Cloud ceilings, or the height of the lowest layer of clouds, are measured using various methods, including instruments that employ laser technology.
Cloud Height Indicator (CHI) Sensors
One modern method of measuring cloud ceilings involves using Cloud Height Indicator (CHI) Sensors. These sensors use a technology called LIDAR (Light Detection and Ranging), which is similar to radar but uses light instead of radio waves (3). Here’s how it works:
- Vertically Pointing Laser: The CHI sensor emits a laser beam vertically into the sky.
- Round Trip Time: When the laser beam encounters a cloud layer, it bounces back to the sensor.
- Height Calculation: The sensor measures the time it takes for the laser beam to travel to the cloud and back. Using this "round trip time" and the speed of light, the sensor calculates the height of the cloud layer.
Essentially, the CHI sensor acts like a laser-based measuring tape to determine the cloud height.
Other Methods
While not detailed in the provided references, it's worth noting that other historical or supplementary methods exist, such as estimating cloud height using trigonometry.
