Remote sensing in Plants
- 1. REMOTE SENSING PREPARED BY BASIM ANEES T
- 2. Remote sensing is the science of obtaining information about objects or areas from a distance, without coming direct contact with the object
- 3. It can be done with devices on the ground or on ships, planes and even satellites. This helps us to give a broad perspective on vegetation, climatic change, environmental issues etc.
- 4. Remote sensors collect data by detecting the energy that is reflected Remote sensors can be: Passive sensors respond to external stimuli They record natural energy that is reflected or emitted Passive sensors Active sensors
- 5. Active sensors use internal stimuli to collect data For example: A laser beam remote sensing system projects a laser beam onto the surface of earth and measures the time it takes for laser to reflect back to its sensors
- 6. APPLICATIONS Remote sensing is used in numerous fields like: Geography Earth science (Hydrology, ecology, oceanography, glaciology, geology) Military Intelligence Commercial, economic planning and humanitarian applications Vegetation and environment
- 7. ELEMENTS IN REMOTE SENSING Energy source Radiation and atmosphere Interaction with the target Recording of energy by sensors Transmission, reception and processing Interpretation and analysis
- 8. DATA ACQUISITION Data acquisition can be done using: Radars Satellites Ultrasound Lidar (light detection and ranging) Photometers and Radiometers Aerial photographs Seismographs Geodetic
- 9. Electromagnetic energy may be detected either photographically or electronically And image produced can be analog or digital Aerial photographs are examples of analog images, while satellite images are of digital images
- 10. SATELLITE SENSORS They revolve around the earth The path followed by a satellite is referred to as its orbit They are of two types: Geostationary Near polar
- 12. APPLICATION IN VEGETATION CLASSIFICATION The reflectance quality of a vegetation detected using remote sensors enables its classification Green vegetation will reflect more energy than dry vegetation Tree leaves and crop canopies reflect more in shorter radar wavelengths, While tree trunks and limbs reflect more in longer wavelengths
- 14. The density of the tree or plant canopy will affect the scattering of wavelengths Thus by analyzing reflectance, we can determine characteristics of a vegetation. Moreover, Aerial photographs, color infrared photographs, black and white infra red photographs helps to identify species. They also give the details of branching characteristics, crown shapes, spatial distribution and patterns of species.
- 16. This information along with the topographic variables obtained through field work is a valuable tool in vegetation classification Different types of images will display diverse characteristics of vegetation Band 1 of AVHRR (advance very high resolution radiometer) will allow chlorophyll to absorbed in red wavelength. And a low value indicate high concentration of chlorophyll
- 17. Similarly, Band 2 of AVHRR include infrared wavelengths and record the cell structure of the leaves High values indicate more growth, indicated by dark green signatures While low value are indicated by orange signatures
- 19. Some satellites that successfully identify vegetation types include: Landsat MSS Landsat TM SPOT HRV RADARSAT
- 20. LIMITATIONS Difficulty in distinguishing fine, ecological divisions between certain vegetation classes. If vegetation share common heterogeneous traits and similar spectral responses, difficulties are created in classifying vegetations
- 21. REMOTE SENSING IN ECOSYSTEM MANAGEMENT AND ENVIRONMENTAL ISSUES Remote sensing helps in : Habitat suitability mapping Monitor habitat loss and fragmentation Wetland mapping and monitoring Identifying and monitoring threats Predicting biodiversity richness Predicting species presence or absence
- 23. Provide data on vegetation land cover and pattern of distribution of plant communities Mapping and characterizing species habitats Identifying biodiversity Hotspots at broad spatial scale In measuring biological productivity Forest fire monitoring
- 25. For establishing base – lines and ongoing monitoring for deforestation, pollutant emissions, spread of invasive species, climate change impacts etc. Assisting in stratified random sampling strategies for field inventories. In carbon sequestration monitoring ( aforestation/deforestation) In coral reef monitoring Oil spill verification
- 26. To monitor marine protected areas Monitor desertification process To raise public awareness, e.g. Toms data on ozone hole, receding glaciers and climate change It can bring people together across boundaries to address common problems Powerful tool for international cooperation To detect changes in water and to test water quality
- 28. In Air quality – remote sensing of particulate aerosols in the atmosphere helps in this Conservation of endangered species To identify flood plains To update highly dynamic, rapidly changing coastal environment In distinguishing landscape categories etc.
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