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Variations in the northern permafrost boundary over the last four decades in the Xidatan region, Qinghai–Tibet Plateau

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Journal of Mountain Science 2018年第4期15卷 765-778页

作者： LUO Jing niu fu-jun LIN Zhan-ju LIU Ming-hao YIN Guo-an State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China South China Institute of Geotechnical Engineering School of Civil Engineering and Transportation South China University of Technology Guangzhou 510641 China

The distribution and variations of permafrost in the Xidatan region, the northern permafrost boundary of the Qinghai-Tibet Plateau, were examined and analyzed using ground penetrating radar(GPR), borehole drilling, and thermal monitoring data. Results from GPR profiles together with borehole verification indicate that the lowest elevation limit of permafrost occurrence is 4369 m above sea level in 2012. Compared to previous studies, the maximal rise of permafrost limit is 28 m from 1975 to 2012. The total area of permafrost in the study region has been decreased by 13.8%. One of the two previously existed permafrost islands has disappeared and second one has reduced by 76% in area during the past ~40 years. In addition, the ground temperature in the Xidatan region has increased from 2012 to 2016, with a mean warming rate of ~0.004℃ a^(-1) and ~0.003℃ a^(-1) at the depths of 6 and 15 m, respectively. The rising of permafrost limit in the Xidatan region is mainly due to globalwarming. However, some non-climatic factors such as hydrologic processes and anthropic disturbances have also induced permafrost degradation. If the air temperature continues to increase, the northern permafrost boundary in the Qinghai-Tibet Plateau may continue rising in the future.

关键词： Qinghai-Tibet Plateau Permafrost Climate warming Permafrost limit Ground penetrating radar Thermal monitoring.

Performance comparison of permafrost models in Wudaoliang Basin,Qinghai-Tibet Plateau,China

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Journal of Mountain Science 2016年第7期13卷 1162-1173页

作者： YIN Guo-an niu fu-jun LIN Zhan-ju LUO Jing LIU Ming-hao State Key Laboratory of Frozen Soils Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Knowledge of the spatial distribution of permafrost and the effects of climate on ground temperature are important for land use and infrastructure development on the Qinghai-Tibet Plateau(QTP). Different permafrost models have been developed to simulate the ground temperature and active layer thickness(ALT). In this study, Temperature at Top of Permafrost(TTOP) model, Kudryavtsev model and modified Stefan solution were evaluated against detailed field measurements at four distinct field sites in the Wudaoliang Basin to better understand the applicability of permafrost models. Field data from 2012 to 2014 showed that there were notable differences in observed ground temperatures and ALTs within and among the sites. The TTOP model is relatively simple, however, when driven by averaged input values, it produced more accurate permafrost surface temperature(Tps) than the Kudryavtsev model. The modified Stefan solution resulted in a satisfactory accuracy of 90%, which was better than the Kudryavtsev model for estimating ALTs. The modified Stefan solution had the potential of being applied to climate-change studies in the future. furthermore, additional field investigations over longer periods focusing on hydrology, which has significant influence on permafrost thaw, are necessary. These efforts should employ advanced measurement techniques to obtain adequate and extensive local parameters that will help improve model accuracy.

关键词： Permafrost model Active layer thickness Soil freeze-thaw Soil temperature

Data-driven spatiotemporal projections of shallow permafrost based on CMIP6 across the Qinghai‒Tibet Plateau at 1 km^(2) scale

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Advances in Climate Change Research 2021年第6期12卷 814-827页

作者： YIN Guo-An niu fu-Jun LIN Zhan-Ju LUO Jing LIU Ming-Hao Liu State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

