Qinghai Lake Basin Critical Zone Observatory on the Qinghai‐Tibet Plateau

Abstract

The surface-subsurface architecture of the critical zone (CZ) regulates the hydrologic and geochemical processes that drive the CZ function. Due to the complex heterogeneity, highly coupled processes, and the dynamic controlling mechanisms across scales, CZ science faces grand challenges on interface coupling, process integration, and scaling. Carbon-water cycles are important physical-geochemical processes in the CZ. However, the key factors that govern the carbon-water processes across spatiotemporal scales under natural conditions are poorly understood. Especially, such research in the CZ of the alpine region, e.g., the Qinghai-Tibet Plateau (QTP), has not been reported yet is challenging to conduct. The Qinghai Lake Basin Critical Zone Observatory (QLBCZO) is being established to study alpine hydrology, carbon-water processes, and ecological functions on the northeastern QTP. Previous studies in the QLBCZO mainly focused on ecohydrologic processes and the water budget. Currently, the QLBCZO is designed to integrate state-of the-art observation techniques (such as including deep coring, ground-penetrating radar, electrical resistance tomogra-phy, isotope technique, and remote sensing) and frontier modeling approaches to investigate: (i) the three-dimensional architecture of the subsurface environment (vegetation-soil-rock-microbial community) as well as the carbon and water storage, (ii) multiscale carbon-water processes and carbon-water budget, (iii) interactions between freeze-thaw and carbon-water processes, and (iv) carbon sequestration and water resources. The establishment of the QLBCZO and its associated research would be crucial for advancing both theory and methodology for the CZ and Earth system science research on the QTP and alpine regions in general. The critical zone (CZ), the dynamic living skin of the Earth, extends from the top of the vegetative canopy on the land surface to the bottom of the soil-root-rock-groundwater system in the subsurface (National Research Council, 2001; Brooks et al., 2015; Brantley et al., 2017). The fluxes of water, solutes, and energy moving through the CZ are vital to the process of bedrock weathering and soil development, and provide feedbacks to ecohydrological processes (Moore et al., 2015). Critical zone science aims to utilize hydrological and geophysical observations and measurements to quantify those fluxes along with the heterogeneous structures of the subsurface across scales (Brantley et al., 2017). Carbon-water cycles are essential ecohydrological and biogeochemical processes for the development of CZ science. Understanding the fundamental mechanisms that control the interactions of the carbon-water cycles between the terrestrial surface and the atmosphere is vitally important for monitoring and predicting the responses of environments and ecosystems under global climate change (Brunsell and Wilson, 2013). For example, the Jemez-Santa Catalina Critical Zone Observatory has been investigating how water, carbon, and energy drive CZ evolution (Chorover et al., 2011). However, previous research on carbon-water processes was mostly conducted in low-altitude CZs, while there are limited studies focused in the alpine CZ of the QTP, the so-called "third pole" of the Earth. Core Ideas • The QLBCZO is an observatory to study carbon-water processes on the Qinghai-Tibet Plateau. • Multiscale, multi-interface, and multi-process studies investigate the CZ in the alpine region. • Models predict carbon sequestration and water resources in the Qinghai Lake Basin.