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Decadal Changes in Dry and Wet Heatwaves in Eastern China:Spatial Patterns and Risk Assessment
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作者 Yue ZHANG Wen ZHOU Ruhua ZHANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第10期2011-2026,共16页
Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in easte... Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in eastern China over recent decades.Spatial trend analysis displays pronounced warming in inland midlatitudes and the Yangtze River Valley,with increased humidity in coastal regions.EOF results indicate intensifying dry heatwaves in northern China,while the Yangtze River Valley sees more frequent dry heatwaves.On the other hand,Indochina and regions north of 25°N also experience intensified wet heatwaves,corresponding to regional humidity increases.Composite analysis is conducted based on different situations:strong,frequent dry or wet heatwaves.Strong dry heatwaves are influenced by anticyclonic circulations over northern China,accompanied by warming SST anomalies around the coastal midlatitudes of the western North Pacific(WNP).Frequent dry heatwaves are related to strong subsidence along with a strengthened subtropical high over the WNP.Strong and frequent wet heatwaves show an intensified Okhotsk high at higher latitudes in the lower troposphere,and a negative circumglobal teleconnection wave train pattern in the upper troposphere.Decaying El Niño SST patterns are observed in two kinds of wet heatwave and frequent dry heatwave years.Risk analysis indicates that El Niño events heighten the likelihood of these heatwaves in regions most at risk.As global warming continues,adapting and implementing mitigation strategies toward extreme heatwaves becomes crucial,especially for the aforementioned regions under significant heat stress. 展开更多
关键词 decadal changes dry heatwave wet heatwave eastern China
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The relationship between interannual dry/wet changes and nomadic wars in the Hexi Corridor region of China during the period 241–1912 A.D.
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作者 Fei TANG Zhilin SHI +2 位作者 Qinhua TIAN Xiaogang DU Yong ZHANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2024年第6期1922-1931,共10页
The link between climate and war has long been a topic of great scientific and social interest.In this study,we investigate the influence of climate on warfare in China’s Hexi Corridor region since 241 A.D.Using the ... The link between climate and war has long been a topic of great scientific and social interest.In this study,we investigate the influence of climate on warfare in China’s Hexi Corridor region since 241 A.D.Using the superposed epoch analysis of tree-ring data and historical war data,we observe a notable correlation between interannual dry-wet variations and wars instigated by nomadic groups in the Hexi Corridor.However,this relationship is dynamic and influenced by the region’s relative unity.During periods in which the Hexi Corridor was ruled by multiple regimes,wars tended to follow dry climatic conditions,which may be due to the fact that unusual drought during these periods likely heightened competition for resources and land.Conversely,during times of regional unity,wars were more likely to occur when climatic conditions were wet because the expansion of rangelands and the accumulation of resources helped fuel the nomads’outward conquest.These findings underscore the complexity of the relationship between war and climate change.To gain a more comprehensive understanding of this relationship,continuous,high-resolution historical temperature and humidity datasets with broader and more uniform coverage are needed across multiple regions.In addition,collecting and examining disaggregated historical war data for regions with distinct characteristics is essential. 展开更多
关键词 DROUGHT Interannual dry and wet variations WAR The Hexi Corridor Tree ring Nomadic groups
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Asymmetric Drying and Wetting Trends in Eastern and Western China 被引量:1
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作者 Wen WU Fei JI +1 位作者 Shujuan HU Yongli HE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第2期221-232,共12页
As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous ... As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China. 展开更多
关键词 aridity index EEMD dry/wet conditions asymmetric evolution
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Hydraulic and volume change behaviors of compacted highly expansive soil under cyclic wetting and drying 被引量:4
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作者 Mohamed Farid Abbas Abdullah Ali Shaker Mosleh A.Al-Shamrani 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期486-499,共14页
The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and bounda... The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions. 展开更多
关键词 Expansive soils Hydraulic conductivity Volume change potential Cyclic wetting and drying(CWD) Swell pressure
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Wetting alternating with partial drying during grain filling increases lysine biosynthesis in inferior rice grain
