The Qilian Mountains, located on the northeastern edge of the Qinghai-Tibet Plateau, are characterized by unique high-altitude and cold-climate terrain, where permafrost and seasonally frozen ground are extensively distributed. In recent years, with global warming and increasing precipitation on the Qinghai-Tibet Plateau, permafrost degradation has become severe, further exacerbating the fragility of the ecological environment. Therefore, timely research on surface deformation and the freeze-thaw patterns of alpine permafrost in the Qilian Mountains is imperative. This study employs Sentinel-1A SAR data and the SBAS-InSAR technique to monitor surface deformation in the alpine permafrost regions of the Qilian Mountains from 2017 to 2023. A method for spatiotemporal interpolation of ascending and descending orbit results is proposed to calculate two-dimensional surface deformation fields further. Moreover, by constructing a dynamic periodic deformation model, the study more accurately summarizes the regular changes in permafrost freeze-thaw and the trends in seasonal deformation amplitudes. The results indicate that the surface deformation time series in both vertical and east-west directions obtained using this method show significant improvements in accuracy over the initial data, allowing for a more precise reflection of the dynamic processes of surface deformation in the study area. Subsidence is predominant in permafrost areas, while uplift mainly occurs in seasonally frozen ground areas near lakes and streams. The average vertical deformation rate is 1.56 mm/a, with seasonal amplitudes reaching 35 mm. Topographical (elevation; slope gradient; aspect) and climatic factors (temperature; soil moisture; precipitation) play key roles in deformation patterns. The deformation of permafrost follows five distinct phases: summer thawing; warm-season stability; frost heave; winter cooling; and spring thawing. This study enhances our understanding of permafrost deformation characteristics in high-latitude and high-altitude regions, providing a reference for preventing geological disasters in the Qinghai-Tibet Plateau area and offering theoretical guidance for regional ecological environmental protection and infrastructure safety.

Hydrologic-land surface models (H-LSMs) offer a physically-based framework for representing and predicting the present and future states of the extensive high-latitude permafrost areas worldwide. Their primary challenge, however, is that soil temperature data are severely limited, and traditional model validation, based only on streamflow, can show the right fit to these data for the wrong reasons. Here, we address this challenge by (1) collecting existing data in various forms including in-situ borehole data and different large-scale permafrost maps in addition to streamflow data, (2) comprehensively evaluating the performance of an H-LSM with a wide range of possible process parametrizations and initializations, and (3) assessing possible trade-offs in model performance in concurrently representing hydrologic and permafrost dynamics, thereby pointing to the possible model deficiencies that require improvement. As a case study, we focus on the sub-arctic Liard River Basin in Canada, which typifies vast northern sporadic and discontinuous permafrost regions. Our findings reveal that different process parameterizations tend to align with different data sources or variables, which largely exhibit inconsistencies among themselves. We further observe that a model may fail to represent permafrost occurrence yet seemingly fit streamflows adequately. Nonetheless, we demonstrate that accurately representing essential permafrost dynamics, including the active soil layer and insulation effects from snow cover and soil organic matter, is crucial for developing high-fidelity models in these regions. Given the complexity of processes and the incompatibility among different data sources/variables, we conclude that employing an ensemble of carefully designed model parameterizations is essential to provide a reliable picture of the current conditions and future spatio-temporal co-evolution of hydrology and permafrost.

Warming leads to significant loss of CO2 in high-altitude regions (HAR), posing threat to the carbon sink of terrestrial ecosystem. Additionally, the spatial distribution of environmental factors and underlying surfaces also determine the carbon sink pattern. Therefore, it is necessary to systematically explore the carbon sink of HAR. Based on it, choosing the Qilian Mountains (QLM) as the study area, the continuous observation data of 14 eddy covariance in different ecosystems was used to analyze the variation characteristics of carbon use efficiency (CUE) and net ecosystem primary productivity (NEP), which is helpful to systematically understand the response of carbon cycle to climate change in alpine ecosystem. The research results indicated that the QLM serves as an effective carbon sink (13 of the sites yielded a net carbon sink), owing to the combined influences of environmental factors and vegetation characteristics. Annual NEP varied across the 14 sites, ranging from-192.6 to 524.5 g C/m(2)/yr. Limited observation indicated that wetland/swamp had the highest carbon sink, followed by forest, and shrub have the lowest carbon sink in this study. Along the altitudinal gradient, both gross primary productivity (GPP) and ecosystem respiration (Re) demonstrated a declining trend ( P < 0.05), while, CUE displayed an increasing trend. Soil temperature and photosynthetically active radiation dominated the variation in carbon exchange and CUE along the altitudinal gradient. However, soil moisture was the dominant factor in drought ecosystem. This study provides basis for the assessment of carbon sink of the HAR.

