# Presentation: 083324

## Simulations of the Madden-Julian Oscillation by Global Models: Current Status

*Chidong Zhang, Min Dong*
- RSMAS, University of Miami
*Harry Hendon, Andrew Marshall*
- BMRC
*Eric Maloney*
- Oregon State University
*Kenneth Sperber*
- PCMDI, Lawrence Livermore National Laboratory
*Wanqiu Wang*
- CPC/NCEP

## Objectives: (1) 	To evaluate how well we currently can simulate the 	MJO using 	global climate and weather forecast models(2) 	To gain insight into MJO dynamics from the success and failure of 	global model simulations

- _Issues_: - What is the improvement during the last decade?- What are the remaining common problems?- How does air-sea coupling affect MJO simulations?- How does the mean background state affect MJO simulations?

## Models

| Uncoupled
AGCM | Coupled
CGCM | Institute |
| --- | --- | --- |
| BAM3
(20 yrs) | BAM3C
(20 yrs) | BMRC |
| GFS03
(20 yrs) | GFS03C (CFS)
(20 yrs) | NCEP |
| CAM2R
(16 yrs) | CAM2RC
(15 yrs) | NCAR/OSU |
| ECHAM4 
(20 yrs) | ECHO-G
(20 yrs) | MPI |

## Atmosphere Models

| Models
(Institute) | Horizontal Resolution | Vertical Levels
(top level) | Cumulus Parameterization | Integration
 |
| --- | --- | --- | --- | --- |
| BAM3 
(BMRC) | T47 
(2.5 ̊) | 17 
(10 hPa) | Mass flux (Tiedtke 1989)
Adjustment closure (Nordeng 1994) | 1982 - 2001 |
| GFS03
 (NCEP) | T62 
(1.8 ̊) | 64 
(0.2 hPa) | Mass flux 
(Hong and Pan 1998) | 1979 - 1998
 |
| CAM2R
(NCAR/OSU) | T42 
(2.8 ̊) | 26 
(3.5 hPa) | Relaxed Arakawa-Schubert 
(Moorthi and Suarez 1992) | 16 years |
| ECHAM4 
(MPI) | T42 
(2.8 ̊) | 19 
(10 hPa) | Mass flux (Tiedtke 1989)
Adjustment closure (Nordeng 1994) | 20 years |

## Ocean Models

| Coupled Run | Ocean Models
 | Meridional Resolution | Zonal Resolution | Vertical Levels
 | Flux Correction |
| --- | --- | --- | --- | --- | --- |
| BAM3C
 | ACOM2 
 | 0.5 ̊in 9 ̊N-9 ̊S
1.5 ̊ near the poles | 2 ̊ | 25
(12 in upper 185m) | Yes |
| GFS03C
 | MOM3
 | 1/3 ̊ in 10 ̊N-10 ̊S
1 ̊ beyond 30 ̊N/S | 1 ̊ | 40 
(27 in upper 400m) | No |
| CAM2RC | SOM
 |  0 | 0 | 1 | Yes |
| ECHO-G
 | HOPE-G | 0.5 ̊ in 10 ̊N-10 ̊S
2.8 ̊beyond 30 ̊N/S | 2.8 ̊ | 20
(8 in upper 200m) | Yes |

## Observations: (1) 	NCEP/NCAR reanalysis zonal wind at 850 hPa (U850) (Kalnay et al 	1996)(2) 	CMAP precipitation (Xie and Arkin 1997)

- _Analysis Method_: (1) 	Time-space spectrum (Hayashi 1979) of unfiltered data(2) 	MJO reconstruction using Hilbert SVD (Zhang and Hendon 1997) 	applied to intraseasonally (20-90 day) band-passed data(3) 	Seasonal cycle and geographic distribution of the MJO (Zhang 	and Dong 2004)

## Time-space spectra 

**Time-space spectra **
**10 ̊N-10 ̊S/60-180 ̊E **

- Eastward power > westward power
- Wind signal stronger than precipitation
- Air-sea interaction enhance eastward power

## PEastward/PWestward

|  | OBS | BAM3 | BAM3C | GFS03 | GFS03C | CAM2R | CAM2RC | ECHAM4 | ECHO-G |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| U850 | 3.5 | 2.2 | 2.8 | 2.7 | 4.6 | 2.0 | 3.2 | 2.0 | 2.7 |
| P | 2.4 | 1.2 | 1.3 | 1.2 | 1.7 | 1.5 | 1.9 | 1.3 | 1.2 |

- Ratio of eastward vs. westward intraseasonal power for 850 hPa zonal wind (U850) and precipitation (P). Intraseasonal power is defined as within the window of 30 - 90 days at zonal wavenumber 1 for U850 and zonal wavenumbers 1 and 2 for P.

**P****Eastward****/P****Westward**

- Simulated signal in wind is more realistic than simulated signal in precipitation.
- Air-sea interaction helps strengthen the signals for all models except for precipitation in ECHO-G.

## Isolation of the MJO signal

- and Accumulative Fractional Variance

|  | OBS | BAM3 | BAM3C | GFS03 | GFS03C | CAM2R | CAM2RC | ECHAM4 | ECHO-G |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| U850 | 4
(49%) | 10
(58%) | 4
(40%) | 4
(44%) | 4
(47%) | 2
(22%) | 6
(48%) | 4
(36%) | 4
(41%) |
| P | 4
(36%) | 4
(20%) | 6
(30%) | 4
(23%) | 2
(14%) | 4
(25%) | 4
(47%) | 6
(30%) | 6
(31%) |

**Isolation of the MJO signal**

- Only outstanding Modes are used (Based on the Rule of North et al 1982)

## Propagation of the MJO

- Lag-regression upon MJO of  U850 at 160 ̊E and 0 ̊N
- Equatorial U850 (contours) Equatorial precipitation (colors).

