Performance of the seasonal forecasting of the Asian summer monsoon by BCC_CSM1.1(m)

Abstract

This paper provides a comprehensive assessment of Asian summer monsoon prediction skill as a function of lead time and its relationship to sea surface temperature prediction using the seasonal hindcasts of the Beijing Climate Center Climate System Model, BCC CSM1.1(m). For the South and Southeast Asian summer monsoon, reasonable skill is found in the model's forecasting of certain aspects of monsoon climatology and spatiotemporal variability. Nevertheless, deficiencies such as significant forecast errors over the tropical western North Pacific and the eastern equatorial Indian Ocean are also found. In particular, overestimation of the connections of some dynamical monsoon indices with large-scale circulation and precipitation patterns exists in most ensemble mean forecasts, even for short lead-time forecasts.Variations of SST, measured by the first mode over the tropical Pacific and Indian oceans, as well as the spatiotemporal features over the Niño3.4 region, are overall well predicted. However, this does not necessarily translate into successful forecasts of the Asian summer monsoon by the model. Diagnostics of the relationships between monsoon and SST show that difficulties in predicting the South Asian monsoon can be mainly attributed to the limited regional response of monsoon in observations but the extensive and exaggerated response in predictions due partially to the application of ensemble average forecasting methods. In contrast, in spite of a similar deficiency, the Southeast Asian monsoon can still be forecasted reasonably, probably because of its closer relationship with large-scale circulation patterns and El Niño-Southern Oscillation.

Validity of parameter optimization in improving MJO simulation and prediction using the sub-seasonal to seasonal forecast model of Beijing Climate Center

“…The sea ice component is GFDL Sea Ice Simulator. Details on similar versions of BCC_CSM and their use in climate change projection and short-term climate prediction have been documented in several studies (e.g., Wu et al 2013Wu et al , 2014Liu et al 2014Liu et al , 2015.…”

Evaluation and statistical downscaling of East Asian summer monsoon forecasting in BCC and MOHC seasonal prediction systems

“…For example, the ENSEMBLES, DEMETER, BCC_CSM1.1m, CFS and POAMA have relatively similar skill (e.g. Wang et al, ; Li et al, ; Liu et al, ) when the interannual EASM index defined by Wang and Fan () is employed. But, the prediction skill for summer precipitation over East Asia and the northwest Pacific shows differences in different models (Lee et al, ; Li et al, ), and has only recently been demonstrated in any system (Li et al, ).…”

MJO prediction using the sub-seasonal to seasonal forecast model of Beijing Climate Center

“…The BCC_CSM, with the inclusion of ocean-land-atmosphere-ice coupling and carbon cycle, has coarse-and moderate-resolution versions that participated in the CMIP5 and provided reasonable simulations of climate change (Wu et al 2013. Also, the BCC_CSM with a moderate resolution has been used in seasonal prediction and exhibited reliable performance (Liu et al 2014a(Liu et al , 2015a.…”

“…Also, as one of the participants in the S2S Prediction Project, the BCC has conducted comprehensive S2S reforecast experiments using a coupled model since 2014. Before its participation in the S2S Project, only atmosphere-only models were used at the BCC to fulfill sub-seasonal forecast with a below-50-day integration, while coupled models were only applied in seasonal climate prediction and had reasonable skills in predicting Asian monsoon and ENSO (Liu et al 2014a(Liu et al , 2015a. Because of insufficient practical experience as well as lack of high-quality assimilation analysis, it is found that the initial S2S reforecast experiments showed limited skills in capturing sub-seasonal variability of climate phenomenon, especially the MJO.…”