The degradation of near-surface permafrost under ongoing climate change on the Qinghai‒Tibet Plateau (QTP) is of growing concern due to its impacts on geomorphological and ecological processes, as well as human activities. There is an increased need for an in-depth understanding of the evolution of permafrost temperature (Ttop) and active-layer thickness (ALT) at a fine scale on the QTP under climate change. This study evaluated the permafrost thermal development over the QTP for the period 1980–2100 at a 1 km^(2) scale using a physically analytical model accounting for both climatic and local environmental factors based on multi-source data. The model results were validated against thermal borehole measurements and baseline maps. The modeled current (2001–2018) permafrost area (Ttop ≤ 0 ℃) covers 1.42 × 10^(6) km^(2) (ca. 56.1% of the QTP land area), 10.1% of which thawed over the historical period 1981–2000. To assess how the ground thermal regime could develop in the future, we utilized the multi-model ensemble mean of downscaled outputs from eight climate models under three Shared Socio-economic Pathways (i.e., SSP126, 245, and 585) in CMIP6 to force the permafrost model. Model results suggest that the current (2001–2018) permafrost extent is likely to dramatically contract in the future period (2021–2100), as indicated by consistent Ttop warming and ALT increasing due to climate changing. About 26.9%, 59.9%, 80.1% of the current permafrost is likely to disappear by the end of the 21st century under SSP126, SSP245, and SSP585 scenarios, respectively. The simulation results may further provide new opportunities to assess the future impacts of climate warming on environments and engineering development over the QTP.

关键词： Climate change Analytical model Permafrost degradation Active-layer CMIP6 Qinghai‒Tibet Plateau(QTP)

Cryostructures and ground ice content in ice-rich permafrost area of the Qinghai-Tibet Plateau with Computed Tomography Scanning

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Journal of Mountain Science 2021年第5期18卷 1208-1221页

作者： FAN Xing-wen LIN Zhan-ju GAO Ze-yong MENG Xiang-lian niu fu-jun LUO Jing YIN Guo-an ZHOU fu-jun LAN Ai-yu State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China China Railway First Survey and Design Institute Group Co. LTD.Xi'an 71004China

Permafrost is an important part of the cryosphere,playing an integral role in the hydrologic cycle,ecology,and influencing human *** of ground ice can drastically change landscapes and associated thaw subsidence may induce instability of *** terrain conditions on the Qinghai-Tibet Plateau are complex,and the spatial distribution of ground ice is highly variable,so knowledge of its abundance and variability is required for impact assessments relating to the degradation of *** study examined 55 permafrost samples from warm,ice-rich permafrost region in Beiluhe Basin,Qinghai-Tibet *** samples were examined using Computed Tomography scanning,and the ice content and cryostructure were *** results indicated that:1)variation in volumetric ice content was considerable(0%-70%),with a mean value of 17%;2)seven cryostructures were identified,including crustal,vein,lenticular,ataxitic,reticulate and layered cryostructure;3)volumetric ice content varied by cryostructure,with the highest associated with layered and ataxitic *** ice contents were lowest for samples with pore and lenticular *** work provides detailed ground ice content and will be helpful for assessing thaw subsidence and infrastructure stability on Qinghai-Tibet Plateau.

关键词： Qinghai-Tibet Plateau Permafrost CT scanning Volumetric ice content Cryostructure

Effect of freeze-thaw cycles on uniaxial mechanical properties of cohesive coarse-grained soils

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Journal of Mountain Science 2019年第9期16卷 2159-2170页

作者： QU Yong-long CHEN Guo-liang niu fu-jun NI Wan-kui MU Yan-hu LUO Jing College of Geology Engineering and Geomatics Chang' an University Xi'an 710054 China China Gold Group Tibet Tyrone Mining Development Co. Ltd. Tibet 850000 China State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China South China Institute of Geotechnical Engineering School of Civil Engineering and Transportation South China University of Technology Guangzhou 510641 China

Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions. In this study, cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau to study the effect of cyclic freeze-thaw on their uniaxial mechanical properties. The soil specimens were remolded with three dry densities and three moisture contents. Then, after performing a series of freeze-thaw tests in a closed system without water supply, the soil specimens were subjected to a uniaxial compression test. The results showed that the stress-strain curves of the tested soils mainly performed as strain-softening. The softening feature intensified with the increasing dry density but weakened with an increase in freeze-thaw cycles and moisture content. The uniaxial compressive strength, resilient modulus, residual strength and softening modulus decreased considerably with the increase of freeze-thaw cycles. After more than nine freeze-thaw cycles, these four parameters tended to be stable. These parameters increased with the increase of dry density and decreased with the increasing moisture content, except for the residual strength which did not exhibit any clear variation with an increase in moisture content. The residual strength, however, generally increased with an increase in dry density. The soil structural damage caused by frozen water expansion during the freeze-thaw is the major cause for the changes in mechanical behaviors of cohesive coarse-grained soils. With results in this study, the deterioration effect of freeze-thaw cycles on the mechanical properties of soils should be considered during the slope stability analysis in high-altitude mountain regions.

