Understanding precipitation recycling over the Tibetan Plateau using tracer analysis with WRF
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Understanding precipitation recycling over the Tibetan Plateau using tracer analysis with WRF Yanhong Gao1 · Fei Chen2 · Gonzalo Miguez‑Macho3 · Xia Li4 Received: 13 December 2019 / Accepted: 18 August 2020 © The Author(s) 2020
Abstract The precipitation recycling (PR) ratio is an important indicator that quantifies the land-atmosphere interaction strength in the Earth system’s water cycle. To better understand how the heterogeneous land surface in the Tibetan Plateau (TP) contributes to precipitation, we used the water-vapor tracer (WVT) method coupled with the Weather Research and Forecasting (WRF) regional climate model. The goals were to quantify the PR ratio, in terms of annual mean, seasonal variability and diurnal cycle, and to address the relationships of the PR ratio with lake treatments and precipitation amount. Simulations showed that the PR ratio increases from 0.1 in winter to 0.4 in summer when averaged over the TP with the maxima centered at the headwaters of three major rivers (Yangtze, Yellow and Mekong). For the central TP, the highest PR ratio rose to over 0.8 in August, indicating that most of the precipitation was recycled via local evapotranspiration in summer. The larger daily mean and standard deviation of the PR ratio in summer suggested a stronger effect of land-atmosphere interactions on precipitation in summer than in winter. Despite the relatively small spatial extent of inland lakes, the treatment of lakes in WRF significantly impacted the calculation of the PR ratio over the TP, and correcting lake temperature substantially improved both precipitation and PR ratio simulations. There was no clear relationship between PR ratio and precipitation amount; however, a significant positive correlation between PR and convective precipitation was revealed. This study is beneficial for the understanding of land-atmosphere interaction over high mountain regions. Keywords Precipitation · precipitation recycling · WRF-WVT · Tibetan Plateau · lakes
1 Introduction Terrestrial precipitation can originate from evaporated moisture in remote continental or oceanic regions, which is then advected through long-distance transport, or from local terrestrial sources. The input of the latter is termed precipitation recycling (PR) (Dirmeyer and Brubaker 2007; Dominguez et al. 2006; Eltahir and Bras 1996; Gimeno et al. 2012; van der Ent et al. 2010). Quantifying the respective contributions to terrestrial precipitation from oceanic moisture transport and the land surface is critical for understanding the water cycle and land-atmosphere coupling strength.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00382-020-05426-9) contains supplementary material, which is available to authorized users. * Yanhong Gao [email protected] Extended author information available on the last page of the article
As the highest and widest plateau on Earth and with an average elevation over 4000 m, the Tibetan Plateau (TP) has attracted worldwide attention, not only because of
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