1

ESS

200A

Pro

f. J

in-Y

i Yu

Lec

ture

7: D

istu

rban

ce (

Out

line)

Tra

nsie

nts

and

Edd

ies

Cli

mat

e R

oles

Mid

-Lat

itude

Cyc

lone

s

Tro

pica

l Hur

rica

nes

Mid

-Oce

an E

ddie

s

(Fro

m W

eath

er &

Cli

mat

e)

ESS

200A

Pro

f. J

in-Y

i Yu

Tra

nsie

nt a

nd E

ddy

Tra

nsie

nt: d

evia

tions

fro

m ti

me

mea

n

Edd

y: d

evia

tions

fro

m z

onal

mea

n

Why

tran

sien

ts/e

ddie

s m

atte

r to

zon

al a

nd ti

me

mea

ns?

Tim

e M

ean

Zon

al M

ean

ESS

200A

Pro

f. J

in-Y

i Yu

Flu

x C

ompo

nent

s

Thr

ee c

ompo

nent

s co

ntri

bute

to

the

zona

l-an

d ti

me-

mea

n tr

ansp

ort:

(1)M

ean

Mer

idio

nalC

ircu

latio

n (s

uch

as th

e th

ree-

cell

circ

ulat

ion)

(2)S

tatio

nary

pla

neta

ry W

aves

(su

ch a

s th

e w

aven

umbe

r 1-

3 ed

dies

in th

e N

orth

ern

Hem

isph

ere)

.

(3)T

rans

ient

Edd

ies

(suc

h as

the

wea

ther

sys

tem

s =

mid

latit

ude

cycl

ones

an

d an

ticyc

lone

s).

(2)

(1)

(3)

ESS

200A

Pro

f. J

in-Y

i Yu

Tra

nsie

nt/E

ddy

Flux te

mpe

ratu

rem

otio

n

[V*T

*] >

0

On

zona

l ave

rage

, edd

ies

tran

spor

t he

at n

orth

war

d.E

ddie

s co

ntri

bute

to

zona

l-m

ean

heat

tra

nspo

rt

2

ESS

200A

Pro

f. J

in-Y

i Yu

Cli

mat

e R

oles

of

Edd

ies

Stat

iona

ry a

nd tr

ansi

ent e

ddie

s ar

e im

port

ant t

o th

e po

lew

ard

flux

es o

f te

mpe

ratu

re, m

oist

ure,

en

ergy

, and

ang

ular

mom

entu

m.

ESS

200A

Pro

f. J

in-Y

i Yu

Pole

war

d Fl

ux o

f T

empe

ratu

re

Tra

nsie

nt e

ddy

flux

es

dom

inan

t the

mer

idio

nal f

lux

of te

mpe

ratu

re e

xcep

t in

the

Nor

ther

n H

emis

pher

e du

ring

w

inte

r, w

hen

stat

iona

ry e

ddie

s co

ntri

bute

up

to h

alf

of th

e fl

ux.

The

low

-lev

el m

axim

um in

th

e tr

opos

pher

e is

ass

ocia

ted

with

the

stru

ctur

e of

gro

win

g m

id-l

atitu

de c

yclo

nes

(I.e

., w

eath

er s

yste

ms)

.

(Fro

m G

loba

l Phy

sica

l Cli

mat

olog

y)

ESS

200A

Pro

f. J

in-Y

i Yu

Pole

war

d Fl

ux o

f M

oist

ure

Bot

h th

e m

ean

mer

idio

nal

circ

ulat

ion

and

eddi

es tr

ansp

ort

wat

er a

nd p

lay

an im

port

ant

role

in d

eter

min

ing

the

natu

re

of th

e hy

drol

ogic

al c

ycle

.

Moi

stur

e co

nver

genc

e in

the

trop

ics

is d

omin

ated

by

the

tran

spor

t pro

vide

d by

the

mea

n m

erid

iona

l cir

cula

tion.

The

subt

ropc

sse

rves

as

sour

ce

regi

ons

for

wat

er v

apor

.

Edd

ies

rem

ove

wat

er f

rom

the

trop

ics

and

supp

ly it

to m

iddl

e an

d hi

gh la

titud

es.

(Fro

m G

loba

l Phy

sica

l Cli

mat

olog

y)

ESS

200A

Pro

f. J

in-Y

i Yu

Pole

war

d Fl

ux o

f M

omen

tum

In th

e tr

opic

al e

aste

rlie

s, e

astw

ard

angu

lar

mom

entu

m is

tran

sfer

red

from

Ear

th to

the

atm

osph

ere

via

fric

tiona

l for

ces

and

mou

ntai

n to

rque

.

