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With the depletion of shallow mineral resources, deep shaft mining has become an inevitable trend, but there is a lack of systematic review on the hazards of deep shaft mining ecological environment on miners' occupational health. The aim of this paper is to study the impact and main hazards of deep shaft mining ecological environment on miners' occupational health, summarize the existing research results and reveal their limitations, and put forward the latest targeted improvement technologies. The conclusions show that the environmental characteristics of deep mine dust, noise, and high temperature seriously jeopardize occupational health. Pneumoconiosis has become one of the biggest threats, with nearly 14,000 new cases per year since 2009; harmful noise exposure is widespread in deep mines, directly jeopardizing occupational health, with a detection rate of 29.96% of hearing impairment among China's 480,200,000 miners; and the average ground temperatures at the current mining depths of -1,000 m and -2,000 m are 41.84℃ and 69.62℃, respectively, which are very likely to trigger a variety of heat-related diseases in miners. Miners with a variety of heat-related illnesses. The hazards of these environmental features are seriously underestimated. [ABSTRACT FROM AUTHOR]

The Qinghai–Tibet Plateau is the highest and largest permafrost area in the middle and low latitudes of China. In this region, permafrost thaw settlement is the main form of expressway subgrade disaster. Therefore, the quantitative analysis and regionalization study of permafrost thaw settlement deformation are of great significance for expressway construction and maintenance in the Qinghai–Tibet region. This paper establishes a thaw settlement prediction model using the thaw settlement coefficient and thaw depth. The thaw depth was predicted by the mean annual ground temperatures and active-layer thicknesses using the Radial Basis Function (RBF) neural network model, and the thaw settlement coefficient was determined according to the type of ice content. Further, the distribution characteristics of thaw settlement risk of the permafrost subgrade in the study region were mapped and analyzed. The results showed that the thaw settlement risk was able to be divided into four risk levels, namely significant risk, high risk, medium risk and low risk levels, with the areas of these four risk levels covering 3868.67 km2, 1594.21 km2, 2456.10 km2 and 558.78 km2, respectively, of the total study region. The significant risk level had the highest proportion among all the risk levels and was mainly distributed across the Chumar River Basin, Beiluhe River Basin and Gaerqu River Basin regions. Moreover, ice content was found to be the main factor affecting thaw settlement, with thaw settlement found to increase as the ice content increased. [ABSTRACT FROM AUTHOR]

In space gravitational-wave-detection missions, inertial sensors are used as the core loads, and their acceleration noise needs to reach 3 × 10 − 15   ms − 2 / Hz at a frequency of 0.1   mHz , which corresponds to the capacitive sensing system; the capacitive sensing noise on the sensitive axis needs to reach 1   aF / Hz . Unlike traditional circuit noise evaluation, the noise in the mHz frequency band is dominated by the thermal noise and the 1 / f noise of the device, which is a challenging technical goal. In this paper, a low-frequency, high-precision resonant capacitor bridge method based on a planar transformer is used. Compared with the traditional winding transformer, the developed planar transformer has the advantages of low temperature drift and low 1 / f noise. For closed-loop measurements of capacitive sensing circuits and sensitive structures, the minimum capacitive resolution in the time domain is about 3   aF , which is far lower than the scientific measurement resolution requirement of 5.8   fF for gravitational wave detection. The capacitive sensing noise is converted to 1.095   aF / Hz in the frequency band of 10   mHz – 1   Hz . Although there is a gap between the closed-loop measurement results and the final index, the measurement environment is an experimental condition without temperature control on the ground; additionally, in China, the measurement integrity and actual measurement results of the capacitive sensing function have reached a domestic leading level. This is the realization of China's future space gravitational wave exploration. [ABSTRACT FROM AUTHOR]

