This topic covers the basic principles of remote sensing, including how it is used in oceanography, the types of sensors and platforms used, and the electromagnetic spectrum.
Introduction to Remote Sensing
Key concepts, components, and applications
| Principle | Description | Example |
|---|---|---|
| Electromagnetic Spectrum (EMS) | Remote sensors detect radiation across wavelengths (UV, visible, NIR, SWIR, thermal, microwave). | Multispectral Landsat imagery uses visible‑NIR bands to map vegetation. |
| Interaction with Surface | Energy can be reflected, absorbed, transmitted, or scattered depending on material properties. | Dark water absorbs most NIR, appearing dark in that band. |
| Resolution Types | Spatial – size of ground pixel (e.g., 10 m). Spectral – number & width of wavelength bands. Temporal – revisit frequency (days to weeks). Radiometric – number of intensity levels (bits). |
High‑spatial (WorldView‑3, 0.31 m), high‑temporal (Sentinel‑2, 5‑day revisit). |
| Energy Sources | Passive – sensors detect natural radiation (sunlight, thermal emission). Active – sensors emit their own signal (radar, LiDAR). |
SAR (Synthetic Aperture Radar) penetrates clouds, works day/night. |
| Sensor | Platform | Wavelength | Key Uses |
|---|---|---|---|
| Optical (Multispectral / Hyperspectral) | Satellites (Landsat, Sentinel‑2), UAVs | Visible–NIR–SWIR | Land‑cover classification, vegetation health, mineral mapping |
| Thermal Infrared (TIR) | Satellites (Landsat‑8 TIRS, MODIS) | 8–14 µm | Surface temperature, fire detection, urban heat islands |
| Synthetic Aperture Radar (SAR) | Satellites (Sentinel‑1, RADARSAT) | Microwave (C, L, X bands) | Flood mapping, soil moisture, deformation monitoring |
| LiDAR (Light Detection and Ranging) | Aircraft, UAVs | Near‑infrared laser | High‑resolution elevation models, forest canopy structure |
| Passive Microwave Radiometer | Satellites (SMAP, AMSR) | Microwave | Soil moisture, sea‑ice concentration |
Mission Planning
Data Acquisition
Pre‑processing
Image Enhancement (optional)