Thi

s w

este

rly

angu

lar

mom

entu

m

is tr

ansp

orte

d up

war

d an

d th

en

pola

rwar

d in

to th

e H

adle

y C

ell.

Edd

ies

then

tran

spor

t ang

ular

m

omen

tum

pol

arw

ard

and

dow

nwar

d in

to m

id-l

atitu

de

wes

terl

ies.

In th

e m

id-l

atitu

de, t

he w

este

rly

mom

entu

m is

ret

urne

d to

the

Ear

th.

3

ESS

200A

Pro

f. J

in-Y

i Yu

Stat

iona

ry P

lane

tary

Wav

es

Stat

iona

ry: T

hese

wav

es d

o no

t mov

e ar

ound

muc

h an

d ar

e fi

xed

in c

erta

in

geog

raph

ic lo

catio

ns.

Pla

neta

ry: T

hese

wav

es h

ave

larg

e w

avel

engt

hs, o

ne th

e or

der

of s

ever

al

thou

sand

s of

kilo

met

ers.

Wav

e: T

heir

str

uctu

res

vary

in th

e zo

nal

dire

ctio

n.

Stat

iona

ry p

lane

tary

wav

es a

re f

orce

d by

la

rge-

scal

e m

ount

ains

(su

ch a

s H

imal

aya

and

Roc

ky m

ount

ain

rang

es)

and

heat

co

ntra

sts

betw

een

cont

inen

ts a

nd o

cean

s.

Stat

iona

ry p

lane

tary

wav

es a

re s

tron

ger

in w

inte

r th

an in

sum

mer

.

Janu

ary

Hei

ght

of 5

00-m

b P

ress

ure

Surf

ace

(Fro

m G

loba

l Phy

sica

l Cli

mat

olog

y)E

SS20

0AP

rof.

Jin

-Yi Y

u

Tra

nsie

nt E

ddie

sM

id-l

atitu

de c

yclo

ne a

nd a

ntic

yclo

ne a

re th

e m

ajor

tran

sien

t edd

ies

that

pla

y an

impo

rtan

t ro

le in

mer

idio

nal t

rans

port

s of

hea

t, m

omen

tum

, and

moi

stur

e.

The

se m

id-l

atitu

de w

eath

er s

yste

ms

grow

fr

om th

e ba

rocl

inic

inst

abili

ty a

ssoc

iate

d w

ith th

e st

rong

nor

th-s

outh

tem

pera

ture

gr

adie

nts

in m

id-l

atitu

des.

Mid

-lat

itude

cyc

lone

s ha

ve ty

pica

l spa

tial

scal

es o

f w

aven

umbe

rs 5

-6 a

nd h

ave

typi

cal

time

scal

e of

7-1

0 da

ys.

Mid

-lat

itude

cyc

lone

s ar

e m

arke

d by

wel

l-de

fine

d fr

onts

sep

arat

ing

the

war

m a

ir m

ass

from

the

sout

h an

d th

e co

ld a

ir m

ass

from

th

e no

rth.

(V

ery

diff

eren

t fro

m tr

opic

al

hurr

ican

es, w

hich

do

not h

ave

fron

tal

feat

ures

).

(Fro

m W

eath

er &

Cli

mat

e)

ESS

200A

Pro

f. J

in-Y

i Yu

Col

d an

d W

arm

Fro

nts

cold fr

ont

war

m fr

ont

Mid

-Lat

itude

Cyc

lone

(Fro

m W

eath

er &

Cli

mat

e)

ESS

200A

Pro

f. J

in-Y

i Yu

How

Cyc

lone

Gro

ws?

(Fro

m W

eath

er &

Cli

mat

e)

Pot

entia

l Ene

rgy

Ava

ilab

le P

. Ene

rgy

(col

d/w

arm

air

mov

es s

outh

/nor

th)

(V*T

* >

0)

Ava

ilab

le E

nerg

y K

inet

ic E

nerg

y

(col

d/w

arm

air

mov

es d

own/

up)

(W*T

*>0)

4

ESS

200A

Pro

f. J

in-Y

i Yu

Ava

ilabl

e Po

tent

ial E

nerg

y

ESS

200A

Pro

f. J

in-Y

i Yu

Lif

e C

ycle

of

Mid

-Lat

itude

Cyc

lone

Cyc

loge

nesi

s

Mat

ure

Cyc

lone

Occ

lusi

on

(fro

m W

eath

er &

Cli

mat

e)

ESS

200A

Pro

f. J

in-Y

i Yu

Tro

pica

l Hur

rica

ne

The

hur

rica

ne is

ch

arac

teri

zed

by a

str

ong

ther

mal

ly d

irec

t cir

cula

tion

with

the

risi

ng o

f w

arm

air

ne

ar th

e ce

nter

of

the

stor

m

and

the

sink

ing

of c

oole

r ai

r ou

tsid

e.