As a major parameter in the energy balance of the ground surface, temperature represents the level of exchange of energy and moisture between the ground and air. The Qinghai-Tibet Plateau (QTP) has the permafrost region with the highest altitude and the largest area in low–middle latitude of the world. The variation in ground surface temperature has an impact on the existence and development of the permafrost. Therefore, the analysis of the ground surface temperature in the QTP is significant to reflect the energy exchange in permafrost regions. This paper collected solar radiation data and calculated the conversion coefficient from total solar radiation to long-wave radiation of the ground surface on different underlying surfaces. The ground surface temperature was inversely calculated and modified based on the reception of solar radiation on different underlying surfaces. A simplified calculation model of ground surface temperature was built to reflect the ground surface temperature on different underlying surfaces of the QTP. The calculation results were compared with MODIS and showed good fitness, providing a systematic and reliable method for calculating the ground surface temperature on the QTP. The above model plays a significant role in the estimation of soil moisture, ground surface energy and water balance. [ABSTRACT FROM AUTHOR]

Taking the Suiqi coalfield located in North China as the object, where the coal seam burial depth is more than 1100 m, the water abundance of the roof pore thermal storage aquifer is better than average, the ground temperature is abnormally high, and hydrogeological data are relatively lacking, this paper selects and determines eight index factors that influence the mining of the coalfield. Based on the analytic hierarchy process (AHP), the index factor weight is defined, and then, the threat degree of the roof thermal storage aquifer to the coal mining is quantitatively evaluated and divided by using the fuzzy variable set theory. The evaluation results show that the threat degree of the roof in the eastern region is generally greater than that in the western region and that the closer it is to the coal seam outcrop line, the higher the threat degree is; near the boreholes, in the areas Qs1,Qs5, Qs8, Sx1, Tk5, Zc4, and Zc7, which are close to the hidden outcrop line of the coal seam, the classification characteristic value of the threat degree is greater than 3.5, which is in the high-threat zone for disasters caused by roof thermal storage aquifers during coal seam mining. The area above the medium-threat zone accounts for 71.82% of the total study area, indicating that deep coal mining is affected by multiple factors and that roof water and heat disasters are more likely to occur. [ABSTRACT FROM AUTHOR]

In-situ monitoring system is absolutely necessary for a long-distance linear pipeline infrastructure in permafrost regions due to the complicated interaction between buried pipeline and its harsh permafrost environment. To study this complex problem, a comprehensive in-situ monitoring system has been designed and established along the China–Russia Crude Oil Pipeline (CRCOP), which is one of vital energy channels for importing crude oil from Russia to China. This monitoring system can record the meteorological data, ground temperature and water content within the permafrost foundation, vertical settlement of the oil pipe, ground surface deformation on the pipeline right-of-way (on-ROW), as well as the thaw bulb around the pipeline at four sites with different engineering geological conditions. In this paper, the layout and instrumentation of the whole monitoring system and monitoring methods are described in detail, and then the thermal regime of permafrost on-ROW and off-ROW and cooling performance of the mitigative measures on foundation soils are evaluated. Results show that heat dissipated from the CRCOP lead to the rapid degradation of permafrost on-ROW and produce different sizes of thaw bulb around the oil pipelines. The mitigative measures, including insulation layer, two-phase closed thermosyphon and U-shaped air-ventilated pipes, are effective to minimize permafrost degradation and ensure the thermal stability of permafrost foundation along the CRCOP. Some recommendations are proposed for future research and for the monitoring system to be improved. This monitoring system can provide multi-field data to clarify the interaction between pipeline and permafrost degradation under different geological conditions, and guide the design and maintenance of the buried warm pipeline in permafrost regions. • An in-situ monitoring system is set up along the CRCOP in permafrost regions. • The geological characteristics and layout of instrumentation at four monitoring sites are reported. • The integrated monitoring method for pipeline-permafrost interaction are presented. • Thermal effect of buried warm oil pipe on underlying permafrost is observed. • Cooling performance of the insulation layer, thermosyphon and U-shaped air-ventilated pipes is evaluated. [ABSTRACT FROM AUTHOR]

