What is a scatterometer used for?
Scatterometers are active remote sensing instruments for deriving wind direction and speed from the roughness of the sea. They are used by low Earth orbiting satellites and act like radars: they transmit electromagnetic pulses and detect the backscattered signals.
What does a scatterometer measure?
Introduction. Microwave scatterometers are instruments that transmit low-power pulses of radiation toward the Earth’s surface at intermediate incidence angles and measure the intensity of the signals scattered back at the same angles from surface areas a few kilometers on a side.
Which NASA sensor measures wind over the ocean?
SeaWinds scatterometer
The SeaWinds scatterometer is a specialized microwave instrument that measures near-surface wind speed and direction all the time, even when it is cloudy. Although designed for measurements over the ocean, SeaWinds can also collect data over land and ice.
How does a scatterometer work?
A radar scatterometer operates by transmitting a pulse of microwave energy towards the Earth’s surface and measuring the reflected energy. A separate measurement of the noise-only power is made and subtracted from the signal+noise measurement to determine the backscatter signal power.
What is an active remote sensor?
Remote sensing instruments are of two primary types: Active sensors, provide their own source of energy to illuminate the objects they observe. An active sensor emits radiation in the direction of the target to be investigated. Reflected sunlight is the most common source of radiation measured by passive sensors.
What is the scientific study of wind?
Wind engineering describes the study of the effects of the wind on the built environment, including buildings, bridges and other man-made objects.
How has satellite technology helped the study of oceanography?
What are two ways satellite technology aids oceanographers and astronomers in studying the oceans and outer space? Satellite technology allows oceanographers and astronomers to collect data remotely and communicate across the globe and in real time.
What are examples of active sensors?
Examples of other active sensor-based technologies include: scanning electron microscopes, LiDAR, radar, GPS, x-ray, sonar, infrared and seismic.
What is the difference between an active and a passive remote sensor?
Remote sensing systems which measure energy that is naturally available are called passive sensors. Passive sensors can only be used to detect energy when the naturally occurring energy is available. Active sensors, on the other hand, provide their own energy source for illumination.
How accurate are satellites?
Satellites transfer location information to your device through radio waves. It’s accurate for 7.8 meters, 95% of the time.
What do you need to know about scatterometers?
Scatterometers are microwave radar sensors that measure the normalized radar cross section of the surface, scanned from an airplane or a satellite. Scatterometers are a kind of active microwave remote sensors, which transmit microwave pulses down to the Earth’s surface and then measure the power that is returned to the instrument.
What is the purpose of a scatterometer radar?
A scatterometer is a microwave radar sensor used to measure the reflection or scattering effect produced while scanning the surface of the earth from an aircraft or a satellite. The SeaWinds scatterometer is a microwave radar designed specifically to measure ocean near-surface wind speed and direction.
How are scatterometers used to measure radiometric resolution?
Scatterometers are sidelooking radar sensors designed to precisely evaluate the radar backscatter coefficient σ0 of the surfaces being observed. However, as we will aim to demonstrate, this high radiometric resolution is obtained at the cost of spatial resolution.
How is Sigma-0 calculated in a scatterometer?
Sigma-0 (σ⁰) is computed from the signal power measurement using the distributed target radar equation. Scatterometer instruments are very precisely calibrated in order to make accurate backscatter measurements.