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NCSU > CICS-NC > Monitoring > MJO

Monitoring the MJO and Tropical Waves

 

Updated: 30 Dec, 2013

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Data

Outgoing Longwave Radiation (OLR)

o   OLR is frequently used as a proxy for tropical convection.

o   These data are observed with the AVHRR sensor on the NOAA polar-orbiting satellites.

o   Uninterpolated gridded data are obtained from NOAA/OAR/ESRL/PSD.

Upper Tropospheric Water Vapor (UTWV)

o   These brightness temperatures are observed with the HIRS sensor on the NOAA and MetOp polar-orbiting satellites.

o   Orbital swath data are obtained from NOAA/CLASS.

o   Inter-satellite calibration is performed following Shi & Bates (2011, JGR), which was developed as part of the Climate Data Record program.

o   The calibrated data are binned into daily 2.5¡ latitude–longitude grids.

 

Method

 

Description: Macintosh HD:Users:carl:Downloads:olr.gif

 

The figure above shows the wavenumber–frequency spectrum for OLR, divided by an estimate of the red background following Wheeler & Kiladis (1999, JAS). The panel on the left shows signals that are anti-symmetric about the equator, while the panel on the right shows those that are symmetric. Spectral peaks tend to lie along the dispersion curves for shallow water equatorial waves (black lines).

 

To identify tropical waves in near real-time, the OLR and UTWV data are filtered following Wheeler & Weickmann (2001 MWR). The daily anomalies are calculated using the first 3 harmonics of the seasonal cycle for 1979–2009. Missing values are then filled using linear interpolation in space and time. The most recent 365 days of anomalies are padded with 659 days of zeroes, and the result is filtered for each wave type.

 

No equatorial symmetry is imposed here, and the filters differ somewhat from the original ones defined by Wheeler & Kiladis (1999):

 

Wave Type

Color

Propagation Direction

Wavenumber

Period (days)

Equivalent Depth (m)

Source

Madden–Julian Oscillation (MJO)

Blue

Eastward

0­–9

30–96

n/a

Kiladis et al. (2005 JAS)

Kelvin Waves

Green

Eastward

1–14

2.5–17

8–90

Straub & Kiladis (2002, JAS)

Equatorial Rossby

(ER) Waves

Black

Westward

1–10

9–72

0–90

Kiladis et al. (2009, Rev. Geophys.)

Mixed Rossby–Gravity (MRG) Waves

Red

Westward

1–10

3–10

8–90

Wheeler & Kiladis (1999)

Tropical Depression (TD)-type disturbances

Cyan

Westward

6–20

2.5–5

n/a

Roundy & Frank (2004, JAS)

 

Global Maps of Totals & Anomalies

 

 

OLR

HIRS UTWV

1 day

Last

Previous

Last

Previous

3 days

Last

Previous

Last

Previous

7 days

Last

Previous

Last

Previous

30 days

Last

Previous

Last

Previous

60 days

Last

Previous

Last

Previous

180 days

Last

Previous

Last

Previous

365 days

Last

 

Last

 

 

Hovmšllers

 

 

OLR

HIRS UTWV

Northern Narrow

2.5¡N – 7.5¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Northern Medium

2.5¡N – 17.5¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Northern Wide

2.5¡N – 27.5¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Equatorial Narrow

2.5¡S – 2.5¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Equatorial Medium

7.5¡S – 7.5¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Equatorial Wide

15¡S – 15¡N

Total

Anomaly

Waves

Total

Anomaly

Waves

Southern Narrow

7.5¡S – 2.5¡S

Total

Anomaly

Waves

Total

Anomaly

Waves

Southern Medium

17.5¡S – 2.5¡S

Total

Anomaly

Waves

Total

Anomaly

Waves

Southern Wide

27.5¡S – 2.5¡S

Total

Anomaly

Waves

Total

Anomaly

Waves

 

Paneled Global Maps of Recent and Forecast Data

 

 

OLR

HIRS UTWV

Total

1d - 3d - 5d - 7d - 15d

1d - 3d - 5d - 7d - 15d

Anomaly

1d - 3d - 5d - 7d - 15d

1d - 3d - 5d - 7d - 15d

MJO

5d - 7d

5d - 7d

Kelvin Waves

1d - 2d

1d - 2d

Symmetric Kelvin Waves

1d - 2d

1d - 2d

ER Waves

3d - 5d

3d - 5d

Symmetric ER Waves

3d - 5d

3d - 5d

MRG Waves

1d

1d

Anti-Symmetric MRG Waves

1d

1d

TD-type Disturbances

1d

1d

Sum of Waves

3d - 5d - 7d

3d - 5d - 7d

 

 

Related Links

o   NOAA/CPC Global Tropical Hazards Assessment

o   NOAA/CPC Global Hazards Briefing

o   CAWCR's Current Climate Charts (by Matt Wheeler)

o   TAO/TRITON Data Display

o   NOAA/ESRL/PSD Map Room

o   CIMSS Tropical Cyclones

o   Navy/NRL Tropical Cyclone Page

o   Paul Roundy's Tropical Waves

o   Carl Schreck's Tropical Rainfall and Winds

 

Created and maintained by Carl Schreck.