Predictability and prediction skill of the boreal summer intraseasonal oscillation in the Intraseasonal Variability Hindcast Experiment

Lee, Sun‐Seon; Wang, Bin; Waliser, Duane E.; Neena, J. M.; Lee, June‐Yi

doi:10.1007/s00382-014-2461-5

Cited by 70 publications

(55 citation statements)

References 60 publications

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“…While model deficiencies in depicting cumulus processes are generally blamed to be responsible for model inability to represent the MJO, essential MJO physics and key model processes for its realistic simulations are still elusive. Motivated by a longstanding and urgent need to improve the MJO in current weather forecasting and climate models, the MJO has been a central focus of several recent international projects in the tropical climate research community [ Zhang et al ., ], including the Intraseasonal Variability Hindcast Experiment [ Neena et al ., ; Lee et al ., ], the Year of Tropical Convection (YOTC) virtual field campaign [ Moncrieff et al ., ; Waliser et al ., ], the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY2011) and Dynamics of the MJO [ Yoneyama et al ., ], and the project on Subseasonal to Seasonal Prediction [ Vitart et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Key processes for the eastward propagation of the Madden‐Julian Oscillation based on multimodel simulations

2017

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As a prominent climate variability mode with widespread influences on global weather extremes, the Madden‐Julian Oscillation (MJO) remains poorly represented in the latest generation of general circulation models (GCMs), with a particular challenge in simulating its eastward propagating convective signals. In this study, by analyzing multimodel simulations from a recent global MJO model evaluation project, an effort is made to identify key processes for the eastward propagation of the MJO through analyses of moisture entropy (ME) processes under a “moisture mode” framework for the MJO. The column‐integrated horizontal ME advection is found to play a critical role for the eastward propagation of the MJO in both observations and good MJO models, with a primary contribution through advection of the lower tropospheric seasonal mean ME by the MJO anomalous circulations. By contrast, the horizontal ME advection effect for the eastward propagation is greatly underestimated in poor MJO GCMs, due to model deficiencies in simulating both the seasonal mean ME pattern and MJO circulations, leading to a largely stationary MJO mode in these GCMs. These results thus pinpoint an important guidance toward improved representation of the MJO in climate and weather forecast models. While this study mainly focuses on fundamental physics for the MJO propagation over the Indian Ocean, complex influences by the Maritime Continent on the MJO and also ME processes associated with the MJO over the western Pacific warrant further investigations.

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Section: Introductionmentioning

confidence: 99%

Key processes for the eastward propagation of the Madden‐Julian Oscillation based on multimodel simulations

2017

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“…They found that useful probabilistic forecasts could be generated up to the fourth pentad lead. Lee et al (2015) examined the predictability and prediction skill of BSISO over the ASM region in the IntraSeasonal Variability Hindcast Experiment (ISVHE). They found the multi-model mean BSISO predictability and prediction skill with strong initial amplitude (10% higher than the mean initial amplitude) are about 45 and 22 days, respectively.…”

Section: Introductionmentioning

confidence: 99%

Simulations of the Asian summer monsoon in the sub‐seasonal to seasonal prediction project (S2S) database

