Modeling North Pacific Decadal Variations and Their

Teleconnection Patterns

Speaker/ Pei-Ning Kirsten Feng

Advisor/ Yu-Heng Tseng

Outline

• Motivation • Objective• Overview • Data Source• Methods and Model• Recent Result• Summary and future work

Motivation

• Since the long tern climate is impacted by the ocean-atmospheric interactions, if we want to use modeling to simulate the climate, it is necessary to know what kind of low-frequency oscillation is referred.

• Further it is found that PDO can not explain the oscillations in the ocean, however NPGO seems more related to the variations. Thus we want to know its relationship with other oscillations and climate.

Objective

• First we want to summarize the oscillations and determine their relations, especially stressed on the Pacific area.

• We want to compare the model simulation to the observations and see if those oscillations are shown in the resolutions.

Terms

Pacific Decadal Variations

[Di Lorenzo et al., 2008]

PDO AREA

North Pacific – AL/PDO

• The Pacific Decadal Oscillation (PDO) Index is defined as the leading principal component of North Pacific monthly sea surface temperature (SST) variability (poleward of 20N).

[Mantua et al., 1997]

Warm Phase Cool Phase

North Pacific – AL/PDO

50 100 150 200 250

20

40

60

80

100

SST EOF-1

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

-300 -250 -200 -150 -100-40

-20

0

20

40

60

SLP 1 (27.7905%)

-1 -0.5 0 0.5 1

-300 -250 -200 -150 -100

-30

-20

-10

0

10

20

30

40

50

60

SST 1 (27.7905%)

-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8

•The Pacific Decadal Oscillation (PDO) Index is defined as the leading principal component of North Pacific monthly sea surface temperature (SST) variability (poleward of 20N).

North Pacific – NPO/NPGO

• North Pacific Gyre Oscillation, NPGO:

• The NPGO is defined as the second dominant mode of SSHa variability in the Northeast Pacific [180°–110°W; 25°N–62°N] and is correlated with the second mode of North Pacific SSTa.

[Di Lorenzo et al., 2008]

Atmosphere-Ocean Interaction

[Di Lorenzo et al., 2010]

Global Pattern and Teleconnection

• AO

• AL ←→ PDO

• ENSO / EPW• WP • CPW

• NAO• NPO ←→ NPGO

• KOE

• PNA

• How these oscillations play roles in the long term climate?

Teleconnection

Pacific Pattern -- WP

Atlantic Pattern -- NAO

Global Pattern -- AO

Data source

Data source

• Hadley SST

• Hadley SLP

• NCEP/NCAR Reanalysis

Methods and Model

Model

Atmosphere-Ocean Interaction

• PDO– SSTa PC-1

• NPGO– SSHa PC-2 • ENSO

• AL & NPO forcings

• Model reconstruction– A. PDO (corrcoef)

– B. NPGO (corrcoef)

– C. Teleconnections

• Observation data:– SLP : Hadley SLP

– SST : HadISST

Thanks For Your Attention

……つづく