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

Several monsoon indices have been applied to multiple models from the sub‐seasonal to seasonal (S2S) prediction project database during the period May to October 1999–2010 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.

[1]  D. Waliser,et al.  Model performance metrics and process diagnostics for boreal summer intraseasonal variability , 2017, Climate Dynamics.

[2]  Michel Rixen,et al.  The Subseasonal to Seasonal (S2S) Prediction Project Database , 2017 .

[3]  M. Collins,et al.  Seasonal intercomparison of observational rainfall datasets over India during the southwest monsoon season , 2015 .

[4]  Jun Wang,et al.  Using a deterministic time-lagged ensemble forecast with a probabilistic threshold for improving 6–15 day summer precipitation prediction in China , 2015 .

[5]  Bin Wang,et al.  Predictability and prediction skill of the boreal summer intraseasonal oscillation in the Intraseasonal Variability Hindcast Experiment , 2015, Climate Dynamics.

[6]  Arun Kumar,et al.  Subseasonal forecast skills and biases of global summer monsoons in the NCEP Climate Forecast System version 2 , 2014, Climate Dynamics.

[7]  Jun Wang,et al.  Improvement of 6–15 day precipitation forecasts using a time-lagged ensemble method , 2014, Advances in Atmospheric Sciences.

[8]  Arun Kumar,et al.  Prediction and monitoring of monsoon intraseasonal oscillations over Indian monsoon region in an ensemble prediction system using CFSv2 , 2013, Climate Dynamics.

[9]  Arun Kumar,et al.  Diagnostics of subseasonal prediction biases of the Asian summer monsoon by the NCEP climate forecast system , 2013, Climate Dynamics.

[10]  Bin Wang,et al.  Intraseasonal Forecasting of the Asian Summer Monsoon in Four Operational and Research Models , 2013 .

[11]  Arun Kumar,et al.  Seasonal-to-Interannual Prediction of the Asian Summer Monsoon in the NCEP Climate Forecast System Version 2 , 2013 .

[12]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[13]  Zhichang Guo,et al.  Intercomparison and analyses of the climatology of the West African Monsoon in the West African Monsoon Modeling and Evaluation project (WAMME) first model intercomparison experiment , 2010 .

[14]  Bin Wang,et al.  Impacts of initial conditions on monsoon intraseasonal forecasting , 2009 .

[15]  V. Kousky,et al.  Simulations and Seasonal Prediction of the Asian Summer Monsoon in the NCEP Climate Forecast System , 2008 .

[16]  Bin Wang,et al.  How accurately do coupled climate models predict the leading modes of Asian-Australian monsoon interannual variability? , 2008 .

[17]  M. Wheeler,et al.  An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction , 2004 .

[18]  G. Meehl,et al.  AGCM simulations of intraseasonal variability associated with the Asian summer monsoon , 2003 .

[19]  M. Kanamitsu,et al.  NCEP–DOE AMIP-II Reanalysis (R-2) , 2002 .

[20]  Bin Wang,et al.  Intercomparison of the climatological variations of Asian summer monsoon precipitation simulated by 10 GCMs , 2002 .

[21]  K. Lau,et al.  Interannual Variability of the Asian Summer Monsoon: Contrasts between the Indian and the Western North Pacific–East Asian Monsoons* , 2001 .

[22]  T. Palmer,et al.  Dynamical Seasonal Predictability of the Asian Summer Monsoon , 2001 .

[23]  J. Susskind,et al.  Global Precipitation at One-Degree Daily Resolution from Multisatellite Observations , 2001 .

[24]  K. Lau,et al.  Dynamical and Boundary Forcing Characteristics of Regional Components of the Asian Summer Monsoon , 2000 .

[25]  Bin Wang,et al.  Choice of South Asian Summer Monsoon Indices , 1999 .

[26]  Peter J. Webster,et al.  Monsoon and Enso: Selectively Interactive Systems , 1992 .

[27]  Bin Wang,et al.  Asian summer monsoon rainfall predictability: a predictable mode analysis , 2014, Climate Dynamics.

[28]  Bin Wang,et al.  Real-time multivariate indices for the boreal summer intraseasonal oscillation over the Asian summer monsoon region , 2012, Climate Dynamics.

[29]  Li Tao,et al.  Impact of Atmosphere-Ocean Coupling on the Predictability of Monsoon Intraseasonal Oscillations , 2007 .

[30]  Bhupendra Nath Goswami,et al.  A broad‐scale circulation index for the interannual variability of the Indian summer monsoon , 1999 .

[31]  B. Liebmann,et al.  Description of a complete (interpolated) outgoing longwave radiation dataset , 1996 .