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能源统计数据在企业能量平衡中的应用
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作者 郑成芳 《山东电力技术》 2014年第4期76-80,共5页
根据日常计量数据,采用统计分析的方法,以某电厂实际计量统计数据为例,编制出企业能量平衡表,绘制企业能源网络图。提出计量装置要求、统计分析原则与方法、企业能量平衡表编制原则与方法、企业能源网络图绘制原则与方法。
关键词 计量 统计 能量平衡表 能源网络图
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大型石化项目的能源网络图分析 被引量:3
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作者 侯凯锋 《石油炼制与化工》 CAS CSCD 北大核心 2012年第2期87-91,共5页
能量平衡表和能源网络图是分析项目能效水平高低的有效工具和方法。针对大型石化项目的用能特点,对能源网络图在石化项目的实际应用进行针对性分析和理论探讨,并籍此对项目能源利用的科学合理性进行分析评估。
关键词 石化项目 能量平衡表 能源网络图 节能评估
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苏里格南国际合作区节能设计及评估分析 被引量:2
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作者 薛岗 杨恒远 +1 位作者 张磊 王莉华 《石油石化节能》 2016年第2期46-51,12,共6页
依据国家发改委2010年6号令《固定资产投资项目节能评估和审查暂行办法》,对苏里格南国际合作区采用的"井下节流+井口注醇工艺、中低压集气工艺"等6项主要节能工艺,及往复式压缩机组、空气压缩机橇等6项主要节能设备的节能性... 依据国家发改委2010年6号令《固定资产投资项目节能评估和审查暂行办法》,对苏里格南国际合作区采用的"井下节流+井口注醇工艺、中低压集气工艺"等6项主要节能工艺,及往复式压缩机组、空气压缩机橇等6项主要节能设备的节能性能进行了计算和能效指标分析,对项目能源加工、转换和利用情况编制了能量平衡表和能量平衡图,计算了项目综合能耗指标,项目万元工业总产值综合能耗和万元工业增加值综合能耗,并与国内同类气田及当地"十二五"能耗指标进行了对比。对报告编制过程中涉及的天然气折标准煤计算、电力当量值和等价值、水消耗计算和工业增加值能耗计算等4方面参数选取进行了说明。最后提出了5点建议,希望对国内同类项目节能评估报告的编制起到一定参考和借鉴作用。 展开更多
关键词 节能评估 节能分析 综合能耗 折标系数 能量平衡 能量平衡表
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Estimation of the Land Surface Emissivity in the Hinterland of Taklimakan Desert 被引量:4
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作者 LIU Yong-qiang Ali MAMTIMIN +4 位作者 HUO Wen YANG Xing-hua LIU Xin-chun MENG Xian-yong HE Qing 《Journal of Mountain Science》 SCIE CSCD 2014年第6期1543-1551,共9页
An accurate accounting of land surface emissivity(ε) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets.Since ε is one of the important parameteriz... An accurate accounting of land surface emissivity(ε) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets.Since ε is one of the important parameterizations in land surface models(LSMs),accurate accounting also improves the accuracy of surface temperatures and sensible heat fluxes simulated by LSMs.In order to obtain an accurate emissivity,this paper focuses on estimating ε from data collected in the hinterland of Taklimakan Desert by two different methods.In the first method,ε was derived from the surface broadband emissivity in the 8–14 μm thermal infrared atmospheric window,which was determined from spectral radiances observed by field measurements using a portable Fourier transform infrared spectrometer,the mean ε being 0.9051.The second method compared the observed and calculated heat fluxes under nearneutral atmospheric stability and estimated ε indirectly by minimizing the root-mean-square difference between them.The result of the second method found a mean value of 0.9042,which is consistent with the result by the first method.Although the two methods recover ε from different field experiments and data,the difference of meanvalues is 0.0009.The first method is superior to the indirect method,and is also more convenient. 展开更多
关键词 Taklimakan Desert Land surface emissivity Thermal infrared spectra Surface temperature Heat flux
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Analysis of surface temperature bias over the Tibetan plateau in the CAS FGOALS-f3-L model 被引量:1
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作者 Yao Wu Yimin Liu +5 位作者 Jiandong Li Qing Bao Bian He Lei Wang Xiaocong Wang Jinxiao Li 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第1期69-75,共7页
The Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System atmospheric component model(FGOALS-f3-L)participated in Phase 6 of the Coupled Model Intercomparison Project,but its reproducibility of surf... The Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System atmospheric component model(FGOALS-f3-L)participated in Phase 6 of the Coupled Model Intercomparison Project,but its reproducibility of surface temperature(T_(s))over the Tibetan Plateau(TP)as a key climatically sensitive region remains unclear.This study evaluates the capability of FGOALS-f3-L in reproducing the climatological T_(s)over the TP relative to the Climate Forecast System Reanalysis.The results show that FGOALS-f3-L can reasonably capture the spatial pattern of T_(s)but underestimates the annual mean T_(s)for the whole TP.The simulated T_(s)for the whole TP shows a cold bias in winter and spring and a warm bias in summer and autumn.Further quantitative