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Precipitation and evapotranspiration, respectively, an input and an output for hydrologists and ocean scientists, but the opposite for meteorologists, quantify the intensity of vertical water exchange between land, ocean, and the atmosphere. The interesting paper by Dagan et al. (2019, https://doi.org/10.1029/2019GL084173) analyzed important constraints between such fluxes as a function of spatial scales. This commentary aims to provide a complementary, hydrologic point of view, emphasizing how their intermittency at different spatial and temporal scales is essentially related to the contrasting water storage capacities of the atmosphere and the Earth's surface. Alterations of such storage due to global warming and land cover change are a challenge for the geophysical community and beyond. Plain Language Summary: With the common goal of understanding the water cycle, hydrologists look up at the atmosphere and consider precipitation as an input, whereas meteorologists look down at the surface and think of precipitation as an output. These two perspectives on water cycle result in two distinctive yet closely related approaches, focusing on the land surface and the atmosphere, respectively. These dynamics are expected to change in response to the global warming and land use land cover change, increasing the uncertainties of predicting intense droughts and floods. Collaborative research efforts are needed to improve our understanding of the water cycle and mitigate such effects. Key Points: We add a hydrologic perspective to Dagan et al.'s atmospheric perspective on precipitation and evaporation differencesWe discuss the spatial/temporal scaling constraints imposed by the surface hydrologic cycleThese scaling properties are related to the water storage capacities in the land and atmosphere, both of which are expected to change [ABSTRACT FROM AUTHOR]

This paper attempts to provide some new understanding of the mechanical as well as thermal effects of the Tibetan Plateau (TP) on the circulation and climate in Asia through diagnosis and numerical experiments. The air column over the TP descends in winter and ascends in summer and regulates the surface Asian monsoon flow. Sensible heating on the sloping lateral surfaces appears from the authors’ experiments to be the major driving source. The retarding and deflecting effects of the TP in winter generate an asymmetric dipole zonal-deviation circulation, with a large anticyclone gyre to the north and a cyclonic gyre to the south. Such a dipole deviation circulation enhances the cold outbreaks from the north over East Asia, results in a dry climate in south Asia and a moist climate over the Indochina peninsula and south China, and forms the persistent rainfall in early spring (PRES) in south China. In summer the TP heating generates a cyclonic spiral zonal-deviation circulation in the lower troposphere, which converges toward and rises over the TP. It is shown that because the TP is located east of the Eurasian continent, in summertime the meridional winds and vertical motions forced by the Eurasian continental-scale heating and the TP local heating are in phase over the eastern and central parts of the continent. The monsoon in East Asia and the dry climate in middle Asia are therefore intensified. [ABSTRACT FROM AUTHOR]