What does visibility mean in weather?
Visibility is the greatest distance an observer can clearly see and identify objects. This depends on the weather and the clarity of the air. This parameter is very important for weather forecasting. Many important factor affect it. These include water droplets, ice crystals, dust, smoke,dense fog and pollution. The angle of the sun compared to the horizon also plays a role.
In weather science, visibility shows how clear the air is and affects daily life, travel, and flight safety.
How is visibility assessed?
Researchers usually measure visibility by studying how light moves through the air. Here’s a simple explanation of the process:
Ground-based observation
Manual Observation: This is the oldest and most common method. A ground observer looks at a distant object target.
This target could be something like a black panel or a lighthouse. Observers use their eyes or binoculars to judge how clearly the target can be seen. While simple, this method is influenced by the observer’s personal judgment.
Employment of specialized equipment:
With advances in technology, automated tools like visibility meters and scattering meters are now used to measure visibility. These devices send out a laser or light beam and measure how much it is scattered or absorbed as it travels through the air.
Satellite:
Satellite images can also provide visibility data over large areas. By analyzing the light reflected from the Earth’s surface, weather scientists can estimate visibility in different regions.
Aerial surveillance
In aviation, pilots check visibility while flying. They rely on their eyesight, which is important for flight safety. Additionally, some aircraft equip automated systems to measure affect visibility and deliver more precise data. How is visibility measured?
How is visibility determined?
Researchers usually measure prevailing visibility by studying how light moves through the air. Here’s a simple explanation of the process:
The climatic Optical Range (MOR) is used as the standard measure. MOR shows how far a parallel light beam travels.
This beam comes from a lamp with a color temperature around 2700 K. The light’s brightness drops to about 5% of its original level due to the atmosphere weakening it.
In practical use, an automated device sends out a light beam. It measures how much the light weakens because of scattering or absorption as it travels through the air. You can calculate the current visibility value by inverting this data and the MOR definition.
Reduce visibility depends on many factors like dust, humidity, and temperature. Because of this, researchers use special tools and algorithms to ensure accurate and reliable measurements.
In short, visibility is an important measure of how clear the air is. It is measured using different methods and can change a lot with the weather. Visibility affects aviation, road safety, and outdoor activities, so weather observations agencies worldwide closely watch it.