analysis based on the surface energy budget equation shows that the surface albedo feedback(SAF)term strongly contributes to the annual,winter,and spring mean cold bias in the western TP and to the warm bias in the eastern TP.Compared with the SAF term,the surface sensible and latent heat flux terms make nearly opposite contributions to the T_(s)bias and considerably offset the bias due to the SAF term.The cloud radiative forcing term strongly contributes to the annual and seasonal mean weak cold bias in the eastern TP.The longwave radiation term associated with the overestimated water vapor content accounts for a large portion of the warm bias over the whole TP in summer and autumn.Improving land surface and cloud processes in FGOALS-f3-L is critical to reduce the T_(s)bias over the TP. 展开更多
关键词 Tibetan Plateau Surface temperature FGOALS-f3-L Surface energy budget equation Cloud radiation
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Evapotranspiration Estimation Based on MODIS Products and Surface Energy Balance Algorithms for Land(SEBAL) Model in Sanjiang Plain,Northeast China 被引量:4
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作者 DU Jia SONG Kaishan +2 位作者 WANG Zongming ZHANG Bai LIU Dianwei 《Chinese Geographical Science》 SCIE CSCD 2013年第1期73-91,共19页
In this study,the Surface Energy Balance Algorithms for Land(SEBAL) model and Moderate Resolution Imaging Spectroradiometer(MODIS) products from Terra satellite were combined with meteorological data to estimate evapo... In this study,the Surface Energy Balance Algorithms for Land(SEBAL) model and Moderate Resolution Imaging Spectroradiometer(MODIS) products from Terra satellite were combined with meteorological data to estimate evapotranspiration(ET) over the Sanjiang Plain,Northeast China.Land cover/land use was classified by using a recursive partitioning and regression tree with MODIS Normalized Difference Vegetation Index(NDVI) time series data,which were reconstructed based on the Savitzky-Golay filtering approach.The MODIS product Quality Assessment Science Data Sets(QA-SDS) was analyzed and all scenes with valid data covering more than 75% of the Sanjiang Plain were selected for the SEBAL modeling.This provided 12 overpasses during 184-day growing season from May 1st to October 31st,2006.Daily ET estimated by the SEBAL model was misestimaed at the range of-11.29% to 27.57% compared with that measured by Eddy Covariance system(10.52% on average).The validation results show that seasonal ET from the SEBAL model is comparable to that from ground observation within 8.86% of deviation.Our results reveal that the time series daily ET of different land cover/use increases from vegetation on-going until June or July and then decreases as vegetation senesced.Seasonal ET is lower in dry farmland(average(Ave):491 mm) and paddy field(Ave:522 mm) and increases in wetlands to more than 586 mm.As expected,higher seasonal ET values are observed for the Xingkai Lake in the southeastern part of the Sanjiang Plain(Ave:823 mm),broadleaf forest(Ave:666 mm) and mixed wood(Ave:622 mm) in the southern/western Sanjiang Plain.The ET estimation with SEBAL using MODIS products can provide decision support for operational water management issues. 展开更多
关键词 EVAPOTRANSPIRATION Surface Energy Balance Algorithms for Land (SEBAL) Moderate Resolution Imaging Spectroradiome-ter (MODIS) products Sanjiang Plain China
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Understanding the Global Surface-Atmosphere Energy Balance in FGOALS-s2 through an Attribution Analysis of the Global Temperature Biases
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作者 YANG Yang REN Rong-Cai 《Atmospheric and Oceanic Science Letters》 CSCD 2015年第2期107-112,共6页
Based on an attribution analysis of the global mean temperature biases in the Flexible Global Ocean- AtmOsphere-Land System model, spectral version 2 (FGOALS-s2) through a coupled atmosphere-surface ch- mate feedb... Based on an attribution analysis of the global mean temperature biases in the Flexible Global Ocean- AtmOsphere-Land System model, spectral version 2 (FGOALS-s2) through a coupled atmosphere-surface ch- mate feedback-response analysis method (CFRAM), the model's global surface-atmosphere energy balance in boreal winter and summer is examined. Within the en- ergy-balance-based CFRAM system, the model temperature biases are attributed to energy