Impacts of surface soil organic content on the soil thermal dynamics of alpine meadows in permafrost regions: data from field observations

Geoderma ◽  
2014 ◽  
Vol 232-234 ◽  
pp. 414-425 ◽  
Author(s):  
Genxu Wang ◽  
Tianxu Mao ◽  
Juan Chang ◽  
Jizeng Du
2012 ◽  
Vol 252 ◽  
pp. 433-437
Author(s):  
Zhi Yang Yuan

The ground-source heat pump is a system which takes the shallow surface soil energy as the source of heating and cooling. The temperature of ground source is relatively stable throughout the year, which makes the ground-source heat pump have the higher operation efficiency compared with the traditional air-conditioning system.Study on the ground-source heat pump with properties of thermal dynamics used in heating and air comditioning by ecomomic analysis is still an important issue. In this paper, the ground-source heat pump and the traditional heating and air-conditioning system have been compared in terms of their economic competitiveness. Firstly, it is required to compare the ground-source heat pump with the traditional heating method in terms of the heating economy. Afterwards, it is necessary to compare the ground-source heat pump with the conventional electric refrigeration in terms of the air-conditioning economy. Finally, it is needed to conduct the comprehensive and economic analysis for the ground-source heat pump and the boilers and air conditioning, which includes four programs.


2019 ◽  
Vol 11 (4) ◽  
pp. 416 ◽  
Author(s):  
Cheng Yang ◽  
Tonghua Wu ◽  
Jiemin Wang ◽  
Jimin Yao ◽  
Ren Li ◽  
...  

The ground surface soil heat flux (G0) quantifies the energy transfer between the atmosphere and the ground through the land surface. However; it is difficult to obtain the spatial distribution of G0 in permafrost regions because of the limitation of in situ observation and complication of ground surface conditions. This study aims at developing an improved G0 parameterization scheme applicable to permafrost regions of the Qinghai-Tibet Plateau under clear-sky conditions. We validated several existing remote sensing-based models to estimate G0 by analyzing in situ measurement data. Based on the validation of previous models on G0; we added the solar time angle to the G0 parameterization scheme; which considered the phase difference problem. The maximum values of RMSE and MAE between “measured G0” and simulated G0 using the improved parameterization scheme and in situ data were calculated to be 6.102 W/m2 and 5.382 W/m2; respectively. When the error of the remotely sensed land surface temperature is less than 1 K and the surface albedo measured is less than 0.02; the accuracy of estimates based on remote sensing data for G0 will be less than 5%. MODIS data (surface reflectance; land surface temperature; and emissivity) were used to calculate G0 in a 10 x 10 km region around Tanggula site; which is located in the continuous permafrost region with long-term records of meteorological and permafrost parameters. The results obtained by the improved scheme and MODIS data were consistent with the observation. This study enhances our understanding of the impacts of climate change on the ground thermal regime of permafrost and the land surface processes between atmosphere and ground surface in cold regions.


2020 ◽  
Vol 21 (1) ◽  
pp. 125-130
Author(s):  
Nyoman Sumawijaya ◽  
Asep Mulyono ◽  
Anna Fadliah Rusydi

