[1] A large amount of water is stored in the world's highest and largest plateau, the Tibetan Plateau, in the forms of glaciers, snowpacks, lakes, and rivers. It is vital to understand where these waters come from and whether the supply to these water resources has been experiencing any changes during recent global warming. Here we show the maintenance of water content in the atmosphere over the Tibetan Plateau, the atmospheric circulations and transports of water vapor to this part of the world, and the trend of the water vapor supply. The Tibetan Plateau serves as a role of ''the world water tower'', and its land-ocean-atmosphere interaction provides a profound impact on the global natural and climate environment. The analyses of a half-century time series of atmospheric water vapor, precipitation, and surface temperature indicate that the atmospheric supply to this water tower presents an increasing trend under recent global warming condition.

Abstract. The Tibetan Plateau (TP), referred to as the "roof of the world", is also known as the "world water tower" because it contains a large amount of water resources and ceaselessly transports these waters to its surrounding areas. However, it is not clear how these waters are being supplied and replenished. In particular, how plausible hydrological cycles can be realized between tropical oceans and the TP. In order to explore the mechanism sustaining the atmospheric "water tower" over the TP, the relationship of a "heat source column" over the plateau and moist flows in the Asian summer monsoon circulation is investigated. Here we show that the plateau's thermal structure leads to dynamic processes with an integration of two couplings of lower convergence zones and upper divergences, respectively, over the plateau's southern slopes and main platform, which relay moist air in two ladders up to the plateau. Similarly to the CISK (conditional instability of the second kind) mechanism of tropical cyclones, the elevated warm-moist air, in turn, forces convective weather systems, hence building a water cycle over the plateau. An integration of mechanical and thermal TP forcing is revealed in relation to the Asian summer monsoon circulation knitting a close tie of vapor transport from tropical oceans to the atmospheric "water tower" over the TP.

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Abstract. The Tibetan Plateau (TP), referred to as the "roof of the world" is also known as the "world water tower", because it contains a large amount of water resources and ceaselessly transports these waters to its surrounding areas. However, it is not clear how these waters are being supplied and replenished. In particular, how plausible hydrological cycles can be realized between tropical oceans and the TP. In order to explore the mechanism sustaining the atmospheric "water tower" over the TP, the relationship of a "heat source column" over the plateau and moist flows in the Asian summer monsoon circulation is investigated, here we show that the plateau's thermal structure leads to dynamic processes with an integration of two couples of lower convergences and upper divergences, respectively, over the plateau's southern slopes and main platform, which relay moist air in two ladders up to the plateau. Similarly to the CISK (Conditional Instability of the Second Kind) mechanism of tropical cyclones, the elevated warm-moist air, in turn, forces convective weather systems, hence building a water cycle over the plateau. An integration of mechanical and thermal TP-forcing is revealed in relation to the Asian summer monsoon circulation knitting a close tie of vapor transport from tropical oceans to the atmospheric "water tower" over the TP.

Monsoon rainfall has been the major precipitation source for many East Asian countries, particularly China. This rainfall typically forms as a band with a distinctive northwestward movement from early spring to midsummer and is known as the Meiyu front. Meiyu rainfall constitutes a part of the East Asian monsoon. As spring transitions into summer, the thermal contrast between the land and the ocean drives the monsoon's circulation. The topography of western China's highlands further intensifies this thermal contrast. The present study tries to analyze how Meiyu rainfall responds to the intensification of the monsoon's driving force by China's large‐scale topography. In particular, the cascade of western China's elevated lands toward the northeast seems to act as a “dynamic attractor” that causes the Meiyu rainband to move to the northwest. When this monsoonal rainfall is fully developed along the foot of China's western highlands, the westerly downslope winds stop the convection, resulting in an abrupt cessation of the Meiyu rainband. The general topographic feature of China clearly defines the low‐plain climate as wet versus the plateau climate as arid or semiarid. Analyses of precipitation, water vapor, Earth's surface and near‐surface air temperatures, and atmospheric circulation provide a clear picture of this land‐ocean‐atmosphere interaction.