How does wind over land change direction and speed compared to the gradient wind?
Veers 30° and decreases in strength by 2/3.
How does wind over water change direction and speed compared to the gradient wind?
Veers 10° and decreases in strength by 1/3.
Why does land have a greater effect on wind than water?
More friction from terrain, vegetation, and buildings slows and deflects wind.
Weather associated with low-pressure systems?
Cloudy, rain, strong winds
Weather associated with high-pressure systems?
Clear skies, light winds.
What weather is associated with cold fronts?
Rain, snow, severe weather, thunderstorms.
What is a trough in meteorology?
Area of low atmospheric pressure, often bringing cloud development, showers, and thunderstorms.
How do troughs appear on synoptic charts?
Dashed lines or marked with change in wind direction; often between high and low pressure systems.
How can troughs develop?
Interaction of different air masses, direction, moisture content, and temperature.
How does air behave in low-pressure systems?
Air warms, rises, and is replaced by surrounding air.
How does air behave in high-pressure systems?
Air cools, sinks, and spreads out.
Movement direction of high-pressure systems in the Southern Hemisphere?
Anticlockwise.
Movement direction of low-pressure systems in the Southern Hemisphere?
Clockwise.
What is the Coriolis Effect in the Southern Hemisphere?
Deflects moving air to the left relative to motion; to the right relative to the Earth.
What does “H” on a synoptic chart often indicate about wind turning?
Often see turns to the right.
What does “L” on a synoptic chart indicate about wind turning?
Almost all turns to the right (PG strong)
What happens to air at the poles?
Cold, sinks, moves toward the equator.
What happens to air near the equator?
Warm, rises, creating low pressure.
Why does Australia’s position shift between summer and winter on synoptic charts?
Due to movement of the equatorial trough and Intertropical Convergence Zone.
What is the pressure gradient (PG) effect on wind?
Air moves from high to low pressure; greater gradient = stronger wind.
