Modeling North Pacific Decadal Variations and

Their Teleconnection Patterns

2010/ 11/ 16 Speaker/ Pei-Ning Kirsten Feng

Advisor/ Yu-Heng Tseng

Outline

• Literature Review• Motivation • Objective• Data and Model• Preliminary work• Summary

Teleconnections -- 500 hPa Height -- Sea Level Pressure-- Sea Surface Temperature

Structure

500 hPa – EOF1• PNA

SLP – EOF1 • North Hemisphere -- AO• Pacific -- ENSO/ PDO (SSHa EOF1)• Atlantic – NAO

SST – EOF1• Pacific -- ENSO/ PDO (SSHa EOF1)

500 hPa – EOF2• WP

SLP – EOF2• Pacific -- NPO

SST – EOF2• Pacific – Victoria Mode(NPGO,

SSHa EOF2)

High Level – Low Level Interaction

Surface Interaction

1950 1960 1970 1980 1990 2000 2010-4

-2

0

2

41950~2009 PNA Index

500 hPa Height EOF1 -- PNAPacific / North American Pattern (PNA)

[NOAA CPC http://www.cpc.ncep.noaa.gov]

The Pacific/ North American teleconnection pattern (PNA) is one of the most prominent modes of low-frequency variability in the Northern Hemisphere extratropics.

NH 1000 hPa Height EOF1 -- AOArctic Oscillation (AO)

[NOAA CPC http://www.cpc.ncep.noaa.gov]

The loading pattern of the AO is defined as the leading mode of Empirical Orthogonal Function (EOF) analysis of monthly mean 1000mb height.

1950 1960 1970 1980 1990 2000 2010-4

-2

0

2

41950~2009 AO Index

Pacific SLP EOF1 – AL

• The first co-variability mode captures the mature phase of ENSO and its atmospheric teleconnections to the AL.

Aleutian Low (AL)

[Di Lorenzo et al., 2008]

Atlantic SLP EOF1 -- NAONorth Atlantic Oscillation (NAO)

1950 1960 1970 1980 1990 2000 2010-4

-2

0

2

41950~2009 NAO Index

[NOAA CPC http://www.cpc.ncep.noaa.gov]

One of the most prominent teleconnection patterns in all seasons is the North Atlantic Oscillation (NAO). It combines parts of the East-Atlantic and West Atlantic patterns with a north-south dipole of anomalies

Atlantic Long-term SSTa -- AMOAtlantic Multidecadal Oscillation (NPO)

The Atlantic Multi-decadal Oscillation (AMO) is a mode of natural variability occurring in the North Atlantic Ocean and which has its principle expression in the sea surface temperature (SST) field.

http://www.aoml.noaa.gov/phod/amo_faq.php

Pacific SST EOF1 – PDO/ENSOPacific Decadal Oscillation / El Nino-Southern Oscillation (PDO/ENSO)

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).

Warm Phase Cool Phase

[Mantua et al., 1997] 1950 1960 1970 1980 1990 2000 2010-2

-1

0

1

2

31950~2009 PDO Index

The PDO is highly correlated with the dominant mode of sea surface height anomalies (SSHa).

Pacific SST EOF1 – PDO/ENSOPacific Decadal Oscillation / El Nino-Southern Oscillation (PDO/ENSO)

[Di Lorenzo et al., 2008]

• The first leading mode is well-known as the ENSO pattern. And the mid-high latitude is shown as the PDO pattern (red rectangle).

• This is now thought that those mid-latitude variation may be the footprint of tropical forcing .

Why Second Mode

• PDO index can’t explain those variations in the ocean.

• NPGO is the dominant mode of the salinity and the nutrients.

[Wright et al., 2009]

Why Second Mode

• The NPGO leads decadal variations in the strength of the Kuroshio-Oyashio connecting California and Japan.

Di Lorenzo et al., 2008

500 hPa Height EOF2 -- WP

• The western pacific pattern (WP) is the SLP EOF2 pattern during DJFM in the region of 20～ 85N, 120E～ 120W.

