期刊文献+
共找到2,086篇文章
< 1 2 105 >
每页显示 20 50 100
Studies on Composting Spent Coffee Grounds by <i>Aspergillus sp</i>and <i>Aspergillus sp</i>in Aerobic Static Batch Temperature Control 被引量:1
1
作者 Asmak Afriliana Endar Hidayat +2 位作者 Yoshiharu Mitoma Taizo Masuda Hiroyuki Harada 《Journal of Agricultural Chemistry and Environment》 2021年第1期91-112,共22页
Spent Coffee Ground (SCG) is characterized by high organic content, in the form of insoluble polysaccharides bound and phenol compounds. Phenol compounds are toxic to nature and <span style="font-family:Verdan... Spent Coffee Ground (SCG) is characterized by high organic content, in the form of insoluble polysaccharides bound and phenol compounds. Phenol compounds are toxic to nature and <span style="font-family:Verdana;">are</span><span style="font-family:Verdana;"> a cause of environmental pollution. Composting method of this study is aerobic static batch composting with temperature control with adding activators of some fungi such as </span><i><span style="font-family:Verdana;">Aspergillus sp</span></i><span style="font-family:Verdana;">, and </span><i><span style="font-family:Verdana;">Penicillium sp. </span></i><span style="font-family:Verdana;">The purpose of the research is to fill the research gap from previous studies of spent coffee grounds compost, which requires a long time in composting, so that if it is used directly on the soil and plants, the positive effect also requires a long time. The result of composting for 28 days with this method is that mature compost has black crumb and normal pH, with characteristics of C/N ratio below 10: C1 (7.06), C2 (6.99). This value is far from the control with a C/N ratio of 8.33. Decompose rate of macromolecule are above 40% for lignin and 70% for cellulose. Implementation of compost in radish plants, resulting Germination Index above 80% which indicates that the compost is ripe: control (92.39%), C1 (183.88%), C2 (191.86%). The results of the analysis with FTIR also showed that the compost was mature and stable, and rich in minerals. So, it can be concluded </span><span style="font-family:Verdana;">that</span><span style="font-family:Verdana;"> this composting method can speed up composting time and optimize the results of compost produced.</span> 展开更多
关键词 Spent Coffee ground (SCG) Aspergillus sp Aspergillus sp Aerobic Static Batch temperature Control
下载PDF
Changes and spatial patterns of the differences between ground and air temperature over the Qinghai-Xizang Plateau 被引量:5
2
作者 ZHANG Wengang LI Shuxun +1 位作者 WU Tonghua PANG Qiangqiang 《Journal of Geographical Sciences》 SCIE CSCD 2007年第1期20-32,共13页
The difference between ground soil and air temperature (Ts-Ta) was studied by using the data of ground and air temperature of 99 stations over the Qinghai-Xizang (Tibet) Plateau from 1960 to 2000,and its spatial d... The difference between ground soil and air temperature (Ts-Ta) was studied by using the data of ground and air temperature of 99 stations over the Qinghai-Xizang (Tibet) Plateau from 1960 to 2000,and its spatial distribution and time changing tendency have been diagnosed by principal component analysis and power spectral analysis methods. The results show that the values of (Ts-Ta) are the maximum in June and the minimum in December. The first three loading eigenvectors, which reflect the main spatially anomalous structure of (Ts-Ta) over the Qinghai-Xizang Plateau, contain the contrary changing pattern between the northwestern and the southeastern regions, the pattern response of the sea level elevation and the geography, and the pattern response of the distribution of the permafrost. There are four patterns of time evolution including the patterns of monotonous increasing or decreasing trends, the basic stability pattern and the parabola pattern with the minimum value. (Ts-Ta) has a periodic variation about 2 years. According to the spatial distribution of the third loading eigenvectors of (Ts-Ta) over the Qinghai-Xizang Plateau in cold season, the permafrost response region and the seasonal frozen ground response region are identified. 展开更多
关键词 Qinghai-Xizang Plateau difference between ground and air temperature (Ts-Ta) principal component temperature subarea
下载PDF
The changing process and trend of ground temperature around tower foundations of Qinghai-Tibet Power Transmission line 被引量:2
3
作者 YanLi Xie QiHao Yu +2 位作者 YanHui You ZhongQiu Zhang TingTao Gou 《Research in Cold and Arid Regions》 CSCD 2019年第1期13-20,共8页