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作者 Yi Jiang Wenli Tao +2 位作者 Weiyang Zhang Zhiqin Wang Jianchang Yang 《The Crop Journal》 SCIE CSCD 2024年第1期262-270,共9页
Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breedin... Lysine content is a criterion of the nutritional quality of rice.Understanding the process of lysine biosynthesis in early-flowering superior grain(SG)and late-flowering inferior grain(IG)of rice would advance breeding and cultivation to improve nutritional quality.However,little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism,and whether and how irrigation regimes affect lysine anabolism in these grains.A japonica rice cultivar was grown in the field and two irrigation regimes,continuous flooding(CF)and wetting alternating with partial drying(WAPD),were imposed from heading to the mature stage.Lysine content and activities of key enzymes of lysine biosynthesis,and levels of brassinosteroids(BRs)were lower in the IG than in the SG at the early grainfilling stage but higher at middle and late grain-filling stages.WAPD increased activities of these key enzymes,BR levels,and contents of lysine and total amino acids in IG,but not SG relative to CF.Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD,but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG.WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG.Improvement in lysine biosynthesis in rice should focus on IG. 展开更多
关键词 BRASSINOSTEROIDS Inferior grain Lysine biosynthesis Rice wetting alternating with partial drying
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Effect of Supplementary Irrigation on the Yield of Sorghum (Sorghum bicolor L. Moench) in the Context of Climate Change in the Dry Savannahs of Togo
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作者 Adjiwanou Atiglo-Gbenou Yaovi Ouézou Azouma Jean Mianikpo Sogbedji 《American Journal of Climate Change》 2024年第2期163-174,共12页
Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah regi... Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system. 展开更多
关键词 Climate change Supplementary Irrigation Sorghum Grain Yield dry Savannah TOGO
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Characteristics of Dry and Wet Climate in Shandong Province Based on Standardized Precipitation Index
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作者 Ningxin ZHANG Fengling ZENG Fang LI 《Meteorological and Environmental Research》 2024年第3期6-15,共10页
Based on the monthly precipitation data of 116 meteorological stations in Shandong Province during 1970-2021,standardized precipitation index(SPI)was calculated,and the methods of linear fitting,mutation test and Morl... Based on the monthly precipitation data of 116 meteorological stations in Shandong Province during 1970-2021,standardized precipitation index(SPI)was calculated,and the methods of linear fitting,mutation test and Morlet wavelet analysis were used to analyze the change trend and temporal and spatial distribution characteristics of SPI index in the past 52 years.The results show that there were more normal years in Shandong Province,and the frequency reached 38.46%.There was severe drought in the 1980s and more wet years after 2003.SPI index showed an upward trend in spring,summer and winter but a weak arid trend in autumn.In addition,intense dry weather was more frequent in summer.Spatially,the climate was normal or humid in most areas of Shandong Province.The regions with more wet years were located in the central and northeast Shandong and the peninsula,while the climate was normal in the southwest and north of Shandong.The areas with more dry years were mainly located in the northwest of Shandong Province.There was mainly local and global drought in Shandong Province,and the arid area showed a decreasing trend.In the past 52 years,Shandong Province experienced quasi-4 times of alternation between dry and wet climate.The long period of 21 a was the first main period,and the climate would be still wet in Shandong Province in the future.In terms of mutation,the climate in Shandong Province became humid after 2003,and 2003 was the mutation point.After the abrupt change,the climate changed from gradually drying to wetting. 展开更多
关键词 Standardized precipitation index Shandong Province dry and wet climate characteristics Trend analysis
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Microwave Drying of Scots Pine Lumber:Structure Changes,Its Effect on Liquid Permeability
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作者 Sheng He Weiqi Leng +4 位作者 Yuhe Chen Hongchen Li Jingpeng Li Zaixing Wu Zizhang Xiao 《Journal of Renewable Materials》 SCIE EI 2023年第1期321-331,共11页