Wei

Vitart

et al. 2017

Quart J Royal Meteoro Soc

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to assess their ability to simulate the Asian monsoon. The bivariate anomaly correlation (BAC) of the Boreal Summer IntraSeasonal Oscillation (BSISO) index suggests that the operational models can predict the BSISO1 and BSISO2 events up to 6-24.5 and 6.5-14 days in advance respectively, although the models tend to underestimate the amplitude of BSISO as the lead time increases. For the strong BSISO events, BSISO1 (BSISO2) display lower skill mostly in phases 3-5 for all the models, suggesting that the BSISO1 (BSISO2) is not easy to predict when it is located over India and the Maritime Continent (South China Sea and Bay of Bengal). On the other hand, the higher skills appear in different phases for different models. For instance, the limit of predictive skill of strong BSISO1 and BSISO2 events in phases 6-7 for the ECMWF ensemble forecast could exceed 30 and 28 days, respectively. The comparisons of the BSISO life cycle among the ECMWF, NCEP and CMA models also indicate that the ECMWF model can better predict the evolution of strong BSISO events. Predictions of additional monsoon circulation indices including the Webster-Yang index (WY), Indian Summer Monsoon index (ISM), South Asian Monsoon index (SAM), and SouthEast Asian Monsoon index (SEAM) in the S2S models have statistically significant skill over the corresponding monsoon regions up to 9-31, 3-17, 7-13 and 7-14 days, respectively. However, the significant skill of summer monsoon precipitation over the SAM and SEAM regions varies significantly among the models, with the skill ranging from 2 days to 2 weeks lead time.

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“…The prediction skills for the first two leading modes have increased from 7 days during 1990s to about 25-30 days (ECMWF and GFDL models) during 2010s (Vitart 2014;Xiang et al 2015). However, the models still have large room to reach potential predictability limit (Neena et al 2014;Lee et al 2015). Realistic simulation of MJO in many current general circulation models (GCMs) remains a great challenge .…”

Section: Introductionmentioning

confidence: 99%

A trio-interaction theory for Madden–Julian oscillation

2016

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The Madden-Julian oscillation (MJO) is the dominant mode of tropical atmospheric intraseasonal variability and a primary source of predictability for global sub-seasonal prediction. Understanding the origin and perpetuation of the MJO has eluded scientists for decades. The present paper starts with a brief review of progresses in theoretical studies of the MJO and a discussion of the essential MJO characteristics that a theory should explain. A general theoretical model framework is then described in an attempt to integrate the major existing theoretical models: the frictionally coupled Kelvin-Rossby wave, the moisture mode, the frictionally coupled dynamic moisture mode, the MJO skeleton, and the gravity wave interference, which are shown to be special cases of the general MJO model. The last part of the present paper focuses on a special form of trio-interaction theory in terms of the general model with a simplified Betts-Miller (B-M) cumulus parameterization scheme. This trio-interaction theory extends the Matsuno-Gill theory by incorporating a trio-interaction among convection, moisture, and wave-boundary layer (BL) dynamics. The model is shown to produce robust large-scale characteristics of the observed MJO, including the coupled Kelvin-Rossby wave structure, slow eastward propagation (~5 m/s) over warm pool, the planetary (zonal) scale circulation, the BL low-pressure and moisture convergence preceding major convection, and amplification/decay over warm/cold sea surface temperature (SST) regions. The BL moisture convergence feedback plays a central role in coupling equatorial Kelvin and Rossby waves with convective heating, selecting a preferred eastward propagation, and generating instability. The moisture feedback can enhance Rossby wave component, thereby substantially slowing down eastward propagation. With the trio-interaction theory, a number of fundamental issues of MJO dynamics are addressed: why the MJO possesses a mixed Kelvin-Rossby wave structure and how the Kelvin and Rossby waves, which propagate in opposite directions, could couple together with convection and select eastward propagation; what makes the MJO move eastward slowly in the eastern hemisphere, resulting in the 30-60-day periodicity; why MJO amplifies over the warm pool ocean and decays rapidly across the dateline. Limitation and ramifications of the model results to general circulation modeling of MJO are discussed.

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Predictability and prediction skill of the boreal summer intraseasonal oscillation in the Intraseasonal Variability Hindcast Experiment

Cited by 70 publications

References 60 publications

Key processes for the eastward propagation of the Madden‐Julian Oscillation based on multimodel simulations

Key processes for the eastward propagation of the Madden‐Julian Oscillation based on multimodel simulations

Simulations of the Asian summer monsoon in the sub‐seasonal to seasonal prediction project (S2S) database

A trio-interaction theory for Madden–Julian oscillation

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