After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing proce... After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing process and trend of ground temperature around tower foundations are crucial for the stability of QTPT. We analyzed the change characteristics and tendencies of the ground temperature based on field monitoring data from 2010 to 2014. The results reveal that soil around the tower foundations froze and connected with the artificial permafrost induced during the construction of footings after the first freezing period, and the soil below the original permafrost table kept freezing in subsequent thawing periods. The ground temperature lowered to that of natural fields, fast or slowly for tower foundations with thermosyphons,while for tower foundations without thermosyphons, the increase in ground temperature resulted in higher temperature than that of natural fields. Also, the permafrost temperature and ice content are significant factors that influence the ground temperature around tower foundations. Specifically, the ground temperature around tower foundations in warm and ice-rich permafrost regions decreased slowly, while that in cold and ice poor permafrost regions cooled faster. Moreover, foundations types impacted the ground temperature, which consisted of different technical processes during construction and variant of tower footing structures. The revealed changing process and trend of the ground temperature is beneficial for evaluating the thermal regime evolution around tower foundations in the context of climate change. 展开更多
关键词 Qinghai-Tibet Power Transmission line TOWER FOUNDATION ground temperature change CHARACTERISTIC TREND
下载PDF
The Sensitivity of Ground Surface Temperature Prediction to Soil Thermal Properties Using the Simple Biosphere Model(SiB2) 被引量:2
4
作者 张晓惠 高志球 魏东平 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第3期623-634,共12页
Using the Simple Biosphere Model (SiB2), soil thermal properties (STP) were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model ... Using the Simple Biosphere Model (SiB2), soil thermal properties (STP) were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model by incorporating a revised force-restore method (FRM) to take the vertical heterogeneity of soil thermal diffusivity (k) into account. The results indicate that (1) the revised FRM alleviates daytime overestimation and nighttime underestimation in modeled ground surface temperature (Tg), and (2) its role in little rainfall events is significant because the vertical gradient of k increases with increasing surface evaporation. Since the original formula of thermal conductivity (A) in the SiB2 greatly underestimates soil thermal conductivity, we compared five Mgorithms of A involving soil moisture to investigate the cause of overestimation during the day and underestimation at night on the basis of the revised FRM. The results show that (1) the five algorithms significantly improve Tg prediction, especially in daytime, and (2) taking one of these five algorithms as an example, the simulated Tg values in the daytime are closer to the field measurements than those in the nighttime. The differences between modeled Tg and field measurements are mostly within the margin of error of -4-2 K during 3 August to 4 September 1998. 展开更多
关键词 land surface processes SIB2 sensitivity ground surface temperature soil thermal diffusivity soil thermal conductivity
下载PDF
Causes of geothermal fields and characteristics of ground temperature fields in China 被引量:3
5
作者 MAO Xiao-ping LI Ke-wen WANG Xin-wei 《Journal of Groundwater Science and Engineering》 2019年第1期15-28,共14页
There are many arguments on energy sources and main controlling factors of geothermal fields, so a systematic study on the distribution of ground temperature fields shall be necessary. In this paper the thermal conduc... There are many arguments on energy sources and main controlling factors of geothermal fields, so a systematic study on the distribution of ground temperature fields shall be necessary. In this paper the thermal conduction forward method of geothermal field is used to simulate cooling rate of abnormal heat sources and heat transfer of the paleo-uplift model. Combined with a large number of geothermal field exploration cases and oil exploration well temperature curves of domestic and foreign, the following conclusions are drawn:(1) According to the magmatic activity time, the magmatism activities are divided