The magnitude and spatial patterns of carbon fluxes in alpine grasslands determine the regional terrestrial carbon balance of the Tibetan Plateau. However, the patterns and controlling factors of carbon fluxes on the plateau remain unclear, hampering the understanding of the carbon cycle of these vulnerable ecosystems. In this study, we compared the spatial variations of carbon fluxes of ten alpine ecosystems with diverse grassland types and explored their environmental controls across these different ecosystems. Our results show that the mean annual net ecosystem exchange (NEE) of carbon dioxide (CO₂) varied from -284 to 31 g C m⁻² across sites. The alpine meadow ecosystems in the northeast and east of the plateau were strong CO₂ sinks (∼x223C 200 g C m⁻² y⁻¹), while the western alpine grasslands were weak CO₂ sinks or even sources. During the growing season, soil temperature generally played the dominant role in regulating the daily variations of the carbon fluxes for the alpine meadow ecosystems in the cold and humid northeastern areas, while soil moisture was the main controlling factor for the alpine grassland ecosystems in the dry western areas. Annual gross primary productivity (GPP), ecosystem respiration (Re) and the carbon sink capacity linearly increased with the increasing longitude but linearly decreased with elevation. The spatial pattern of annual NEE was primarily controlled by surface soil moisture, and higher soil water content (SWC) led to greater carbon sink capacity. SWC, vapor pressure deficit (VPD) also had favorable effects on the annual GPP and Re. The spatial variations of carbon fluxes resulted primarily from the longitudinal or altitudinal variations of the dominant environmental factors. This study provides guidance for the assessment of carbon fluxes on the Tibetan Plateau.

高寒草地碳通量的大小和空间格局决定了青藏高原区域陆地碳平衡。然而，高原碳通量的模式和控制因素仍不清楚，阻碍了对这些脆弱生态系统碳循环的理解。在这项研究中，我们比较了具有不同草地类型的 10 个高山生态系统的碳通量的空间变化，并探讨了它们对这些不同生态系统的环境控制。我们的结果表明，二氧化碳 (CO ₂ )的年平均净生态系统交换 (NEE)从 -284 到 31 g C m ^-2不等。高原东北部和东部的高寒草甸生态系统是强 CO ₂汇（~x223C 200 g C m⁻² y ⁻¹ )，而西部高山草原为弱 CO ₂汇甚至源头。生长季期间，土壤温度对东北寒湿地区高寒草甸生态系统碳通量日变化的调控作用普遍起主导作用，而土壤水分则是旱季高寒草地生态系统碳通量的主要调控因子。西部地区。年总初级生产力（GPP）、生态系统呼吸（Re）和碳汇能力随经度增加线性增加，随海拔升高线性减少。年NEE的空间格局主要受表层土壤水分控制，较高的土壤含水量（SWC）导致更大的碳汇能力。SWC、蒸气压赤字 (VPD) 也对年度 GPP 和 Re 产生有利影响。碳通量的空间变化主要是由主导环境因素的纵向或海拔变化引起的。本研究为青藏高原碳通量评估提供指导。