perturbations resulting from model biases in individual radiative and non-radia- tive processes in the atmosphere and at the surface. The results show that, although the global mean surface tem- perature (Ts) bias is only 0.38 K in January and 1.70 K in July, and the atmospheric temperature (Ta) biases from the troposphere to the stratosphere are only around +3 K at most, the temperature biases due to model biases in rep- resenting the individual radiative and non-radiative proc- esses are considerably large (over -4-10 K at most). Spe- cifically, the global cold radiative Ts bias, mainly due to the overestimated surface albedo, is compensated for by the global warm non-radiative Ts bias that is mainly due to the overestimated downward surface heat fluxes. The model biases in non-radiative processes in the lower tro- posphere (up to 5-15 K) are relatively much larger than in upper levels, which are mainly responsible for the warm Ta biases there. In contrast, the global mean cold ira biases in the mid-to-upper troposphere are mainly dominated by radiative processes. The warm/cold Ta biases in the lower/upper stratosphere are dominated by non-radiative processes, while the warm ira biases in the mid-strato- sphere can be attributed to the radiative ozone feedback process. 展开更多
关键词 global surface-atmosphere energy balance temperature bias FGOALS-s2 CFRAM
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Effects of Periodical Salinity Fluctuation on the Growth, Molting, Energy Homeostasis and Molting-Related Gene Expression of Litopenaeus vannamei 被引量:1
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作者 ZHANG Dan GUO Xiantao +1 位作者 WANG Fang DONG Shuanglin 《Journal of Ocean University of China》 SCIE CAS 2016年第5期911-917,共7页
To determine the response of Litopenaeus vannamei to periodical salinity fluctuation, a 30-day experiment was conducted in laboratory. In this experiment, two salinity fluctuation amplitudes of 4(group S4) and 10(grou... To determine the response of Litopenaeus vannamei to periodical salinity fluctuation, a 30-day experiment was conducted in laboratory. In this experiment, two salinity fluctuation amplitudes of 4(group S4) and 10(group S10) were designed. The constant salinity of 30(group S0) was used as the control. Levels of shrimp growth, molting frequency(MF), cellular energy status(ATP, ADP and AMP), as well as the expression of genes encoding molt-inhibiting hormone(MIH), crustacean hyperglycemic hormone(CHH), ecdysteroid-regulated protein(ERP), and energy-related AMP-activated protein kinase(AMPK) were determined. The results showed that periodical salinity fluctuation significantly influenced all indicators except MF which ranged from 13.3% in group S10 to15.4% in group S4. In comparison with shrimps cultured at the constant salinity of 30, those in group S4 showed a significant elevation in growth rate, food conversion efficiency, cellular energy status, ERP and MIH gene transcript abundance, and a significant reduction in CHH and AMPK transcript abundance(P < 0.05). However, salinity fluctuation of 10 only resulted in a significant variation in MIH and CHH gene expression when compared to the control(P < 0.05). According to our findings, L. vannamei may be highly capable of tolerating salinity fluctuation. When ambient salinity fluctuated at approx. 4, the increased MF and energy stores in organisms may aid to promoting shrimp growth. 展开更多
关键词 salinity shrimp fluctuation transcript periodical AMPK ranged Molting abundance Periodical
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Relationship between Diabetes Mellitus and Food Balance in the Kingdom of Saudi Arabia
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作者 Aljabryn Dalai Hamad 《Journal of Agricultural Science and Technology(B)》 2013年第8期591-596,共6页
The present explanatory study was carried out to investigate the relation between diabetes mellitus and food balance in the Kingdom of Saudi Arabia during 2005-2010, using published data. This study was conducted to i... The present explanatory study was carried out to investigate the relation between diabetes mellitus and food balance in the Kingdom of Saudi Arabia during 2005-2010, using published data. This study was conducted to investigate the relationship between food balance and diabetes mellitus, using published data on food balances in the Kingdom of Saudi Arabia during 2005-2007, published by the Ministry of Agriculture in 2012 and Medical Technical papers and Scientific Reports published on Diabetes Mellitus in Saudi Arabia in an explanatory study. Food balance was calculated per capita and then its level of change was compared with changing of diabetes mellitus in the country. Results illustrated that Saudi citizen daily protein consumption (DPC) during 2005-2007 (g/capita/day) is higher than the average global consumption level of protein with 15.27%, daily fat consumption (DFC) with 24.56% and daily energy consumption (DEC) with 16.93% and increases than recommended level by International Nutrition Organizations (INO) with 56% for protein, 60.49% for fat and 27.37% for energy. On the other hand, DPC per capita in Saudi Arabia decreased during the period 2008-2010 from 88.3 g/day to 82.36 g/day. Moreover, DFC per capita in Saudi Arabia decreased during the period 2008-2010 from 3,247.90 Cal/capita/day to 3,176.43 Cal/capita/day, and daily energy consumption (DEC) of Saudi citizen increases than world consumption with 16.93%, while increases with 27.37% than INO. Despite this, DPC, DFC and DEC per capita in Saudi Arabia were still higher than world mean. On the other side, results illustrated that the number of diabetic patients in Saudi Arabia during the same period (2005-2010). The curve of diabetic patient's number in Saudi Arabia during 2005-2010 is regular ascending with increasing level ranged between 7.10% in 2005 and 12.44% in 2010. It is essential to devise Saudi National Programme to educate the public about the relation of food balances and diabetes, so it could be avoided, and provide citizens with healthy dietary balances tables. 展开更多
关键词 Diabetes mellitus food balance PROTEIN FAT energy Saudi Arabia.
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Modeling of Transient Thermal Conditions in Cutting
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作者 T. Augspurger F. Klocke +3 位作者 B. Dobbeler M. Brockmann S. Gierlings A. Lima 《Journal of Mechanics Engineering and Automation》 2017年第3期113-119,共7页
The thermal conditions like the temperature distribution and the heat fluxes during metal cutting have a major influence on the machinability, the tool lifetime, the metallurgical structure and thus the functionality ... The thermal conditions like the temperature distribution and the heat fluxes during metal cutting have a major influence on the machinability, the tool lifetime, the metallurgical structure and thus the functionality of the work piece. This in particular applies for manufacturing processes like milling, drilling and turning for high-value turbomachinery components like impellers, combustion engines and compressors of the aerospace and automotive industry as well as energy generation, which play a major role in modern societies. However, numerous analytical and experimental efforts have been conducted in order to understand the thermal conditions in metal cutting, yet many questions still prevail. Most models are based on a stationary point of view and do not include time dependent effects like in intensity and distribution varying heat sources, varying engagement conditions and progressive tool wear. In order to cover such transient physics an analytical approach based on Green's functions for the solution of the partial differential equations of unsteady heat conduction in solids is used to model entire transient temperature fields. The validation of the model is carried out in orthogonal cutting experiments not only punctually but also for entire temperature fields. For these experiments an integrated measurement of prevailing cutting force and temperature fields in the tool and the chip by means of high-speed thermography were applied. The thermal images were analyzed with regard to thermodynamic energy balancing in order to derive the heat partition between tool, chips and workpiece. The thus calculated heat flow into the tool was subsequently used in order to analytically model the transient volumetric temperature fields in the tool. The described methodology enables the modeling of the transient thermal state in the cutting zone and particular in the tool, which is directly linked to phenomena like tool wear and workpiece surface modifications. 展开更多
关键词 Metal cutting infrared thermography heat sources transient temperature fields model based on Green's functions.
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Simulation of the Bare Soil Surface Energy Balance at the Tongyu Reference Site in Semiarid Area of North China
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作者 ZHANG Xia 《Atmospheric and Oceanic Science Letters》 2010年第6期330-335,共6页
The performance of a I-D soil model in a semiarid area of North China was investigated using observational data from a cropland station at the Tongyu reference site of the Coordinated Enhanced Observing Period (CEOP... The performance of a I-D soil model in a semiarid area of North China was investigated using observational data from a cropland station at the Tongyu reference site of the Coordinated Enhanced Observing Period (CEOP) during the non-growing period, when the ground surface was covered with bare soil. Comparisons between simulated and observed soil surface energy balance components as well as soil temperatures and water contents were conducted to validate the soil model. Results show that the soil model could produce good simulations of soil surface temperature, net radiation flux, and sensible heat flux against observed values with the RMSE of 1.54℃, 7.71 W m^-2, and 27.79 W m^-2, respectively. The simulated volumetric soil water content is close to the observed values at various depths with the maximal difference between them being 0.03. Simulated latent heat and ground heat fluxes have relatively larger errors in relative to net radiation and sensible heat flux. In conclusion, the soil model has good capacity to simulate the bare soil surface energy balance at the Tongyu cropland station and needs to be further tested in longer period and at more sites in semiarid areas. 展开更多
关键词 energy balance bare soil semiarid areas
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Estimation of clear-sky longwave downward radiation from HJ-1B thermal data 被引量:5
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作者 YU ShanShan XIN XiaoZhou LIU QinHuo 《Science China Earth Sciences》 SCIE EI CAS 2013年第5期829-842,共14页
To satisfy the requirement of surface energy budget research on the meso- and micro-scale, a parameterization is developed to calculate high spatial resolution, clear-sky downward longwave radiation (DLR) from HJ-IB... To satisfy the requirement of surface energy budget research on the meso- and micro-scale, a parameterization is developed to calculate high spatial resolution, clear-sky downward longwave radiation (DLR) from HJ-IB thermal data. The DLR algorithm is established based on extensive radiative transfer simulation and statistical analysis. To address the problem that HJ-1B has a single thermal channel and lacks atmospheric information, the brightness temperature of HJ-1B and water vapor content are used in the algorithm. An accuracy evaluation and error analysis for the algorithm is conducted using a simulated radiation da- taset. The result shows that the algorithm performs well in most circumstances, but there is obvious underestimation when wa- ter vapor content is greater than 4 g/cm2. Error analysis indicates the accuracy of estimated DLRs is affected by uncertainties in input parameters, including water vapor content and top-of-atmosphere radiance. It is also affected by the difference between ground and near-surface air temperature. The algorithm is applied to actual HJ-1B data, and validated by ground data from six stations in the Heihe River and Haihe River basins. The estimated DLRs have good consistency with measured data except at Huazhaizi, and root mean square errors at most sites are around 20 W/m2, which is slightly better than the result of MODIS. There is significant overestimation of DLR at Huazhaizi during summer, which is mainly produced by the large ground-air temperature difference. A correction process based on temperature difference is proposed and applied at Huazhaizi. The result shows that the positive bias is largely diminished after correction. 展开更多
关键词 PARAMETERIZATIONS brightness temperature MODIS water vapor ground-air temperature difference correction
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Analysis of observations on the urban surface energy balance in Beijing 被引量:24
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作者 MIAO ShiGuang DOU JunXia +2 位作者 CHEN Fei LI Ju LI AiGuo 《Science China Earth Sciences》 SCIE EI CAS 2012年第11期1881-1890,共10页