into two categories: Magma active areas(activity time < 500 000 years) and weak/magma inactive areas(activity time > 500 000 years). The latter has a fast cooling rate(the cooling time of the magma pocket buried around 10 km is less than 200 000 years) after it has intruded into the shallow layer and it has no direct contribution to modern geothermal fields;(2) China belongs to a weak/magma inactive area such as Tengchong region and Qinghai-Tibet region because the chronological data of these regions show that its magma activity time is more than 500 000 years;(3) The temperature of most geothermal fields can be obviously divided into three segments in the vertical direction: A high geothermal gradient segment(Segment H) at the surface, then a low geothermal gradient segment(Segment L) at a secondary depth, and finally a lower temperature segment(Segment D) at a deeper depth. The temperature isoline presents a mirror reflection relation on the temperature profile, indicating that geothermal field is dominated by heat conduction, rather than having an abnormally high temperature "heat source" to provide heat;(4) Near-surface(0-5 km) materials' lateral heterogeneity caused by tectonic movement shall probably be the main controlling factor of ground temperature fields. 展开更多
关键词 ground temperature FIELD BASEMENT HEAT flow GEOTHERMAL FIELD MAGMA pocket Coefficient of HEAT conduction Palaeouplifth MAGNETOTELLURIC
下载PDF
Monitoring and analysis of ground temperature and deformation within Qinghai-Tibet Highway subgrade in permafrost region 被引量:1
6
作者 YaHu Tian YuPeng Shen +1 位作者 WenBing Yu JianHong Fang 《Research in Cold and Arid Regions》 CSCD 2015年第4期370-375,共6页
In order to study the stability of the Qinghai-Tibet Highway embankment at Chumaerhe in the permafrost region of northwest China, the ground temperature and deformation at different depths were monitored under the lef... In order to study the stability of the Qinghai-Tibet Highway embankment at Chumaerhe in the permafrost region of northwest China, the ground temperature and deformation at different depths were monitored under the left and right shoulders of the embankment where thermosyphons were set up only on the left shoulder. Based on the monitored data, characteristics of ground temperature and deformation of the left and right shoulders are analyzed and discussed. The results show that the start time of freezing or thawing of the seasonal active layer was about one to two months later than that of the embankment body itself. The stability of each shoulder was mainly controlled by the settlement of different soil layers, whereas frost heave of soil had scarcely any effect on the stability of the embankment. For the left shoulder, the settlement was mainly influenced by the seasonal active layer and then by the embankment body itself, due to freeze-thaw cycles which may change the soil properties; however, the permafrost layer remained fairly stable. For the right shoulder, creep of the warm permafrost layer was the main influence factor on its stability, followed by settlement of embankment body itself, and finally settlement of the seasonal active layer. Compared with the deformation of the left shoulder, the permafrost layer under the right shoulder was less stable, which indicates that the thermosyphons had a significantly positive effect on the stability of warm permafrost. 展开更多
关键词 Qinghai-Tibet Highway PERMAFROST DEFORMATION ground temperature MONITORING
下载PDF
Recent changes in ground surface thermal regimes in the context of air temperature warming over the Heihe River Basin, China 被引量:1
7
作者 QingFeng Wang TingJun Zhang +1 位作者 XiaoQing Peng Bin Cao 《Research in Cold and Arid Regions》 CSCD 2014年第4期273-281,共9页
Changes in ground surface thermal regimes play a vital role in surface and subsurface hydrology, ecosystem diversity and productivity, and global thermal, water and carbon budgets as well as climate change. Estimating... Changes in ground surface thermal regimes play a vital role in surface and subsurface hydrology, ecosystem diversity and productivity, and global thermal, water and carbon budgets as well as climate change. Estimating spring, summer, autumn and winter air temperatures and mean annual air temperature(MAAT) from 1960 through 2008 over the Heihe River Basin reveals a statistically significant trend of 0.31 °C/decade, 0.28 °C/decade, 0.37 °C/decade, 0.50 °C/decade, and 0.37 °C /decade, respectively. The averaged time series of mean annual ground surface temperature(MAGST) and maximum annual ground surface temperature(MaxAGST) for 1972–2006 over the basin indicates a statistically significant trend of 0.58 °C/decade and 1.27 °C/decade, respectively. The minimum annual ground surface temperature(MinAGST) in the same period remains unchanged as a whole. Estimating surface freezing/thawing index as well as the ratio of freezing index to thawing index(RFT) in the period between 1959 and 2006 over the basin indicates a statistically significant trend of-42.5 °C-day/decade, 85.4 °C-day/decade and-0.018/decade, respectively. 展开更多