Global warming in tandem with surface albedo reduction caused by black carbon (BC) deposition on glaciers accelerated glacier melting; however, their respective contributions remain unclear. Glaciers in the Qilian Mountains are crucial for the development of oases in the Hexi Corridor; however, their area has decreased by more than 20% over the past half-century. Thus, this study developed a dynamic deposition model for light-absorbing particles (LAPs), coupled with a surface energy and mass balance model. We comprehensively assessed the effects of BC and warming on the melting of a typical glacier in the Qilian Mountains based on the coupled model. BC on the glacier surface caused 13.1% of annual glacier-wide melting, of which directly deposited atmospheric BC reduced the surface albedo by 0.02 and accounted for 9.1% of glacier melting. The air temperature during 2000-2010 has increased by 1.5 degrees C relative to that during the 1950s, accounting for 51.9% of current glacier melting. Meanwhile, BC emission have increased by 4.6 times compared to those of the early Industrial Revolution recorded in an ice core, accounting conservatively for 6.3% of current glacier melting. Mitigating BC emissions has a limited influence on current glacier melting; however, in the long-term, mitigation should exert a noteworthy impact on glacier melting through the self-purification of glaciers.

In the context of global research in snow-affected regions, research in the Australian Alps has been steadily catching up to the more established research environments in other countries. One area that holds immense potential for growth is hydrological modelling. Future hydrological modelling could be used to support a range of management and planning issues, such as to better characterise the contribution of the Australian Alps to flows in the agriculturally important Murray-Darling Basin despite its seemingly small footprint. The lack of recent hydrological modelling work in the Australian Alps has catalysed this review, with the aim to summarise the current state and to provide future directions for hydrological modelling, based on advances in knowledge of the Australian Alps from adjacent disciplines and global developments in the field of hydrologic modelling. Future directions proffered here include moving beyond the previously applied conceptual models to more physically based models, supported by an increase in data collection in the region, and modelling efforts that consider non-stationarity of hydrological response, especially that resulting from climate change.

Climate warming can lead to permafrost degradation, potentially resulting in slope failures such as retrogressive thaw slumps (RTSs). The formation of and changes in RTSs could exacerbate the degradation of permafrost and the environment in general. The mechanisms of RTS progression and the potential consequences on the analogous freeze-thaw cycle are not well understood, owing partly to necessitating field work under harsh conditions and with high costs. Here, we used multi-source remote sensing and field surveys to quantify the changes in an RTS on Eboling Mountain in the Qilian Mountain Range in west-central China. Based on optical remote sensing and SBAS-InSAR measurements, we analyzed the RTS evolution and the underlying drivers, combined with meteorological observations. The RTS expanded from 56 m2 in 2015 to 4294 m2 in 2022, growing at a rate of 1300 m2/a to its maximum in 2018 and then decreasing. Changes in temperature and precipitation play a dominant role in the evolution of the RTS, and the extreme weather in 2016 may also be a primary contributor to the accelerated growth, with an average deformation of -8.3 mm during the thawing period, which decreased slope stability. The RTS evolved more actively during the thawing and early freezing process, with earthquakes having potentially contributed further to RTS evolution. We anticipate that the rate of RTS evolution is likely to increase in the coming years.

Understanding temperature variability especially elevation dependent warming (EDW) in high-elevation mountain regions is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. EDW means that temperature is warming faster with the increase of altitude. In this study, we used observed temperature data during 1979-2017 from 23 meteorological stations in the Qilian Mountains (QLM) to analyze temperature trend with Mann-Kendall (MK) test and Sen's slope approach. Results showed that the warming trends for the annual temperature followed the order of T_min > T_mean > T_max and with a shift both occurred in 1997. Spring and summer temperature have a higher increasing trend than that in autumn and winter. T_mean shifts occurred in 1996 for spring and summer, in 1997 for autumn and winter. T_max shifts occurred in 1997 for spring and 1996 for summer. T_min shifts occurred in 1997 for spring, summer and winter as well as in 1999 for autumn. Annual mean diurnal temperature range (DTR) shows a significant decreasing trend (-0.18 degrees C/10a) from 1979 to 2017. Summer mean DTR shows a significant decreasing trend (-0.26 degrees C/10a) from 1979 to 2017 with a shift occurred in 2010. After removing longitude and latitude factors, we can learn that the warming enhancement rate of average annual temperature is 0.0673 degrees C/km/10a, indicating that the temperature warming trend is accelerating with the continuous increase of altitude. The increase rate of elevation temperature is 0.0371 degrees C/km/10a in spring, 0.0457 degrees C/km/10a in summer, 0.0707 degrees C/km/10a in autumn, and 0.0606 degrees C/km/10a in winter, which indicates that there is a clear EDW in the QLM. The main causes of warming in the Qilian Mountains are human activities, cloudiness, ice-snow feedback and El Nino phenomenon.