Rapid permafrost thawing triggered by heat release from the buried warm-oil pipeline would result in the instability of the pipeline, posing a potential risk of an oil spill in permafrost regions. Therefore, how to precisely control the ground temperature to mitigate pipeline foundation permafrost from thawing is of significant importance. Thermosyphon is a widely-accepted and extensively-used countermeasure against permafrost thawing in permafrost engineering. This paper presents 3-year (2015–2018) monitored data of ground temperature and geophysical survey results conducted by electrical resistivity tomography in April 2018, to investigate the thermal stabilizing effect of thermosyphons installed nearby the China-Russia crude oil pipeline (CRCOP) and the influencing factors. Furthermore, numerical simulation tests were conducted to evaluate their long-term cooling applicability and to optimize their layout parameters. Field observations show that the thermosyphons can cool down and even freeze the thawed soil layers around the CRCOP, prohibiting the infiltration of water into the thawing front to some extent and effectively mitigating the rapid thawing of permafrost beneath the pipeline. The performance of the thermosyphons is greatly influenced by the method and time of thermosyphon installation, as well as layout parameters including the number and longitudinal spacing. Two pairs of thermosyphons with a shorter spacing are unable to control the thawing of the underlying permafrost due to the non-anticipated higher oil temperature, the thermal erosion of water ponding, and climate warming. The simulated results indicate that thermosyphons perform well in the first 5 years after installation. Thermosyphon lowers the mean annual temperature of soils surrounding it by about 2 and 1.4 times when the evaporator section length is increased by 50% and the longitudinal spacing is decreased by 0.5 m, respectively. The application of thermosyphons has proven its strength for thermally stabilizing the pipeline foundation permafrost along the CRCOP. • 3-year ground temperature data and geophysical survey results are presented. • Thermosyphon can mitigate the rapid thawing of permafrost beneath the pipeline. • Thermosyphons performs most significantly in the first five years. • Lengthening thermosyphon and decreasing spacings are favorable for the better cooling effect. [ABSTRACT FROM AUTHOR]

This paper combines observations, climatic analysis, and numerical modeling to investigate the Tibetan Plateau's (TP) surface heating conditions' influence on extreme persistent precipitation events (PEPEs) in southeastern China. Observations indicated an increase of TP surface air temperature 3-4 days prior to extreme persistent precipitation events in southeastern China. NCEP reanalysis data revealed a significant low pressure anomaly in southern China and a high pressure anomaly in northern China during extreme persistent precipitation event periods. Using correlation analysis and random resampling nonparametric statistics, a typical PEPE event from 17 to 25 June 2010 was selected for numerical simulation. The Weather Research and Forecasting (WRF) Model was used to investigate the impact of the TP's surface heating on the evolution of this event. Three contrasting WRF experiments were conducted with different surface heating strengths by changing initial soil moisture over the TP. Different soil conditions generate different intensities of surface sensible heat fluxes and boundary layer structures over the TP resulting in two main effects on downstream convective rainfall: modulating large-scale atmospheric circulations and modifying the water vapor transport at southern China. Increased surface heating in the TP strengthens a high pressure system over the Yangtze Plain, thereby blocking the northward movement of precipitation. It also enhances the water vapor transport from the South China Sea to southern China. The combined effects substantially increase precipitation over most of the southeastern China region. [ABSTRACT FROM AUTHOR]

The Sichuan-Chongqing area in China has complex basin topography and is known for its extremely hot summer weather. In this paper, the mesoscale model WRF version 3.6.1 was used to simulate a period of 1–10 days in advance of the hot weather that occurred in Sichuan-Chongqing on August 10, 2006, to investigate the effect of six different land surface schemes (LSSs) (SLAB, RUC, PX, NOAH, NOAH_MP, and CLM4) on short- and medium-range simulations of high temperatures. The simulated surface air temperatures (SATs) are sensitive to the LSSs and simulation lengths. Specifically, all of the LSSs except PX generally reproduce the observed high temperatures, with CLM4 SATs at 06 UTC (SAT06) the most consistent with measurements whereas the short-range (medium-range) results from NOAH_MP (NOAH) are the worst. Detailed explanations were given in terms of surface fluxes and physical processes. RUC soil moisture initialization appears poor and the LSS reflects too strong gravity drainage. When the LSSs with increased numbers of soil layers are used, the simulated high temperatures are found more consistent with measurements. Additionally, regional sensible heat flux (SHF) does not show high consistency with SAT. The results that differ from the previous studies are partly due to the complex geography and the LSS deficiencies. [ABSTRACT FROM AUTHOR]

