EMR Spectrum Remote Sensing

The Electromagnetic Radiation (EMR) Spectrum is like a set of invisible waves that carry energy. In remote sensing, satellites and sensors use these waves to collect information about the Earth—like forests, water, cities, clouds, temperature, and more.

Just like how our eyes can only see visible light (like colors in a rainbow), sensors in remote sensing can "see" many more types of waves that humans can't.

Types of EMR Used in Remote Sensing:

Type of Wave	Wavelength	What It's Used For	Example
Visible Light	0.4 – 0.7 micrometers	To take normal satellite images	Google Earth pictures
Near-Infrared	0.7 – 1.0 µm	To check plant health	Green areas, farming
Shortwave Infrared (SWIR)	1.0 – 3.0 µm	To see moisture in soil and vegetation	Drought or wetness studies
Thermal Infrared (TIR)	8.0 – 14.0 µm	To measure surface temperature	Heat from buildings, forest fires
Microwaves	1 mm – 1 meter	To see through clouds and at night (radar)	Flood detection, weather, disasters

How Does It Work?

The Sun sends out energy waves.
These waves hit the Earth and reflect back.
Satellites or sensors in space or airplanes catch these waves.
Scientists study these waves to understand what is on the Earth—like whether an area has trees, water, buildings, or is too hot or cold.

What We See vs. What Sensors See

Our eyes can only see visible light.
But remote sensing sensors can "see" infrared, thermal, and microwaves—this helps us see things that are invisible to the human eye!

Key Points to Remember

✅ EMR spectrum has different types of waves—some short, some long.
✅ Each type of wave gives different information about the Earth.
✅ Remote sensing uses these waves to study our planet safely from space.
✅ It helps in weather prediction, disaster monitoring, farming, forest health, and city planning.

Comments

Natural Disasters

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Types of Remote Sensing

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geostationary and sun-synchronous

Orbital characteristics of Remote sensing satellite geostationary and sun-synchronous Orbits in Remote Sensing Orbit = the path a satellite follows around the Earth. The orbit determines what part of Earth the satellite can see , how often it revisits , and what applications it is good for . Remote sensing satellites mainly use two standard orbits : Geostationary Orbit (GEO) Sun-Synchronous Orbit (SSO) Geostationary Satellites (GEO) Characteristics Altitude : ~35,786 km above the equator. Period : 24 hours → same as Earth's rotation. Orbit type : Circular, directly above the equator . Appears "stationary" over one fixed point on Earth. Concepts & Terminologies Geosynchronous = orbit period matches Earth's rotation (24h). Geostationary = special type of geosynchronous orbit directly above equator → looks fixed. Continuous coverage : Can monitor the same area all the time. Applications Weather...

Linear Arrays Along-Track Scanners or Pushbroom Scanners

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India remote sensing

1. Foundational Phase (Early 1970s – Early 1980s) Objective: To explore the potential of space-based observation for national development. 1972: The Space Applications Programme (SAP) was initiated by the Indian Space Research Organisation (ISRO), focusing on applying space technology for societal benefits. 1975: The Department of Space (DoS) was established, providing an institutional base for space applications, including remote sensing. 1977: India began aerial and balloon-borne experiments to study Earth resources and assess how remote sensing data could aid in agriculture, forestry, and hydrology. 1978 (June 7): Bhaskara-I launched by the Soviet Union — India's first experimental Earth Observation satellite . Payloads: TV cameras (for land and ocean surface observation) and a Microwave Radiometer. Significance: Proved that satellite-based Earth observation was feasible for India's needs. 1981 (November 20): Bhaskara-II launche...

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