Western Pacific Pattern (WP)

[Barnston and Livezey, 1987] 1950 1960 1970 1980 1990 2000 2010

-3

-2

-1

0

1

2

31950~2009 WP Index

Pacific SLP EOF2 – NPO

• NPO, the second mode of North Pacific SLPa, dominantly forces the North Pacific Gyre Oscillation (NPGO).

North Pacific Oscillation (NPO)

[Di Lorenzo et al., 2008]

Pacific SST EOF2 – Victoria ModeSSH EOF2 -- North Pacific Gyre Oscillation (NPGO)

[Di Lorenzo et al., 2008]

In the midlatitude and the North Pacific, the spatial pattern of the SSTa SEOF2 is nearly identical to the SSTa expression of the NPGO and of the second EOF of North Pacific SSTa, which has been referred to as the Victoria Mode [Bond et al., 2003].

Motivation / Objective -- Motivation-- Objective

Motivation

• Decadal and low-frequency climate variabilities in the Pacific and other basins are not well understood. What are the underlying physical mechanisms for these low-frequency climate variability?

• Can the latest AOGCM capture these climate patterns and variabilities for better future prediction?

• What is the role of atmospheric-ocean interaction? Are these climate variabilities related?

Objective

• To summary and clarify the low frequency variability in the North Pacific Ocean and their links with the global patterns.

• To assess and evaluate the coupled climate model capability in capturing the patterns of variability in the North Pacific.

• To understand and verify the underlying physical mechanisms in North Pacific climate variability.

• To bridge the regional climate variability in the North Pacific with a complete picture of global climate change throughout the Pacific basin.

Methods and Model - Data Source- Model - Methods

Data source

• Hadley SST– 1º x 1º HadISST1 from 1900 to 2009.

• Hadley SLP– 5º x 5º HadSLP2 from 1900 to 2009

• NCEP/NCAR Reanalysis 1– 2.5º x 2.5º Reanalysis 500 Height from 1950 to 2009

Preliminary Work - Ongoing Work- Future Work

1960 1970 1980 1990 2000-3

-2

-1

0

1

2

3500hPa Height PC1 & PNA index

500hPa Height PC1 & PNA index (R=0.501)500hPa Height PC1(positive)500hPa Height PC1 (negative)PNA Index

500 hPa Height EOF1 -- PNAPacific / North American Pattern (PNA)

125oE 150oE 175oE 160oW 135oW

36oN

48oN

60oN

72oN

84oN

500hPa Height EOF 1 (30.1177%)

-4

-3

-2

-1

0

1

2

3

4

Corrcoef = 0.501

1960 1970 1980 1990 2000-3

-2

-1

0

1

2

31950~2009 500hPa Height PC3 & WP Index

500hPa Height PC3 & WP index (R=0.528)500hPa Height PC3 (positive)500hPa Height PC3 (negative)WP Index

500 hPa Height EOF2 -- WP

• The western pacific pattern (WP) is the SLP EOF2 pattern during DJFM in the region of 20~85N, 120E~120W.

125oE 150oE 175oE 160oW 135oW

36oN

48oN

60oN

72oN

84oN

500hPa Height EOF 3 (11.5935%)

-4

-3

-2

-1

0

1

2

3

4

Western Pacific Pattern (WP)

[Barnston and Livezey, 1987]

Corrcoef = 0.528

NH SLP EOF1 -- AOArctic Oscillation (AO)

1950 1960 1970 1980 1990 2000 2010-4

-2

0

2

41950~2009 AO Index

120o W

60oW

0 o 60

o E

120

o E

180 oW

36 oN 48 oN

60 oN 72 oN

84 oN

SLP EOF 1 (46.9407%)

-2

-1

0

1

2

3

4

5

Pacific SLP EOF1 -- ALAleutian Low (AL)

-260 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60-40

-20

0

20

40

60

SLP 1 (28.1137%)

-1.5 -1 -0.5 0 0.5 1 1.5

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-3

-2

-1

0

1

2

3

4

1900-2009 Combined EOF PC1

Combined EOF PC1 & Nino 3.4 index (R=0.898)

