Analysis on Thermal Stresses Adaptability to High Grade Asphalt Pavement Structure in Qinghai-Tibet Plateau

2015 ◽  
Vol 723 ◽  
pp. 395-399
Author(s):  
Ning Li ◽  
Xue Yan Zhou ◽  
Yu Xiang Tian ◽  
Peng Wei Liu
Keyword(s):  
Low Temperature ◽  
Thermal Stresses ◽  
Asphalt Pavement ◽  
Structure Type ◽  
Climatic Conditions ◽  
Tibet Plateau ◽  
Large Temperature ◽  
Climate Conditions ◽  
Pavement Structure ◽  
Qinghai Tibet Plateau

Permafrostregions have harsh climate conditions, continuous low temperature, abrupt cooling, large temperature difference, winds, etc. It has an extremely obvious influencetoasphalt pavement structures and materials. Take Lhasa-Gongga airport highway as an example to analyze the low temperature cracking problem of asphalt pavement caused by the climatic conditions. Using finite element method to contrast and analyze the thermal stresses variation of different asphalt layer, and recommend suitable asphalt pavement structure for Qinghai-Tibet plateau permafrost regions.The results indicate that the thermal stresses of asphalt layer gradually reduce along with the thickness direction of structure, moment of maximum and minimum value also been delayed and thermal stresses of base cause is fairly few. It can reduce thermal stresses of base cause and asphalt layer effectively while using the AC-25, and 4cmAC13 + 6cmAC20 + 8cmAC25 is recommended for Lhasa-Gonggaairport highway pavement structure type.

scholarly journals Locomotion of Slope Geohazards Responding to Climate Change in the Qinghai-Tibetan Plateau and Its Adjacent Regions

2021 ◽  
Vol 13 (19) ◽  
pp. 10488
Author(s):  
Yiru Jia ◽  
Jifu Liu ◽  
Lanlan Guo ◽  
Zhifei Deng ◽  
Jiaoyang Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Climatic Factors ◽  
High Sensitivity ◽  
Spatial Location ◽  
Future Climate ◽  
Tibet Plateau ◽  
The South ◽  
Climate Conditions ◽  
Temperature And Precipitation ◽  
Qinghai Tibet Plateau

Slope geohazards, which cause significant social, economic and environmental losses, have been increasing worldwide over the last few decades. Climate change-induced higher temperatures and shifted precipitation patterns enhance the slope geohazard risks. This study traced the spatial transference of slope geohazards in the Qinghai-Tibet Plateau (QTP) and investigated the potential climatic factors. The results show that 93% of slope geohazards occurred in seasonally frozen regions, 2.6% of which were located in permafrost regions, with an average altitude of 3818 m. The slope geohazards are mainly concentrated at 1493–1988 m. Over time, the altitude of the slope geohazards was gradually increased, and the mean altitude tended to spread from 1984 m to 2562 m by 2009, while the slope gradient varied only slightly. The number of slope geohazards increased with time and was most obvious in spring, especially in the areas above an altitude of 3000 m. The increase in temperature and precipitation in spring may be an important reason for this phenomenon, because the results suggest that the rate of air warming and precipitation at geohazard sites increased gradually. Based on the observation of the spatial location, altitude and temperature growth rate of slope geohazards, it is noted that new geohazard clusters (NGCs) appear in the study area, and there is still a possibility of migration under the future climate conditions. Based on future climate forecast data, we estimate that the low-, moderate- and high-sensitivity areas of the QTP will be mainly south of 30° N in 2030, will extend to the south of 33° N in 2060 and will continue to expand to the south of 35° N in 2099; we also estimate that the proportion of high-sensitivity areas will increase from 10.93% in 2030 to 14.17% in 2060 and 17.48% in 2099.