Embankment deformation is a key consideration in high speed railway construction. Frost heave due to temperature and moisture variation is critical to consider in areas of seasonally frozen ground. This paper examined ground temperatures, frost heave, and moisture content in 2013–2014 at two sites along the embankment of the Harbin-Dalian Passenger Dedicated Line (HDPDL) railway. The railway is in seasonally-frozen ground of Jilin Province, China. The embankment at one site (K977) was built on the undisturbed ground surface while the other was in a cut section (K1004). Displacement measurements over one year indicated that frost heave of 14 mm at K977 and 25 mm at K1004 occurred in ballast during the freezing season. During the annual freeze-thaw period, soil moisture content varied drastically in the upper 0.6 m. The frost depth and freezing index were strongly and positively correlated during the freezing season. Soil moisture content was regarded as the primary control on the amount of frost heave, while frost depth was secondary. Furthermore, water vapor diffusion may have been an important contributor to the formation of near-surface ice. At K1004 site, the maximum recorded deformation was large and exceeded the 15 mm Chinese standard for maximum allowable heave. This suggested that high ground water level increased the amount of frost heave. [ABSTRACT FROM AUTHOR]

Permafrost in Northeastern China has significantly degraded due to global warming, deforestation and urbanization in the last few decades. The frost heave and thaw subsidence induced by freeze-thaw cycles of deep seasonal frozen ground have caused serious damage to infrastructures. The Shiwei-Labudalin (Shi-La) Highway is an important infrastructure connecting Shiwei town and Labudalin town of Argun city, Inner Mongolia, which passes through the areas covered by deep seasonal frozen ground or isolated patchy permafrost. In this paper, we mapped the long-term linear displacement trend and amplitude of seasonal displacement of the Shi-La Highway and its nearby areas, with an ascending Sentinel-1 dataset acquired from September 2016 to April 2020. Seasonal displacement amplitudes of 5–20 mm are widely detected in low-lying areas (e.g., the basin of the Gen and Derbugan rivers). The time lags between frozen ground displacement and temperature variations generally range from 10 to 80 days while larger values of 100–120 days caused by soil moisture or land cover difference are also observed. Linear creep displacement rates greater than −20 mm/yr are detected on mountainous slopes and sections of the Shi-La Highway in the line-of-sight (LOS) direction. Our results provide a method for evaluating highway stability in cold regions, which is helpful to highway route selection and design in Northeastern China. • Map displacement of frozen ground in northern Inner Mongolia using InSAR. • Freeze-thaw related and creep movement were identified on Shi-La highway. • Time lags between displacement and temperature are 10–120 days in flat areas. [ABSTRACT FROM AUTHOR]

Although previous studies show that urbanization contributes to less than 10 % of the long-term regional total warming trend of mean surface air temperature in northeast China (Li et al. ), the urban heat island (UHI) impact on extreme temperatures could be more significant. This paper examines the urbanization impact on extreme winter minimum temperatures from 33 stations in North China during the period of 1957-2010. We use the Generalized Extreme Value (GEV) distribution to analyze the distribution of extreme minimum temperatures and the long-term variations of the three distributional characteristics parameters. Results suggest that among the three distribution parameters, the position parameter is the most representative in terms of the long-term extreme minimum temperature change. A new classification method based on the intercommunity (factors analysis method) of the temperature change is developed to detect the urbanization effect on winter extreme minimum temperatures in different cities. During the period of rapid urbanization (after 1980), the magnitude of variations of the three distribution parameters for the urban station group is larger than that for the reference station group, indicating a higher chance of occurrence of warmer weather and a larger fluctuation of temperatures. Among different types of cities, the three parameters of extreme minimum temperature distribution of the urban station group are, without exception, higher than those of the reference station group. The urbanization of different types of cities all show a warming effect, with small-size cities have the most evident effects on extreme minimum temperatures. [ABSTRACT FROM AUTHOR]

