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The thermal state of permafrost in the present and future is fundamental to the ecosystem evolution, hydrological process, carbon release, and infrastructure integrity in cold regions. From 2011, we began to establish permafrost monitoring network along the China-Russia crude oil pipelines (CRCOPs) route at the eastern flank of the northern Da Xing'anling Mountains in Northeast China. Based on meteorological data near the southern limit of latitudinal permafrost (SLLP), ground temperature data in 20 boreholes with the depths of 10-60.6 m, soil volumetric liquid water contents and 2-D electrical resistivity tomography (ERT) data, we compiled an integrated dataset of the ground thermal state along the CRCOPs route. Study results demonstrate that permafrost in the vicinity of SLLP has experienced marked warming (2011-2020) to climate change, manifested as the rising permafrost temperatures depth. Local thermal disturbances triggered by the construction and operation of CRCOPs have resulted in significant permafrost warming and subsequent thawing on the right-of-way (ROW) of the pipeline. This permafrost thaw will persist, but it can be alleviated by adopting mitigative measures, such as insulation layer and thermosyphons. The in29 situ observational dataset is of great value for assessing the variability of permafrost under the linear disturbances of the CRCOPs and related environmental effects, for understanding hydro-thermal-mechanical interactions between the buried pipelines and permafrost foundation soils, and for evaluating the operational and structural integrity of the pipeline systems in the future. The dataset is available at the National Tibetan Plateau/Third Pole Environment Data Center (http://doi.org/10.11888/Cryos.tpdc.272357; Li, 2022). [ABSTRACT FROM AUTHOR]

In permafrost regions, the pipelines buried under the ground are widely used for long-distance transportation of fossil fuel, which contributed to research focusing on the interaction between such pipelines and surrounding permafrost. In this study, field observations were conducted since 2011 to investigate the thermal interaction between the China-Russia Crude Oil Pipeline and the surrounding permafrost. Air and oil temperatures at the study site were collected, and the ground temperatures on and off the right-of-way of the pipeline were observed. The observations showed that the large heat loss from the buried pipeline made a rapid increase in the ground temperatures and thawing of underlying permafrost. To slow down the rapid permafrost thawing, a new design was proposed by combining a seasonal air-cooled embankment and pipe insulation. A coupled model was developed to describe the complicated heat transfer process among the ambient air, embankment, warm-oil pipe and permafrost. The numerical simulations showed the design could effectively transfer the heat from the pipeline to the environments in the cold season and reduce the heat intake of the permafrost subgrade in the warm season. The design can be effectively used to control the ground thermal regimes of pipeline systems built in cold regions. • Thermal interaction between warm-oil pipeline and permafrost is investigated in situ. • Permafrost warming and thawing induced by heat losses from the pipe is evaluated. • A new design is proposed for warm-oil pipeline systems built in permafrost regions. • The design can effectively slow down permafrost thaw by using ambient cold energy. [ABSTRACT FROM AUTHOR]