Signals In Temperature Extremes Emerge in China During The Last Millennium Based On CMIP5 and CMIP6 Simulations

2021 ◽  
Author(s):  
Yue Sui ◽  
Yuting Chen
Keyword(s):  
Southern China ◽  
Signal To Noise Ratio ◽  
Coupled Model ◽  
Volcanic Eruptions ◽  
Climatic Conditions ◽  
Tibet Plateau ◽  
Temperature Extremes ◽  
13Th Century ◽  
Early 19Th Century ◽  
Climate Conditions

Abstract Though the magnitude of any change is important, regions which have a larger signal of change relative to the background variations will potentially face greater risks than other regions, as they will see unusual or novel climate conditions more quickly (Frame et al. 2017). Providing more information about signal and noise on regional scales, and the associated attribution to particular causes, is therefore important for adaptation planning (Chen et al. 2021). However, whether a detectable signal in temperature extremes emerges in China at the local or regional level during 850−2005 has not been discussed. Based on six selected and bias-corrected global models under the Coupled Model Intercomparison Project phase 5, relative to pre-industrial levels (ca 1850), we show that the temporal information of signal-to-noise ratio (S/N) in annual temperature extremes are consistent with annual mean temperature variations in China during 850−2005. Before 1850, absolute values of regional mean S/N in temperature extremes under cold climatic conditions are generally larger than that under warm climatic conditions. At the level of S/N > 1, local increasing signals of cold extremes emerge in the second half of 13th century and in the early 19th century after intensively volcanic eruptions in 1257 and 1815 in most part of China, especially in southern China and Tibet Plateau. Over the past 150 years under global warming, absolute values of regional mean S/N in temperature extremes have increasing trends. The regional mean increasing signals of warm extremes over China begin to exceed natural variability in 1969 at the level of S/N > 1, and local warm signals first occur in 1929 in Tibet Plateau. These warming signals are related to greenhouse gas forcing.

scholarly journals Organ Mass Variation in a Toad Headed Lizard Phrynocephalus vlangalii in Response to Hypoxia and Low Temperature in the Qinghai-Tibet Plateau, China

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162572 ◽  
Author(s):  
Jimin Han ◽  
Ronghui Guo ◽  
Jiaqi Li ◽  
Chen Guan ◽  
Yu Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Tibet Plateau ◽  
Mass Variation ◽  
Organ Mass ◽  
Qinghai Tibet Plateau

scholarly journals Ammonia Oxidizers in High-Elevation Rivers of the Qinghai-Tibet Plateau Display Distinctive Distribution Patterns

2019 ◽  
Vol 85 (22) ◽  
Author(s):  
Sibo Zhang ◽  
Xinghui Xia ◽  
Siling Li ◽  
Liwei Zhang ◽  
Gongqin Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Solar Radiation ◽  
Nitrogen Cycle ◽  
Ammonia Oxidation ◽  
Distribution Patterns ◽  
High Elevation ◽  
Tibet Plateau ◽  
Ammonium Concentration ◽  
Ammonia Oxidizers ◽  
Qinghai Tibet Plateau

