Assessing Spatiotemporal Characteristics of Atmospheric Water Cycle Processes over the Tibetan Plateau using the WRF Model and Finer Box Model

Abstract The Tibetan Plateau (TP) is the highest and largest plateau in the world and serves as a "vanguard" for global climate change. In the context of climate warming, changes in evapotranspiration (ET) and external water vapor transport cause more uncertainty in assessing the atmospheric water cycle processes over the TP. By using the Weather Research and Forecasting (WRF) model for long-term simulations and the finer box model for the calculation of water vapor along the boundary, the external atmospheric water vapor transport and its spatiotemporal characteristics over the TP are finely described. The model-simulated precipitation and evapotranspiration are well-simulated compared with observation. Research results show that: (1) The atmospheric water storage on the TP decreases from southeast to northwest. Water vapor is mainly transported into the TP from the western and southern boundaries. The net water vapor flux transported from the western boundary to the TP by westerly wind is negative, while the net water vapor flux transported from the southern boundary to the TP by southerly wind is positive. (2) In spring and winter, water vapor is mainly transported into the TP by mid-latitude westerlies from the western boundary. In summer, water vapor transport controlled by mid-latitude westerlies weakens, and water vapor is mainly transported into the TP from the southern boundary. In autumn, water vapor controlled by mid-latitude westerlies gradually strengthens, and water vapor is mainly transported into the TP from the western boundary. In addition, the ratio of ET to precipitation on the TP is about 0.48, and the moisture recycling is about 0.37. Water vapor mainly comes from external water vapor transport.