Refractory black carbon (rBC) is an important climate-forcing agent emitted by biomass burning and fossil fuel combustion. Antarctica can receive rBC aerosols emitted in Southern Hemisphere (SH) and preserve the history of emissions and atmospheric transport. Here, we present a high-resolution record of rBC in an ice core (CA2016-75) acquired from the coastal Eastern Antarctica, which accumulated during the past 100 years (1915-2015). The rBC concentration (0.030 ng g(-1)) and flux (7.22 mu g m(-2) yr(-1)) are both among the lowest values in Antarctic snow and ice. The rBC concentration reaches higher values on average in the period aligned with the austral Winter. The rBC concentrations show a long-term descending trend during the period between 1950s and mid-1990s, followed by an ascending trend to 2015. Back trajectory analysis indicates that the emissions resulting from the biomass burning and anthropogenic biofuel consumption in Southern America and Australia were the main sources for the rBC deposition. Wavelet spectral analysis and temporal correlation analysis on rBC deposition and the atmospheric circulation indices (El Nino-Southern Oscillation, Southern Annular Mode and Antarctic Oscillation) confirmed that the atmospheric circulations have certain influences on the rBC deposition, likely by their direct effects on rBC transport and on weather conditions driving the occurrence of fires and subsequent emissions in source regions.

In this work, samples of surface snow, surface ice, snow pit and meltwater from the Laohugou Glacier No. 12 on the northern edge of Tibetan Plateau (TP) were collected during the summer of 2015. The average concentration of Hg in surface snow/ice was 22.41 ng L-1, while the percentage of dissolved mercury (Hg-D) was observed to be around 26%. An altitudinal magnification of Hg was not observed for surface snow; however, in contrast, a significant positive magnification of Hg with altitude was observed in the surface ice. A higher concentration of Hg corresponded with the dust layer of the snow pit. It was observed that about 42% of Hg was lost from the surface snow when the glacier was exposed to sunlight within the first 24 h indicating some Hg was emitted back to the atmosphere while some were percolated downwards. The result from the principal component analysis (PCA) showed that the sources of Hg in Laohugou Glacier No. 12 were from crustal and biomass burning. Finally, it was estimated that total export of Hg from the outlet river of Laohugou glacier No. 12 in the year 2015 was about 1439.46 g yr(-1) with yield of 22.77 mu g m(2) yr(-1). This study provides valuable insights for understanding the behavior of Hg in the glacier of the northern Tibetan Plateau.

A bacterial strain, designated GEM5(T), was isolated from sand soil samples from the Qinghai-Tibet Plateau. The polyphasic study confirmed the affiliation of the isolate with the genus Massilia. GEM5(T) had Gram-stain-negative, non-spore-forming and rod-shaped cells and grew at 4-30 degrees C. pH 6-8 and with 0-2% (w/v) NaCl. Its cell wall contained ribose. Q8 was the predominant respiratory quinone, and summed feature 3 (C-1(6:1), omega 6c/w7c) and C-16:0 were the major components of the fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid and four unidentified lipids. The DNA G+C content was 65.1 mol%. The phylogenetic analysis based on the 16S rRNA gene showed a stable Glade being formed by GEM5(T), Massilia timonae CCUG 45783(T) (97.94%) and Massilia oculi CCUG 43427A(T) (97.58%). The average nucleotide identity (ANIb) values between GEM5(T) and M. timonae CCUG 45783(T), M.oculi CCUG 43427A(T) were 91.3 and 91.7%, respectively. On the basis of the morphological, physiological and chemotaxonomic pattern, it was proposed that strain GEM5(T) (=JCM 32744(T)=CICC 24458(T)) should be classified as representing a member of the genus Massilia with the name Massilia arenae sp. nov.