Remote Sensing

What is remote sensing?

Remote sensing can be defined as the practice of observing earth’s land and water surfaces through images acquired from a distance, using reflected or emitted electromagnetic energy (Campbell et al, 2011). The process, factors and uses of the remote sensing technique will be explored throughout this blog.

The history of remote sensing

Remote sensing could be argued to have started from the first photograph in 1839, and developed as images and image acquisition progressed. However, the term remote sensing was not being used in research until the 1960’s (Campbell, 2011). Remote sensing has since been able to progress, as global technology improved and knowledge was expanded. The first earth-orbiting satellite for observation was Landsat-1, launched in 1972 (Campbell, 2011). Satellites and methods of observing the Earth continued to develop, with global coverage remote sensing being established in the 1990s (Campbell, 2011). The first satellite with the specific aim to obtain global coverage was the NASA Terra-1 in 1999, designed to monitor changes in Earth’s ecosystems (Campbell, 2011). Future developments are focusing on making remotely sensed data more accessible to a greater number of people (Schmidt, 2011). Advances are also being made in hyperspectral remote sensing, and equipping satellites with ‘active’ sensors (Schmidt, 2011). These developments will improve remotely sensed data by extracting greater amounts of data, and allowing for greater targeting of areas to observe (Schmidt, 2011).

Examples of Sensors and Satellites:

landsat7_orbit2


Image of the Landsat-7 satellite (sourced from: NASA, 2016)

SENSOR – SATELLITES

  • MODIS – Terra

  • Hyperion – EO

  • ETM – Landsat-7

  • MSS (multi-spectral scanner system) – World View

It will be interesting to discover what each of these sensors, and others, are most appropriate and best used for, and why. I hope to find out the difference in sensors, and why some are better at monitoring features than others. I aim to find this out by first learning how sensors work and differ, and then how these are put into practical use.

Remote sensing can be used to monitor:

  • Climate change and it’s effects

  • Vegetation cover and productivity

  • Anthropogenic effects on land and land cover

  • Photosynthesis occurrence

  • Effect and extent of natural disasters

  • Extents and shifts in ecosystems and ecosystem boundaries

References:

Campbell, J.B., and Wynne R.H. (2011) Introduction to remote sensing, 5th edition, Guildford press.

NASA (2016) Landsat Science. Available at: http://landsat.gsfc.nasa.gov/?page_id=2290 (accessed on 20/05/2016).

Schmidt, C.W. (2011) Beyond the Internet, RAND, Available at: http://smapp.rand.org/ise/ourfuture/Internet/sec4_sensing.html

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