Combined EOF PC1 (positive)Combined EOF PC1 (negative)Nino 3.4 IndexCorrcoef = 0.898

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-4

-3

-2

-1

0

1

2

3

41900-2009 Combined EOF PC2

Combined EOF PC2 & NPGO Index (R=0.486)Combined EOF PC2 (positive)Combined EOF PC2 (negative)NPGO Index

Pacific SLP EOF2 -- NPONorth Pacific Oscillation (NPO)

-260 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60-40

-20

0

20

40

60

SLP 2 (6.6139%)

-1.5 -1 -0.5 0 0.5 1 1.5

Corrcoef = 0.486

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-3

-2

-1

0

1

2

31900-2009 North Atlantic SLP EOF PC1

SLP PC 1 & NAO index (R=0.670)SLP PC1 (positive)SLP PC1 (negative)NAO Index

Atlantic SLP EOF1 -- NAONorth Atlantic Oscillation (NAO)

75oW 50oW 25oW 0o 25oE

30oN

45oN

60oN

75oN

90oN SLP EOF 1 (51.0839%)

-2 -1 0 1 2 3 4

Corrcoef = 0.670

Atlantic Long-term SSTa -- AMOAtlantic Multidecadal Oscillation (NPO)

1900 1925 1950 1975 2000-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time

STD

1900-2009 AMO Time Series

SSTa in AMO Region & AMO Index (R=0.442)Corrcoef = 0.442

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-3

-2

-1

0

1

2

3

4

1900-2009 Combined EOF PC1

Combined EOF PC1 & Nino 3.4 index (R=0.898)

Combined EOF PC1 (positive)Combined EOF PC1 (negative)Nino 3.4 Index

Pacific SST EOF1 – PDO/ENSOPacific Decadal Oscillation / El Nino-Southern Oscillation (PDO/ENSO)

-260 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60-40

-20

0

20

40

60

SLP 1 (28.1137%)

-1.5 -1 -0.5 0 0.5 1 1.5

Corrcoef = 0.898

Pacific SST EOF2 – Victoria ModeSSH EOF2 -- North Pacific Gyre Oscillation (NPGO)

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-4

-3

-2

-1

0

1

2

3

41900-2009 Combined EOF PC2

Combined EOF PC2 & NPGO Index (R=0.486)Combined EOF PC2 (positive)Combined EOF PC2 (negative)NPGO Index

-260 -240 -220 -200 -180 -160 -140 -120 -100 -80-40

-20

0

20

40

60

SST 2 (6.6139%)

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

Corrcoef = 0.486

Future Work

• To assess and evaluate the coupled climate model capability in capturing the patterns of variability in the North Pacific.– compare the atmospheric and the teleconnection patterns between these models

and observations.– evaluate the characteristics of modeled ENSO and the two associated types in the

coupled runs.

• To understand and verify the underlying physical mechanisms in North Pacific climate variability.– Verify the framework of the North Pacific Climate Variability

• To bridge the regional climate variability in the North Pacific with a complete picture of global climate change throughout the Pacific basin.

ECHAM (AGCM) 19 levels T31

DIECAST (OGCM) 31 Levels (2 deg)

SIT (A

ir/Snow/Ice/Therm

ocline) 2snow

+2ice+41 water levels

Model ( ECHAM5 / SIT / DIECAST )

ECHAM5 – AGCM, running at various resolutions.

SIT – a one-columnsnow/ice/ocean model with 41-level ocean+ 2-level ice + 2-level snow.

DIECAST – OGCM with 2 degree in the equator, covering from 60°S to 60°N, with 31 levels.

Year: 1871 to 2008

Summary

Summary

• The leading EOF patterns in the 500hPa, SLPa, and SSTa in the North Pacific are all related to the Aleutian Low. And the ENSO pattern may impact the mid-high latitude variations by atmosphere.

• The second mode in the Pacific now becomes more important because its time series is highly related to the changes of ocean variables.

• The further we want to realize is about what role other teleconnections play in the north hemisphere.

Atmosphere-Ocean Interaction

[Di Lorenzo et al., 2010]

PNA / AO / NAO ?WP ?

Thank You～ To Be Continued～