关键词 air temperature ground surface temperature freezing index thawing index tendency rate Heihe River Basin
下载PDF
GROUND TEMPERATURE AND ROCK THERMOPHYSICAL PROPERTIES IN FILDES PENINSULA 被引量:1
8
作者 Yang Shuzhen Zhang Wenren Shen Xianjie Institute of Geology, Academia Sinica, Beijing 100029 《Chinese Journal of Polar Science》 1990年第1期58-66,共9页
During 1985-1986, 1986-1987, and 1988-1989 expeditions on Fildes Peninsula the ground temperature was measured. A total number of 218 ground temperature data were obtained. The thermal conductivity measurements were m... During 1985-1986, 1986-1987, and 1988-1989 expeditions on Fildes Peninsula the ground temperature was measured. A total number of 218 ground temperature data were obtained. The thermal conductivity measurements were made on 121 rock samples collected during expedition. This article gives a brief analysis and summarization of these data. 展开更多
关键词 ground temperature Fildes Peninsula temperature probe Rock thermal conductivity Hydrothermal process.
下载PDF
PANDERIVATIVE BLOWN-UP OF GROUND TEMPERATUREAND PREDICTING EARTHQUAKE
9
作者 李超 欧阳首承 汤懋苍 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1998年第3期253-262,共10页
According to the blown-up theory (described in references [1,2]) for nonlinear dynamic system on the relationship of general pansystem transformation, optimisation and panderivative blown-up, by means of blown-up theo... According to the blown-up theory (described in references [1,2]) for nonlinear dynamic system on the relationship of general pansystem transformation, optimisation and panderivative blown-up, by means of blown-up theory, we demonstrate that the blown-up of nonlinear heat conductive equation is similar to the evolution of observational ground temperature 'flow' in this paper. And a successful simulation of Tang Shan Earthquake in 1976 has been given. The result of simulation indicates that the blown-up of ground temperature 'flow' around earthquake can be applied to predict earthquake. As for Tang Shan Earthquake, the predicting time is about five months. If ground temperature 'flow' that embodies the earth's crust satisfies the unintegral panderivative equation, we can demonstrate its mechanism and forecast earthquake with enough information. 展开更多
关键词 ground temperature 'flow' blown-up panderivative predicting
下载PDF
The Impact and Harm on Deep Ground Temperature by Rainstorm
10
作者 Zhang Yuan 《Meteorological and Environmental Research》 CAS 2017年第6期27-31,共5页
There were two heavy rainstorms in Henan in July of 2016. Via MDOS and CDQC,quality control analysis of deep ground temperature at four stations of Henan with heavy rainstorm was conducted,and the cause for observatio... There were two heavy rainstorms in Henan in July of 2016. Via MDOS and CDQC,quality control analysis of deep ground temperature at four stations of Henan with heavy rainstorm was conducted,and the cause for observation data anomaly was analyzed and studied. Results showed that rainstorm made deep ground temperature rise,and ground temperature rise range in Huixian was the maximum,while ground temperature in Linzhou changed little. There were three kinds of causes for the problem: one was ground temperature casing pipe seepage or inlet; the other was rainfall causing bad line contact at automatic station; another was complex composition of surface soil layer of observation site,which might contain the element easy to heat or dissipate heat. These all could cause ground temperature abnormality when heavy rainfall happens or the problem of ground temperature changes too fast. It should use the original soil to build observation field,making ground temperature stable and reliable.It should notice if observation data was normal or not to avoid disaster occurrence when rainstorm occurred. 展开更多
关键词 RAINSTORM Deep ground temperature ABNORMALITY HENAN Research
下载PDF
