Quantifying the spatial-temporal patterns of land-atmosphere water, heat and CO₂ flux exchange over the Tibetan Plateau from an observational perspective

Abstract. Land-atmosphere (LA) interaction process, through the turbulent exchange of water, heat and CO₂ flux, significantly influences regional micro-climates, local water cycles, energy budgets, and ecosystem dynamics. The Tibetan Plateau (TP), characterized by vast extent, high elevation, strong solar radiation and convection, as well as extreme weather fluctuations, has been under-explored due to the scarcity of LA interaction stations, particularly in the western and northern regions. To address this gap, this study introduces a newly constructed research and observation platform, which consists of 16 planetary boundary layer towers, spans diverse landscapes and covers dynamic meteorological conditions, with average annual air temperature, wind speed and liquid precipitation ranging from -3.5 to 18.5 °C, 0.6 to 5.6 m s^-1, and 43 mm to 2164 mm. Elevation correlates significantly with all meteorological variables, highlighting a strong spatial heterogeneity distribution patterns of LA coupling. The turbulent flux of water and heat show clear seasonal variations, with highest sensible heat flux (SH) in April–May and largest latent heat flux (LE) in July–August. Further, most stations report negative net ecosystem exchange (NEE) values, ranging from -3.2 g C m^-2 a^-1 at Mangai to -174.3 g C m^-2 a^-1 at NADORS, and function as carbon sinks. However, Medog station, locating in the densely forested Yarlung Zangbo valley, functions as a carbon source which is most probably related to the vegetation destruction and human activities. LE is significantly and closely correlated with SH, NEE and ecosystem respiration, indicating strong coupling between water, heat and carbon fluxes. Precipitation as well as soil water content provide favorable moisture sources and show significance in the water-carbon coupling process. The observation and research platform and the quality-controlled high-temporal resolution data provide valuable in situ measurements for studying water-heat-carbon interactions, validating numerical models and satellite algorithms, and offering ground truth for research on hydrological, meteorological, and ecological responses to global climate change.