Altitude
Definition
Altitude in the context of geography refers to the height of an object or point in relation to sea level or ground level. Altitude is used extensively in aviation, where it is usually measured in feet. In the broader scientific context, altitude can also refer to the height of an object above the average surface of a celestial body such as Mars or Earth. This is distinguished from elevation, which measures height above the ground level.
Measurement
Altitude is primarily measured using three methods: barometric, radar, and geometric altitude.
Barometric Altitude
Barometric altitude is measured using a barometer, a device that measures atmospheric pressure. As altitude increases, atmospheric pressure decreases. This relationship is used to calculate the altitude. However, this method is not always accurate as atmospheric pressure can vary with weather conditions.
Radar Altitude
Radar altitude, also known as radio altitude, is measured using radar. A radar altimeter sends a radio wave down to the ground and measures the time it takes for the wave to bounce back. This method provides a very accurate measurement of the altitude above the ground level, but it does not provide the altitude above sea level.
Geometric Altitude
Geometric altitude is measured using a GPS or other satellite-based system. It provides the most accurate measurement of altitude above sea level. However, it requires a clear view of the sky and can be affected by factors such as signal strength and the number of satellites in view.
Impact on Human Body
The human body can be significantly affected by changes in altitude. These effects are primarily due to changes in atmospheric pressure and oxygen levels.
Acute Mountain Sickness
Acute Mountain Sickness (AMS) is a condition that can occur when a person ascends to a high altitude too quickly. Symptoms include headache, nausea, dizziness, and shortness of breath. Severe cases can lead to High Altitude Cerebral Edema (HACE) or High Altitude Pulmonary Edema (HAPE), both of which can be life-threatening.
Altitude Adaptation
The human body can adapt to high altitude through a process called acclimatization. This involves physiological changes such as increased breathing and heart rate, and production of more red blood cells to carry oxygen. However, acclimatization takes time and the rate of ascent must be carefully managed to avoid AMS.
Altitude in Aviation
In aviation, altitude is a critical factor in flight safety and efficiency. Aircraft are often assigned specific altitudes to fly at to avoid collisions and to take advantage of favorable wind conditions. Altitude is also a factor in aircraft performance, with many aircraft performing better at higher altitudes where the air is thinner.
Altitude and Air Traffic Control
Air Traffic Control (ATC) uses altitude to manage aircraft in flight. Aircraft are assigned specific altitudes to fly at based on their direction of flight, speed, and other factors. This helps to ensure separation between aircraft and prevent collisions.
Altitude and Aircraft Performance
Aircraft performance can vary significantly with altitude. At higher altitudes, the air is thinner, which can improve fuel efficiency but can also reduce engine performance. Pilots must carefully consider altitude when planning their flights.