Chapter 6

the force exerted by the weight of a column of air above a particular location

serves as the division between what we call “high pressure” and “low pressure” at the surface

values greater than 1013.2 mb

below 1013.2 mb

nothing more than the movement of air molecules from one place to the next

The spacing of isobars indicates the change in pressure over distance

a mass moving in a rotating system experiences a force acting perpendicular to the direction of motion and to the axis of rotation

The friction imposed on air mechanically slows the wind and diverts its direction.

areas of low pressure

areas of high pressure that exhibit nearly circular isobars

moving towards a point/area

moving away from a point/area

The Equatorial trough

Upper air convergence and radiational cooling cause the air to subside in the subtropics. As the air reaches the surface, atmospheric pressure increases forming the subtropical highs

The polar easterlies collide with the westerly wind belt at about 60 N and S creating a broad belt of low pressure

dome of high pressure created by loss of energy at the poles

the pressure gradient between the high at 30 N and the low over the equator

wind belt

Air moving equatorward is turned in an easterly direction

wind that changes direction with season

created along coasts where land and water create variations in pressure due to differences in the way these two bodies heat and cool.

a warm dry wind on the leeward side of a mountain

During the daytime, mountain slopes warm causing the air over the slope to be warmer than the air over the valley at the same elevation. Warming the air causes it to rise upwards creating a valley wind. During the evening, the air chills due to a loss of surface energy to space. The cool dense air moves down slope as a mountain wind.

warm and dry wind.