ABSTRACTThe leather tanning industry in Sukaregang, Garut Regency, produces liquid waste containing Chromium and is discharged directly into the Ciwalen River without a waste treatment process. The content of Cr6+ as metal ions in the waste can also contaminating groundwater. The movement of Cr6+ will pass through the soil media before entering to the groundwater wells. The capability of the soil to adsorb the contaminant will reduce the impact on groundwater. The purpose of this study was to determine the ability of the soil in adsorbing and inhibiting the movement of Cr6+ into groundwater. The study was carried out at Sukaregang, Garut Regency and conducting adsorption experiments with a batch system. The analysis was carried out using the Langmuir and Freundlich isotherm model. The experimental results showed that Cr6+ adsorbed ranged from 38% to 57% of the initial concentration. The results from Langmuir Isotherm were: the distribution coefficient (Kads) was 0.45 L/mg and the maximum adsorption capacity (qm) was 2.44 mg/100g sorbent with R2 = 0.959 and Freundlich Isotherm was: qm was 2,86 mg/100g sorbent and Kads was 0,35 L/mg with R2 = 0,860. This large adsorption capacity is caused by soil texture and soil organic content. The soil in Sukaregang tanning industries has a high adsorption capacity towards Cr6+ contaminants.Keywords: adsorption, chromium, Cr6+, contaminant, volcanic soil, GarutABSTRAKIndustri penyamakan kulit di wilayah Sukaregang, Kabupaten Garut, menghasilkan limbah cair yang mengandung Kromium dan dibuang ke Sungai Ciwalen tanpa proses pengolahan limbah. Kandungan ion logam Cr6+ pada limbah dapat mencemari air tanah. Pergerakan ion logam Cr6+ akan melalui media tanah sebelum memasuki sumur-sumur penduduk. Beberapa jenis tanah mempunyai kemampuan untuk mengadsorpsi ion pencemar sehingga tidak semua limbah yang meresap ke dalam tanah mencemari air tanah. Tujuan dari penelitian ini adalah untuk mengetahui peranan tanah dalam menghambat pergerakan ion logam Cr6+ ke dalam air tanah. Penelitian dilaksanakan dengan pengambilan sampel tanah di daerah Sukaregang, Garut, dan melakukan percobaan adsorpsi dengan sistem batch. Sementara analisis dilakukan dengan menggunakan model isotherm Langmuir dan Freundlich. Hasil percobaan menunjukkan konsentrasi Cr6+ yang teradsorpsi berkisar 38 – 57 % dari konsentrasi awal. Kads sebesar 0,45 L/mg dan qm sebesar 2,44 mg/100g tanah dengan nilai R2 = 0,959 menggunakan isoterm Langmuir dan isoterm Freundlich memberikan nilai qm sebesar 2,86 mg/100 g sorbent dan Kads sebesar 0,35 L/mg dengan R2 = 0,860. Tingginya daya adsorpsi ini disebabkan oleh tekstur tanah dan kandungan bahan organik. Tanah di wilayah penelitian memiliki daya adsorpsi yang besar terhadap kontaminan Cr6+.Kata kunci: adsorpsi, kromium, Cr6+, kontaminan, tanah vulkanik, Garut


1999 ◽  
Vol 94 ◽  
pp. 167-189 ◽  
Author(s):  
Glynis Jones ◽  
Amy Bogaard ◽  
Paul Halstead ◽  
Michael Charles ◽  
Helen Smith

A question of broad economic and social significance is the extent to which farming in prehistoric times, and perhaps even in historical times, was characterised by cultivation on a small scale and with intensive methods. Archaeobotanically, a distinction may be possible between intensive and extensive cultivation on the basis of the weed seeds associated with ancient grain samples. To this end, an ecological study was carried out in central Ewia of the weeds of winter-sown pulses grown both intensively in gardens and extensively in fields. The recorded weed flora was demonstrably influenced by relevant husbandry variables, such as method of tillage (with hoe or plough), weeding, manuring and soil organic content. The closest correspondence, however, was with the size, type and location of cultivated plots, suggesting that the weed flora was determined by a combination of these husbandry variables. In conclusion, the potential is briefly discussed of disentangling these variables for application in an archacobotanical context.


Environments ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 72
Author(s):  
Ioannis Zafeiriou ◽  
Dionisios Gasparatos ◽  
Ioannis Massas

Selenium adsorption/desorption behavior was examined for eight Greek top soils with different properties, aiming to describe the geochemistry of the elements in the selected soils in terms of bioavailability and contamination risk by leaching. Four soils were acid and four alkaline, and metal oxides content greatly differed between the two groups of soils. The concentrations of Se(IV) used for the performed adsorption batch experiments ranged from 1 to 50 mg/L, while the soil to solution ratio was 1 g/0.03 L. Acid soils adsorbed significantly higher amounts of the added Se(IV) than alkaline soils. Freundlich and Langmuir equations adequately described the adsorption of Se(IV) in the studied soils, and the parameters of both isotherms significantly correlated with soil properties. In particular, both KF and qm values significantly positively correlated with ammonium oxalate extractable Fe and with dithionite extractable Al and Mn, suggesting that amorphous Fe oxides and Al and Mn oxides greatly affect exogenous Se(IV) adsorption in the eight soils. These two parameters were also significantly negatively correlated with soil electrical conductivity (EC) values, indicating that increased soluble salts concentration suppresses Se(IV) adsorption. No significant relation between adsorbed Se(IV) and soil organic content was recorded. A weak salt (0.25 M KCl) was used at the same soil to solution ratio to extract the amount of the adsorbed Se(IV) that is easily exchangeable and thus highly available in the soil ecosystem. A much higher Se(IV) desorption from alkaline soils was observed, pointing to the stronger retention of added Se(IV) by the acid soils. This result implies that in acid soils surface complexes on metal oxides may have been formed restricting Se desorption.