Microwave(MW)drying method was adopted to enhance the liquid permeability of Scots pine lumber.Structure changes were characterized by stereoscope microscope,scanned electron microscope(SEM)and transmission electron m... Microwave(MW)drying method was adopted to enhance the liquid permeability of Scots pine lumber.Structure changes were characterized by stereoscope microscope,scanned electron microscope(SEM)and transmission electron microscope(TEM)examination.Pore parameters before and after MW treatment were detected by mercury intrusion porosimetry(MIP)method,and the effect of structure changes on liquid permeability were analyzed.As stereoscope microscope,SEM and TEM examination results showed,macro and micro checks mainly developed at intercellcular of tracheids,intercellular of ray parenchyma and tracheid,while these checks extend main along the radial-longitudinal plane.Pit border destruction,aspirated pits’orus translocation and micro-checks in tracheid cell wall were also observed.MIP test shown that pore volume and pore area increased as macro and micro checks generated to form new cavities.Microstructure changes would increase the quantity of pores or enlarge the pore diameter.Liquid flow pathways increased as macro and micro checks generated,aspirated pits reopened to form new pathways;liquid flow efficiency improved as porosity,pore volume and pore diameter increased which facilitated the liquid flow. 展开更多
关键词 Microwave drying structure change pore structure liquid permeability Scots pine lumber
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Changes in terrestrial surface dry and wet conditions on the Loess Plateau(China) during the last half century 被引量:15
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作者 YuBi YAO RunYuan WANG +5 位作者 JinHu YANG Ping YUE DengRong LU Guo,Ju XIAO Yang WANG LinChun LIU 《Journal of Arid Land》 SCIE CSCD 2013年第1期15-24,共10页
This paper, using a revised Penman-Monteith model, computed the terrestrial surface humidity index of the Loess Plateau (China) based on climatic factors of monthly mean temperature, maximum temperature, minimum tem... This paper, using a revised Penman-Monteith model, computed the terrestrial surface humidity index of the Loess Plateau (China) based on climatic factors of monthly mean temperature, maximum temperature, minimum temperature, relative humidity, precipitation, wind speed and sunshine duration observed on the plateau from 1961 to 2008. The temporal-spatial distribution, anomaly distribution and sub-regional temporal variations of the terrestrial surface dry and wet conditions were analyzed as well. The results showed a decreasing trend in the annual average surface humidity from the southeast to the northwest in the research anna. Over the period of 1961-2008, an aridification tendency appeared sharply in the central interior region of the Loess Plateau, and less sharply in the middle part of the region. The border region showed the weakest tendency ol; aridification. It is clear that aridification diffused in all directions from the interior region. The spatial anomaly distribution of the terrestrial surface dry and wet conditions on the Loess Plateau can be divided into three key areas: the southern, western and eastern regions. The terrestrial annual humidity index displayed a significantly descending trend and showed remarkable abrupt changes from wet to dry in the years 1967, 1977 and 1979. In the above mentioned three key areas for dry and wet conditions, the terrestrial annual humidity index exhibited a fluctuation period of 3-4 years, while in the southern region, a fluctuation period of 7-8 years existed at the same time. 展开更多
关键词 dry and wet conditions spatial distribution temporal variation Penman-Monteith model Loess Plateau
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Precipitation Changes in Wet and Dry Seasons over the 20th Century Simulated by Two Versions of the FGOALS Model 被引量:3
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作者 MA Shuangmei ZHOU Tianjun 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第6期839-854,共16页
Seasonal precipitation changes over the globe during the 20th century simulated by two versions of the Flexible Global Ocean-Atmosphere-Land System (FGOALS) model are assessed. The two model versions differ in terms... Seasonal precipitation changes over the globe during the 20th century simulated by two versions of the Flexible Global Ocean-Atmosphere-Land System (FGOALS) model are assessed. The two model versions differ in terms of their AGCM component, but the remaining parts of the system are almost identical. Both models reasonably reproduce the mean-state features of the timings of the wet and dry seasons and related precipitation amounts, with pattern correlation coefficients of 0.65-0.84 with observations. Globally averaged seasonal precipitation changes are analyzed. The results show that wet sea- sons get wetter and the annual range (precipitation difference between wet and dry seasons) increases during the 20th century in the two models, with positive trends covering most parts of the globe, which is consistent with observations. However, both models show a moistening dry season, which is opposite to observations. Analysis of the globally averaged moisture budget in the historical climate simulations of the two models shows little change in the horizontal moisture advection in both the wet and dry seasons. The globally averaged seasonal precipitation changes are mainly dominated by the changes in evaporation and vertical moisture advection. Evaporation and vertical moisture advection combine to make wet seasons wetter and enhance the annual range. In the dry season, the opposite change of evaporation and vertical moisture advection leads to an insignificant change in precipitation. Vertical moisture advection is the most important term that determines the changes in precipitation, wherein the thermodynamic component is dominant and the dynamic component tends to offset the effect of the thermodynamic component. 展开更多
