S.-Y. Simon Wang, Lawrence Hipps, Robert R Gillies,(Utah State U) &

J.-H. Yoon (PNNL)

Fire and Ice California drought and "polar vortex" with

the changing climate

2013-14: A TWO-FACE WINTER

2013-14 winter

normal

geopotential height @ 250 hPa

anomaly

X anomaly

the “dipole”!

Not an isolated event!

X

one-point correlation map

geopotential height @ 250 hPa

SST

X

2013-14 El Nino

“Precursor”

El Nino “Precursor”

X

optimal pattern

PMM WNP SPMM

What’s an El Nino Precursor?

IndO

NPO

wait till Wed morning.

ENSO precursor Nino#(Y+1)

correlation with Nino4 (Y+1)

Function of the ridge

W/m^2

Wave flux (250 hPa)

OLR

NDJ 2013-14

W/m^2

Wave flux (850 hPa)

OLR

evolution

active convection

WNP

Composite for one year before an El Nino

ENSO Precursor - has it changed?

1951-1979

1980-2008

Forecasting CESM large ensemble (x30)

WNP composite:

CCSM4 (x6)

WNP composite:

CCSM4 (x6)

WNP composite:

greenhouse gas (GHG)

natural forcing (NAT) Attribution

1 yr before

El Niño

1 yr before

El Niño (simulated)

GHG

NAT

OBS

1 yr before

El Niño

GHG

NAT

Z250 anomalies

OBS X X

X X

X X GHG

OBS

NAT

Sliding correlation:

dipole vs. Nino4(Y-1)

GHG

NAT

X X

18 models

X X

El Nino Precursor

El Nino Precursor

Dipole’s 30-yr running variance

CMIP5 projection

Looking ahead

Kim et al. (2014)

X X

♨ ️

Arctic forcing?

- well developed water markets - modernize irrigation infrastructure - clear water entitlements

vs.

PDSI

Ground- water

sliding correlation

Oct 2013 SSTA

teleconnection

1 yr before

El Niño

“Dipole”

CMIP5 performance on ENSO precursor

Spatial correlation of SSTA