In Situ Measurement of the Undisturbed Ground Temperature for Ground Source Heat Pump System 被引量:1
11
作者 周亚素 《Journal of Donghua University(English Edition)》 EI CAS 2008年第1期73-77,共5页
The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump(GSHP) systems.In this paper,the undisturbed ground temperatures measured in two different methods a... The undisturbed ground temperatures are important for design of the ground heat exchangers in ground source heat pump(GSHP) systems.In this paper,the undisturbed ground temperatures measured in two different methods are presented.The investigation was carried out in two cases.The temperature measured with the direct method is assumed to give the correct undisturbed ground temperature profile.The temperature measured with indirect method overestimates the undisturbed ground temperature by 2.1℃ and 1.7℃.This difference is mainly caused by the circulation pump and ambient air to the fluid.Therefore,the results that are decreased about 2℃ as compared with the indirect measured are recommended to estimate the undisturbed ground temperature in situ measuring.A smaller pump or deeper borehole or mild weather would result in a more correct temperature.Because the undisturbed ground temperature is affected by many factors.Whether or not these conclusions are correct to other areas,this would need further investigation. 展开更多
关键词 蒸汽泵 测量方法 地下温度 热分析
下载PDF
Relevant Analysis of Grassland Temperature and Ground Net Radiation in Guilin
12
作者 HUANG Lin CHENG Feng-juan 《Meteorological and Environmental Research》 CAS 2011年第6期11-13,18,共4页
[Objective] The aim was to study the relevance of grassland temperature and ground net radiation in Guilin.[Method] By dint of ground observation data and net radiation of national benchmark climate station in Guilin ... [Objective] The aim was to study the relevance of grassland temperature and ground net radiation in Guilin.[Method] By dint of ground observation data and net radiation of national benchmark climate station in Guilin from 2007 to 2009,the changes of grassland temperature and ground net radiation were expounded and their relations were pointed out.[Result] The annual changes trends of grassland temperature and ground net radiation in Guilin were basically the same.Monthly average maximum value all appeared in summer(July to August).Monthly average lowest value appeared in winter(December to next January);monthly average grassland temperature and monthly average ground net radiation had positive relation.Grassland temperature and ground net radiation had basically same distribution in four seasons.The average largest value of ground net radiation in summer was the largest and average smallest value was the smallest;the average largest value of ground net radiation in cloudy days was the smallest and average minimum value was the largest;the daily difference was the largest in sunny day and daily difference was the smallest in cloudy day.The daily changes trend of grassland temperature and ground net radiation in different weather state were basically the same;when it was sunny or cloudy,the daily largest value of grassland temperature and ground net radiation occurred between 15:00 and 19:00;when it was overcast,there was no distinct peak and daily changes.The largest value of the daily extreme value of grassland temperature and ground net radiation took place from 12:00 to 15:00.The daily lowest value took place from 20:00 to 07:00 on the next day.[Conclusion] The study provided reference for the analysis of temperature changes in Guilin. 展开更多
关键词 Grassland temperature ground net radiation Relevant analysis GUILIN China
下载PDF
Analysis of Relation between Variation Characteristics and Climatic Influencing Factors of Shallow Ground Temperature in Shijiazhuang
13
作者 Zhang Cuihua 《Meteorological and Environmental Research》 CAS 2014年第4期5-8,共4页