关键词 20th century historical climate simulation FGOALS-g2 FGOALS-s2 wet season dry season precipitation change water vapor budget diagnosis
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Impacts of different drying strategies on drying characteristics,the retention of bio-active ingredient and colour changes of dried Roselle 被引量:7
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作者 Thing Chai Tham Mei Xiang Ng +6 位作者 Shu Hui Gan Lee Suan Chua Ramlan Aziz Luqman Chuah Abdullah Sze Pheng Ong Nyuk Ling Chin Chung Lim Law 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第2期303-316,共14页
The drying kinetics of Roselle (Hibiscus sabdariffa L) of variety Terengganu (UMKL-1) and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, includ... The drying kinetics of Roselle (Hibiscus sabdariffa L) of variety Terengganu (UMKL-1) and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying (SD), solar greenhouse with intermittent heat pump drying (SIHP), hot air drying (HA) and heat pump drying (HP). Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H20-(g DM)-1. rain-1 to 0.212 g H20-(g DM)-1. rain 1 while SD had the lowest drying rate, measured at 0.042 g H2O. (g DM) 1.min- 1. The analysis on colour kinetics revealed that there is no significant colour loss (p 〉 0.05) observed from HP's dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP's dried Roselle contains higher percentage of catechin as compared to other drying methods. 展开更多
关键词 Hibiscus sabdariffa L.drying Heat pump Total colour change Protocatechuic acid Catechin
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THE WET-DRY CHANGES IN RECENT 40YEARS IN TAKLIMAKAN AREA 被引量:2
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作者 袁玉江 李江风 叶玮 《Chinese Geographical Science》 SCIE CSCD 1999年第1期57-62,共6页
Using the precipitation data in recent 40 years of 48 meteorological stations in Taklimakan area and neighboring areas, this paper analyzes the stage and periodicity of the wet-dry changes in a year and four seasons. ... Using the precipitation data in recent 40 years of 48 meteorological stations in Taklimakan area and neighboring areas, this paper analyzes the stage and periodicity of the wet-dry changes in a year and four seasons. The paper also compares the correlativity of precipitation between Taklimakan area and around Mountains, and obtained some statisticconclusions as follows. (1) The precipitation changes of a year and four seasons in Taklimakan area have different wet-dryperiods and change periodicities. (2) Summer precipitation has well directive sense to annual precipitation in Taklimakanarea with a correlation coefficient 0. 901, and the negative correlation between precipitation and temperature in summer isvery remarkable. (3) There is definite correlation between annual precipitation in Taklimakan area and position of polarvortex. When longitude of polar vortex is partial west in February and its latitude is partial north in September of the lastyear, annual precipitation is above its mean in the area. In addition, it is beneficial to obtain more summer precipitation inthe area when position of polar vortex is partial west in February. 展开更多
关键词 Taklimakan area wet-dry changE CLIMATE changE
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Dry/Wet Changes and Their Standing Characteristics in China During the Past 531 Years
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作者 龚志强 支蓉 +1 位作者 封国林 张强 《Acta meteorologica Sinica》 SCIE 2011年第2期142-155,共14页
Time series of the dryness-wetness(DW) index of 531 yr(AD 1470-2000) at 42 stations in regions A(most of North China and the east of Northwest China) and B(the Yangtze-Huaihe River valley) in China are applied... Time series of the dryness-wetness(DW) index of 531 yr(AD 1470-2000) at 42 stations in regions A(most of North China and the east of Northwest China) and B(the Yangtze-Huaihe River valley) in China are applied to investigating the historical DW characteristics over various periods of the series with a relatively stationary average value using Bernaola-Galvan(BG) algorithm.The results indicate that region A/B underwent three drought-intensive periods(DIP;1471-1560,1571-1640,and 1920-2000/1501-1540,1631-1690,and 1911-1960) in the last 531 years.In the DIP of the last 130 years,the frequency of DW transition has increased in region A,but not obviously changed in region B in comparison with the other two historical DIPs.The dry period started in about 1920 in region A with severe drought events occurring from the late 1970s to the early 1980s.It lasted for about 50-70 yr in this century,and then a DW shift took place.The wet period in region B might maintain for the coming several decades.The variations of DW in region A are positively correlated with changes in temperature,but in region B,the correlation with temperature is weaker.It is found that the number of DW indices of various categories within a running window is an exponential function of the running window length.The dryness scale factor(DSF) is defined as the reciprocal of the characteristic value of the exponential distribution,and it has a band-like fluctuation distribution that is good for the detection of extreme drought(flood) clustering events.The results show that frequencies of the severe large-scale drought events that concurrently occurred in regions A and B were high in the late 12th century,the early 13th century,the early 17th century,and the late 20th century.This provides evidence for the existence of the time-clustering phenomena of droughts(floods). 展开更多
