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CHAPTER 4. ATMOSPHERIC CIRCULATION. INTRODUCTION. Mechanisms of global energy transfer Factors affecting the strength of the general circulation The importance of angular momentum The global circulation cells. GLOBAL SURFACE WIND ZONES AND PRESSURE CELLS.
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CHAPTER 4 ATMOSPHERIC CIRCULATION
INTRODUCTION • Mechanisms of global energy transfer • Factors affecting the strength of the general circulation • The importance of angular momentum • The global circulation cells
GLOBAL SURFACE WIND ZONES AND PRESSURE CELLS • The role of Pressure Gradient Force (PG) • Coriolis force and its influence on wind • Intertropical Convergence Zone (ITCZ) • The south-east trade winds • The subtropical high pressure belts • The westerlies • Polar circulation
UPPER TROPOSPHERIC – LOWER STRATOSPHERIC CIRCULATION • The geostrophic wind • The circumpolar vortex • Rossby Waves • Jet streams • Their creation • Influence on circulation • Geographical location
SYNOPTIC CIRCULATION BRINGS WEATHER VARIATIONS • Definition and scale • Characteristics of synoptic high pressure systems • Characteristics of synoptic low pressure systems • How to read a weather map • How high pressure aids egret migrations
BUSHFIRE WEATHER • (Blocking) high pressure affected by approaching cold front • Strong winds from the continental interior • High temperatures • Very dry conditions • Fuel availability
SYNOPTIC CIRCULATION PATTERNS OVER AUSTRALIA • Winter • SE trades affect the northern half (dry) • Westerlies influence the southern half • Alternating high and low pressure systems • Summer • NW monsoon affects the northern third • High pressure circulation affects the southern two-thirds • Influence of ocean along the coasts
WINDS ASSOCIATED WITH HIGHS AND LOWS • Pressure Gradient Force (PG) • Coriolis force (H) • Centrifugal force (C) • Friction (F) • Defining winds around highs and lows
REGIONAL AND LOCAL CIRCULATION • Defining the appropriate scale • Measuring the weather • Australian regional-scale circulation systems • Foehn winds • The southerly buster • West coast trough
LOCAL WIND ENVIRONMENTS • Drainage and katabatic flows • Anabatic winds • Sea breezes • Land breezes • Sea breeze ‘doctors’ in Western Australia • The Morning Glory (Gulf of Carpenteria)