Final answer:
In meteorology, a 'high' refers to an area of high-pressure while a 'low' is an area of low pressure. A 'ridge' is an extended area of high pressure, and a 'trough' is an extended area of low pressure. These patterns help determine weather conditions, and are related to the concept that air pressure and density decrease with altitude, affecting activities such as mountain climbing.
Step-by-step explanation:
When referring to air pressure, the terms high, low, ridge, and trough relate to different features of atmospheric pressure patterns. A 'high' refers to a high-pressure area where the air density is higher, typically resulting in clearer skies and calmer weather. A 'low' indicates a low-pressure area, often associated with stormier conditions and increased precipitation. A 'ridge' is an elongated area of high atmospheric pressure, and a 'trough' is an elongated area of low pressure. These features influence weather patterns significantly and are often depicted on weather maps. As altitude increases, air density and pressure decrease, which is why the air at higher elevations is thinner. This is depicted in line graphs showing the relationship between altitude and air density, such as the graph in Figure A4 which demonstrates that a cubic meter of air at 500 meters weighs approximately one kilogram, compared to only about 0.023 kilograms at the top of Mount Everest. The varying atmospheric pressure at different altitudes explains why mountain climbers need oxygen tanks at high altitudes. As you climb a mountain, the decrease in air pressure and density means there is less oxygen available to breathe.