2020 ◽  
Author(s):  
Tamar Jolokhava ◽  
Zaal Kikvidze

<p>Alpine deserts are noteworthy habitats in high mountain systems such as the Caucasus. However, very little is known on the soil properties in these habitats. Another unexplored question is the transition between subnival (lower part of alpine desert) and nival (upper part of alpine desert) belts. We studied soils and vegetation in an alpine desert along its practically entire elevation range (3000-4000 m a.s.l.) on two contrasting slope aspects (north vs south) of Mt. Kazbegi, the Central Great Caucasus, Georgia. Vegetation with standardized stratified-random design and collected soil samples for measuring pH, soil organic content (SOM) and available nutrients (N, P, K) were sampled; the collected data were analyzed with direct gradient methods as well as multivariate ordination. 63 species were recorded and, as expected, strong dependence of species distribution on elevation and between slopes was documented. We found that soil pH increased monotonically with altitude on both N and S slopes and reached alkaline values with bare bedrock. The changes were steeper on the northern slope than on the southern slope, and, remarkably, many relatively abundant species changed their preference to slope aspect from N to S in parallel with the increasing difference in soil pH.  We suspect that the pH  observed shift in slope preference, at least in part, can be explained by the effect of different soil pH. As for SOM, it decreased from very low values to zero at the higher altitudes, whilst available nutrients dropped dramatically and predominantly multispecific vegetation patches characteristic for subnival belt changed abruptly to monospecific patches or solitary plants typical for nival belt. These abrupt changes occurred at 3400-3500m a.s.l., and most probably indicate a vegetation switch between the mentioned belts on Mt. Kazbegi.</p><p>Overall, our results show two characteristics of alpine desert vegetation and soils, which have not been documented to date: (1) an unexpected change of slope preference of many relatively abundance plants which probably is associated with different soil pH profiles on N and S slopes, and (2) a vegetation switch between subnival and nival belts that occurs at relatively lower elevations than expected from the concept of alpine-nival ecotone.</p>


2019 ◽  
Vol 11 (24) ◽  
pp. 7177 ◽  
Author(s):  
Chi Zhang ◽  
Hong Zhang ◽  
Fuqiang Zhao ◽  
Jing Sun

Permafrost is characterized by low temperature, and its thermal stability is key to geohydrological cycles, energy exchange, and climate regulation. Increasing engineering activities, i.e., road construction and operations, are affecting the thermal stability in permafrost regions and have already led to the degradation of permafrost and caused environmental problems. To understand the spatiotemporal influence of road construction and operations on the thermal dynamics in permafrost regions, we conducted a study in the Ela Mountain Pass where multiple roads intersect on the Qinghai–Tibet Plateau (QTP) and calculated the thermal dynamics from 2000 to 2017 using normalized spectral entropy (measuring the disorderliness of time-series data). Our results indicate that road level is a significant influencing factor, where high-level roads (expressways) exhibit stronger thermal impacts than low-level roads (province- and county-level roads). Our results also indicate that duration of operation is the most significant factor that determines the thermal impacts of roads on permafrost: the thermal impacts of the newly paved expressway are positively related to elevation, while the thermal impacts of the old expressway are positively related to less vegetated areas. The study provides an excellent method for understanding the spatiotemporal impacts of engineering activities on the temperature dynamics in permafrost regions, thereby helping policymakers in China and other countries to better plan their infrastructure projects to avoid environmentally vulnerable regions. The study also calls for advanced techniques in road maintenance, which can reduce the accumulated disturbance of road operations on permafrost regions.


Author(s):  
Zheng Teng ◽  
Joseph A. Smithson ◽  
Ping Zhou ◽  
John J. Sansalone

Highway traffic generates heavy metals and particulate matter through various vehicular and tire-pavement abrasion mechanisms. These abraded materials are deposited, they accumulate, and they are transported by storm water. Soils subject to years of such loading can serve as a sink and a potential source for heavy metals. The results of geotechnical analyses, heavy metal distributions, drainage influences, and correlations to geotechnical indices for surficial (0 to 15 cm) glacial till samples recovered from two transects along a heavily traveled urban interstate highway were compared with a control site subjected to only urban atmospheric deposition. This investigation indicated, for this site, that heavy metal accretion in the surficial soils is a function of depth, surface drainage patterns, distance from the pavement edge, and soil indices. Particulate-bound heavy metal deposition and accretion or export were a function of surface flow conditions such as velocity, flow depth, and surface cover. Results indicated that heavy metal accretion rapidly decreases as a function of distance from the traveled roadway. Along the longitudinal transect, correlations between heavy metals and soil organic content were statistically significant, particularly for copper. Along the transverse transect, correlations between soil plasticity, organic content, and heavy metals were statistically significant. Although there is little control of traffic levels and past accretion, indices such as soil organic content and plasticity index, as well as pavement runoff surface drainage patterns, can provide information about whether highway soils might act as a sink or source of heavy metals and, consequently, if best management practices may be justified.


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