175. Remote sensing of ocean-atmospheric parameters carried out in the microwave channels is based on the
phenomenon of:
(1) emission.
(2) reflection.
(3) scattering.
(4) diffraction
Remote Sensing in Microwave Channels: Why Emission Matters
Remote sensing plays a critical role in studying Earth’s oceanic and atmospheric systems. Among the various sensing technologies, microwave remote sensing stands out due to its ability to penetrate clouds and function in all weather conditions. But what makes this possible? The answer lies in the phenomenon of emission.
What Is Microwave Remote Sensing?
Microwave remote sensing involves detecting natural or artificial microwave radiation from Earth’s surface and atmosphere. Unlike visible or infrared sensors, microwave sensors can gather data regardless of cloud cover, time of day, or weather conditions.
There are two main types:
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Passive microwave sensing – relies on natural emission from objects.
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Active microwave sensing – sends a signal and measures the backscatter (like radar).
Why Emission Is Key
In passive microwave sensing (which is used to study many ocean-atmosphere parameters), objects naturally emit microwave radiation due to their temperature. This emission carries information about:
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Sea surface temperature
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Soil moisture
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Ocean salinity
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Wind speed over oceans
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Rainfall rates
The sensor detects this thermal emission, which varies with temperature and electrical properties of the surface or atmosphere.
Other Options Explained
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Reflection: More relevant in optical remote sensing (e.g., visible and infrared light).
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Scattering: Important for radar and active systems, but not the primary mechanism in passive microwave sensing.
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Diffraction: A wave-based phenomenon, not typically used as a sensing principle in microwave remote sensing.
Applications in Ocean-Atmosphere Monitoring
Microwave emission data is vital for:
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Weather prediction
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Climate studies
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Tracking hurricanes and cyclones
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Monitoring sea ice and polar regions
Satellites like SMAP (Soil Moisture Active Passive) and AMSR-E (Advanced Microwave Scanning Radiometer) use this principle extensively.
Conclusion
Remote sensing in microwave channels relies heavily on natural emission phenomena, making it a powerful tool for continuous, real-time monitoring of our oceans and atmosphere. It provides reliable data even when optical sensors fail, making it indispensable for Earth observation.