Abstract: Vitrinite reflectance (VR, Ro%) measurements from residual kerogen of pyrolysis experiments were performed on immature Maoming Oil Shale substituted the samples for the gas-prone source rocks of Yacheng formation of the Qiongdongnan Basin in the South China Sea. The work was focused on determination an upper limit of maturity for gas generation (ULMGG) or “the deadline of natural gas generation”. Ro values at given temperatures increase with increasing temperature and prolonged heating time, but ΔRo-value, given a definition of the difference of all values for VR related to higher temperature and adjacent lower temperature in open-system non-isothermal experiment at the heating rate of 20°C/min, is better than VR. And representative examples are presented in this paper. It indicates that the range of natural gas generation for Ro in the main gas generation period is from 0.96% to 2.74%, in which ΔRo is in concordance with the stage for the onset and end of the main gas generation period corresponding to 0.02% up to 0.30% and from 0.30% up to 0.80%, respectively. After the main gas generation period of 0.96–2.74%, the evolution of VR approach to the ULMGG of the whole rock for type II kerogen. It is equal to 4.38% of VR, where the gas generation rates change little with the increase of maturation, ΔRo is the maximum of 0.83% corresponding to VR of 4.38%Ro, and the source rock does not nearly occur in the end process of hydrocarbon gas generation while Ro is over 4.38%. It shows that it is the same the ULMGG from the whole rock for type II kerogen as the method with both comparison and kinetics. By comparing to both the conclusions of pyrolysis experiments and the data of VR from the source rock of Yacheng formation on a series of selected eight wells in the shallow-water continental shelf area, it indicate that the most hydrocarbon source rock is still far from reaching ULMGG from the whole rock for type II kerogen. The source rock of Yacheng formation in the local areas of the deepwater continental slope basin have still preferable natural gas generative potential, especially in the local along the central depression belt (namely the Ledong, Lingshui, Songnan and Baodao sags from southwest to northeast) from the depocenter to both the margin and its adjacent areas. It help to evaluate the resource potential for oil and gas of the hydrocarbon source rock in the deepwater continental slope of the Qiongdongnan Basin or other basins with lower exploration in the northern of the South China Sea and to reduce the risk in exploration. [Copyright &y& Elsevier]

Abstract: The analysis of the passive microwave radiance transfer equation certifies that there is a linear relationship between satellite-generated brightness temperatures (BT) and in situ observation temperature and that land surface temperature (LST) is largely influenced by vegetation cover conditions. Microwave polarization difference index (MPDI) is an effective indicator for characterizing the land surface vegetation cover density. Based on the analysis of LST models from AMSR-E BT with 6.9GHz MPDI intervals at 0.04, 0.02 and 0.01, respectively, this paper developed a simplified LST regression model with MPDI-based five land cover types, combining observation temperatures from 86 meteorological observation stations. The study shows that smaller MPDI intervals can obtain higher accuracy of AMSR-E LST simulation, and that the combination of HDF Explorer and ArcGIS software was useful for automatically processing the pixel latitude, longitude and BT information from the AMSR-E HDF imagery files. The RMSE of the five LST simulation algorithms is between 1.47 and 1.92°C, with an average LST retrieval error of 0.91–1.30°C. Besides, only 7 polarization bands and 5 land surface types are required by the proposed simplified model. The new LST simulation models appears to be more effective for producing LST compared to past most studies, of which the accuracy used to be more than 2°C. This study is one of the rare applications that combine the meteorological observation temperature with MPDI to produce the LST regression analysis algorithms with less RMSE from AMSR-E data. The results can be referred to similar areas of the world for LST retrieval or land surface process research, in particular under extreme bad weather conditions. [Copyright &y& Elsevier]