关键词 dryness-wetness index abrupt change temperature the dryness/wetness scale factor consecutive
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Investigation on microstructure evolution of clayey soils: A review focusing on wetting/drying process 被引量:3
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作者 Chao-Sheng Tang Qing Cheng +2 位作者 Xuepeng Gong Bin Shi Hilary I.Inyang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第1期269-284,共16页
Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of ... Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of great significance for interpretation of soil macro hydro-mechanical behavior.In this review paper,methods that are commonly used to study soil microstructure are summarized.Among them are scanning electron microscope(SEM),environmental SEM(ESEM),mercury intrusion porosimetry(MIP)and computed tomography(CT)technology.Moreover,progress in research on the soil microstructure evolution during drying,wetting and wetting/drying cycles is summarized based on reviews of a large body of research papers published in the past several decades.Soils compacted on the wet side of op-timum water content generally have a matrix-type structure with a monomodal pore size distribution(PSD),whereas soils compacted on the dry side of optimum water content display an aggregate structure that exhibits bimodal PSD.During drying,decrease in soil volume is mainly caused by the shrinkage of inter-aggregate pores.During wetting,both the intra-and inter-aggregate pores increase gradually in number and sizes.Changes in the characteristics of the soil pore structure significantly depend on stress state as the soil is subjected to wetting.During wetting/drying cycles,soil structural change is not completely reversible,and the generated cumulative swelling/shrinkage deformation mainly derives from macro-pores.Furthermore,based on this analysis and identified research needs,some important areas of research focus are proposed for future work.These areas include innovative methods of sample preparation,new observation techniques,fast quantitative analysis of soil structure,integration of microstructural parameters into macro-mechanical models,and soil microstructure evolution charac-teristics under multi-field coupled conditions. 展开更多
关键词 Soil microstructure Pore size distribution(PSD) wetting/drying cycle SUCTION Volume change
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Diversity of Arbuscular Mycorrhizal Fungi Associated with Six Rice Cultivars in Italian Agricultural Ecosystem Managed with Alternate Wetting and Drying 被引量:1
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作者 Veronica VOLPE Franco MAGURNO +2 位作者 Paola BONFANTE Stefano GHIGNONE Erica LUMINI 《Rice science》 SCIE CSCD 2023年第4期348-358,I0028-I0030,共14页
Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was propo... Alternate wetting and drying(AWD)system,in which water has been reduced by approximately 35%with an increased occurrence of beneficial arbuscular mycorrhizal(AM)symbiosis and no negative impact on rice yield,was proposed to utilize water and nutrients more sustainable.In this study,we selected six rice cultivars(Centauro,Loto,Selenio,Vialone nano,JSendra and Puntal)grown under AWD conditions,and investigated their responsiveness to AM colonization and how they select diverse AM taxa.In order to investigate root-associated AM fungus communities,molecular cloning-Sanger sequencing on small subunit rDNA data were obtained from five out of the six rice cultivars and compared with Next Generation Sequencing(NGS)data,which were previously obtained in Vialone nano.The results showed that all the cultivars were responsive to AM colonization with the development of AM symbiotic structures,even if with differences in the colonization and arbuscule abundance in the root systems.We identified 16 virtual taxa(VT)in the soil compartment and 7 VT in the root apparatus.We emphasized that the NGS analysis gives additional value to the results thanks to a more in-depth reading of the less represented AM fungus taxa. 展开更多
关键词 alternate wetting and drying system arbuscular mycorrhizal fungi rice molecular diversity virtual taxa
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Thermal–moisture dynamics and thermal stability of active layer in response to wet/dry conditions in the central region of the Qinghai–Tibet Plateau,China 被引量:1
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作者 MingLi Zhang ZhiXiong Zhou +3 位作者 Zhi Wen FengXi Zhou Zhao Ma BingBing Lei 《Research in Cold and Arid Regions》 CSCD 2023年第1期27-38,共12页
The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy bala... The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy balance and the energy-water transfer within soils. To clarify the thermal-moisture dynamics and thermal stability of the active layer in permafrost regions under wet/dry conditions, the verified water-vapour-heat coupling model was used. Changes in the surface energy balance, energy-water transfer within the soil, and thickness of the active layer were quantitatively analyzed. The results demonstrate that rainfall changes significantly affect the Bowen ratio, which in turn affects surface energy exchange. Under wet/dry conditions, there is a positive correlation between rainfall and liquid water flux under the hydraulic gradient;water vapour migration is the main form under the temperature gradient, which indicates that the influence of water vapour migration on thermalmoisture dynamics of the active layer cannot be neglected. Concurrently, regardless of wet or dry conditions,disturbance of the heat transport by conduction caused by rainfall is stronger than that of convection by liquid water. In addition, when rainfall decreases by 1.5 times(212 mm) and increases by 1.5 times(477 mm), the thickness of the active layer increases by 0.12 m and decreases by 0.21 m, respectively. The results show that dry conditions are not conducive to the preservation of frozen soil;however, wet conditions are conducive to the preservation of frozen soil, although there is a threshold value. When this threshold value is exceeded, rainfall is unfavourable for the development of frozen soil. 展开更多
关键词 Active layer wet/dry conditions Qinghai-Tibet Plateau(QTP) Thermal-moisture dynamics Permafrost thermal stability Numerical modelling
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Root distribution and influencing factors of dry-sowing and wet-growing cotton plants under different water conditions
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作者 DING Yu ZHANG Jianghui +4 位作者 BAI Yungang LIU Hongbo ZHENG Ming ZHAO Jinghua XIAO Jun 《排灌机械工程学报》 CSCD 北大核心 2023年第10期1073-1080,共8页
To study the effect of soil water and salt environment factors on the root growth of cotton under different moisture control,three different emergence water volumes(60,105,and 150 m^(3)/hm^(2)),two different frequenci... To study the effect of soil water and salt environment factors on the root growth of cotton under different moisture control,three different emergence water volumes(60,105,and 150 m^(3)/hm^(2)),two different frequencies(high frequency and low frequency)and one double film cover winter irrigation control treatment(CK:2250 m^(3)/hm^(2))were set up to analyze the spatial distribution patterns of soil water and salt environment and root density in dry sown and wet emerged cotton fields under diffe-rent moisture control conditions.The results show that the soil water content and water infiltration range gradually become larger with the increase of seedling water quantity,and the larger the seedling water quantity,the higher the soil water content.With the same seedling water quantity,the soil water content of the high-frequency(HF)treatment becomes obviously larger.The soil conductivity of each treatment tends to decrease gradually with the increase of seedling water and drip frequency,among which the distribution of soil conductivity of S6 treatment is closest to that of CK.With the increase in soil depth,the soil conductivity tends to increase first and then decrease.Compared with the low-frequency(LF)treatment,the high-frequency treatment shows a significantly deeper soil salt accumulation layer.The root length density(RLD)of cotton gradually increases with the amount of seedling water and the frequency of dripping.The soil layer of root distribution gradually deepens with the amount of seedling water in the vertical direction,and the RLD value in the horizontal direction is significantly greater in the mulched area than that in the bare area between films.This research can serve as a solid scientific foundation for the use of dry sowing and wet emergence techniques in cotton fields in southern Xinjiang. 展开更多
关键词 COTTON double film mulching dry sowing and wet germination moisture regulation water and salt distribution root distribution cotton double film mulching dry sowing and wet germination moisture regulation water and salt distribution root distribution
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DRY/WET CLIMATE CHANGE SINCE 960 A.D.IN TAIHU DRAINAGE BASIN OF CHINA 被引量:2
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作者 WANG Zhang-hua, CHEN Zhong-yuan, KOU Ying, CHEN Yu (Department of Geography, East China Normal University, Shanghai 200062, P. R. China) 《Chinese Geographical Science》 SCIE CSCD 2001年第4期57-63,共7页