Based on the daily observation data of shallow ground temperature, total cloud cover, precipitation, evaporation capacity and frozen soil of 5 stations in Shijiazhuang from 1981 to 2010, using methods such as linear t... Based on the daily observation data of shallow ground temperature, total cloud cover, precipitation, evaporation capacity and frozen soil of 5 stations in Shijiazhuang from 1981 to 2010, using methods such as linear trend and complete correlation coefficient, relation between variation characteristics and climatic influencing factors of shallow ground temperature was analyzed to lay the foundation for studying impact factors of shallow ground temperature and provide references for daily maintenance of automatic observation business. The results showed that fluctuant variability and fluctuant range of mean shallow layer ground temperature in Shijiazhuang became smaller with soil layer being deeper for all years and seasons, and the fluctuant variability was maximal in spring and minimal in winter, while the fluctuant range was maximal in summer and minimal in winter; mean shallow layer ground temperature for all years had a warming trend with an obvious warming trend in winter, and warming range in winter was smaller and the extent was weaker with soil layer being deeper while a cooling trend occurred in summer; there was a coincident trend between total cloud cover at night and shallow ground temperature in winter, and between evaporation capacity and shallow ground temperature in summer, while there was an inconsistent trend between maximum depth of frozen soil, period of freezing weather and shallow ground temperature in winter, and between total cloud cover in the davtime, orecioitation and shallow around temperature in summer. 展开更多
关键词 Shallow ground temperature Variation characteristics Climate factors Relation analysis Shijiazhuang China
下载PDF
The Influence of Earth Temperature on the Dynamic Characteristics of Frozen Soil and the Parameters of Ground Motion on Sites of Permafrost 被引量:2
14
作者 WangLanmin ZhangDongli +2 位作者 WuZhijian MaWei LiXiaojun 《Earthquake Research in China》 2004年第1期1-12,共12页
Earth temperature is one of the most important factors influencing the mechanical properties of frozen soil. Based on the field investigation of the characteristics of ground deformation and ground failure caused by t... Earth temperature is one of the most important factors influencing the mechanical properties of frozen soil. Based on the field investigation of the characteristics of ground deformation and ground failure caused by the M S8 1 earthquake in the west of the Kunlun Mountain Pass, China, the influence of temperature on the dynamic constitutive relationship, dynamic elastic modulus, damping ratio and dynamic strength of frozen soil was quantitatively studied by means of the dynamic triaxial test. Moreover, the characteristics of ground motion on a permafrost site under different temperatures were analyzed for the four profiles of permafrost along the Qinghai Xizang(Tibet) Railway using the time histories of ground motion acceleration with 3 exceedance probabilities of the Kunlun Mountains area. The influences of temperature on the seismic displacement, velocity, acceleration and response spectrum on permafrost ground were studied quantitatively. A scientific basis was presented for earthquake disaster mitigation for engineering foundations, highways and underground engineering in permafrost areas. 展开更多
关键词 地温 电磁感应 冻土 动力学 地质调查 地震学
下载PDF
Calculation of gas content in coal seam influenced by in-situ stress grads and ground temperature 被引量:1
15
作者 王宏图 李时雨 +3 位作者 吴再生 杨晓峰 秦大亮 杜云贵 《Journal of Coal Science & Engineering(China)》 2002年第2期60-64,共5页
On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new cal... On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new calculating method of gas content in coal seam influenced by in situ stress grads and ground temperature. At the same time, the contrast of the measuring results of coal bed gas pressure with the computing results of coal bed gas pressure and gas content in coal seam in theory indicate that the computing method can well reflect the authenticity of gas content in coal seam,and will further perfect the computing method of gas content in coal seam in theory,and have important value in theory on analyzing gas content in coal seam and forecasting distribution law of gas content in coal seam in deep mine. 展开更多
关键词 煤层 地面温度 气体压力 裂隙 渗透性 吸附参数 瓦斯
下载PDF
Ground temperature variation and its response to climate change on the northern Tibetan Plateau
16
作者 GuoNing Wan MeiXue Yang XueJia Wang 《Research in Cold and Arid Regions》 CSCD 2021年第4期299-313,共15页