关键词： Freeze thaw cycles Residual strength Resilient modulus Softening modulus Uniaxial compressive strength Slope stability

Porosity of crushed rock layer and its impact on thermal regime of Qinghai-Tibet Railway embankment

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Journal of Central South University 2017年第4期24卷 977-987页

作者： LIU Ming-hao LI Guo-yu niu fu-jun LIN Zhan-ju LIN Zhan-ju State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences School of Resources and Environment University of Chinese Academy of Sciences

It has been proven that crushed rock layers used in roadbed construction in permafrost regions have a cooling effect. The main reason is the existence of large porosity of the rock layers. However, due to the strong winds, cold and high radiation conditions on the Qinghai-Tibet Plateau(QTP), both wind-blown sand and/or weathered rock debris blockage might reduce the porosity of the rock layers, resulting in weakening the cooling effect of the crushed rock layer(CRL) in the crushed rock embankment(CRE) of the Qinghai-Tibet Railway(QTR) in the permafrost regions. Such a process might warm the underlying permafrost, and further lead to potential threat to the QTR's integrity and stability. The different porosities corresponding to the different equivalent rock diameters were measured in the laboratory using water saturation method, and an empirical exponential equation between porosity and equivalent rock diameter was proposed based on the measured experimental data and an important finding is observed in our and other experiments that the larger size crushed rock tends to lead to the larger porosity when arbitrarily packing. Numerical tests were carried out to study impacts of porosity on permafrost degradation and differential thaw depths between the sunny and shady shoulders. The results show that the decrease in porosity due to wind-blown sand or weathered rock debris clogging can worsen the permafrost degradation and lead to the asymmetric thermal regime. In the traditional embankment(without the CRL within it), the largest differential thaw depth can reach up to 3.1 m. The optimized porosity appears in a range from 34% to 42% corresponding to equivalent rock diameter from 10 to 20.5 cm. The CRE with the optimized porosities can make underlying permafrost stable and 0 ℃ isotherms symmetric in the coming 50 years, even under the condition that the climate warming can lead to permafrost degradation under the CRE and the traditional embankment. Some practical implica

关键词： Qinghai-Tibet Railway crushed rock embankment porosity wind-blown sand permafrost degradation

New Stably Expressed Loci Responsible for Panicle Angle Trait in Japonica Rice in Four Environments

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Rice science 2013年第2期20卷 111-119页

作者： niu fu-an LIU Jian GUO Yuan CHEN Lan JIANG Jian-hua HONG De-lin State Key Laboratory of Crop Genetics and Germplasm Enhancement Nanjing Agricultural University Shanghai Academy of Agricultural Sciences

Panicle angle （PA） of 254 recombinant inbred lines derived from a cross between two japonica varieties Xiushui 79 and C Bao was investigated under four environments,and a genetic linkage map including 111 SSR markers was *** analysis was conducted by mixed major gene plus polygene inheritance models,and quantitative trait loci （QTLs） identification by the QTLNetwork 2.0 and the composite interval mapping approach of WinQTLCart 2.5 *** showed that the PA trait was controlled by two major genes plus polygenes,mainly by major *** QTLs for PA were detected by the QTLNetwork 2.0 software,and each locus explained 0.01% to 39.89% of the phenotypic *** QTLs for PA were detected by the WinQTLCart 2.5 software,with each locus explaining 2.83% to 30.60% of the phenotypic *** major QTLs （qPA9.2 and qPA9.5） distributed between RM3700 and RM3600 and between RM5652 and RM410,respectively,and a moderate QTL （qPA9.7） distributed between RM257 and OSR28,were both detected by the two methods in all of the four *** negative effect alleles of the three QTLs were from Xiushui *** addition,eight pairs of epistatic QTLs with minor effects were also *** × environment interactions were not significant for additive QTLs and epistatic QTL pairs.