**Propagation of the MJO**

## Horizontal Structure

- Zero-lag regression upon MJO U850 at 160 ̊E and 0 ̊N.
- U850 (vectors)
- precipitation (colors)

**Horizontal Structure**

## U850 Geographic distribution

- Colors: 		Mean

**U850 Geographic distribution**

- December -March

## Precipitation Geographic distribution

- Contours: 	MJO variance
- Shadings: 			Mean

**Precipitation Geographic distribution**

- December -March

## Modeled Variance  / Observed Variance

|  | BAM3 | BAM3C | GFS03 | GFS03C | CAM2R | CAM2RC | ECHAM4 | ECHO-G |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| U850 | 1.5 | 1.1 | 0.8 | 1.0 | 1.4 | 2.4 | 0.9 | 1.5 |
| P | 0.4 | 0.6 | 0.4 | 0.1 | 0.5 | 0.8 | 0.6 | 1.1 |

**Modeled Variance  ****/ ****Observed Variance**
- December – March
- (15 ̊S- 15 ̊N, 50 - 180 ̊E)

## MJO Seasonal migration

- Color: 	Mean

**60E - 180 ̊E average**

**MJO Seasonal migration**

## Effect of mean state

- RMS mean:	15 ̊S - 15 ̊N, 50 - 270 ̊E

- MJO RMS error vs Mean state RMS error
- (December - March)

- Blue:  Uncoupled
- Red:    Coupled

**Effect of mean state**

## Effect of mean state

- Mean variance of MJO precipitation (contour) overlaid with mean moisture convergence
- December - March

- 850 hPa MC

- 925 hPa MC

**Effect of mean state**

## Summary Improvement:(1)	intraseasonal, planetary-scale, eastward propagating spectral power in winds 		stronger than westward propagating spectral power; (2) 	realistic eastward phase speed of the MJO in the western Pacific.Common problems:  (1) 	weak MJO signal in precipitation, (2)	unrealistic phase relation between precipitation and wind  (maximum 			precipitation not in low-level westerlies in the western Pacific), (3) 	split of precipitation maxima in the western Pacific, (4) 	seasonal migration unrealistic in many models.

## Summary (cont.) Important issues:(1) 	Effects of air-sea coupling on MJO simulation are highly model-dependent. (2)	Biases in MJO simulations are related to biases in simulated mean low-	level zonal wind and mean precipitation.   (3) 	The MJO activity depend on mean boundary-layer (925 hPa) moisture 	convergence.(4) 	The incoherence between MJO wind and precipitation in the simulations 	raises questions regarding our understanding of the MJO dynamics. 

## Thank You!

## Time - latitude plot of variance in MJO U850 (contour, interval of 2 m2 s-2) and precipitation (contour, interval of 2 mm2 day-2) averaged over 60 - 180 ̊E. Mean U850 (color, m s-1, zero outlined by white contours) is overlaid with MJO U850 and mean precipitation (color, mm day-1) overlaid with MJO precipitation. 

- Time - latitude plot of variance in MJO U850 (contour, interval of 2 m2 s-2) and precipitation (contour, interval of 2 mm2 day-2) averaged over 60 - 180 ̊E. Mean U850 (color, m s-1, zero outlined by white contours) is overlaid with MJO U850 and mean precipitation (color, mm day-1) overlaid with MJO precipitation.

**Notes:**
Next we will discuss the seasonal migration.

## Scatter diagrams of RMS differences between individual simulations and observations in (a) MJO U850 variance (m2 s-2) and mean U850 (m s-1), (b) MJO precipitation variance (mm2 d-2) and mean precipitation (mm d-1), (c) MJO precipitation variance (mm2 d-2) and mean 925 hPa moisture convergence (g kg-1 m-1),and (d) MJO precipitation and mean 850 hPa moisture convergence. Symbols represent: circles for BAM3/BAM3C, crosses for GFS03/GFS03C, plus signs for CAM2R/CAM2RC, and squares for ECHAM4/ECHO-G, with blue for uncoupled and red for coupled simulations. RMS differences were calculated over 15 ̊S - 15 ̊N, 50 - 180 ̊E for the MJO variables and 15 ̊S - 15 ̊N, 50 - 270 ̊E for the mean state variables during December - March. Arrows in (d) highlight changes from uncoupled to coupled simulations. 

- Scatter diagrams of RMS differences between individual simulations and observations in (a) MJO U850 variance (m2 s-2) and mean U850 (m s-1), (b) MJO precipitation variance (mm2 d-2) and mean precipitation (mm d-1), (c) MJO precipitation variance (mm2 d-2) and mean 925 hPa moisture convergence (g kg-1 m-1),and (d) MJO precipitation and mean 850 hPa moisture convergence. Symbols represent: circles for BAM3/BAM3C, crosses for GFS03/GFS03C, plus signs for CAM2R/CAM2RC, and squares for ECHAM4/ECHO-G, with blue for uncoupled and red for coupled simulations. RMS differences were calculated over 15 ̊S - 15 ̊N, 50 - 180 ̊E for the MJO variables and 15 ̊S - 15 ̊N, 50 - 270 ̊E for the mean state variables during December - March. Arrows in (d) highlight changes from uncoupled to coupled simulations.

- (a)

- (b)

- (c)

- (d)

## 850 hPa MC

- Mean variance of MJO precipitation (contour) overlaid with mean moisture convergence (g kg-1 s-1) at (a) 850 hPa and (b) 925 hPa for December - March. Contour intervals are 2 mm d-1 starting from 1.

- 925 hPa MC