8.14 Local Winds

8.14.2 Describe the development of sea breezes with reference to:

Sea breeze

The Sea Breeze is a cool, moist breeze that blows onshore during the day.

• The land heats up faster than the sea causing the air above the land to rise.
• This creates a low pressure above the land due to the decreased density.
• High pressure air from the sea moves inland to replace the low pressure above the land.

(a) horizontal and vertical limits around New Zealand;

• Sea breezes can travel inland as far as 25 – 40 km and have a vertical extent of approximately 2000 – 3000 ft.

(b) timing of the occurrence;

• Starts late morning around 10am and reaches maximum mid afternoon between 2pm and 4pm. Dies out early evening.

(c) average strength of the sea breeze;

• Sea breezes are strongest in the summer with clear skies and average around 10 – 15 knots in strength.

(d) associated cloud and precipitation;

• Fair weather cumulus mostly confined to the land.
• Associated precipitation is not common, unless in tropical regions where rain fall can occur at the peak of the sea breeze.

(e) associated turbulence.

• Turbulence due to obstacles such as sand dunes, trees, cliffs and hills can occur.

8.14.4 Describe the development of katabatic winds with reference to: