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2022, 14 (4) 发布日期: 2022-08-31 上一期
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  • Soil freezing process and different expressions for the soil-freezing characteristic curve
  • JunPing Ren, Sai K. Vanapalli, Zhong Han
  • DOI:10.3724/SP.J.1226.2017.00221
  • 2017, 9 (3): 221–228 摘要 (626) PDF (4411 KB) (829)
  • The soil-freezing characteristic curve (SFCC), which represents the relationship between unfrozen water content and sub-freezing temperature (or suction at ice-water interface) in a freezing soil, can be used for understanding the transportation of heat, water, and solute in frozen soils. In this paper, the soil freezing process and the similarity between the SFCC of saturated frozen soil and soil-water characteristic curve (SWCC) of unfrozen unsaturated soil are reviewed. Based on similar characteristics between SWCC and SFCC, a conceptual SFCC is drawn for illustrating the main features of soil freezing and thawing processes. Various SFCC expressions from the literature are summarized. Four widely used expressions (i.e., power relationship, exponential relationship, van Genuchten 1980 equation and Fredlund and Xing 1994 equation) are evaluated using published experimental data on four different soils (i.e., sandy loam, silt, clay, and saline silt). Results show that the exponential relationship and van Genuchten (1980) equation are more suitable for sandy soils. The simple power relationship can be used to reasonably best-fit the SFCC for soils with different particle sizes; however, it exhibits limitations when fitting the saline silt data. The Fredlund and Xing (1994) equation is suitable for fitting the SFCCs for all soils studied in this paper.
  • Light-absorbing impurities on Keqikaer Glacier in western Tien Shan: concentrations and potential impact on albedo reduction
  • YuLan Zhang, ShiChang Kang, Min Xu, Michael Sprenger, TanGuang Gao, ZhiYuan Cong, ChaoLiu Li, JunMing Guo, ZhiQiang Xu, Yang Li, Gang Li, XiaoFei Li, YaJun Liu, HaiDong Han
  • DOI:10.3724/SP.J.1226.2017.00097
  • 2017, 9 (2): 97–111 摘要 (259) PDF (1325 KB) (676)
  • Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western Tien Shan, Central Asia, was measured. We found that the average concentrations of black carbon was 2,180 ng/g, with a range from 250 ng/g to more than 10,000 ng/g. The average concentrations of organic carbon and mineral dust were 1,738 ng/g and 194 μg/g, respectively. Based on simulations performed with the Snow Ice Aerosol Radiative model simulations, black carbon and dust are responsible for approximately 64% and 9%, respectively, of the albedo reduction, and are associated with instantaneous radiative forcing of 323.18 W/m2 (ranging from 142.16 to 619.25 W/m2) and 24.05 W/m2 (ranging from 0.15 to 69.77 W/m2), respectively. For different scenarios, the albedo and radiative forcing effect of black carbon is considerably greater than that of dust. The estimated radiative forcing at Keqikaer Glacier is higher than most similar values estimated by previous studies on the Tibetan Plateau, perhaps as a result of black carbon enrichment by melt scavenging. Light-absorbing impurities deposited on Keqikaer Glacier appear to mainly originate from central Asia, Siberia, western China (including the Taklimakan Desert) and parts of South Asia in summer, and from the Middle East and Central Asia in winter. A footprint analysis indicates that a large fraction (>60%) of the black carbon contributions on Keqikaer Glacier comes from anthropogenic sources. These results provide a scientific basis for regional mitigation efforts to reduce black carbon.
