Atmospheric_Dynamics_I-v4

Atmospheric_Dynamics_I-v4 - Atmospheric Dynamics Leila M V...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Atmospheric Dynamics Leila M. V. Carvalho Dept. Geography, UCSB Review: Kinematic of the horizontal flow Streamlines: lines parallel to the horizontal velocity V at a particular level and at a particular instant in time http://weather.unisys.com/surface/sfc_con_stream.html Natural Coordinates: Y X n n s s n and s are natural coordinates (perpendicular and parallel to the flow Definitions Sheared with no curvature, no diffluence, stretching or divergence Rotation with cyclonic curvature (NH) and cyclonic shear , no diffluence or stretching (and divergence Radial flow with velocity directly proportional to radius. Diffluence, stretching, divergence and NO CURVATURE Hyperbolic flow: difluence and straching, no divergence (terms cancel). Shear and curvature cancel (vorticity free) What is going on here? Y X n n s s Forces in the Atmosphere • Equation of motion: ( First and second Laws of Newton ) • Real forces (independent on the rotating system): gravity, pressure gradient force and frictional force • Apparent forces due to rotation: apparent centrifugal force (affects gravity) and Coriolis (correction for horizontal movements). Apparent forces: • Centrifugal force: Where RA is vector perpendicular to axis of rotation and is angular velocity of earth Combine with gravity to define "effective" gravity Coriolis force: • Coriolis force takes care of rotational effects caused by motion relative to surface Ω At rest over the Earth surface will have cetrifugal acceleration= Ω2R. Suppose it moves eastward with speed u : the centrifugal force would increase to: Centrifugal force= R R u 2 + Ω R Coriolis force: 2 2 2 2 2 R R u R uR R R R u + Ω + Ω = + Ω Expanding the equation we have now: Centrifugal force due to rotation of the Earth (independent of the relative Deflecting forces that act outward along the vector R Synoptic scale motions u<< ΩR: Last term can be neglected in a first approximation Coriolis Force Coriolis force can be divided into vertical and meridional components : R φ R uR Ω 2 φ φ cos 2 u Ω φ sin 2 u Ω A relative motion along the east-west coordinate will produce an acceleration in the north-south direction given by: φ sin 2 u dt dv Co Ω- = And vertical acceleration given by: φ cos 2 u dt dw Co Ω = To the right of the movement in the NH Suppose now that a particle initially at rest on the Earth is set in motion equatoward by impulsive forces Ω R As it moves equatorward it will conserve its angular momentum in the absence of torques: a relative westward velocity must develop R + δ R If we expand the right hand side and neglect second order differentials (and assume that δ << R R and solve for δ , : u we get o a...
View Full Document

This note was uploaded on 12/28/2011 for the course GEOG 226 taught by Professor Leila during the Fall '09 term at UCSB.

Page1 / 48

Atmospheric_Dynamics_I-v4 - Atmospheric Dynamics Leila M V...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online