The 1-year(2009-2010) measurements are analyzed of the urban surface energy balance(SEB) obtained from the sensors located at three vertical layers of a 325-m tower in downtown Beijing.Results show that:(1) The... The 1-year(2009-2010) measurements are analyzed of the urban surface energy balance(SEB) obtained from the sensors located at three vertical layers of a 325-m tower in downtown Beijing.Results show that:(1) The measurements from the 325-m tower represent the SEB characteristics of the cities located in semi-humid warm-temperate continental monsoon climate zone.In a typical hot and rainy summer,cold and dry winter,the measured Bowen ratio is minimum in summer and maximum in winter.The Bowen ratio measured at 140 m for spring,summer,autumn,and winter are 2.86,0.82,1.17,and 4.16 respectively.(2) At the height of 140-m(in the constant flux layer),the noontime albedo is ~0.10 for summer,~0.12 for spring and autumn,and ~0.14 for winter.The ratios of daytime sensible heat flux,latent heat flux,and storage heat flux to net radiation are 0.25,0.16,and 0.59 for clear-sky days,and 0.33,0.19,and 0.48 for cloudy days respectively.(3) Under clear-sky days,the nighttime sensible heat flux is almost zero,but the latent heat flux is greater than zero.For cloudy days,the nighttime sensible heat flux is slightly greater than the latent heat flux in winter.The nighttime upward heat flux is presumably due to the anthropogenic release(mainly latent heat for summer,while latent and sensible heat for winter). 展开更多
关键词 urban surface energy balance tower based observation eddy covariance technique Bowen ratio anthropogenic heat flux
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On the atmospheric movement and the imbalance of observed and calculated energy in the surface layer 被引量:5
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作者 ZUO HongChao XIAO Xia +3 位作者 YANG QiDong DONG LongXiang CHEN JiWei WANG ShuJin 《Science China Earth Sciences》 SCIE EI CAS 2012年第9期1518-1532,共15页
Based on existing researches,here we theoretically summarized the characteristics of the atmospheric movement and turbulent transport of energy and substance in the surface layer as well as the ideal and the actual mo... Based on existing researches,here we theoretically summarized the characteristics of the atmospheric movement and turbulent transport of energy and substance in the surface layer as well as the ideal and the actual models for the turbulent transport.Then,using the data observed with eddy covariance at the semiarid climate and environment monitoring station(SACOL) in Lanzhou University from May to October during four consecutive years(September 2006-August 2010),we conducted a detailed analysis of the turbulent transport in the surface layer,through introducing the relative vertical turbulence intensity to characterize the turbulence strength,RIw=wn(wn+U),and also by adopting the method for controlling data quality at different levels.Our conclusions are:(1) The turbulent transport of energy and substance in the surface layer must obey the law of conservation of energy and the law of conservation of matter,the observed and calculated energy in the surface layer must be balanced,or closed in theory,but the actual observed and calculated energy just approximates the ideal in some degree and is difficult to achieve the energy balance.(2) The energy closure rate depends much on the atmospheric state in the surface layer,and the energy closure rate increases generally with the relative vertical turbulence intensity.(3) By the way of controlling data quality at different levels,it is found that the degree of data quality control can affect the closure rate,but it does not change the fact that the energy closure rate depends on the atmospheric state.(4) The calculation method of surface soil heat flux can affect energy closure rate,but does not change its dependence on the atmospheric state. 展开更多
关键词 surface layer energy balance state relative vertical turbulence intensity turbulence transport data quality control
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Modification of the land surface energy balance relationship by introducing vertical sensible heat advection and soil heat storage over the Loess Plateau 被引量:14
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作者 ZHANG Qiang LI HongYu ZHAO JianHua 《Science China Earth Sciences》 SCIE EI CAS 2012年第4期580-589,共10页
Little is known about the surface energy balance problem for a complex underlying surface.Taking data from the Loess Plateau Land-surface Processes Experiment(LOPEX) and investigating the characteristics of the surfac... Little is known about the surface energy balance problem for a complex underlying surface.Taking data from the Loess Plateau Land-surface Processes Experiment(LOPEX) and investigating the characteristics of the surface energy balance over a complex underlying surface,this paper calculates the soil heat storage and vertical sensible heat advection,analyzes their contributions to the surface energy imbalance,and discusses the mechanism by which the vertical velocity and temperature gradient in the surface layer affect the vertical sensible heat advection transfer.We found that the vertical velocity in the surface layer provides the necessary dynamic power for vertical sensible heat advection,and a relatively strong temperature gradient is the energy source generating vertical sensible heat advection.Under an ascending condition,the effect of vertical sensible heat advection on the surface energy budget is more obvious.It is also found that when the soil heat storage term and the vertical sensible heat advection term are added to the energy balance equation,the imbalance significantly improves.The peak of average diurnal residuals decreases from 125.1 to 41.5 W m-2,the daily average absolute value of residuals falls from 59.0 to 26.4 W m-2,and the surface energy balance closure increases from 78.4% to 94.0%. 展开更多
关键词 land surface energy imbalance Loess Plateau vertical sensible heat advection soil heat storage vertical velocity tem-perature gradient
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Characteristics of land surface thermal-hydrologic processes for different regions over North China during prevailing summer monsoon period 被引量:28
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作者 ZHANG Qiang ZENG Jian ZHANG LiYang 《Science China Earth Sciences》 SCIE EI CAS 2012年第11期1872-1880,共9页
The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface... The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface thermal-hydrologic processes among the three regions were studied based on the normalization of major variables of land surface thermal-hydrologic processes,using data collected during prevailing summer monsoon period(July and August,2008).It is shown that differences of surface thermal-hydrologic processes are remarkable among the three regions because of different impacts of summer monsoon.Especially their soil wet layers occur at different depths,and the average albedo and its diurnal variations are distinctly different.Surface net short-wave radiation in the Loess Plateau is close to that in the cool Northeast China,but its surface net long-wave radiation is close to that in the arid Northwest China.And the ratio of net radiation to global solar radiation in the cool Northeast China is higher than the other two regions,though its temperature is lower.There are obvious regional differences in the ratios of surface sensible and latent heat fluxes to net radiation for the three regions because of distinct contribution of sensible and latent heat fluxesto land surface energy balance.The three regions are markedly different in the ratio of water vapor flux to pan evaporation,but they are consistent in the ratio of water vapor flux to precipitation.These results not only indicate different influences of climate and environmental factors on land surface thermal-hydrologic processes in the three regions,but also show that summer monsoon is important in the formation and variation of the pattern of land surface thermal-hydrologic processes. 展开更多
关键词 different regions of North China prevailing summer monsoon period coordinated experiment land surface thermalhydrologic processes influence factors
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Distribution and changes of active layer thickness(ALT) and soil temperature(TTOP) in the source area of the Yellow River using the GIPL model 被引量:15
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作者 LUO DongLiang JIN HuiJun +1 位作者 Sergei MARCHENKO Vladimir ROMANOVSKY 《Science China Earth Sciences》 SCIE EI CAS 2014年第8期1834-1845,共12页
Active layer thickness(ALT) is critical to the understanding of the surface energy balance, hydrological cycles, plant growth, and cold region engineering projects in permafrost regions. The temperature at the botto... Active layer thickness(ALT) is critical to the understanding of the surface energy balance, hydrological cycles, plant growth, and cold region engineering projects in permafrost regions. The temperature at the bottom of the active layer, a boundary layer between the equilibrium thermal state(in permafrost below) and transient thermal state(in the atmosphere and surface canopies above), is an important parameter to reflect the existence and thermal stability of permafrost. In this study, the Geophysical Institute Permafrost Model(GIPL) was used to model the spatial distribution of and changes in ALT and soil temperature in the Source Area of the Yellow River(SAYR), where continuous, discontinuous, and sporadic permafrost coexists with seasonally frozen ground. Monthly air temperatures downscaled from the CRU TS3.0 datasets, monthly snow depth derived from the passive microwave remote-sensing data SMMR and SSM/I, and vegetation patterns and soil properties at scale of 1:1000000 were used as input data after modified with GIS techniques. The model validation was carried out carefully with in-situ ALT in the SAYR interpolated from the field-measured soil temperature data. The results of the model indicate that the average ALT in the SAYR has significantly increased from 1.8 m in 1980 to 2.4 m in 2006 at an average rate of 2.2 cm yr–1. The mean annual temperature at the bottom of the active layer, or temperature at the top of permafrost(TTOP) rose substantially from –1.1°C in 1980 to –0.6°C in 2006 at an average rate of 0.018°C yr–1. The increasing rate of the ALT and TTOP has accelerated since 2000. Regional warming and degradation of permafrost has also occurred, and the changes in the areal extent of regions with a sub-zero TTOP shrank from 2.4×104 to 2.2×104 km2 at an average rate of 74 km2 yr–1. Changes of ALT and temperature have adversely affected the environmental stability in the SAYR. 展开更多