  • Comparative study of probable maximum precipitation and isohyetal maps for mountainous regions, Pakistan
  • Muhammad Waseem Boota, Ghulam Nabi, Tanveer Abbas, HuiJun Jin, Ayesha Yousaf, Muhammad Azeem Boota
  • DOI:10.3724/SP.J.1226.2018.00055
  • 2018, 10 (1): 55–68 摘要 (423) PDF (4789 KB) (629)
  • Probable maximum precipitation (PMP) is widely used by hydrologists for appraisal of probable maximum flood (PMF) used for soil and water conservation structures, and design of dam spillways. A number of methods such as empirical, statistical and dynamic are used to estimate PMP, the most favored being statistical and hydro-meteorological. In this paper, PMP estimation in mountainous regions of Pakistan is studied using statistical as well as physically based hydro-meteorological approaches. Daily precipitation, dew point, wind speed and temperature data is processed to estimate PMP for a one-day duration. Maximum precipitation for different return periods is estimated by using statistical approaches such as Gumble and Log-Pearson type-III (LP-III) distribution. Goodness of fit (GOF) test, chi-square test, correlation coefficient and coefficient of determination were applied to Gumble and LP-III distributions. Results reveal that among statistical approaches, Gumble distribution performed the best result compared to LP-III distribution. Isohyetal maps of the study area at different return periods are produced by using the GIS tool, and PMP in mountainous regions varies from 150 to 320 mm at an average value of 230.83 mm. The ratio of PMP for one-day duration to highest observed rainfall (HOR) varied from 1.08 to 1.29 with an average value of 1.18. An appropriate frequency factor (Km) is very important which is a function of mean for observed precipitation and PMP for 1-day duration, and Km values varies from 2.54 to 4.68. The coefficient of variability (Cv) varies from minimum value of 28% to maximum value of 43.35%. It was concluded that the statistical approach gives higher results compared to moisture maximization (MM) approach. In the hydro-meteorological approach, moisture maximization (MM) and wind moisture maximization (WMM) techniques were applied and it was concluded that wind moisture maximization approach gives higher results of PMP as compared to moisture maximization approach as well as for Hershfield technique. Therefore, it is suggested that MM approach is the most favored in the study area for PMP estimation, which leads to acceptable results, compared to WMM and statistical approaches.
  • Cutting of Phragmites australis as a lake restoration technique: Productivity calculation and nutrient removal in Wuliangsuhai Lake, northern China
  • Jan Felix Köbbing, Niels Thevs, Stefan Zerbe
  • DOI:10.3724/SP.J.1226.2016.00400
  • 2016, 8 (5): 400–410 摘要 (322) PDF (2545 KB) (602)
  • Reed is one of the most frequent and dominant species in wetlands all over the world, with common reed (Phragmites australis (Cav.) Trin. ex Steud.) as the most widely distributed species. In many wetlands, P. australis plays a highly ambivalent role. On the one hand, in many wetlands it purifies wastewater, provides habitat for numerous species, and is a potentially valuable raw material, while on the other hand it is an invasive species which expands aggressively, prevents fishing, blocks ditches and waterways, and builds monospecies stands. This paper uses the eutrophic reed-swamp of Wuliangsuhai Lake in Inner Mongolia, northern China, as a case to present the multiple benefits of regular reed cutting. The reed area and aboveground biomass production are calculated based on field data. Combined with data about water and reed nutrient content, the impact of reed cutting on the lake nutrient budget (N and P) is investigated. Currently, at this lake around 100,000 tons of reed are harvested in winter annually, removing 16% and 8% of the total nitrogen and phosphorus influx, respectively. Harvesting all available winter reed could increase the nutrient removal rates to 48% and 24%, respectively. We also consider the effects of summer harvesting, in which reed biomass removal could overcompensate for the nutrient influx but could potentially reduce reed regrowth.
  • Research on pile performance and state-of-the-art practice in cold regions
  • JianKun Liu, TengFei Wang, Zhi Wen
  • DOI:10.3724/SP.J.1226.2018.00001
  • 2018, 10 (1): 1–11 摘要 (1031) PDF (3430 KB) (563)
  • A pile foundation is commonly adopted in geotechnical engineering to support structures, and its application has been extended to cold-regions engineering. In past decades, a host of scholars investigated pile behaviors and proposed design guidelines for seasonally frozen ground or permafrost. This paper reviews the research with respect to pile performance and engineering practice in cold regions, organized as follows: (1) creep tests and bearing capacity, (2) frost-jacking hazards, (3) laterally loaded piles, (4) dynamic responses, (5) refreezing due to concrete-hydration heat, and (6) improved countermeasures and design methods. We first summarize previous research and recent progress; then, predict the development trend of pile foundations in cold regions and recommend further research.
