LARGE-SCALE C

HANGES IN PRECIPI

TATION

AND T

EMPE

RATURE IN S

OUTH A

MERICA

UNDER C

LIMATE C

HANGE -

ENSEMBLE

CLIMATE M

ODEL PROJECTIONS A

ND

UNCERTAINTY A

SSESSMENTS

MINISTÉRIO DA CIÊNCIA E TECNOLOGIA

MINISTÉRIO DA CIÊNCIA E TECNOLOGIA

INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS

INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS

Linco

ln A

lves, José Maren

go, Richard Betts, Richard Jon

es, Gillian

Kay

, Chou

Sin Chan

II Entre

namiento en

Mod

elad

o Num

érico de Escen

arios de Cam

bio Clim

ático

Cachoe

ira Pa

ulista –

São

Pau

lo -

Brazil

02/S

et/2009

CLIMATE M

ODEL PROJECTIONS A

ND

UNCERTAINTY A

SSESSMENTS

MOTIV

ATIO

N

Direc

t Obse

rvations

IPCC AR4

Climate Chan

ge Projections

Outline

•Unc

ertainty on un

certainty

•Pe

rturbed

Physics Ensem

bles (“QUMP”)

•Ong

oing

work

The un

certainty “casca

de”

Predicting

the impa

cts of

climate

chang

e

Emission

s

Con

centration

sCO

2, methan

e, sulph

ates

, etc.

Sce

narios from pop

ulation,

ener

gy, e

cono

mics mod

els

Carbon

cyc

le and

chem

istry

mod

els

Global climate ch

ange

Tem

perature

, rainfall, pre

ssure, etc.

Reg

iona

l detail

Mou

ntains, co

asts, ex

trem

e wea

ther

, etc.

Impa

cts

Flood

ing, droug

ht, foo

d sup

ply, etc.

Cou

pled

global climate mod

els

Reg

iona

l climate mod

els

Impa

cts mod

els

Ensem

ble sim

ulations

•Ena

ble exploration of

the

diffe

rent unc

ertainties

–In

itial co

nditions (ch

aos)

Ensem

ble sim

ulations

•Ena

ble exploration of

the

diffe

rent unc

ertainties

–In

itial co

nditions (ch

aos)

–Bou

ndary co

nditions (respon

se

to external forcing

s)to external forcing

s)

Ensem

ble sim

ulations

•Ena

ble exploration of

the

diffe

rent unc

ertainties

–In

itial co

nditions (ch

aos)

–Bou

ndary co

nditions (respon

se

to external forcing

s)

Global m

ean tempe

rature

chan

ge

to external forcing

s)

–Diffe

rent m

odel struc

tures

(“en

sembles of

opp

ortunity”)

Ensem

ble sim

ulations

•Ena

ble exploration of

the

diffe

rent unc

ertainties

–In

itial co

nditions (ch

aos)

–Bou

ndary co

nditions (respon

se to

external forcing

s)

Global m

ean tempe

rature

chan

ge

external forcing

s)

–Diffe

rent m

odel struc

tures

(“en

sembles of

opp

ortunity”)

–Diffe

rent proce

ss rep

rese

ntations

(perturb

ed physics)

Perturbed

physics ap

proa

ch

•The pe

rturbed

physics ap

proa

ch allo

ws un

certainties

(in variou

s co

mpo

nents of

the mod

el) to be

system

atically explored

.

•This is don

e by:

–Id

entify

ing pa

rameter

s in the mod

el which are

both

–Id

entify

ing pa

rameter

s in the mod

el which are

both

unce

rtain an

d impo

rtan

t fo

r th

e mod

el res

ponse

–Using

an en

semble of mod

els to explore th

e im

plications of th

ese pa

rameter

unc

ertainties

The QUMP en

semble

Parameter

Per

turb

ations

Stand

ard Value

Min

Max

•29 param

eter

s, 300+ en

semble m

ember

s (som

e pa

rameter

s are sw

itch

es)

