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Regional processes on land-water-air interface carbon (C) budget and balance that interconnect the land and sea are in fact C neutrality critical processes within the earth system. It is therefore essential to quantitatively analyze synergistic land-water-air interface C transport and C exchange processes to gain a deep understanding of the important role that terrestrial ecosystems play in "missing C sink". This paper systematically analyzes global land-water-air interface C migration processes as well as C budget changes and associated impact mechanisms. It also investigates the important role that these C budgets and C cycling processes play in inland water bodies, respective to C budgets at the land-water-air interface. Moreover, this study reveals the regulatory mechanisms of land-water-air interface C budgets and balances under a background of global climate change. It also quantitatively evaluates the status of China's regional land-sea-air interface C budgets as well as the C sequestration potential of its lake systems. Finally, this study concludes that the explicit quantification of anthropogenic activity impacts on land-water-air interface C transport and exchange processes is of great significance to global C balances and C neutrality. [ABSTRACT FROM AUTHOR]

The extent and mechanisms by which precipitation extremes affect hydrological processes in the critical zone (CZ) of loess possessing a thick unsaturated zone remains poorly understood. To this end, we here employed a coupled liquid‒vapor‒heat‒airflow STEMMUS (simultaneous transfer of energy, mass, and momentum in unsaturated soil) model to investigate the impact of extreme precipitation, at both event and annual scales, on CZ hydrological processes within a semiarid loess site vegetated by apple trees on China's Loess Plateau. At the event scale, the vapor flux was two orders of magnitude lower than the liquid water flux. However, the thermal vapor flux penetrated to depths of 200 cm, whereas the isothermal liquid water flux only infiltrated to 100 cm during the study period, implying that thermal‐gradient‐driven vapor transfer is an important mechanism for deep‐layer recharge (DLR). At the annual scale, the DLR below 200 cm during extremely wet years was 6.5 times larger than that during extremely dry years. In contrast, extreme changes in climate had only limited impacts on evapotranspiration; the difference between extremely wet and extremely dry years averaged only 35 mm, much less than the difference in precipitation, which averaged 310 mm. However, the extremely dry years showed a higher ratio (0.58) between transpiration and evapotranspiration than did the extremely wet years (0.51). The findings reported here improve our understanding of CZ hydrological processes related to precipitation extremes in semiarid loess regions. Key Points: Thermal‐gradient‐driven vapor transfer is an important mechanism for deep‐layer recharge (DLR) in loessThe DLR below 200 cm during extremely wet years was 6.5 times larger than that during extremely dry yearsExtreme changes in precipitation had only limited impacts on evapotranspiration [ABSTRACT FROM AUTHOR]