Modulation of the Extratropical Circulation By Combined Activity of the Madden–Julian Oscillation and Equatorial Rossby Waves

Lawrence C. Gloeckler and Paul E. RoundyDepartment of Atmospheric and Environmental Sciences

University at Albany, Albany, New York

30th Conference on Hurricanes and Tropical MeteorologySawgrass Marriott Resort

Ponte Vedra Beach, Florida20 April 2012

lgloeckler@albany.edu||proundy@albany.edu

Three-way Feedback

MJO Convection

Extratropical Rossby Waves

Equatorial Rossby Waves

MJO Circulation

MJO

200-hPa streamfunction (contoured every 10 × 105 m2 s−1), total wind (vectors in m s−1), and MJO-filtered Outgoing Longwave Radiation (OLR) anomaly (shaded < −16 W m−2).

Adapted from Fig. 2b of Kiladis et al. (2005).

EQMJO

300-hPa

MJO Circulation

JET

JET

EQMJO

300-hPa

MJO Circulation

JET

JET

EQMJO

300-hPa

MJO Circulation

JET

JET

EQMJO

300-hPa

MJO Circulation

JET

JET

EQMJO

300-hPa

MJO Circulation

Data and Methodology

• Analyzed satellite derived OLR data and NCEP—NCAR geopotential height and wind 40 year reanalysis data

• Anomalies generated by subtracting annual cycle and first four harmonics

• Identified a set of dates when the MJO was in RMM phase 4

• Identified longitude at which ER wave crossings occurred most frequently, and found dates of ER filtered OLR minima at longitude

• Generated composites based on MJO, ER, and simultaneous MJO and ER signals

ResultsER ONLY

•OLR composite anomaly averaged 7.5°S–7.5°N (shaded) • 300-hPa geopotential height

anomaly averaged 40°N–50°N (contoured every 20 m starting at 20 m; red=positive, blue=negative)

Tim

e La

g (d

ays)

30

20

10

10

-10

-20

-30

30-30 10-20 -10 10 20

60E 180 60W

W m-2

ResultsMJO ONLY

•OLR composite anomaly averaged 7.5°S–7.5°N (shaded) • 300-hPa geopotential height

anomaly averaged 40°N–50°N (contoured every 20 m starting at 20 m; red=positive, blue=negative)

30-30 10-20 -10 10 20

Tim

e La

g (d

ays)

30

20

10

10

-10

-20

-30 60E 180 60W

W m-2

ResultsSUM ER & MJO

•OLR composite anomaly averaged 7.5°S–7.5°N (shaded) • 300-hPa geopotential height

anomaly averaged 40°N–50°N (contoured every 20 m starting at 20 m; red=positive, blue=negative)

30-30 10-20 -10 10 20

Time Lag (days)

30

20

10

10

-10

-20

-3060E 180 60W

W m-2

ResultsSIMULTANEOUS

•OLR composite anomaly averaged 7.5°S–7.5°N (shaded) • 300-hPa geopotential height

anomaly averaged 40°N–50°N (contoured every 20 m starting at 20 m; red=positive, blue=negative)

30-30 10-20 -10 10 20

Time Lag (days)

30

20

10

10

-10

-20

-3060E 180 60W

W m-2

ResultsSIMULTANEOUSER ONLY MJO ONLY SUM ER & MJO

30-30 10-20 -10 10 20

Tim

e La

g (d

ays)

30

20

10

10

-10

-20

-30 60E 180 60W 60E 180 60W 60E 180 60W 60E 180 60W

W m-2

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day -5

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day -4

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day -3

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day -2

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day -1

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 0

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 1

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 2

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 3

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 4

Composites – ER Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, ER Base Longitude=157.5E, Lag=Day 5

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day -5

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day -4

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day -3

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day -2

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day -1

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 0

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 1

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 2

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 3

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 4

Composites – MJO Only

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, Lag=Day 5

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day -5

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day -4

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day -3

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day -2

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day -1

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 0

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 1

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 2

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 3

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 4

Composites – ER and MJO

10-20 -10 10 20 30-30

W m-2

0 60E 120E 180 120W 60W

0

20S

20N

40N

60N

OLR, 300-hPa Height and Wind Anomaly, RMM=4, ER Base Longitude=157.5E, Lag=Day 5

Conclusion

• Separate ER wave and MJO composites demonstrate importance of assessing ER wave events relative to MJO

• Sum of two sets of events yields little additional information about extratropical circulation than MJO alone

• Simultaneous assessment of MJO and ER wave events yields more information about extratropical circulation than can be obtained from either mode alone

Conclusion

MJO Convection

Extratropical Rossby Waves

Equatorial Rossby Waves

Thank You

Lawrence C. Gloeckler and Paul E. RoundyDepartment of Atmospheric and Environmental Sciences

University at Albany, Albany, NY

Lgloeckler@albany.edu||Roundy@atmos.albany.edu

http://www.atmos.albany.edu/student/lgloeckl/www.atmos.albany.edu/facstaff/roundy/