  • Surface-deformation monitoring in the permafrost regions over the Tibetan Plateau, using Sentinel-1 data
  • ZhenMing Wu, Lin Zhao, Lin Liu, Rui Zhu, ZeShen Gao, YongPing Qiao, LiMing Tian, HuaYun Zhou, MeiZhen Xie
  • DOI:10.3724/SP.J.1226.2018.00114
  • 2018, 10 (2): 114–125 摘要 (438) PDF (2925 KB) (553)
  • Differential Interferometric Synthetic Aperture Radar (D-InSAR) has been widely used to measure surface deformation over the Tibetan Plateau. However, the accuracy and applicability of the D-InSAR method are not well estimated due to the lack of in-situ validation. In this paper, we mapped the seasonal and long-term displacement of Tanggula (TGL) and Liangdaohe (LDH) permafrost regions with a stack of Sentinel-1 acquisitions using the Small Baseline Subset InSAR (SBAS-InSAR) method. In the TGL region, with its dry soils and sparse vegetation, the InSAR-derived surface-deformation trend was consistent with ground-based leveling results; long-term changes of the active layer showed a settlement rate of around 1 to 3 mm/a due to the melting of ground ice, indicating a degrading permafrost in this area. Around half of the deformation was picked up on monitoring, in contrast with in-situ measurements in LDH, implying that the D-InSAR method remarkably underestimated the surface-deformation. This phenomenon may be induced by the large soil-water content, high vegetation coverage, or a combination of these two factors in this region. This study demonstrates that surface deformation could be mapped accurately for a specific region with Sentinel-1 C-band data, such as in the TGL region. Moreover, although the D-InSAR technology provides an efficient solution for broad surface-deformation monitoring in permafrost regions, it shows a poor performance in the region with high soil-water content and dense vegetation coverage.
  • Characteristics of land-atmosphere energy and turbulent fluxes over the plateau steppe in central Tibetan Plateau
  • MaoShan Li, ZhongBo Su, YaoMing Ma, XueLong Chen, Lang Zhang, ZeYong Hu
  • DOI:10.3724/SP.J.1226.2016.00103
  • 2016, 8 (2): 103–115 摘要 (228) PDF (676 KB) (538)
  • The land-atmosphere energy and turbulence exchange is key to understanding land surface processes on the Tibetan Plateau(TP).Using observed data for Aug.4 to Dec.3,2012 from the Bujiao observation point(BJ) of the Nagqu Plateau Climate and Environment Station(NPCE-BJ),different characteristics of the energy flux during the Asian summer monsoon(ASM) season and post-monsoon period were analyzed.This study outlines the impact of the ASM on energy fluxes in the central TP.It also demonstrates that the surface energy closure rate during the ASM season is higher than that of the post-monsoon period.Footprint modeling shows the distribution of data quality assessments(QA) and quality controls(QC) surrounding the observation point.The measured turbulent flux data at the NPCE-BJ site were highly representative of the target land-use type.The target surface contributed more to the fluxes under unstable conditions than under stable conditions.The main wind directions(180°and 210°) with the highest data density showed flux contributions reaching 100%,even under stable conditions.The lowest flux contributions were found in sectors with low data density, e.g.,90.4% in the 360°sector under stable conditions during the ASM season.Lastly,a surface energy water balance(SEWAB) model was used to gap-fill any absent or corrected turbulence data.The potential simulation error was also explored in this study.The Nash-Sutcliffe model efficiency coefficients(NSEs) of the observed fluxes with the SEWAB model runs were 0.78 for sensible heat flux and 0.63 for latent heat flux during the ASM season,but unrealistic values of-0.9 for latent heat flux during the post-monsoon period.
  • Proline and soluble sugars accumulation in three pepper species (Capsicum spp) in response to water stress imposed at different stages of growth
  • Gideon O. Okunlola, Richard O. Akinwale, Adekunle A. Adelusi
  • DOI:10.3724/SP.J.1226.2016.00205
  • 2016, 8 (3): 205–211 摘要 (481) PDF (325 KB) (524)
  • Drought is a major production constraint for major fruits and vegetable crops in the tropics.This study was conducted to investigate the effect of limited water supply at three growth stages (vegetative,flowering and fruiting) on the accumulation of proline and soluble sugars in three pepper species.Seeds of the three pepper species,Capsicum chinense Jacq.,C.annuum L.and C.frutescens L.were raised in a nursery and the seedlings were transplanted into seventy two plastic pots arranged in a randomized complete block design with three replicates,25 days after planting.Four water treatments,200 mL of water supplied twice daily (W1),once in every three days (W2),once in every five days (W3),and zero water supplied throughout growing period (W0) were imposed at three vegetative,flowering,and fruiting growth stages.Data were collected on relative water content,free proline and total soluble sugar.Data collected were subjected to analysis of variance and means were separated using Duncan's multiple range test.Results show that the concentration of proline and soluble sugar in leaves of the three pepper species were found to be remarkable at the different stages of growth in the stressed plants.
  • Spatiotemporal change of carbon storage in the Loess Plateau of northern Shaanxi, based on the InVEST Model
  • ShaoYang Liu, NingKe Hu, Jin Zhang, ZhiChao Lv
  • DOI:10.3724/SP.J.1226.2018.00240
  • 2018, 10 (3): 240–250 摘要 (442) PDF (3607 KB) (519)
  • In recent years, land use and land cover have under gone tremendous change on the Loess Plateau, leading to temporal and spatial variation over many ecological factors, such as carbon storage. Based on four series of land-use data from remote-sensing imaging, spatiotemporal changes of land-use types and volume changes were analyzed. Combined with carbon-stock-assessment modules of the InVEST (integrated valuation ecosystem services and tradeoffs) model, the carbon-storage change was estimated and analyzed at the subcounty and subbasin scales. The results show that (1) cultivated land and grassland area decreased, while woodland and urban land area increased in northern Shaanxi; (2) the average carbon storage in Huangling County and the Beiluo River Basin is the largest, while that of Yuyang County and the Xinshui River Basin is the minimum, and that of Wuqi County showed the greatest growth; (3) carbon storage in the study area showed a definite decrease in 2000, but in general has increased from 1995 to 2010; (4) carbon-storage figures of subbasins and counties are all restricted by the natural status and land-use landscape of the whole study area. From the results, it can be seen that the effect of ecological policies is remarkable. This study has important implications for the rational planning of land use, adjustment of the ecosystem carbon cycle, and related policies.
  • Cracking in an expansive soil under freeze–thaw cycles
  • Yang Lu, SiHong Liu
  • DOI:10.3724/SP.J.1226.2017.00392
  • 2017, 9 (4): 392–397 摘要 (501) PDF (2977 KB) (490)
  • Expansive soils located in cold regions can easily endure the action of frost heaving and cyclic freezing–thawing. Cracking can also occur in expansive clayey soils under freeze–thaw cycles, of which little attention has been paid on this issue. In this study, laboratory experiment and cracking analysis were performed on an expansive soil. Crack patterns were quantitatively analyzed using the fractal concept. The relationships among crack pattern, water loss, number of freeze–thaw cycles, and fractal dimension were discussed. It was found that crack patterns on the surface exhibit a hierarchical network structure that is fractal at a statistical level. Cracks induced by freeze–thaw cycles are shorter, more irregularly oriented, and slowly evolves from an irregularly rectilinear pattern towards a polygonal or quasi–hexagonal one; water loss, closely related to specimen thickness, plays a significant role in the process of soil cracking; crack development under freeze-thaw cycles are not only attributed to capillary effect, but also to expansion and absorption effects.