The

war

m c

ore

of th

e hu

rric

ane

serv

es a

s a

rese

rvoi

r of

pot

enti

al e

nerg

y,

whi

ch is

con

tinu

ousl

y be

ing

conv

erte

d in

to k

inet

ic

ener

gy b

y th

e th

erm

ally

di

rect

cir

cula

tion.

(fro

m W

eath

er &

Cli

mat

e)

ESS

200A

Pro

f. J

in-Y

i Yu

The

y A

re th

e Sa

me

Thi

ngs…

Hur

rica

nes:

extr

eme

trop

ical

sto

rms

over

Atl

antic

and

eas

tern

Pac

ific

O

cean

s.

Typ

hoon

s:ex

trem

e tr

opic

al s

torm

s ov

er w

este

rn P

acif

ic O

cean

.

Cyc

lone

s:ex

trem

e tr

opic

al s

torm

s ov

er I

ndia

n O

cean

and

Aus

tral

ia.

(fro

m W

eath

er &

Cli

mat

e)

5

ESS

200A

Pro

f. J

in-Y

i Yu

Air

Par

cel E

xpan

ds A

s It

Ris

es…

Air

pre

ssur

e de

crea

ses

with

ele

vati

on.

If a

hel

ium

bal

loon

1 m

in d

iam

eter

is

rele

ased

at

sea

leve

l, it

expa

nds

as it

fl

oats

upw

ard

beca

use

of t

he p

ress

ure

decr

ease

. The

bal

loon

wou

ld b

e 6.

7 m

in

diam

eter

as

a he

ight

of

40 k

m.

(fro

m T

he B

lue

Pla

net)

ESS

200A

Pro

f. J

in-Y

i Yu

Adi

abat

ic L

apse

Rat

e

Adi

abat

ic la

pse

rate

= 1

0°C

/km

or

1°C

/100

m

= a

ir t

empe

ratu

re in

a r

isin

g ba

lloon

dro

ps 1

°C e

very

100

m.

(fro

m U

nder

stan

ding

Wea

ther

& C

lim

ate)

ESS

200A

Pro

f. J

in-Y

i Yu

Wat

er V

apor

In

the

Air

Eva

pora

tion

:th

e pr

oces

s w

here

by m

olec

ules

bre

ak f

ree

of t

he li

quid

vol

ume.

Con

dens

atio

n:w

ater

vap

or m

olec

ules

ran

dom

ly c

ollid

e w

ith t

he w

ater

sur

face

and

bo

nd w

ith a

djac

ent

mol

ecul

es.

(fro

m U

nder

stan

ding

Wea

ther

& C

lim

ate)

Satu

rati

on

ESS

200A

Pro

f. J

in-Y

i Yu

Spec

ific

.vs.

Rel

ativ

e H

umid

ity

Spe

cifi

c H

umid

ity:

How

man

y gr

ams

of w

ater

vap

or i

n on

e ki

logr

amof

air

(in

uni

t of

gm

/kg)

.

Rel

ativ

e H

umid

ity:

The

per

cent

age

of c

urre

nt m

oist

ure

cont

ent t

oth

e sa

tura

ted

moi

stur

e am

ount

(in

un

it o

f %

).

Clo

uds

form

whe

n th

e re

lati

ve h

umid

ity

reac

hes

100%

.

spec

ific

hum

idit

y6

gm/k

g

satu

rate

dsp

ecif

ic h

umid

ity

10 g

m/k

g

satu

rate

dsp

ecif

ic h

umid

ity

20 g

m/k

gR

elat

ive

hum

idit

y 6/

20 x

100

%=

30 %

Rel

ativ

e hu

mid

ity

6/10

x 1

00%

=60

%

6

ESS

200A

Pro

f. J

in-Y

i Yu

Why

Clo

uds

For

m?

Clo

uds

form

whe

n ai

r ri

ses

and

beco

mes

sat

urat

ed in

res

pons

e to

ad

iaba

tic

cool

ing.

ESS

200A

Pro

f. J

in-Y

i Yu

Clo

ud T

ype

Bas

ed O

n Pr

oper

ties

Four

bas

ic c

loud

cat

egor

ies:

Cir

rus

---

thin

, wis

py c

loud

of

ice.

