Progress and Prospects of Research on Subseasonal to Seasonal Variability and Prediction of the East Asian Monsoon

Subseasonal to seasonal (S2S) variability represents the atmospheric disturbance on the 10–90-day timescale, which is an important bridge linking weather and climate. In 2015, China Meteorological Administration (CMA) listed the S2S prediction project that was initiated by WMO programs three years ago as one of its key tasks. After five years of research, significant progress has been made on the mechanisms of the East Asian monsoon (EAM) S2S variability, related impact of climate change, as well as the predictability on the S2S timescale of numerical models. The S2S variability of the EAM is closely linked to extreme persistent climate events in China and is an important target for seasonal climate prediction. However, under the influence of global warming and the interactions among climate systems, the S2S variability of the EAM is so complex that its prediction remains a great challenge. This paper reviews the past achievement and summarizes the recent progress in research of the EAM S2S variability and prediction, including characteristics of the main S2S modes of the EAM, their impact on the extreme events in China, effects of external and internal forcing on the S2S variability, as well as uncertainties of climate models in predicting the S2S variability, with a focus on the progress achieved by the S2S research team of the Chinese Academy of Meteorological Sciences. The present bottlenecks, future directions, and critical research recommendations are also analyzed and presented.