The present study investigates relationship between interannual variations of snow cover and local surface and atmospheric variables, and the formation of interannual snow cover anomalies over the Tibetan Plateau in the cold seasons (autumn, winter, and spring). It is shown that the snow‐related surface heat flux and atmospheric heat source anomalies increase from autumn to spring, whereas precipitation anomalies are most prominent in autumn. This suggests that snow cover anomalies over the central eastern Tibetan Plateau are mainly formed in autumn and their impacts are most prominent in spring. The central eastern Tibetan Plateau snow cover anomalies have high month‐to‐month persistence during October through April, indicative of a large contribution of persistence to snow cover anomalies in winter and spring. The Tibetan Plateau snow cover anomalies in cold seasons are influenced by large‐scale atmospheric circulation anomaly pattern of different paths. In autumn, a wave pattern from the North Pacific to the Tibetan Plateau via the North Atlantic, induced by eastern North Pacific and western North Atlantic sea surface temperature anomalies, plays an important role in the formation of snow cover anomalies. In winter, a North Atlantic Oscillation related wave pattern from the North Atlantic to East Asia may contribute to snow cover anomalies. In spring, a midlatitude wave pattern originating over the western North Atlantic and propagating through the Mediterranean Sea to southern Tibetan Plateau may have a supplementary contribution to snow cover anomalies.

The current study investigates the interdecadal changes in the relationship between the winter precipitation anomalies in southeastern China, El Niño–Southern Oscillation (ENSO), and the East Asian winter monsoon (EAWM) at the end of the twentieth century. It appears that the relationships between the interannual variability of the southeastern China winter precipitation and ENSO as well as EAWM are obviously weakened after 1998/99. The possible mechanisms accounting for this interdecadal change in the relationship have been examined by dividing the data into two subperiods [1980–98 (P1) and 1999–2015 (P2)]. The results indicate that, without the linear contribution of EAWM, ENSO only play a limited role in the variability of winter precipitation in southeastern China in both subperiods. In contrast, in P1, corresponding to an ENSO-independent weaker-than-normal EAWM, anomalous southerlies along coastal southeastern China associated with an anticyclone over the northwestern Pacific transport water vapor to China. However, in P2 the impact of EAWM on winter precipitation in southeastern China is weakened because of the regime shift of EAWM. The EAWM-related positive SLP anomalies over the North Pacific move eastward in P2, causing an eastward migration of the associated anomalous southerlies along its western flank and therefore cannot significantly contribute to the positive winter precipitation anomalies in southeastern China.

The diverse influences of the El Niño Southern Oscillation (ENSO) on wintertime precipitation over the Maritime Continent are herein investigated using observational data. The ENSO events are divided into four categories—strong El Niño, strong La Niña, moderate El Niño and moderate La Niña—according to their amplitudes. Significant negative Maritime Continent precipitation anomalies are observed during strong El Niño events, whereas wet conditions occur during strong La Niña events. In the case of moderate La Niña events, the Maritime Continent rainfall anomalies are similar in spatial structure and comparable in amplitude to strong La Niña events, whereas almost no significant rainfall anomalies are observed in moderate El Niño years. Further analysis shows that strong El Niño (strong/moderate La Niña) events are associated with a significant anticyclone (cyclone) surface response over the western tropical Pacific and related to a significant descending (ascending) branch of the Walker circulation around the Philippines. However, during moderate El Niño events, both the central‐eastern and the western tropical sea surface temperature anomalies (SSTA) are weak and cannot significantly change the Walker circulation over the tropical Pacific. Therefore, the descending branch anomalies of the Walker circulation associated with moderate El Niño events around the Philippines are quite weak and cannot cause significant negative precipitation anomalies in that location. In addition, there is large case‐to‐case variance in the tropical Pacific SSTA associated with moderate El Niño events, which also contributes to the weak Maritime Continent rainfall response in the composite analysis.

The interannual variations and the prediction of the leading two empirical orthogonal function (EOF) modes of spring (April–May) precipitation over China for the period from 1951 to 2014 are investigated using both observational data and the seasonal forecast made by six coupled climate models. The leading EOF mode of spring precipitation over China (EOF1-prec) features a monosign pattern, with the maximum loading located over southern China. The ENSO-related tropical Pacific SST anomalies in the previous winter can serve as a precursor for EOF1-prec. The second EOF mode of spring precipitation (EOF2-prec) over China is characterized by a dipole structure, with one pole near the Yangtze River and the other one with opposite sign over the Pearl River delta. A North Atlantic sea surface temperature (SST) anomaly dipole in the preceding March is found contribute to the prec-EOF2 and can serve as its predictor. A physics-based empirical (P-E) model is then formulated using the two precursors revealed by the observational analysis to forecast the variations of EOF1-prec and EOF2-prec. Compared to coupled climate models, which have little skill in forecasting the time variations of the two EOF modes, this P-E model can significantly improve the forecast skill of their time variations. A linear regression model is further established using the time series forecast by the P-E model to forecast the spring precipitation over China. Results suggest that the seasonal forecast skill of the spring precipitation over southeastern China, especially over the Yangtze River area, can be significantly improved by the regression model.

This study investigates the interdecadal changes in the relationship between the Eurasian snow cover extent (SCE) and spring precipitation over southern China. The results show that the spring precipitation over southern China has experienced an obvious change from an active to a quiet period since the late 1980s. The entire data set is divided into two subperiods, that is, 1972–1987 (P1) and 1988–2009 (P2). The interannual variation of the spring precipitation of southern China is found to be significantly related to Eurasian SCE anomalies around northwest of Lake Baikal. Less‐than‐normal SCE northwest of Lake Baikal corresponds to more‐than‐normal spring precipitation over southern China. The result of a numerical experiment performed using a baroclinic atmospheric model indicates that the Eurasian snow anomalies around northwest of Lake Baikal can impact the variation of spring precipitation over southern China by modulating the atmospheric circulations over eastern Asia and the western North Pacific region. Further examination shows that the SCE anomalies around Lake Baikal contribute differently to the variation of spring precipitation over southern China before and after the late 1980s. During P1, the SCE anomalies around Lake Baikal contribute to the variation of spring precipitation over China in the form of a mono‐sign pattern, which is similar to the first empirical orthogonal function mode of spring precipitation, while in P2, the SCE anomalies around Lake Baikal favor a north‐south dipole mode of the spring precipitation variation, which bears considerable similarity to the second empirical orthogonal function mode of spring precipitation over China.