ABSTRACT: The present study reconstructs an annual dry/wet grade series from 960 A. D. to 1992 A. D. in the Tai-hu drainage basin of eastern coast, China by collecting historical climatic records, to examine the clima... ABSTRACT: The present study reconstructs an annual dry/wet grade series from 960 A. D. to 1992 A. D. in the Tai-hu drainage basin of eastern coast, China by collecting historical climatic records, to examine the climate periodicity and climate jumps. Power Spectrum analysis reveals that the dry/wet climate in the study area was a superposed phenomenon with the major period of quasi-100-year, and several other notable periods. These periods were supposed to be closely linked with the celestial activity. Climate jumps are detected using moving t-test. The two abrupt changes around 1247 - 1263 A. D. and 1618 - 1635 A. D. are proved as regional events. The 14th to 15th century appeared as the wettest period during the last 1000 years in the Taihu drainage basin. These are interpreted as the consequence of east Asia climate change. 展开更多
关键词 CLIMATE PERIODICITY CLIMATE JUMP annual dry/wet grade series Taihu drainage basin
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Dry cropland changes in China's Three Gorges Reservoir Region during the period 1990 to 2015 被引量:1
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作者 WANG Ming-feng TIAN Feng-xia +3 位作者 HE Xiu-bin Raheel ANJUM BAO Yu-hai Adrian LCOLLINS 《Journal of Mountain Science》 SCIE CSCD 2020年第3期516-527,共12页
Monitoring and analyzing changes in the extent of cultivated land may inform strategic decisions on issues of environmental and food security.The dry cropland area of 12000 km^2in the Three Gorges Reservoir Region(TGR... Monitoring and analyzing changes in the extent of cultivated land may inform strategic decisions on issues of environmental and food security.The dry cropland area of 12000 km^2in the Three Gorges Reservoir Region(TGRR)of China is essential for feeding the local population of^20 million,but is highly prone to soil erosion,leading to the delivery of excessive amounts of sediment and associated pollutants to the Three Gorges Reservoir(TGR),and causing serious eco-environmental consequences.Against this background,this paper used Landsat images and a digital elevation model to analyze the altitudinal distribution of,and dynamic changes in,the area of dry cropland during the period 1990 to 2015.The results suggest that dry cropland was mainly distributed in the elevation range of 200-600 m.The dry cropland area decreased from 12525.37 km^2to 11796.27 km^2during the 25-year study period,including a particularly significant decrease in the rate of decrease from 6.93 km^2/yr to 43.99 km^2/yr after 2000.The largest decline in the dry cropland area occurred in the elevation range of 600-900 m.The transformations between dry cropland and forest revealed the impact of the TGR operation on the extent of dry cropland.A total of 528.79 km^2of dry cropland with slopes>25°were converted to forest after 2000,whereas a total of 642 km^2of forest was converted to dry cropland during the study period,and these conversions mainly occurred between the elevation of 200–900 m.These spatiotemporal changes in the dry cropland area are likely to raise new issues concerning food security in the TGRR. 展开更多
关键词 dry CROPLAND ALTITUDE RESERVOIR operation Three Gorges RESERVOIR Region LANDUSE change Soil EROSION
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Decadal (2003–2013) changes in liana diversity,abundance and aboveground biomass in four inland tropical dry evergreen forest sites of peninsular India 被引量:1
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作者 Elumalai Pandian Narayanaswamy Parthasarathy 《Journal of Forestry Research》 SCIE CAS CSCD 2016年第1期133-146,共14页
In 2013, we re-inventoried all lianas (≥1 cm diameter measured at 1.3 m from the rooting point) in four I-ha permanent plots distributed one each in four sites of inland tropical dry evergreen forest on the Coroman... In 2013, we re-inventoried all lianas (≥1 cm diameter measured at 1.3 m from the rooting point) in four I-ha permanent plots distributed one each in four sites of inland tropical dry evergreen forest on the Coromandel Coast (Pudukottai district) of peninsular India, established in 2003. Among the four sites, Shanmuganathapuram (SP) and Araiyapatti (AP) were much disturbed and the other two sites (Karisakkadu--KR and Maramadakki--MM) were moderately disturbed. We inventoried a total of 3425 lianas representing 37 species of 33 genera and 22 families. Over a decade (2003-2013) liana species richness increased at two sites (MM and SP) and no changes occurred at the other two sites. Liana abundance increased by 210, 211,164 and 162 individuals at sites AP, KR, MM and SP, respectively, and basal area increased (from 1.09 to 1.76 m2 at AP, 0.67 to 0.86 m2 at KR, 1.68 to 2.06 mz at MM, and from 0.44 to 1.06 m2 at SP). Over a 10-year period, three species (Abrus precatorius, Canavalia virosa, and Cocculus hirsutus) were lost and five species (Gloriosa superba, Ampelocissus tomentosa, Capparis sepiaria, Aganosma cymosa and Tiliacora acuminata) were newly added. Total aboveground biomass increased by 18.5, 0.74, 3.6 and 9.5 Mg ha-1, respectively, at sites AP, KR, MM and SP. 展开更多
关键词 Tropical dry evergreen forest Lianaabundance Re-inventory Aboveground biomassHuman disturbance Decadal change
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