Ground temperature plays a significant role in the interaction between the land surface and atmosphere on the Tibetan Plateau(TP).Under the background of temperature warming,the TP has witnessed an accelerated warming... Ground temperature plays a significant role in the interaction between the land surface and atmosphere on the Tibetan Plateau(TP).Under the background of temperature warming,the TP has witnessed an accelerated warming trend in frozen ground temperature,an increasing active layer thickness,and the melting of underground ice.Based on high-resolution ground temperature data observed from 1997 to 2012 on the northern TP,the trend of ground temperature at each observation site and its response to climate change were analyzed.The results showed that while the ground temperature at different soil depths showed a strong warming trend over the observation period,the warming in winter is more significant than that in summer.The warming rate of daily minimum ground temperature was greater than that of daily maximum ground temperature at the TTH and MS3608 sites.During the study period,thawing occurred earlier,whereas freezing happened later,resulting in shortened freezing season and a thinner frozen layer at the BJ site.And a zero-curtain effect develops when the soil begins to thaw or freeze in spring and autumn.From 1997 to 2012,the average summer air temperature and precipitation in summer and winter from six meteorological stations along the Qinghai-Tibet highway also demonstrated an increasing trend,with a more significant temperature increase in winter than in summer.The ground temperature showed an obvious response to air temperature warming,but the trend varied significantly with soil depths due to soil heterogeneity. 展开更多
关键词 ground temperature soil freezing-thawing processes the Tibetan Plateau climate change
下载PDF
Ground and Shallow Ground Temperature Changes Trends in Sanhe City in 40 Years
17
作者 LIU Xiao-ying CHENG Xiao-hui 《Meteorological and Environmental Research》 2012年第1期18-20,25,共4页
[ Objective] The aim was to analyze the ground and shallow ground temperature trend in Sanhe in recent 40 years. [ Method] According to the annual and seasonal average ground temperature in 2010, by dint of line chart... [ Objective] The aim was to analyze the ground and shallow ground temperature trend in Sanhe in recent 40 years. [ Method] According to the annual and seasonal average ground temperature in 2010, by dint of line charts and trend diagram, the ground temperature in Sanhe City in recent 40 years was discussed. [ Result] The annual ground temperature, annual ground highest and lowest temperature in Sanhe City in recent 40 years was increasing. The lowest temperature in annual and seasonal surface temperature increased at fastest speed. The annual changes of the 5, 10, 15 and 20 cm ground temperature was decreasing and the 20 cm ground temperature decreased most significantly. In spring, the 5 -15 cm ground temperature increased and the 20 cm reduced. In summer, the 20 cm temperature decreased significantly. In autumn, the 10 cm ground temperature enhanced fastest. In winter, the 10 cm and 15 cm temperature increase rate was large and the 15 cm temperature increased fastest. [ Conclusion] The study provided reference for the influence of global warming on the ground and shallow ground temperature. 展开更多
关键词 Sanhe City The ground temperature The shallow ground temperature Trend analysis China
下载PDF
Air-Ground Temperature Coupling: Analysis by Means of Thermal Orbits
18
作者 Vladimir Cermak Louise Bodri 《Atmospheric and Climate Sciences》 2016年第1期112-122,共11页
Long-term measurements of air, near-surface (soil) and ground temperatures that were collected between 1994 and 2013 at the drill site of the Geothermal Climate Change Observatory (Prague) were analyzed to understand ... Long-term measurements of air, near-surface (soil) and ground temperatures that were collected between 1994 and 2013 at the drill site of the Geothermal Climate Change Observatory (Prague) were analyzed to understand the relationship between these variables and to reveal the mechanisms of heat transport at the land-atmosphere boundary layer. The 2D Thermal Orbit (TO) method was applied to detect regularities that were hidden in noisy and highly variable temperature time series. The results showed that the temperatures at shallow depths were affected by surface air temperature (SAT) variations on seasonal and annual time scales and could be regarded as an accurate proxy for low frequency temperature variations at the Earth’s surface. Only low-frequency/ high-amplitude surface temperature variations penetrate into the subsurface because of strong damping and the filtering effect of the ground surface. The borehole temperatures have good potential to capture temperature variations (periodicities) over long time scales that cannot be detected in the SAT series themselves because of the interference of higher frequency noise. The TO technique is a useful and powerful tool to quickly obtain diagnostics of the presence of long periodicities in borehole temperature time series. 展开更多