•Pa

rameter

s an

d their rang

es deter

mined

by

expe

rt elicitation

Parameter

Per

turb

ations

Large S

cale C

loud

Ice fall sp

eed

Critica

l relative hum

idity fo

r fo

rmation

Cloud

droplet to rain: co

nver

sion

rate an

d

thre

shold

Cloud

fraction ca

lculation

Bou

ndary

layer

Turbulen

t mixing co

efficien

ts: stab

ility-

dep

enden

ce, n

eutral m

ixing leng

th

Rou

ghne

ss le

ngth

ove

r se

a: Charno

ck con

stan

t,

free

con

vective value

Dyna

mics

Diffu

sion

: order

and

e-folding time

Gravity wave drag: surface

and

trapp

ed le

e wave co

nstants

Cloud

fraction ca

lculation

Con

vection

Entrainmen

t rate

Intensity of

mass flux

Shap

e of

cloud

(an

vils) (*)

Cloud

water

see

n by radiation

(*)

Radiation

Ice pa

rticle size/

shap

e

Cloud

ove

rlap

assum

ptions

Water

vap

our co

ntinuu

m absorption

(*)

wave co

nstants

Gravity wave drag start leve

l

Land

surfa

ce proce

sses

Roo

t dep

ths

Fores

t roug

hne

ss len

gths

Surface

-can

opy co

upling

CO2 dep

enden

ce of stom

atal con

duc

tanc

e (*)

Sea ice

Albed

o dep

enden

ce on tempe

rature

Oce

an-ice

hea

t tran

sfer

Effect of ph

ysics

perturbation

s on

climate

p1

p2

p3

Global mean te

mpe

rature

rise

over 21st

century

Atm

osph

eric and

som

e land

surfac

e/se

a ice

unce

rtainties

Prec

ipitation ch

ange

(%) fo

r 2071-2099 relative to 1961-19

89

over

Sou

th Amer

ica from

the PP

E (SRES A1B

sce

nario)

© Crown copyright Met OfficeSum

mer

Winter

Tem

perature

chan

ge (%) fo

r 2071-2099 relative to 1961-19

89

over

Sou

th Amer

ica from

the PP

E (SRES A1B

sce

nario)

Sum

mer

Winter

Ann

ual cy

cle from

the PP

E (SRES A

1B sce

nario) for

selected

lan

d reg

ions ove

r Sou

th Amer

ica

tempe

rature

ano

malies (oC)

prec

ipitation ch

ange

(%)

ENSO E

pisodes

EL N

INO

LA N

INA

Com

posite of se

veral ye

ars:

1963/6

5/6

8/6

9/7

2/8

3/8

7Com

posite of se

veral ye

ars:

1962/6

4/7

1/74/8

5/8

9

Ong

oing

work…

Ong

oing

work…

Prec

ipitation an

d

Tem

perature

ch

ange

ove

r Sou

th Amer

ica

from

A1B

Eta

simulation.

Projec

ted trend

s of

extrem

e clim

ate indices

for 2071-2099 relative

do 19

61-89. P

anels a-f sh

ow projections for the A1B

sce

nario

TN90

CDD

R95P

SUMMARY

•Theen

semble

mem

berssh

areto

agrea

teror

lesser

extent

the

tend

ency

towardsan

enhan

cedElNiño-like

statein

thefu

ture

•In

allof

thePP

Emem

berswarmingis

projec

ted

over

the21st

century,

withen

han

cedwarmingover

land

•Theen

semble

prod

uces

arang

eof

region

alch

ange

smuc

hwider

than

indicated

by

trad

itiona

lmethod

sbased

onscaling

the

respon

sepa

tterns

ofan

individua

lsimulation;

•Theen

semble

tech

niqu

eane

cessarytool

toreduc

eth

eef

fect

ofBou

ndaryCon

ditions;

•Thereca

nbelargediffe

renc

esbetwee

nth

ePP

Emem

bersin

the

projec

tion

sof

future

clim

ates

over

Brazil.Thes

eun

certaintiesin

projec

tion

sca

nbe

explored

infine

rdetailusing

dyn

amical

dow

nsca

ling

.

•W

ithou

tap

prop

riateregion

alprojec

tion

sof

clim

atech

ange

,it

isargu

able

whether

region

alad

aptation

strategies

can

be

dev

elop

edor

implem

ented.

Than

k yo

u! O

briga

do! Gracias!

Con

tact D

eta

ils:

Linc

oln Alves

linc

oln.alve

s@cp

tec.inpe

.br

+55 12 318

6-8

580