  • The mass-balance characteristics and sensitivities to climate variables of Laohugou Glacier No. 12, western Qilian Mountains, China
  • JiZu Chen, ShiChang Kang, Xiang Qin, WenTao Du, WeiJun Sun, YuShuo Liu
  • DOI:10.3724/SP.J.1226.2017.00543
  • 2017, 9 (6): 543–553 摘要 (383) PDF (3481 KB) (487)
  • Due to global warming, glaciers on the Tibetan Plateau (TP) are experiencing widespread shrinkage; however, the mechanisms controlling glacier variations across the TP are still rather unclear, especially on the northeastern TP. In this study, a physically based, distributed surface-energy and mass-balance model was used to simulate glacier mass balance forced by meteorological data. The model was applied to Laohugou No. 12 Glacier, western Qilian Mountains, China, during 2010~2012. The simulated albedo and mass balance were validated and calibrated by in situ measurements. The simulated annual glacier-wide mass balances were -385 mm water equivalent (w.e.) in 2010/2011 and -232 mm w.e. in 2011/2012, respectively. The mean equilibrium-line altitude (ELA) was 5,015 m a.s.l., during 2010~2012, which ascended by 215 m compared to that in the 1970s. The mean accumulation area ratio (AAR) was 39% during the two years. Climatic-sensitivity experiments indicated that the change of glacier mass balance resulting from a 1.5 ℃ increase in air temperature could be offset by a 30% increase in annual precipitation. The glacier mass balance varied linearly with precipitation, at a rate of 130 mm w.e. per 10% change in total precipitation.
  • Laboratory and field performance of recycled aggregate base in a seasonally cold region
  • Tuncer B. Edil, Bora Cetin, Ali Soleimanbeigi
  • DOI:10.3724/SP.J.1226.2017.00183
  • 2017, 9 (3): 183–191 摘要 (450) PDF (757 KB) (482)
  • The objective of this project was to characterize the freeze-thaw properties of recycled concrete (RCA) and asphalt (RAP) as unbound base and to assess how they behaved in the field for nearly 8 years. This paper includes an examination of existing information, laboratory studies of freeze-thaw behavior, and evaluation of data from MnROAD field-test sections in a seasonally cold region, i.e., in Minnesota, USA. Test sections were constructed using recycled materials in the granular base layers at the MnROAD test facility. One test section included 100% RAP, another 100% RCA, a third one a 50/50 blend of RCA/natural aggregate, and a fourth one only natural aggregate (Class 5) as a control. The stiffness (i.e., elastic modulus) was monitored during construction and throughout the pavement life by the Minnesota Department of Transportation, along with the variation of temperatures and moisture regimes in the pavement to determine their effects on pavement performance. The resilient modulus of each material was determined by bench-scale testing in accordance with NCHRP 1-28a, as well as by field-scale tests incorporating a falling-weight deflectometer. Specimens were subjected to as many as 20 cycles of freeze-thaw in the laboratory, and the change in their resilient modulus was measured. In the field-test sections constructed with the same materials as the base course, temperature, moisture, and field modulus (from falling-weight deflectometer tests) were monitored seasonally for nearly 8 years. From the temperatures in the base course layer, the number of freeze-thaw cycles experienced in the field was determined for each test section. Inferences were made relative to modulus change versus freeze-thaw cycles. Conclusions were drawn for long-term field performances of the recycled base (RAB) in comparison to natural aggregate.
  • High-resolution mass spectrometric characterization of dissolved organic matter from warm and cold periods in the NEEM ice core
  • JianZhong Xu, Amanda Grannas, CunDe Xiao, ZhiHeng Du, Amanda Willoughby, Patrick Hatcher, YanQing An
  • DOI:10.3724/SP.J.1226.2018.00038
  • 2018, 10 (1): 38–46 摘要 (450) PDF (3711 KB) (479)
  • Dissolved organic matter (DOM) is an important component of ice cores but is currently poorly characterized. DOM from one Holocene sample (HS, aged at 1600-4500 B.P.) and one Last Glacial Maximum sample (LS, aged at 21000-25000 B.P.) from the North Greenland Eemian Ice Drilling (NEEM) ice core were analyzed by ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). CHO compounds contributed 50% of the compounds identified in negative-ionization mode in these two samples, with significant contributions from organic N, S, and P compounds, likely suggesting that marine DOM was an important source in these samples. Overall, the chemical compositions are similar between these two samples, suggesting their consistent DOM sources. However, subtle differences in the DOM between these two samples are apparent and could indicate differences in source strength or chemistry occurring through both pre- and post-depositional processes. For example, higher relative amounts of condensed carbon compounds in the HS DOM (5%), compared to the LS DOM (2%), suggest potentially important contributions from terrestrial sources. Greater incorporation of P in the observed DOM in the LS DOM (22%), compared to the HS DOM (13%), indicate more active microbiological processes that likely contribute to phosphorus incorporation into the DOM pool. Although these two samples present only a preliminary analysis of DOM in glacial/interglacial periods, the data indicate a need to expand the analysis into a broader range of ice-core samples, geographical locations, and glacial/interglacial periods.