关键词 Thermal Orbits temperature Monitoring Air temperature vs ground temperature Climate Change Subsurface temperature
下载PDF
Analysis on Ground Temperature Changes and Thermal Effects of Duct-Ventilated Embankment of the Qinghai-Tibet Railway
19
作者 Niu Fujun Cheng Guodong Ma Lifeng 《工程科学(英文版)》 2006年第2期108-116,共9页
Cooling principle is adopted in roadbed constructions in permafrost regions on the Qinghai-Tibet Plateau for protecting the underlying permafrost. One way is to use duct-ventilated emban kment. Based on ground tempera... Cooling principle is adopted in roadbed constructions in permafrost regions on the Qinghai-Tibet Plateau for protecting the underlying permafrost. One way is to use duct-ventilated emban kment. Based on ground temperature data collected along experimental emban kments in Beiluhe section of the Qinghai-Tibet Railway, engineering effects of duct-ventilation for protection of the permafrost beneath the emban kment were studied. Analyses of ground temperature changes and heat inlux indicate that ventilation ducts effectively cool the soils surrounding the ducts in the emban kment and that yearly heat collection of the ambient soils appears as heat release. Permafrost behaviour beneath conventional emban kment and test emban kments with ducts installed at a high and low positions were studied to determine temperature-changing tendency during three years. Where the permafrost under the conventional emban kment and the duct high-positioned emban kment decreasingly absorbs heat during the period. The ground temperature of the permafrost under the conventional emban kment rises and that under the high-positioned emban kment decreases slightly. The temperature of the permafrost under the duct low-positioned emban kment decreased remarkable due to release of heat. These findings demonstrate that ventilated emban kments with low-positioned ducts produce beneficial temperature-controlling effects that actively cool the roadbed soils and keep the roadbed thermally stable. Accordingly, they were strongly recommended for use in the construction of emban kments in the permafrost regions on the plateau. 展开更多
关键词 青藏铁路 永久冻结带 管道通风堤防 热通量 地面温度变化 热效应
下载PDF
Average temperature calculation for straight single-row-piped frozen soil wall 被引量:7
20
作者 XiangDong Hu SiYuan She RuiZhi Yu 《Research in Cold and Arid Regions》 2011年第2期124-131,共8页
The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety manage- ment of artificial ground freezing engineering. It is the basis of calculating frozen s... The average temperature of frozen soil wall is an essential parameter in the process of design, construction, and safety manage- ment of artificial ground freezing engineering. It is the basis of calculating frozen soil's mechanical parameters, fiarther prediction of bearing capacity and, ultimately, safety evaluation of the frozen soil wall. Regarding the average temperature of sin- gle-row-piped frozen soil wall, this paper summarizes several current calculation methods and their shortcomings. Furthermore, on the basis of Bakholdin's analytical solution for the temperature field under straight single-row-piped freezing, two new calcula- tion models, namely, the equivalent trapezoid model and the equivalent triangle model, are proposed. These two approaches are used to calculate the average temperature of a certain cross section which indicates the condition of the whole frozen soil wall. Considering the possible parameter range according to the freezing pipe layout that might be applied in actual construction, this paper compares the average temperatures of frozen soil walls obtained by the equivalent trapezoid method and the equivalent tri- angle method with that obtained by numerical integration of Bakholdin's analytical solution. The results show that the discrepancies are extremely small and these two new approaches are better than currently prevailing methods. However, the equivalent triangle method boasts higher accuracy and a simpler formula compared with the equivalent trapezoid method. 展开更多
关键词 artificial ground freezing single-row-piped freezing frozen soil wall average temperature equivalent trapezoid method equivalent triangle method Bakholdin's solution
下载PDF
上一页 1 2 105 下一页 到第
使用帮助 返回顶部