OCO-2 Orbiting Carbon Observatory: OCO-2Click on the images for the videos to play!

The earth is on the brink of a “mass extinction event” that could be similar to the one that killed off the dinosaurs 65 million years ago, a landmark study by international scientists has concluded.

Researchers warned that deforestation, climate change and overfishing had driven the extinction rates to 1000 times their normal level, Reuters reported.

Extract from the Sunday Times Newspaper 22 June 2014.

SMAP: NASA’S Latest Mission SMAP: NASA’S Latest Mission

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