ABSTRACT Ammonia-oxidizing bacteria (AOB) and archaea (AOA) as well as comammox catalyze ammonia oxidation. The distribution and biogeography of these ammonia oxidizers might be distinctive in high-elevation rivers, which are generally characterized by low temperature and low ammonium concentration but strong solar radiation; however, these characteristics have rarely been documented. This study explored the abundance, community, and activity of ammonia oxidizers in the overlying water of five rivers in the Qinghai-Tibet Plateau (QTP). Potential nitrification rates in these rivers ranged from 5.4 to 38.4 nmol N liter−1 h−1, and they were significantly correlated with ammonium concentration rather than temperature. Comammox were found in 25 of the total 28 samples, and they outnumbered AOA in three samples. Contrary to most studied low-elevation rivers, average AOB amoA gene abundance was significantly higher than that of AOA, and AOB/AOA ratios increased with decreasing water temperature. The Simpson index of the AOA community increased with elevation (P < 0.05), and AOA and AOB communities exhibited high dissimilarities with low-elevation rivers. Cold-adapted (Nitrosospira amoA cluster 1, 33.6%) and oligotrophic (Nitrosomonas amoA cluster 6a, 31.7%) groups accounted for large proportions in the AOB community. Suspended sediment concentration exerted significant effects on ammonia oxidizer abundance (r > 0.56), and owing to their elevational variations in source and concentration, suspended sediments facilitated distance-decay patterns for AOA and AOB community similarities. This study demonstrates distinctive biogeography and distribution patterns for ammonia oxidizers in high-elevation rivers of the QTP. Extensive research should be conducted to explore the role of these microbes in the nitrogen cycle of this zone. IMPORTANCE Ammonia-oxidizing archaea (AOA) and bacteria (AOB) as well as comammox contribute to ammonia oxidation, which plays significant roles in riverine nitrogen cycle and N2O production. Source regions of numerous rivers in the world lie in high-elevation zones, but the abundance, community, and activity of ammonia oxidizers in rivers in high-elevation regions have rarely been investigated. This study revealed distinctive distribution patterns and community structures for ammonia oxidizers in five high-elevation rivers of the Qinghai-Tibet Plateau, and the individual and combined effects of low temperature, low nutrients, and strong solar radiation on ammonia oxidizers were elucidated. The findings of this study are helpful to broaden our knowledge on the biogeography and distribution pattern of ammonia oxidizers in river systems. Moreover, this study provides some implications to predict the performance of ammonia oxidizers in high-elevation rivers and its variations under global climate warming.

scholarly journals Evaluation of ERA-5 Precipitable Water Vapor Data in Plateau Areas: A Case Study of the Northern Qinghai-Tibet Plateau

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1367
Author(s):  
Jie Zhao ◽  
Tiejian Li ◽  
Kaifang Shi ◽  
Zhen Qiao ◽  
Zhongye Xia
Keyword(s):  
Water Vapor ◽  
Cloud Cover ◽  
Coincidence Degree ◽  
Precipitable Water ◽  
Climatic Conditions ◽  
Precipitable Water Vapor ◽  
Radiosonde Data ◽  
Tibet Plateau ◽  
Total Cloud Cover ◽  
Qinghai Tibet Plateau

In order to verify the accuracy of precipitable water vapor (PWV) in remote sensing and reanalysis datasets under different climatic conditions and ensure the reliability of analysis results, the performances of ERA-5 reanalysis PWV data and the Atmospheric Infrared Sounder (AIRS) remotely-sensed PWV data were tested in the northern Qinghai-Tibet Plateau by using weather balloon radiosonde data from meteorological stations from 2002 to 2016. The coincidence degree of total cloud cover was also verified, and then the PWV data precision with different levels of cloud cover was analyzed. The results show that: (1) Both ERA-5 and AIRS data underestimate PWV in the studied high plateau region, and higher altitude leads to greater deviation. (2) Compared with AIRS data, ERA-5 data have better consistency with radiosonde data in PWV and total cloud cover. (3) For the long-term trend of PWV, the ERA-5 data are the opposite to the radiosonde data with a clear sky, but both datasets showed a significant increasing trend in cloudy skies. It can be concluded that in high altitude areas, the ERA-5 data can be used for general analysis, but are not well qualified to reflect the changing trend of PWV under climate change.

scholarly journals Study on Low-Temperature Cracking Performance of Asphalt under Heat and Light Together Conditions

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1541 ◽  
Author(s):  
Limin Li ◽  
Zhaoyang Guo ◽  
Longfei Ran ◽  
Jiewen Zhang
Keyword(s):  
Low Temperature ◽  
Early Stage ◽  
Asphalt Pavement ◽  
Climatic Conditions ◽  
Asphalt Binders ◽  
Composition Analysis ◽  
Cracking Resistance ◽  
Modified Asphalt ◽  
Cracking Performance ◽  
Low Temperature Cracking