关键词 GIPL model active layer thickness TTOP degradation of permafrost
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Effects of different gap filling methods and land surface energy balance closure on annual net ecosystem exchange in a semiarid area of China 被引量:3
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作者 DU Qun LIU HuiZhi +1 位作者 FENG JianWu WANG Lei 《Science China Earth Sciences》 SCIE EI CAS 2014年第6期1340-1351,共12页
Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance ... Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange. 展开更多
关键词 the semiarid area NEE eddy covariance gap filling energy balance ratio
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Sensitivity experiments of impacts of large-scale urbanization in East China on East Asian winter monsoon 被引量:12
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作者 CHEN HaiShan ZHANG Ye 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第3期809-815,共7页
By using the global atmospheric general circulation model CAM4.0 including an urban canopy parameterization scheme,the possible impacts of large-scale urbanization in East China on East Asian winter monsoon was invest... By using the global atmospheric general circulation model CAM4.0 including an urban canopy parameterization scheme,the possible impacts of large-scale urbanization in East China on East Asian winter monsoon was investigated via idealized numerical experiments.Results suggest that large-scale urbanization can cause a significant warming effect in both surface temperature and air temperature near the surface over most areas of East China.Meanwhile,large-scale urbanization also alters the surface energy balance,causing evident increases in net surface long-wave radiation and sensible heat flux as well as intensified surface thermal heating to the atmosphere.Forced by the surface thermal heating anomalies induced by the large-scale urban expansion,East Asian winter monsoon circulation exhibits distinct changes.Overall,the extensive urbanization over East China will weaken East Asian winter monsoon,but intensify winter monsoon in northeast China. 展开更多
关键词 large-scale urbanization East Asian winter monsoon sensitivity experiment
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A thermal physical index to explore current tectonic activity with satellite remote sensing
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作者 CHEN ShunYun MA Jin +2 位作者 LIU PeiXun LIU LiQiang HU XiaoYan 《Science China Earth Sciences》 SCIE EI CAS 2012年第2期290-295,共6页
The use of satellite thermal infrared information is being developed as a method of exploring current tectonic activity. To realize real world application, an objective, stable and testable thermal physical index that... The use of satellite thermal infrared information is being developed as a method of exploring current tectonic activity. To realize real world application, an objective, stable and testable thermal physical index that is simultaneously related with tectonic activity must be established. From the viewpoint of the energy balance, the land surface is a boundary where energy is exchanged between outer space and the solid Earth. Regardless of how complex the influencing factors are, the land surface is mainly affected by the Sun, atmosphere and underground heat. In this paper, first, the relationships among land surface temperature, solar radiation, atmospheric temperature and thermal information from underground are obtained employing a mathematic physical method based on the equation of heat conduction and energy balance at the land surface. Second, a thermal physical index called the geothermal flux index (GFI), which can provide the activity state of underground heat, is constructed. Third, the theoretical basis of the thermal physical index is verified using stable annual variations in land surface temperature and solar radiation. Finally, combined with known crustal deformations derived using a global positioning system, the effectiveness of the GFI in extracting field tectonic motion is tested. The results indicate that the GFI is effective in providing information on current tectonic activity. 展开更多
关键词 current tectonic activity thermal physical index geothermal flux index remote sensing
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