Abstract: The China–Russia Crude Oil Pipeline (CRCOP), 813mm in diameter, is designed to transport 603,000 barrels of Siberian crude oil per day across 1030km of frozen-ground. About 500 boreholes, with depths of 5 to 20m, were drilled and cored for analyses, and the frozen-ground conditions were evaluated. After detailed surveys and analyses of the permafrost conditions along the pipeline route, a conventional burial construction mode at a nominal depth of 1.5m was adopted. This paper discusses the principles and criteria for the zonation and assessment of the frozen-ground environments and conditions of engineering geology for the design, construction, and operation of the pipeline system based on an extensive and in-depth summary and analysis of the survey and exploration data. The characteristics of pipelining crude oil at ambient temperatures in the permafrost regions and the interactive processes between the pipeline and foundation soils were taken into account. Two zones of frozen-ground environment and conditions of engineering geology, i.e., seasonally-frozen-ground and permafrost, were defined on the basis of the regional distribution and differentiations in frozen-ground environments and conditions. Then, four subzones of the permafrost zone were classified according to the areal extent, taking into consideration the temperatures and thicknesses of permafrost, as well as changes in vegetation coverage. In the four subzones, 151 sections of engineering geology were categorized according to the ice/moisture contents of the permafrost, as well as the classes of frost-heaving and thaw-settlement potentials. These 151 sections are comprehensively summarized into four types for engineering construction and operation: good, fair, poor, and very poor, for overall conditions of engineering geology. The zonation, assessment principles and criteria have been applied in the design of the pipeline. They have also been used as the scientific bases for the construction, environmental management, operation and maintenance/contingency plans. [Copyright &y& Elsevier]

• A numerical model is proposed and validated to predict ground temperature profiles. • Three typical meteorological year databases are compared to provide the weather parameters for the numerical model. • Two-harmonic analytical correlation (THAC) with high accuracy is introduced to obtain ground temperature rapidly. • THACs of main cities in two climate regions in China are provided on the standard condition. • THACs of all types of soil can be derived according to the developed universal correction formulas and the standard THACs. The lacking of ground temperature measurement data has been preventing the development of underground engineering in China. Therefore, this paper proposed and validated a numerical prediction model that comprehensively considered the effects of short-wave solar radiation, long-wave radiation, latent evaporation energy, heat convection, heat conduction, soil freezing and thawing latent heat on ground temperature. Three frequently-used typical meteorological year databases were used to provide the weather parameters for the numerical model. Comparison of three city cases showed that the model using the "Chinese typical year weather" performed best in accuracy. Moreover, due to the much calculation time required for the numerical model, the two-harmonic analytical correlation (THAC) with higher accuracy than Kusada correlation and Baggs correlation was introduced to obtain ground temperature rapidly. Considering the variety of soil types, the universal correction formulas about the relationship between the THAC coefficients and the soil thermal diffusivity were developed through a series of typical city cases. Simultaneously, THACs of main cities in two climate regions corresponding to soil thermal diffusivity of 8.13*10-2 m2/day were provided as the standard THACs. The THACs of other types of soil were proved to be derived according to the universal correction formulas and the standard THACs. [ABSTRACT FROM AUTHOR]

The Zhujiang Delta of South China has experienced a rapid urban expansion over the past two decades due to accelerated economic growth. This paper reports an investigation into the application of the integration of remote sensing and geographic information systems (GIS) for detecting urban growth and assessing its impact on surface temperature in the region. Remote sensing techniques were used to carry out land use/cover change detection by using multitemporal Landsat Thematic Mapper data. Urban growth patterns were analysed by using a GIS-based modelling approach. The integration of remote sensing and GIS was further applied to examine the impact of urban growth on surface temperatures. The results revealed a notable and uneven urban growth in the study area. This urban development had raised surface radiant temperature by 13.01 K in the urbanized area. The integration of remote sensing and GIS was found to be effective in monitoring and analysing urban growth patterns, and in evaluating urbanization impact on surface temperature. [ABSTRACT FROM AUTHOR]

