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It’s important to understand the role of permafrost in the future climate and water resources management, for huge storage of soil organic carbon and ground ice in the permafrost. To date, large uncertainties still exist in permafrost simulations for many reasons. One reason is being a lack of long-term meteorological, permafrost and carbon observations. Here, we therefore present datasets for air temperatures, precipitation, soil temperature and moisture, active layer thickness, ground temperatures at different depths, soil organic carbon contents, and ecosystem carbon emission rates for the Qilian Mountains of the Northeastern Qinghai-Tibetan Plateau during 2011–2020. The data come from 5 automatic meteorological stations, 21 boreholes with depths from 11.5 to 149.3 m, and 12 active layer monitoring sites, which are used to obtain the hydrothermal and thermal states, and climate change in the study area. Soil organic carbon contents is available from 10 deep boreholes, down to a depth of 20 m. Ecosystem respiration rates are obtained from the prevalent vegetation types of alpine wet meadow, meadow, and steppe for the growing seasons. This decade’s high-quality datasets are expected to serve as useful inputs for earth system models, and are for researchers working in those disciplines including geophysics, ecology, and hydrology in alpine environments. The datasets are available from the National Tibetan Plateau/Third Pole Environment Data Center and can be downloaded from http://dx.doi.org/10.11888/Cryos.tpdc.272840 (Mu and Peng, 2022).

Air temperature is an important indicator of climate change, as well as for understanding changes in hydrology, ecology, and other natural systems. However, meteorological stations that provide reliable temperature observations are usually sparse in areas of complex terrain, thus limiting our ability to quantify high spatial resolution temperature variability in these regions. Here, we apply three statistical downscaling methods to daily air temperature output from the sixth Coupled Model Intercomparison Project (CMIP6), validated with 22 meteorological stations over the Qilian Mountains. Based on different downscaling methods, we find RMSE and MAE are reduced as much as 59–66%, with the ratio of RMSE and MAE to the annual average temperature of stations decreasing from 147.9% to 61.0% and 143.3% to 64.7%, respectively, depending on the method. Compared to the original data, annual temperature based on the best downscaling methods differed by −2.85±3.61°C during the historical 1850–2014 period and, for the 2015–2100 projections, by 2.13±3.30°C for SSP1-2.6, −2.13±3.29°C for SSP2-4.5, −2.11±3.24°C for SSP3-7.0, and −2.12±3.23°C for SSP5-8.5. The downscaled annual air temperatures show a warming trend ranging 0.15­0.22°C/10yr for the historical experiment, 0.08°C­0.14°C/10yr for SSP1-2.6, 0.24­0.35°C/10yr for SSP2-4.5, 0.43­0.63°C/10yr for SSP3-7.0, and 0.52­0.76°C/10yr for SSP5-8.5 in the Qilian Mountain. These results indicate that the accuracy of the downscaled temperatures is improved compared to the original data. However, we also find that, compared with the downscaled data, the original projections have been overestimated.

Rising temperatures result in permafrost degradation in cold regions, but with considerable spatial heterogeneity due to local factors including peat. Peat plays an important role in the permafrost carbon cycle by impacting the soil thermal and hydrologic characteristics. Here we use field observations to describe the role of peat on permafrost thaw based on comparisons at two sites: EBoTA characterized by primarily peat, and PT5 with more mineral soils. Compared to PT5, soil temperature at the EBoTA site was lower in the warm season, but higher in the cold season. Freezing onset was generally 0–19 days later at the PT5 site compared to EBoTA throughout the soil column, except at the 0.1 m depth where it occurred 11 days earlier. The average thawing onset at PT5 was 18–96 days earlier. There were 20–119 more freezing days and 19–118 fewer thawing days at EBoTA than at PT5, and the zero annual amplitude and active layer thickness were lower at EBoTA. Finally, the mean annual ground temperature was greater at PT5, and was even above 0 °C in three recent years. These results illustrate peat’s thermal insulation effect on permafrost due to its low thermal conductivity and high moisture content. Snow depth increases also amplify the insulation effect. These field observations therefore not only verify, but also quantify the protective role of peatlands on permafrost.