关键词： japonica rice panicle angle growing environment mixed inheritance model quantitative trait locus

QTL Analysis for Seven Quality Traits of RIL Population in Japonica Rice Based on Three Genetic Statistical Models

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Rice science 2013年第1期20卷 31-38页

作者： LIU Qiang-ming JIANG Jian-hua niu fu-an HE Ying-jun HONG De-lin State Key Laboratory of Crop Genetics and Germplasm Enhancement Nanjing Agricultural University Institute of Crops Anhui Academy of Agricultural Sciences

QTL mapping for seven quality traits was conducted by using 254 recombinant inbred lines （RIL） derived from a japonica-japonica rice cross of Xiushui 79/C Bao. The seven traits investigated were grain length （GL）, grain length to width ratio （LWR）, chalk grain rate （CGR）, chalkiness degree （CD）, gelatinization temperature （GT）, amylose content （AC） and gel consistency （GC） of head rice. Three mapping methods employed were composite interval mapping in QTLMapper 2.0 software based on mixed linear model （MCIM）, inclusive composite interval mapping in QTL IciMapping 3.0 software based on stepwise regression linear model （ICIM） and multiple interval mapping with regression forward selection in Windows QTL Cartographer 2.5 based on multiple regression analysis （MIMR）. Results showed that five QTLs with additive effect （A-QTLs） were detected by all the three methods simultaneously, two by two methods simultaneously, and 23 by only one method. Five A-QTLs were detected by MCIM, nine by ICIM and 28 by MIMR. The contribution rates of single A-QTL ranged from 0.89% to 38.07%. All the QTLs with epistatic effect （E-QTLs） detected by MIMR were not detected by the other two methods. Fourteen pairs of E-QTLs were detected by both MCIM and ICIM, and 142 pairs of E-QTLs were detected by only one method. Twenty-five pairs of E-QTLs were detected by MCIM, 141 pairs by ICIM and four pairs by MIMR. The contribution rates of single pair of E-QTL were from 2.60% to 23.78%. In the Xiu-Bao RIL population, epistatic effect played a major role in the variation of GL and CD, and additive effect was the dominant in the variation of LWR, while both epistatic effect and additive effect had equal importance in the variation of CGR, AC, GT and GC. QTLs detected by two or more methods simultaneously were highly reliable, and could be applied to improve the quality traits in japonica hybrid rice.

关键词： quantitative trait locus quality trait genetic statistical model japonica rice

Bidirectional regulation of the brain-gut-microbiota axis following traumatic brain injury

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Neural Regeneration Research 2025年第8期20卷 2153-2168页

作者： Xinyu You Lin niu Jiafeng fu Shining Ge Jiangwei Shi Yanjun Zhang Pengwei Zhuang National Key Laboratory of Chinese Medicine Modernization Tianjin University of Traditional Chinese MedicineTianjinChina Haihe Laboratory of Modern Chinese Medicine Tianjin University of Traditional Chinese MedicineTianjinChina First Teaching Hospital of Tianjin University of Traditional Chinese Medicine TianjinChina National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion TianjinChina

Traumatic brain injury is a prevalent disorder of the central nervous *** addition to primary brain parenchymal damage,the enduring biological consequences of traumatic brain injury pose long-term risks for patients with traumatic brain injury;however,the underlying pathogenesis remains unclear,and effective intervention methods are *** dysfunction is a significant consequence of traumatic brain *** the most densely innervated peripheral tissue in the body,the gut possesses multiple pathways for the establishment of a bidirectional“brain-gut axis”with the central nervous *** gut harbors a vast microbial community,and alterations of the gut niche contribute to the progression of traumatic brain injury and its unfavorable prognosis through neuronal,hormonal,and immune pathways.A comprehensive understanding of microbiota-mediated peripheral neuroimmunomodulation mechanisms is needed to enhance treatment strategies for traumatic brain injury and its associated *** comprehensively reviewed alterations in the gut microecological environment following traumatic brain injury,with a specific focus on the complex biological processes of peripheral nerves,immunity,and microbes triggered by traumatic brain injury,encompassing autonomic dysfunction,neuroendocrine disturbances,peripheral immunosuppression,increased intestinal barrier permeability,compromised responses of sensory nerves to microorganisms,and potential effector nuclei in the central nervous system influenced by gut ***,we reviewed the mechanisms underlying secondary biological injury and the dynamic pathological responses that occur following injury to enhance our current understanding of how peripheral pathways impact the outcome of patients with traumatic brain *** review aimed to propose a conceptual model for future risk assessment of central nervous system-related diseases while elucidating novel insights into the bidirectional effec

关键词： traumatic brain injury brain-gut-microbiome axis gut microbiota neuroimmune immunosuppression host defense vagal afferents bacterial infection dorsal root ganglia nociception neural circuitry