RE

FE

RE

NC

ES

:D

ixon

, K. W

., et

al.,

201

6: E

valu

atin

g th

e st

atio

nari

ty a

ssum

ptio

n in

sta

tistic

ally

dow

nsca

led

clim

ate

proj

ectio

ns: i

s pa

st

per

form

ance

an

indi

cato

r of

fut

ure

resu

lts?

Cli

mat

ic C

hang

e, 1

35, 3

95–4

08.

Lan

zant

e, J

. R.,

et a

l., 2

017:

Som

e P

itfal

ls I

n S

tatis

tical

Dow

nsca

ling

Of

Fut

ure

Clim

ate.

Bul

l. A

mer

. Met

eor.

Soc.

, in

pres

s.L

i, H

., J

. She

ffie

ld, a

nd E

. F. W

ood,

201

0: B

ias

corr

ectio

n of

mon

thly

pre

cipi

tatio

n an

d te

mpe

ratu

re f

ield

s fr

om I

nter

gove

rn-

men

tal P

anel

on

Clim

ate

Cha

nge

AR

4 m

odel

s us

ing

equi

dist

ant q

uant

ile m

atch

ing.

J. G

eoph

ys. R

es.,

115,

D10

101.

crea

te d

ata

sets

that

ser

ve a

s pr

oxie

s fo

r co

arse

res

olut

ion

GC

M o

utpu

t.

A k

ey d

iffe

renc

e be

twee

n th

is P

M e

xper

imen

tal d

esig

n an

d ty

pica

l SD

ap

plic

atio

ns is

the

avai

labi

lity

of "

futu

re o

bser

vatio

ns"

(OF

) in

the

PM

de

sign

, whi

ch a

llow

s us

to e

valu

te a

n S

D m

etho

d's

futu

re s

kill,

ther

eby

quan

tifyi

ng a

spec

ts o

f th

e st

atio

nari

ty a

ssum

ptio

n.

Mon

th: A

ugus

t. L

ocat

ion

: ne

ar &

inla

nd o

f P

adre

Is

land

, Tex

as. A

25k

m g

rid

cell

sim

ilar

to m

any

coas

tal p

oint

s in

that

it is

mos

tly la

nd, b

ut th

e ov

erly

ing

200k

m g

rid

valu

es a

re m

ore

mar

itim

e.

Th

e S

tati

stic

al D

own

scal

ing

Ch

alle

nge

: D

istr

ibu-

tions

of

daily

Aug

ust t

asm

ax O

H &

OF

val

ues

have

larg

er v

aria

nces

, hig

her

mea

ns, a

nd d

iffe

rent

sh

apes

(m

ore

posi

tivel

y sk

ewed

) th

an d

o th

e m

ore

mar

itim

e M

H, M

F d

istr

ibut

ions

. A

lso,

the

clim

ate

chan

ge s

igna

l cau

ses

mos

t lat

e 21

st c

entu

ry M

F

valu

es to

exc

eed

the

war

mes

t his

tori

cal M

H v

alue

.

His

tori

cal P

erio

d S

D P

erfo

rman

ce:

All

thre

e S

D

met

hods

per

form

rel

ativ

ely

wel

l, yi

eldi

ng A

ugus

t m

onth

ly m

ean

dow

nsca

ling

err

ors

(DH

- O

H)

of

< 0

.25K

. A

lso,

all

SD

met

hods

gen

erat

e D

H

dist

ribu

tions

with

sha

pes

and

vari

ance

s th

at m

ore

clos

ely

rese

mbl

e th

e O

H d

istr

ibut

ion

than

the

larg

e-sc

ale

and

mor

e m

ariti

me

MH

tasm

ax d

ata.

Fu

ture

Per

iod

SD

Per

form

ance

: T

he E

DQ

M &

B

CQ

Man

om m

etho

ds p

erfo

rm m

arke

dly

bette

r th

an B

CQ

M d

oes

in th

e w

arm

er f

utur

e –

the

oppo

site

of

the

resu

lts s

een

in th

e C

arbo

ndal

e, C

Oca

se. A

t the

Pad

re I

slan

d 25

km g

rid

cell,

BC

QM

in

trod

uces

a m

ean

bias

of

+4.

6K f

or th

e la

te 2

1st

cent

ury

Aug

ust c

ase,

and

mul

ti-de

gree

war

m

bias

es o

ccur

at m

ost U

.S. s

outh

ern

coas

tal l

and

poin

ts (

uppe

r m

ap).

Suc

h S

D-c

reat

ed w

arm

bia

ses

are

not f

ound

in th

e E

DQ

M (

low

er m

ap)

&

BC

QM

anom

cas

es. M

etho

ds li

ke B

CQ

M th

at d

ono

t adj

ust f

or f

utur

e tr

ends

can

bre

ak d

own

whe

npo

sed

with

MF

> m

ax(M

H),

as

they

may

rel

y on

ad h

oc ta

il ad

just

men

ts to

app

ly th

e co

rrec

tion

at m

ax(M

H)

to a

ll w

arm

er M

F v

alue

s –

a po

orch

oice

whe

n th

e M

H a

nd O

H d

istr

ibut

ion

shap

esdi

ffer

. SD

met

hods

that

inco

rpor

ate

adju

stm

ents

fo

r tr

ends

gua

rd a

gain

st th

is p

artic

ular

pitf

all.

His

tori

cal P

erio

d D

ow

nsc

alin

g E

rro

rs v

s. M

H v

alu

es(B

CQ

M r

esul

ts s

how

n. O

ther

SD

met

hods

are

sim

ilar)

Fu

ture

Per

iod

Do

wn

sca

ling

Err

ors

vs.

MF

val

ues

(BC

QM

& E

DQ

M s

how

n. B

CQ

Man

om s

imila

r to

ED

QM

)

a

rrow

on

map

spo

ints

to P

adre

Is

land

grid

cel

l

Exa

min

ing

th

e P

erfo

rman

ce o

f S

tati

stic

al D

ow

nsc

alin

g M

eth

od

s:To

war

d M

atch

ing

Ap

plic

atio

ns

to D

ata

Pro

du

cts

Kei

th W

. Dix

on ,

John

R. L

anza

nte

, & D

enni

s A

dam

s-S

mith

(1

) N

OA

A G

eoph

ysic

al F

luid

Dyn

amic

s La

bora

tory

, Prin

ceto

n, N

J

(2)

Uni

vers

ity C

orpo

ratio

n fo

r Atm

osph

eric

Res

ear

ch

Th

is w

ork

 was

 fu

nd

ed i

n p

art 

by 

the 

U.S

. D

ept.

 of 

the 

Inte

rior'

sSou

th C

entr

al C

lim

ate 

Sci

ence

 Cen

ter

Pro

ject

Web

Pag

e: w

ww

.gfd

l.no

aa.g

ov/

esd

1

1

2

PA43B-0321

Var

iab

le o

f In

tere

st =

Dai

ly M

axim

um

Tem

per

atu

re (

tasm

ax);

F

utu

re S

cen

ario

= L

ate

21s

t C

entu

ry H

igh

Gre

enh

ou

se G

as E

mis

sio

ns;

C

om

par

ing

3 U

niv

aria

te S

D M

eth

od

s