Stra

tus

---

laye

red

clou

dC

umul

us--

-cl

ouds

hav

ing

vert

ical

dev

elop

men

t.N

imbu

s--

-ra

in-p

rodu

cing

clo

ud

The

se b

asic

clo

ud ty

pes

can

be c

ombi

ned

to

gene

rate

ten

diff

eren

t clo

ud ty

pes,

suc

h as

ci

rros

trat

us c

loud

s th

at h

ave

the

char

acte

rist

ics

of

cirr

us c

loud

s an

d st

ratu

s cl

ouds

.

ESS

200A

Pro

f. J

in-Y

i Yu

Clo

ud T

ypes

Bas

ed O

n H

eigh

t

If b

ased

on

clou

d ba

se h

eigh

t, th

e te

n pr

inci

pal c

loud

type

s ca

nth

en g

roup

ed

into

fou

r cl

oud

type

s:

Hig

h cl

ouds

--ci

rrus

, cir

rost

ratu

s, c

irro

scum

ulus

.

Mid

dle

clou

ds–

alto

stra

tus

and

alto

cum

ulus

Low

clo

uds

–st

ratu

s, s

trat

ocum

ulus

, and

nim

bost

artu

s

Clo

uds

wit

h ex

tens

ive

vert

ical

dev

elop

men

t–cu

mul

us a

nd c

umul

onim

bus.

(fro

m “

The

Blu

e P

lane

t”)

ESS

200A

Pro

f. J

in-Y

i Yu

Clo

ud C

lass

ific

atio

ns

(fro

m “

The

Blu

e P

lane

t”)

7

ESS

200A

Pro

f. J

in-Y

i Yu

Hig

h C

loud

s

Hig

h cl

ouds

hav

e lo

w c

loud

te

mpe

ratu

re a

nd lo

w w

ater

con

tent

an

d co

nsis

t mos

t of

ice

crys

tal.

1. C

irru

s C

loud

s

2. C

irro

stra

tus

Clo

uds

3. C

irro

cum

ulus

Clo

uds

(fro

m A

ustr

alia

n W

eath

er S

ervi

ce)

ESS

200A

Pro

f. J

in-Y

i Yu

Mid

dle

Clo

uds

Mid

dle

clou

ds a

re u

sual

ly c

ompo

site

of

liqui

d dr

ople

ts.

The

y bl

ock

mor

e su

nlig

ht to

the

surf

ace

than

the

hig

h cl

ouds

.

5. A

ltocu

mul

us C

loud

s4.

Alto

stra

tus

Clo

uds

(fro

m A

ustr

alia

n W

eath

er S

ervi

ce)

ESS

200A

Pro

f. J

in-Y

i Yu

Low

Clo

uds

Low

, thi

ck, l

ayer

ed c

loud

s w

ith la

rge

hori

zont

al e

xten

ds, w

hich

can

exc

eed

that

of

seve

ral s

tate

s.

6. S

trat

usC

loud

s

7. S

trat

ocum

ulus

Clo

uds

8. N

imbo

stra

tus

Clo

uds

(fro

m A

ustr

alia

n W

eath

er S

ervi

ce)

ESS

200A

Pro

f. J

in-Y

i Yu

Clo

uds

With

Ver

tical

Dev

elop

men

t

The

y ar

e cl

ouds

with

sub

stan

tial v

ertic

al d

evel

opm

ent a

nd o

ccur

whe

n th

e ai

r is

ab

solu

te o

r co

ndit

iona

lly u

nsta

ble.

9. C

umul

us C

loud

s10

. Cum

ulon

imbu

s C

loud

s

(fro

m A

ustr

alia

n W

eath

er S

ervi

ce)

8

ESS

200A

Pro

f. J

in-Y

i Yu

Mid

-Oce

an E

ddie

sT

he G

ulf

Str

eam

and

the

Kur

oshi

o sp

in o

ff lo

ng-l

ived

edd

ies

via

baro

clin

ic a

nd b

arot

ropi

c in

stab

ilitie

s.

The

rol

e of

edd

ies

for

heat

tran

spor

t in

the

ocea

n is

like

ly m

uch

less

than

in

the

atm

osph

ere.

The

oce

anic

edd

ies

are

best

de

velo

ped

wel

l pol

ewar

d of

the

latit

ude

of th

e m

axim

um o

cean

ic

tran

spor

t.

The

win

d-dr

iven

and

ther

moh

alin

e ci

rcul

atio

ns a

re li

kely

to p

rovi

de

muc

h m

ore

impo

rtan

t con

trib

utio

ns to

th

e m

erid

iona

l hea

t flu

x in

the

subt

ropi

cs.

(Fig

ure

from

Oce

anog

raph

yby

Tom

Gar

riso

n)