Circulation in the Atmosphere Circulation in the atmosphere

Circulation in the Atmosphere Circulation in the atmosphere

What regulates the motion of fluid particles in the ocean and atmosphere? Newton’s Law

What drives the circulation of the atmosphere? Differential Heating From Equators to Poles

What drives the circulation of the atmosphere? troposphere surface Equator/Tropics Higher Latitudes

Vertical view of air pressure (global convection) High Pressure Low Pressure

Horizontal view of air pressure at ocean surface High Pressure + Higher Latitudes Surfaces of constant pressure y (latitude) x (longitude) _ Low Pressure Equator/Tropics

v y (latitude) Newton’s Law x (longitude) u Motion across Latitudes Motion along Latitude

Non rotating view of Atmospheric Circulation

Hurricane IVAN H L H H H

Rate of Rotation North Hemisphere Low Pressure B t 3 t 4 t 2 t 5 t 1 A F pressure High Pressure F Coriolis

v y (latitude) Newton’s Law x (longitude) u Motion across Latitudes Motion along Latitude

Rate of Rotation North Hemisphere A t 1 Low Pressure t 2 High Pressure B t 3 t 4 F t 5 F Coriolis pressure

v y (latitude) Newton’s Law x (longitude) u Motion across Latitudes Motion along Latitude

F pressure F Coriolis F pressure F F F Coriolis F pressure Coriolis When this balance is reached the movement of the particles (and therefore of the flow) is called geostrophic motion

v y (latitude) Newton’s Law x (longitude) u Motion across Latitudes Motion along Latitude

Some practical rules to remember: F pressure F Coriolis Low Pressure High Pressure 1) Particle will have the Coriolis force 90 degrees to the right 2) Particles will tend to move along line of constant pressure 3) Particles will have the high pressure on their right (same as Coriolis)

Hurricane IVAN H LF H H pressure H F Coriolis

Vortices LF HF pressure F Coriolis Low Pressure System Coriolis F pressure High Pressure System

Atmosheric Circulation Important Concepts to remember: Redistribution of Heat Effects of Rotation The role of friction Conservation of angular momentum

Differential Heating From Equators to Poles

Non rotating view of Atmospheric Circulation High Pressure Low Pressure

Schematic depiction of the development of the atmospheric circulation, starting from a state of rest Easterlies (Trades) Westerlies Redistribution of Heat – Large scale convective Cells

Schematic depiction of the development of the atmospheric circulation, starting from a state of rest Easterlies (Trades) Westerlies

Problem? Circulation in the atmosphere

Role of Friction

Schematic depiction of the development of the atmospheric circulation, starting from a state of rest Easterlies (Trades) Westerlies

Diagram of Atmospheric Circulation in the atmosphere

Vertical view of the atmosphere and Poleward Transport of Heat Hadley Cell Polar Cell Pole Ferrel Cell Equator

Midlatitude Cyclones

Poleward Heat Transport

Role of Friction on synoptic scales

Vortices LF HF pressure F Coriolis Low Pressure System Coriolis F pressure High Pressure System

Hurricane IVAN H LF H H pressure H F Coriolis

Polar High H Subtropical High Eq. Low L L Subpolar Low L H L H H H L

Rotation effects are not always important

Land-Sea Breeze

Moons, a continental scale land-sea breeze

Atmosheric Circulation Part II Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Huricanes, their formation and the oceanic response Zonal average circulation Radiative Budget

Atmosheric Circulation Part III Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Huricanes, their formation and the oceanic response Zonal average circulation Radiative Budget

Schematic depiction of the development of the atmospheric circulation, starting from a state of rest Easterlies (Trades) Westerlies

Atmosheric Circulation Part III Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Huricanes, their formation and the oceanic response Zonal average circulation Radiative Budget

A look at the atmospheric circulation from space http: //www. atmos. washington. edu/~ov ens/loops/wxloop. cgi? wv_moll+/14 d/ Advection of water vapour associated with Eastrerlies and Westerlies Strong convection over tropical region Generation of Tropical Cyclones

equator

ITCZ: Inter-Tropical Convergenze Zone

ITCZ: Inter-Tropical Convergenze Zone Midlatitude Instabilities http: //www. atmos. washington. edu /~ovens/loops/wxloop. cgi? ir_centr al+/48 h/3 h

Poleward Heat Transport

Midlatitude Cyclones

Tropical Air Warm Front Polar Air Tropical Air Cold Front Polar Air

ITCZ: Inter-Tropical Convergenze Zone Midlatitude Instabilities http: //www. atmos. washington. edu /~ovens/loops/wxloop. cgi? ir_centr al+/48 h/3 h

Polar High H Subtropical High Eq. Low L L Subpolar Low L H L H H H L

Atmosheric Circulation Part III Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Tropical Cyclones, their formation and the oceanic response Zonal average circulation Radiative Budget

Tropical Cyclones RITA http: //www. atmos. wash ington. edu/~ovens/loop s/wxloop. cgi? fronts_ir_e ast+/48 h/ Articles Webster P. J , G. J. Holland, J. A. Curry, H. -R. Chang (2005) Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment, SCIENCE Emmanuel, K. (2004) Increasing destructiveness of tropical cyclones over the past 30 years, NATURE

LF pressure F Coriolis

Why do tropical storms intensify?

Vortices LF HF pressure F Coriolis Low Pressure System Coriolis F pressure High Pressure System

Tropical cyclone have an eye of anticyclonic circulation!

Storm Surge: sea level rises because of the low atmospheric pressure system

Atmosheric Circulation Part III Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Tropical Cyclones, their formation and the oceanic response Zonal average circulation Radiative Budget

Vertical view of the atmosphere and Poleward Transport of Heat Hadley Cell Polar Cell Pole Ferrel Cell Equator

Atmosheric Circulation Part III Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Tropical Cyclones, their formation and the oceanic response Zonal average circulation Radiative Budget

Radiative Budget