The increasing severity of droughts/floods and worsening air quality from increasing aerosols in Asia monsoon regions are the two gravest threats facing over 60% of the world population living in Asian monsoon regions. These dual threats have fueled a large body of research in the last decade on the roles of aerosols in impacting Asian monsoon weather and climate. This paper provides a comprehensive review of studies on Asian aerosols, monsoons, and their interactions. The Asian monsoon region is a primary source of emissions of diverse species of aerosols from both anthropogenic and natural origins. The distributions of aerosol loading are strongly influenced by distinct weather and climatic regimes, which are, in turn, modulated by aerosol effects. On a continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulations. The atmospheric thermodynamic state, which determines the formation of clouds, convection, and precipitation, may also be altered by aerosols serving as cloud condensation nuclei or ice nuclei. Absorbing aerosols such as black carbon and desert dust in Asian monsoon regions may also induce dynamical feedback processes, leading to a strengthening of the early monsoon and affecting the subsequent evolution of the monsoon. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of different monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcing of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

[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.

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61The Tibetan Plateau (TP), known as the "sensible heat pump" and the 62 "atmospheric water tower", modifies monsoon circulations and regional energy and 63 water cycles over Asia (Wu and Zhang 1998; Zhao and Chen 2001a; Wu et al. 2007; 64 Xu et al. 2008b; Zhou et al. 2009). Strong ascent over the TP may transport lower-65 tropospheric water vapor and anthropogenic pollutants into the upper troposphere-66 lower stratosphere (UT-LS), which exerts an influence on the local ozone valley 67 (Zhou et al. 1995; Liu et al. 2003; Bian et al. 2011) and the aerosol-layer 68 enhancements near the tropopause (Tobo et al. 2007; Vernier et al. 2015). The TP also In the 1990s, a longer-term field experiment was conducted over the TP with the 84 support of the Japanese Experiment on Asian Monsoon (JEXAM). It estimated the 2008a; Zhang et al. 2012; Chen et al. 2011 Chen et al. , 2013. It found diurnal variations of et al. 2013; Hu et al. 2014; Zheng et al. 2014 Zheng et al. , 2015a Zheng et al. , b, c, 2016 Guo et al. 2015; 161 Zhuo et al. 2016; Wan et al. 2017). These problems may also cause large uncertainties 162 in reanalysis datasets and satellite products (such as air temperature, soil moisture, 163 surface heat fluxes, and radiation) over the TP (Li et al. 2012; Wang et al. 2012; Zhu 164 et al. 2012; Su et al. 2013; Zeng et al. 2016). 165To promote Tibetan meteorological research, the Third Tibetan Plateau 166Atmospheric Scientific Experiment (TIPEX-III), to continue for eight to ten years, OBJECTIVES. 173The field observational objective of TIPEX-III is to constitute a 3-D observation 174 system of the land surface, PBL, troposphere, and lower stratosphere over the TP. 175This system integrates ground-, air-, and space-based platforms based on the 176 meteorological operational networks, the TIPEX-III network, the existing NIOST (Fig. 1a). Consistent with the operational observations of the 265 CMA, at each site the measurement system measures soil water content ( Fig. 1a). The regional network consists of 33 sites over 270 Naqu (Fig. 1c), which began operating in August 2015, and 17 sites over Shiquanhe This network consists of six additional sites at Bange, Namucuo, Anduo, Nierong, 280Jiali, and Biru, and contributes to integrated research on the high-resolution land-281 surface and PBL processes over the central TP and their effects on mesoscale systems. 282These observations have been conducted at Shiquanhe, Namucuo, Naqu, Anduo, Gongshan (98.67°E, 27.75°N) station on the southeastern slope of the TP (Fig. 1b), a 300 key area for gauging water-vapor transports from the Indian Ocean to East Asia. (Fig. 1b). A primary goal of these observations is to explore the cloud (Fig. 1b). A follow-up field campaign using ground-based radars Tuotuohe, Mangya, Golmud, and Xining meteorological stations (Fig. 1b). Using PRELIMINARY ACHIEVEMENTS OF TIPEX-III. 328The implementation of TIPEX-III has enhanced the monitoring capability for the 380(1) Cloud diurnal variation and warm rain process. 3...

Abstract. A high O 3 episode with the large increases in surface ozone by 21-42 ppbv and the nocturnal surface O 3 levels exceeding 70 ppbv was observed in the region between Xiamen and Quanzhou over the southeastern coast of China during 12-14 June 2014, before the Typhoon Hagibis landing. Variations in the surface O 3 , NO 2 , CO and meteorology during the Typhoon Hagibis event clearly suggest a substantial impact of the peripheral downdrafts in the large-scale typhoon circulation on such an O 3 episode excluding the contributions of photochemical production and the horizontal transport. The influence of vertical O 3 transport from the upper troposphere and lower stratosphere (UTLS) region on high surface O 3 levels is further confirmed by a negative correlation between surface O 3 and CO concentrations as well as dry surface air observed during the O 3 episode. This study provides observational evidence of typhoon-driven intrusion of O 3 from the UTLS region to surface air, revealing a significant effect of such a process of stratosphere-troposphere exchange (STE) of O 3 on tropospheric O 3 and ambient air quality.