Q. For the measurement/estimation of which of the following are satellite images/remote sensing data used?

  1. Chlorophyll content in the vegetation of a specific location
  2. Greenhouse gas emissions from rice paddies of a specific location
  3. Land surface temperatures of a specific location

Select the correct answer using the code given below.

  • 1 Only
  • 2 and 3 only
  • 3 only
  • 1, 2 and 3

Answer: (d) 1, 2 and 3

Remote Sensing
  • Remote sensing is the acquiring of information from a distance. Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance (typically from satellite or aircraft).
  • Special cameras collect remotely sensed images, which help researchers “sense” things about the Earth. Some examples are:
    • Cameras on satellites and airplanes take images of large areas on the Earth’s surface, allowing us to see much more than we can see when standing on the ground.
    • Sonar systems on ships can be used to create images of the ocean floor without needing to travel to the bottom of the ocean.
    • Cameras on satellites can be used to make images of temperature changes in the oceans.
  • Some specific uses of remotely sensed images of the Earth include:
    • Large forest fires can be mapped from space, allowing rangers to see a much larger area than from the ground.
    • Tracking clouds to help predict the weather or watching erupting volcanoes, and help watching for dust storms.
    • Tracking the growth of a city and changes in farmland or forests over several years or decades.
    • Discovery and mapping of the rugged topography of the ocean floor (e.g., huge mountain ranges, deep canyons, and the “magnetic striping” on the ocean floor).
    • With the development of remote sensing from space, satellite data offers the possibility for measuring land surface temperature over the entire globe with sufficiently high temporal resolution and with complete spatially averaged rather than point values.
    • It is also possible to measure chlorophyll content in the vegetation of a specific location as chlorophyll will reflect more light in the green and near infrared spectrum compared to other wavelengths.
    • Remote sensing from satellites can also deliver information on green house gas(GHGs) soil emissions by estimating tropospherical, near-surface CO2 and CH4 concentrations based on the measurement of the intensity of the reflected sunlight in small wavelength bands in the visible and short-wavelength IR portion of the spectrum.
Indian Remote Sensing (IRS) Satellite System
  • The launch of India’s first civilian IRS-1A spacecraft in March 1988 marked the start of a successful journey for the Indian Space Programme.
  • The National Natural Resources Management System (NNRMS) governs Indian Earth Observation activities.
  • The Indian Earth Observation (EO) system has been providing operational services to the user community with a slew of payloads in the thematic series of Indian Remote Sensing Satellites (IRS) and the INSAT systems.
  • The Indian Remote Sensing Satellite System operates one of the world’s largest constellations of remote sensing satellites.
  • IRS satellites provide data at various spatial, spectral, and temporal resolutions.
  • The National Remote Sensing Centre (NRSC) serves as the hub for the distribution of remote sensing satellite data products in India and neighbouring countries.
  • NRSC has an earth station in Shadnagar, about 55 kilometres from Hyderabad, that receives data from nearly all modern remote sensing satellites.
  • IRS Satellites:
    • IRS-1A and IRS-1B
      • IRS-1A and IRS-1B were both launched in 1988 and 1991.
      • These satellites were designed primarily for remote sensing applications such as cartography, land use mapping, and forestry.
      • They had a spatial resolution of 36 metres and a 148-kilometer swath width.
    • IRS-1C and IRS-1D
      • IRS-1C and IRS-1D were both launched in 1995 and 1997.
      • With a spatial resolution of 5.8 metres and a swath width of 140 kilometres, these satellites outperformed their predecessors.
      • They were used for a variety of purposes, including mineral exploration, coastal monitoring, and disaster management.
    • Resourcesat-1, Resourcesat-2
      • Resourcesat-1 was launched in 2003, followed by Resourcesat-2 in 2011.
      • These satellites were designed primarily for resource mapping and management applications such as soil moisture mapping, crop inventory, and forestry.
      • They had a swath width of 23 kilometres and a spatial resolution of 5.8 metres.
    • Cartosat-1, Cartosat-2 and Cartosat-3
      • Cartosat-1, Cartosat-2, and Cartosat-3, respectively, were launched in 2005, 2007, and 2019.
      • These satellites were used for cartography as well as high-resolution imaging.
      • The spatial resolution of Cartosat-1 was 2.5 metres, while Cartosat-2 and Cartosat-3 were 1 metre.
      • Cartosat-1 data is used to create cartographic maps, update cadastral mapping, and create GIS applications.
      • Cartosat-3 also had the ability to capture hyperspectral images.
    • RISAT-1 and RISAT-2
      • RISAT-1 and RISAT-2 were both launched in 2009 and 2012.
      • These satellites were equipped with synthetic aperture radar (SAR) sensors, which allowed them to capture images of the Earth even when it was cloudy or dark.
      • The spatial resolution of RISAT-1 was 3.6 metres, while that of RISAT-2 was 1 metre.
    • Oceansat-1 and Oceansat-2
      • Oceansat-1 was launched in 1999, followed by Oceansat-2 in 2009.
      • These satellites were used for oceanographic applications such as mapping sea surface temperature, ocean colour, ocean wind vectors, chlorophyll concentrations are measured, phytoplankton blooms monitoring, and atmospheric aerosols and suspended sediments in the water are investigated.
    • Resourcesat-3
      • Resourcesat-3, which was launched in 2021, is the most recent addition to India’s fleet of remote sensing satellites.
      • This satellite is outfitted with cutting-edge sensors capable of capturing images with a spatial resolution of 5.8 metres and a swath width of 120 kilometres.
      • The primary application of Resourcesat-3 is for resource mapping and management applications such as crop monitoring, forestry, and water resource management.
    • SARAL
      • SARAL, or Satellite with ARgos and ALtiKa, is an ISRO and CNES (Space Agency of France) cooperative altimetry technology mission that was successfully launched on February 25, 2013.
      • The overall goals are to assess operational oceanography development, climate understanding, and forecasting capabilities.