• China has abundant SGE resources but the utilization of which remains still low. • SGE is mainly used for building heating and cooling via GSHP technology. • Energy efficiencies of GSHP systems are generally not high in China. • Some measures can be considered to enhance the utilization efficiency of SGE. • AI technology will be a significant measure for SGE resource evaluation. This paper summarized the shallow geothermal resources within a depth of 200 m in China. This geothermal resource is divided into five regions based on the geological structures, geomorphology, geology, and hydrogeology. The recoverable amount of shallow geothermal energy (SGE) is equivalent to 7 × 1012 kg of standard coal in a survey area of 1.69 × 105 km2, 60% of which is distributed in the mid-eastern region of China. SGE is mainly used for building heating and cooling via ground source heat pump (GSHP) technology since 1990s. The coefficient of performance (COPs) of the GSHP system exhibits large regional differences, and the energy utilizing efficiencies of GSHP systems are not high. The utilization rate of SGE is still low compared with those of other forms of renewable energy. Some measures, including a standardized and simplified management system, a feasible evaluation and utilization plan, modified technology and standards, an intelligence environmental impact assessment, and intelligence monitoring, can be considered to enhance the utilization efficiency of SGE. [ABSTRACT FROM AUTHOR]

Taking only the mean value of cover transmittance and cover absorbance would lead to a large error in estimating the thermal performance of a greenhouse. This paper discusses an innovative dynamic energy balance model of a glass greenhouse, incorporating dynamic cover absorbance and transmittance. Different cover absorbances and transmittances for diffuse, beam, and ground-reflected radiation are used. The model primarily comprises nine differential energy conservation equations for indoor air, seven layers of soil, and the greenhouse's cover. Greenhouse temperature trends are acquired by solving the unsteady-state equations with MATLAB. The model was verified using experimental data recorded during three non-continuous periods of 15 days each in northern China (36.08°N, 116.95°E), during which the daily maximum outdoor solar radiation flux intensity fell between 191 and 894 Wm-2, the outdoor air temperature fell between −12.3 °C and 24.5 °C, the ground surface temperature fell between 0.6°C and 44.3 °C, and the indoor air temperature fell between −9.0 °C and 51.8 °C. The estimates agree well with the measurements, suggesting that the dynamic model is valid. Meanwhile, the dynamic cover absorbance and transmittance, the solar radiation absorbed by the cover, the solar radiation transmitted into the glass greenhouse and the proportion of solar radiation from each surface are discussed. • The model considers dynamic cover absorbance and transmittance with an improved performance. • Use of a sub-model of seven-layer soil resulted in an improved performance. • The solar radiation transmitted into the greenhouse from side walls was studied. • Study of the dynamic absorbance and transmittance of various greenhouse surfaces. • Analysis of solar radiation absorbed by cover and solar radiation transmitted into the greenhouse. [ABSTRACT FROM AUTHOR]

The structural functionality of roads and railways in warm permafrost regions is influenced by both physical and mechanical processes at work within the underlying subgrade. This paper uses ten-years worth of monitoring data to examine the thermal regimes and deformation behaviors of three different types of crushed-rock embankments employed in the construction of the Qinghai-Tibet Railway, which is located in a warm permafrost region of the Tibetan Plateau, China. More specifically, the efficiency of U-shaped crushed-rock, crushed-rock revetment, and crushed-rock basement embankments in stabilizing permafrost temperature is evaluated with consideration to the permafrost table, ground temperature, and mean annual ground temperature. Then, deformation laws in the three embankments were analyzed. Finally, deformation characteristics and sources for general subgrade are discussed and summarized on the basis of monitoring data and previous research. Results show the permafrost table of each of the three crushed-rock embankments to be higher than that of the natural ground at all times, and that the underlying permafrost warms with time regardless of the type of embankment employed. The deformation characteristics of general subgrade in permafrost regions are determined to be non-uniform and persistent. Furthermore, U-shaped crushed-rock embankment out-performed both crushed-rock revetment embankment and crushed-rock basement embankment in terms of cooling capacity and ability to weaken the sunny-shady slope effect. These findings stand to provide important guidance for understanding the deformation mechanisms of subgrade in warm permafrost regions, as well as for improving Qinghai-Tibet Railway embankment quality and operational safety. • Ten-years monitoring data was used to analyze cooling effects of three CREs. • It is concluded that UCRE demonstrates a better cooling effect. • Deformation laws and causes for three CREs were analyzed. • Deformation characteristics and sources for general subgrade are summarized. [ABSTRACT FROM AUTHOR]