The low-temperature cracking performance of asphalt is considered one of the main deteriorations in asphalt pavements. However, there have been few studies on the low-temperature cracking performance of asphalt under heat and light together. Hence, the ductility test, bending beam rheometer (BBR) test, and asphalt composition analysis test are combined to investigate the low-temperature cracking performance under heat and light together based on the climatic conditions of China. The styrene–butadiene–styrene block copolymer (SBS)-modified asphalt binders were prepared with different modifier types and base asphalt in this research. The results show that the low-temperature cracking resistance of asphalt reduces under heat and light together. It is obviously reduced at the early stage, and it becomes worse with the increase of the aging time, temperature, and ultraviolet (UV) intensity. The asphalt composition has a significant impact on its low-temperature cracking performance, and the SBS modifier can improve the low-temperature cracking resistance of asphalt. The rational selection of base asphalt and modifier can improve the low-temperature cracking performance of asphalt. Under heat and light together, whether base asphalt or modified asphalt, the change trends of their ductility and component content are similar. Therefore, to improve the anti-cracking ability of the asphalt pavement, it is suggested to use the ductility of asphalt aged by heat and light together for 15 days as the evaluation index of the low-temperature cracking performance of asphalt, and asphalt should be selected according to the temperature and UV intensity of the asphalt pavement use area.

scholarly journals Simultaneously monitoring aquatic and terrestrial biodiversity using riverine water eDNA: seasonal variation of monitoring effectiveness

2020 ◽  
Author(s):  
Haile Yang ◽  
Hao Du ◽  
Hongfang Qi ◽  
Luxian Yu ◽  
Xindong Hou ◽  
...  
Keyword(s):  
Environmental Dna ◽  
Operational Taxonomic Unit ◽  
Climatic Conditions ◽  
Biological Information ◽  
Tibet Plateau ◽  
Riverine Water ◽  
Terrestrial Biodiversity ◽  
Effectiveness Assessment ◽  
Qinghai Tibet Plateau ◽  
Biodiversity Information

AbstractBoth aquatic and terrestrial biodiversity information can be detected in riverine water environmental DNA (eDNA). However, the monitoring effectiveness (i.e., the proportion of aquatic and terrestrial biodiversity information detected in riverine water eDNA samples) is unknown. To investigate the monitoring effectiveness, we introduced the concept of watershed biological information flow (WBIF) and proposed that the monitoring effectiveness depended on the transportation effectiveness of the WBIF. Then, the monitoring effectiveness could be assessed in the WBIF framework. Here, we conducted a monitoring effectiveness assessment case study in a watershed on the Qinghai-Tibet Plateau according to analysis of the bacterial operational taxonomic unit (OTU) assemblages detected in riverine water eDNA samples and riparian soil eDNA samples during three seasons. The results showed that (1) the downstream-to-upstream monitoring effectiveness: only 76% of the bacterial OTUs could be detected 1 km downstream in spring and more than 97% and 96% could be detected in summer and autumn, respectively. (2) The river-to-land monitoring effectiveness: more than 62% of the bacterial OTUs in riparian soil eDNA samples could be detected in adjacent riverine water eDNA samples on rainy summer days and 16% and 48% could be detected on cloudy spring and autumn days, respectively. These results suggested that riverine water eDNA was viable for simultaneously monitoring aquatic and terrestrial biodiversity and that rainy days in summer or autumn were suitable sampling times on the Qinghai-Tibet Plateau. More studies on monitoring effectiveness in other taxonomies and in other watersheds with different climatic conditions are needed to support simultaneous aquatic and terrestrial biodiversity assessments.

Prediction of Temperature Field of Asphalt Pavement Structure

CICTP 2020 ◽  
2020 ◽  
Author(s):  
Zhizhong Zhao ◽  
Mengchen Li ◽  
Yu Wang ◽  
Wenwen Chen ◽  
Yulong Zhao ◽  
...  
Keyword(s):  
Temperature Field ◽  
Asphalt Pavement ◽  
Pavement Structure
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