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Tropical cyclones (TCs) over the Bay of Bengal (BOB) can interact with the South Branch Trough (SBT) as they move northward and potentially amplify Rossby waves. This study evaluates the features of Rossby waves and their downstream impact on rainfall in South China. Results indicate that TC‐SBT interactions primarily occur in May and October‐November (Oct‐Nov), with probabilities of 59% and 53% respectively. Notably, the Rossby wave train associated with BOB TCs is more pronounced during Oct‐Nov due to the stronger subtropical westerly jet, in contrast to May. The downstream atmospheric response results in positive (negative) rainfall anomalies over South China in May (Oct‐Nov), particularly on the day following the maximum interaction day. Previous researches concerning TC‐extratropical flow interaction mainly focus on other basins where TCs move to higher latitudes, this study provides fresh insights into Rossby waves related to TC‐SBT interactions over the southern Tibetan Plateau. Plain Language Summary: During bimodal periods of tropical cyclone (TC) activity over the Bay of Bengal (BOB) in May and October‐November (Oct‐Nov), the Asian subtropical westerly jet is usually located at lower latitudes over the southern Tibetan Plateau, where South Branch Trough (SBT) is active. We quantified the extent of BOB TC‐SBT interaction based on the negative potential vorticity advection by TC‐associated irrotational wind. The mean location of the TC center and maximum interaction point are around (20°N, 88°E) and (33°N, 89°E), respectively. Rossby wave trains (RWT) associated with BOB TCs may extend eastward to 150°W, dispersing at a faster zonal group speed in May compared to Oct‐Nov. In May, the downstream response in South China featured by amplified upper‐level divergent outflow, intensified mid‐level warm and cold air convergence, and enhanced low‐level southwesterly water vapor transport, which was conducive to precipitation. In Oct‐Nov, the RWT shifted northward and the anticyclone anomaly related to the subtropical high dominated South China, leading to a northward shift in water vapor transport, unfavorable for precipitation in South China. The results are significant for the short‐ to medium‐range weather forecasts in downstream regions of BOB TCs. Key Points: Tropical cyclones (TC) over the Bay of Bengal (BOB) interacting with the South Branch Trough (SBT) can amplify mid‐latitude Rossby wavesThe Rossby wave associated with interactions between BOB TCs and SBTs is stronger in October‐November than in MayThe atmospheric response results in positive (negative) precipitation anomalies over South China in May (October‐November) [ABSTRACT FROM AUTHOR]

Based on a Normalized Difference Vegetation Index (NDVI) and remote sensing data of snow cover, we analyzed the variation in NDVI in relation to trends in snow cover and vegetation of the source regions of large rivers on the Qinghai-Tibetan Plateau. We then calculated the relationship between snow cover duration, snow depth, and NDVI to reveal the effect of snow cover change on vegetation growth on a regional scale. The results show that both snow depth and duration tend to reduce gradually from northeast to southwest on the Qinghai-Tibetan Plateau. Furthermore, snow cover duration (snow depth > 0 cm) has high interannual fluctuation and generally shows an increasing trend ( P < 0.01) from 1980 to 2004. The interannual fluctuations of the duration of days with snow depth ≥ 5 cm as well as the maximum and average snow depth are also quite high, but they generally show insignificant tendencies ( P > 0.05) from 1980 to 2004. The snow cover characteristics (duration and depth) are insignificantly correlated to annual maximum NDVI. However, a significant positive correlation ( P < 0.05) is observed between snow cover duration (snow depth > 0 cm) and the NDVI values of both April and July, and an obvious negative correlation ( P < 0.05) is observed between snow depth and the NDVI value in October across all source regions from 1981 to 2004. In the study area, increasing snow depth and the prolongation of the duration of snow cover have adverse effects on vegetation growth the following year. The melting of snow brings increasing effects to the NDVI value in the spring. [ABSTRACT FROM AUTHOR]