Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis t...Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.展开更多
This study presents a multi-physical modeling approach to analyze the dynamics of moisture potential and stress-deformation features near deep desiccation cracks in clayey soils under three consecutive years’climate ...This study presents a multi-physical modeling approach to analyze the dynamics of moisture potential and stress-deformation features near deep desiccation cracks in clayey soils under three consecutive years’climate variability in an arid region.A triple research approach of statistical analysis,analytical framework,and numerical modeling was used to investigate the complex thermo-hydro-mechanical behavior of desiccation-cracked soil,incorporating realistic climatic data of Qom,Iran.The results revealed the interplay between stress,strain,and pore water pressure over time,demonstrating that soil experiences significant swelling and shrinkage due to cyclic wetting and drying.The horizontal stress distribution shows compressive stress concentration at crack tips during wetting,transitioning to tensile stresses uniformly across the soil surface during drying paths.Similarly,vertical stress distributions exhibit localized compressive stresses along crack boundaries during wetting and tensile stresses during drying,highlighting the critical stress conditions at crack tips.The model differentiates between microstructural and macrostructural changes in porosity.Annual trends in micro-porosity revealed cyclic-dependent behavior,with significant volumetric changes occurring in the first year,stabilizing with successive cycles.The results also indicated that part of the volumetric changes are irreversible,with volumetric plastic strain increasing exponentially but at a decreasing rate over three years.Principal stress analysis indicates a shift from compressive to tensile stress states around cracks,driven by climate-induced wetting and drying cycles.These findings underscore the critical role of climate variability in shaping cracked soil behavior in arid regions,providing insights into the heterogeneous behavior of cracked soil surfFicial layers.展开更多
Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is es...Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems.This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices(FIs)including time to ignition(TI),duration of combustion(DC),and flame height(FH)of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran.The results showed that there was a significant difference in FIs between land covers.Shrublands had higher flammability potential compared with woodlands.Plant moisture content had a negative relationship with TI(P<0.010)and no significant relationship with DC and FH(P>0.050).Artemisia spp.,Astragalus gossypinus Fischer,Amygdalus scoparia Spach,and Cymbopogon jwarancusa(Jones)Schult.had the highest FI.Tree species such as Rhazya stricta Decne.,and Pistacia atlantica Desf.showed greater resistance to fire.Using principal component analysis,the relationship between species and FIs was examined,and TI of wet fuel was the most important FI in relation to species.Structural equation model showed that life form(P<0.001)was the most important flammability driver.Precipitation(P<0.010)and legume species(P<0.010)were significantly related to the flammability in arid land.This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.展开更多
High-concentration photovoltaic(HCPV)systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation,especially in arid environments.Effective he...High-concentration photovoltaic(HCPV)systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation,especially in arid environments.Effective heat dissipation is critical to prevent performance degradation and structural failure.This study investigates the thermal performance and design optimization of an enhanced HCPV module,integrating numerical,analytical,and experimental methods.A coupled optical-thermal-electrical model was developed to simulate ray tracing,heat transfer,and temperature-dependent electrical behaviour,with predictions validated under real-world desert conditions.Compared to a baseline commercial module operating at 106℃,the optimized design achieved a peak temperature reduction of 16℃,lowering the cell temperature to 90℃under a concentration ratio of 961×and direct normal irradiance(DNI)of 950 W/m^(2).The total thermal resistance was reduced from 0.25 to 0.15 K/W(a 40%improvement),and the electrical efficiency increased from 37.5%to 38.6%,representing a relative gain of approximately 3.1%.The system consistently maintained a fill factor exceeding 78%,underscoring stable performance under high thermal load.These findings demonstrate that targeted thermal design,informed by integrated modeling,is essential for unlocking the reliability and efficiency of high-flux solar energy systems.展开更多
Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influenci...Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.展开更多
Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid ...Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid region boundary delineated by different indices remain unclear.In this study,the annual precipitation(AP),humidity index(H),and aridity index(K)were calculated for delineating arid region of China using 106 meteorological stations during 1990–2019.The results suggest that AP and H can accurately delineate arid region,because they are consistent with the distribution of typical soil and vegetation in arid region,whereas K is not.Moreover,AP is the best index for delineating arid region in regions with limited meteorological data,especially in studying long-term patterns and mechanisms of area changes.The accuracy of delineating arid region using H is enhanced in regions with abundant meteorological data.Over the past 30 years,influenced by the increase of atmospheric moisture influx and precipitation,the area in arid region of northwestern China decreased by 70×10^(3)–90×10^(3)km^(2),resulting in the present area of approximately 1.55×10^(6)km^(2).This study provides appropriate indices for delineating arid region,contributing to improving our knowledge of regional responses difference to climate change.展开更多
