Remort sensing

Remort sensing

• 1.
  ©Joynal_Abedin_Coastal Zone Management-AEM-311 Symposium1. "Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analysing, and applying that information." Remote sensing: - “The art, science, and technology of observing an object, scene or phenomenon by instrument-based techniques. ‘Remote’ because observation is done at a distance without physical contact with the object or interest” -FAO_ITC (2013). Commandment 1. energy comes to the earth and a part is reflected and detected by a sensor; 2. this detection is captured as data, which is sent to a receiving station; 3. some pre-processing takes place in the receiving station, and then the pre-processed data is handed over to the users; 4. the users analyse the data for their own application. 1. Energy Source or Illumination (A) – the first requirement for remote sensing is to have an energy source which illuminates or provides electromagnetic energy to the target of interest. 2. Radiation and the Atmosphere (B) – as the energy travels from its source to the target, it will encounter and interact with the atmosphere it passes through. This interaction may take place a second time as the energy travels from the target to the sensor. 3. Interaction with the Target (C) - once the energy makes its way to the target through the atmosphere, it interacts with the target depending on the properties of both the target and the radiation. 4. Recording of Energy by the Sensor (D) - after the energy has been scattered by, or emitted from the target, we require a sensor (remote - not in contact with the target) to collect and record the electromagnetic radiation.
• 2.
  ©Joynal_Abedin_Coastal Zone Management-AEM-311 5.Transmission, Reception, and Processing (E) - the energy recorded by the sensor has to be transmitted, often in electronic form, to a receiving and processing station where the data are processed into an image (hardcopy and/or digital). 6. Interpretation and Analysis (F) - the processed image is interpreted, visually and/or digitally or electronically, to extract information about the target which was illuminated. 7. Application (G) - the final element of the remote sensing process is achieved when we apply the information we have been able to extract from the imagery about the target in order to better understand it, reveal some new information, or assist in solving a particular problem. These seven elements comprise the remote sensing process from beginning to end. We will be covering all of these in sequential order throughout. CZCS The Nimbus-7 satellite, launched in 1978, carried the first sensor, the Coastal Zone Colour Scanner (CZCS), specifically intended for monitoring the Earth's oceans and water bodies. The primary objective of this sensor was to observe ocean colour and temperature, particularly in coastal zones, with sufficient spatial and spectral resolution to detect pollutants in the upper levels of the ocean and to determine the nature of materials suspended in the water column. MOS The first Marine Observation Satellite (MOS-1) was launched by Japan in February, 1987 and was followed by its successor, MOS-1b, in February of 1990. These satellites carry three different sensors: a four-channel Multispectral Electronic Self-Scanning Radiometer (MESSR), a four-channel Visible and Thermal Infrared Radiometer (VTIR), and a two-channel Microwave Scanning Radiometer (MSR), in the microwave portion of the spectrum.
• 3.
  ©Joynal_Abedin_Coastal Zone Management-AEM-311 SeaWiFS TheSeaWiFS (Sea-viewing Wide-Field-of View Sensor) on board the SeaStar spacecraft is an advanced sensor designed for ocean monitoring. It consists of eight spectral bands of very narrow wavelength ranges (see accompanying table) tailored for very specific detection and monitoring of various ocean phenomena including: ocean primary production and phytoplankton processes, ocean influences on climate processes (heat storage and aerosol formation), and monitoring of the cycles of carbon, sulfur, and nitrogen. The orbit altitude is 705 km with a local equatorial crossing time of 12 PM. RADAR RADAR stands for RAdio Detection And Ranging. RADAR systems are active sensors which provide their own source of electromagnetic energy. Active radar sensors, whether airborne or spaceborne, emit microwave radiation in a series of pulses from an antenna, looking obliquely at the surface perpendicular to the direction of motion. When the energy reaches the target, some of the energy is reflected back towards the sensor. This backscattered microwave radiation is detected, measured, and timed. The time required for the energy to travel to the target and return back to the sensor determines the distance or range to the target. By recording the range and magnitude of the energy reflected from all targets as the system passes by, a two-dimensional image of the surface can be produced. Because RADAR provides its own energy source, images can be acquired day or night. Also, microwave energy is able to penetrate through clouds and most rain, making it an all-weather sensor. Because of the unique characteristics and applications of microwave remote sensing, OCEANOGRAPHIC APPLICATION Ocean applications of remote sensing include the following: 􀂄 Ocean pattern identification: 􀂄 currents, regional circulation patterns, shears 􀂄 frontal zones, internal waves, gravity waves, eddies, upwelling zones, shallow water bathymetry , 􀂄 Storm forecasting 􀂄 wind and wave retrieval 􀂄 Fish stock and marine mammal assessment 􀂄 water temperature monitoring 􀂄 water quality 􀂄 ocean productivity, phytoplankton concentration and drift 􀂄 aquaculture inventory and monitoring 􀂄 Oil spill 􀂄 mapping and predicting oilspill extent and drift 􀂄 strategic support for oil spill emergency response decisions 􀂄 identification of natural oil seepage areas for exploration 􀂄 Shipping 􀂄 navigation routing
• 4.
  ©Joynal_Abedin_Coastal Zone Management-AEM-311 􀂄traffic density studies 􀂄 operational fisheries surveillance 􀂄 near-shore bathymetry mapping 􀂄 Intertidal zone 􀂄 tidal and storm effects 􀂄 delineation of the land /water interface 􀂄 mapping shoreline features / beach dynamics 􀂄 coastal vegetation mapping 􀂄 human activity / impact The CZCS sensor ceased operation in 1986.