  • Photosynthetic pigments accumulation and some growth indices of cowpea, maize and tomato in response to interspecific and intraspecific competition stress
  • Ezekiel Dare Olowolaju, Adekunle Ajayi Adelusi
  • DOI:10.3724/SP.J.1226.2017.00120
  • 2017, 9 (2): 120–126 摘要 (473) PDF (2148 KB) (475)
  • This study aimed at investigating the photosynthetic pigment accumulation and some growth indices of cowpea, maize and tomato in response to interspecific and intraspecific competition stress. The study was carried out under a screen-house to minimize extraneous factors such as pests and rodents using a randomized complete block design (RCBD). Seeds of cowpea, maize and tomato were collected from the Department of Crop Production and Protection, Faculty of Agriculture, Obafemi Awolowo University, Ile Ife, Osun state, Nigeria. These seeds were planted at a depth of about 3 mm below the soil. The seeds were sown at the rate of six seeds per pot in the monoculture, while in the pots designed for the mixed culture of maize and cowpea, maize and tomato, cowpea and tomato, three seeds of each plant were sown. Two seeds of each plant were sown in the pots with the three crops. The treatments were then supplied with 500 mL of tap water in the morning and in the evening respectively until the seedlings become fully established. The photosynthetic pigments were determined spectrophotometrically with three replicates. Plant growth indices were determined according to Hunts (1978) using leaf area and dry matter data collected at four and six weeks after planting. Statistical analysis was performed using statistical analytical software SAS version 9.2. The results indicated that photosynthetic pigments accumulation (Chlorophyll a, b and carotenoid) in maize (15.98, 23.92 and 44.72 μM), Chlorophyll b and carotenoid in tomato plants (12.48 and 1,178.7 μM) in the sole stands were more than the mixed culture of maize with cowpea and tomato (7.195, 14.74 and 0.00 μM). Also, total Chlorophyll in maize (1,127.8 μM), Chlorophyll a and total Chlorophyll in tomato (3.95 and 1,317.5 μM) in the mixed culture were more than in the sole culture of maize (1,030.9 μM) and tomato plants (-9.40 and 546.3 μM). The different photosynthetic pigments accumulated in cowpea were greatly enhanced in the mixed culture than in the sole culture. All the photosynthetic pigments of maize, cowpea and tomato in all the treatments analysed in this study were significantly different at P>0.05. Plant growth indices such as net assimilation rate, relative growth rate, crop growth rate and tissue water contents of these plants had higher value in the intercropped than the check crop (sole). These plant growth indices were significantly different to one another at P>0.05. This study concluded that competition for shared resources in the mixed culture of tomato, maize and cowpea enhanced growth and accumulation of photosynthetic pigments.
  • Influence of fines content on the anti-frost properties of coarse-grained soil
  • TianLiang Wang, ZuRun Yue, TieCheng Sun, JinChuang Hua
  • DOI:10.3724/SP.J.1226.2015.00407
  • 2015, 7 (4): 407–413 摘要 (384) PDF (4001 KB) (474)
  • This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows:(1) the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; (2) the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; (3) with increasing numbers of freeze-thaw cycles,the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engineering design values; and (4) considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway subgrade coarse-grained soil fillings in frozen regions.