In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future...In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future extreme climate changes in the Asian arid region and Tibetan Plateau,this study applied the NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP-CMIP6)to assess the changes in EHP(Rx5d and R95pTOT)and EHT(TX90p and TXx)under different emission scenarios in the 21st century.Findings suggest that both the frequency and the intensity of the extreme indices will increase,exhibiting accelerated growth under higher emission scenarios,particularly under the SSP5-8.5 emission scenario.It is suggested that the growth of EHT and EHP in the early subperiod of the 21st century(2026-2045)will be relatively moderate,with small differences between different emission scenarios.However,by the middle subperiod of the 21st century(2041-2060),the differences between different emission scenarios will become larger than the 2035s and the growth will become more intense.In western central Asia,TX90p,TXx,Rx5d,and R95pTOT increase by 9.7%-14.2%(13.3%-24.7%),1.3℃-1.7℃(1.6℃-2.7℃),6.5%-8.9%(8.2%-8.8%),and 18.1%-27.0%(25.6%-30.0%)by the early(middle)subperiod;in eastern central Asia,TX90p,TXx,Rx5d,and R95pTOT increase 8.1%-12.0%(11.3%-21.1%),1.4℃-1.8℃(1.9℃-2.9℃),7.4%-9.7%(10.4%-13.8%),and 20.2%-29.3%(32.0%-40.8%)by the early(middle)subperiod;and over the Tibetan Plateau,TX90p,TXx,Rx5d,and R95pTOT increase 12.5%-17.4%(17.0%-31.0%),1.2℃-1.5℃(1.6℃-2.5℃),7.2%-10.0%(9.9%-15.0%),and 26.6%-33.1%(36.1%-55.3%)by the early(middle)subperiod.展开更多
The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowle...The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.展开更多
[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and...[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and tolerance to poor soil,and has strong ecological,landscape and economic value.To provide a theoretical basis for the propagation and application of A.tangutica in Minqin and similar arid sandy areas of Northwest China,this paper explored its introduction and cultivation technology through field experiments,considering the natural geographical conditions of the study area.[Methods]High-quality seeds were introduced from forest farms of Chankou Town,Anding District,Dingxi City,and Dian ga Town,Diebu County,Gannan Prefecture,and the introduction and cultivation experiments of A.tangutica were carried out in the greenhouse of Wuwei Oasis Station.[Results](1)Soaking treatment at different temperatures combined with gibberellin treatment and stratification germination could effectively break the dormancy of A.tangutica seeds,thereby accelerating germination and shortening the germination cycle.The germination peak appeared 15-20 d after sowing,and the final germination rate could reach about 50%.(2)In the introduction and cultivation of A.tangutica in arid areas,large fruit seeds with higher thousand-grain weight should be given priority.The emergence rate of large fruit seeds was significantly higher than that of small fruit seeds,with the highest reaching 57%,while the highest of small fruit seeds was only 20%.Soaking treatment at different temperatures had no significant difference in the germination performance and germination potential of A.tangutica seeds,but the germination index of large fruit seeds was higher than that of small fruit seeds.(3)Under the current conditions,seedling propagation is a reliable way to propagate A.tangutica in arid areas.The cutting propagation technology,particularly hardwood cutting which exhibits an extremely low survival rate,is not yet mature and is currently unsuitable for large-scale production.Consequently,future efforts should prioritize more in-depth research on softwood cutting techniques.[Conclusions]This study provides a theoretical foundation for the propagation and broader application of A.tangutica in Minqin and similar arid sandy areas of Northwest China.展开更多
The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The...The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.展开更多
The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topogr...The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topographical attributes,surface characteristics,soil properties and vegetation patterns vary between alluvial landforms,and(2) define whether morphometric,soil and surface properties influence vegetation patterns along alluvial landscape.Morphometric data were obtained by processing a 5 m digital elevation model.The coverage of rock fragments,fine sediments and mulch was quantified.Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm.Vegetation properties were calculated using a Point Quadrat Method.The relationship between variables was evaluated through multivariate statistical analysis.The main results show the presence of 45 plant species distributed in 19 families,where shrubs are dominant.The wind effect,topographic wetness and dissection of the landscape are limiting factors of diversity.The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater.Furthermore,the different soil textures reveal that the silt content favors an increase in vegetation coverage.The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.展开更多
Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the...Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the evolution of the Shule River in the western Qilian Mountains,China.The results indicate that during the early to mid-Holocene,the river evolution of the Shule River alluvial fan was closely related to regional climate fluctuations.In the late Holocene,flood agriculture began to emerge along the Shule River.During the historical period,population growth and the expansion of arable land led to increased river water usage,resulting in decreased access to the expected distribution of water resources in other regions,which in turn has caused imbalances in the regional hydrological ecosystem.展开更多
Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly infl...Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.展开更多
基金Under the auspices of the General Project of Science and Technology Department of Shaanxi Province(No.2023-JCYB-264)General Program of National Natural Science Foundation of China(No.41801004,42371008,42471012)。
文摘Riparian dunes in deserts exhibit unique geographic features due to aeolian-fluvial interactions.In this study,we collected 510 surface sediment samples from eight drainage basins and conducted a systematic analysis to examine the grain size characteristics of major riparian dunes in the typical cold and arid deserts of China.The results indicate that major riparian dunes of deserts in study area can be classified into three types based on their grain size characteristics.The Bartlett test of sphericity and the Kaiser-Meyer-Olkin(KMO)test were also performed,and their significance values were found to be 0.000 and 0.584,respectively.The results of the principal component analysis revealed that the cumulative contribution rate of the total variance reached 85.9%for the two principal components with characteristic roots greater than 1.0.The primary principal component included medium sand,whereas the secondary principal component included fine sand.We conducted a cluster analysis and classified the samples into three major types.Type I rivers include the Keriya River,Langqu River,Tora River and Heihe River,which are characterized by by fine particle size,and well-sorted.Type II includes Mu Bulag River,Kuye River,and the Xar Moron River,Compared with type I,it has a relatively coarser mean grain size and relatively poor sorting for this type.Type III includes the Maquan River,which is characterized mainly by fine sand and medium sand,accounting for more than 90%,and the sorting coefficient(0.52)suggests relatively well sorting in this pattern.Moreover,principal component analysis was applied to determine the particle sizes of samples from different watersheds.Moreover,these sediments exhibit both hydromorphic and aeolian features.At the drainage basin scale,the mode and intensity of aeolian-fluvial interactions depend on climatic conditions.In arid and semi-arid climate regions,wind is the dominant force,and the grain size exhibits significant aeolian features.Conversely,in the semi-humid region,flowing water is the dominant force,and riparian dunes in this region are formed by aeolian-fluvial interaction.The angle between the wind direction and flow direction in different reaches influences both the supply of sediment sources and the development of riparian dunes.This study will provide a new perspective for evaluating aeolian-fluvial interactions on riparian dunes in the deserts of China’s cold and arid regions.
基金support provided by the Research Grant Office at Sharif University Technology by way of grants G4010902 and QB020105 is gratefully acknowledged.
文摘This study presents a multi-physical modeling approach to analyze the dynamics of moisture potential and stress-deformation features near deep desiccation cracks in clayey soils under three consecutive years’climate variability in an arid region.A triple research approach of statistical analysis,analytical framework,and numerical modeling was used to investigate the complex thermo-hydro-mechanical behavior of desiccation-cracked soil,incorporating realistic climatic data of Qom,Iran.The results revealed the interplay between stress,strain,and pore water pressure over time,demonstrating that soil experiences significant swelling and shrinkage due to cyclic wetting and drying.The horizontal stress distribution shows compressive stress concentration at crack tips during wetting,transitioning to tensile stresses uniformly across the soil surface during drying paths.Similarly,vertical stress distributions exhibit localized compressive stresses along crack boundaries during wetting and tensile stresses during drying,highlighting the critical stress conditions at crack tips.The model differentiates between microstructural and macrostructural changes in porosity.Annual trends in micro-porosity revealed cyclic-dependent behavior,with significant volumetric changes occurring in the first year,stabilizing with successive cycles.The results also indicated that part of the volumetric changes are irreversible,with volumetric plastic strain increasing exponentially but at a decreasing rate over three years.Principal stress analysis indicates a shift from compressive to tensile stress states around cracks,driven by climate-induced wetting and drying cycles.These findings underscore the critical role of climate variability in shaping cracked soil behavior in arid regions,providing insights into the heterogeneous behavior of cracked soil surfFicial layers.
文摘Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems.This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices(FIs)including time to ignition(TI),duration of combustion(DC),and flame height(FH)of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran.The results showed that there was a significant difference in FIs between land covers.Shrublands had higher flammability potential compared with woodlands.Plant moisture content had a negative relationship with TI(P<0.010)and no significant relationship with DC and FH(P>0.050).Artemisia spp.,Astragalus gossypinus Fischer,Amygdalus scoparia Spach,and Cymbopogon jwarancusa(Jones)Schult.had the highest FI.Tree species such as Rhazya stricta Decne.,and Pistacia atlantica Desf.showed greater resistance to fire.Using principal component analysis,the relationship between species and FIs was examined,and TI of wet fuel was the most important FI in relation to species.Structural equation model showed that life form(P<0.001)was the most important flammability driver.Precipitation(P<0.010)and legume species(P<0.010)were significantly related to the flammability in arid land.This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.
基金funded by King Abdullah City for Atomic and Renewable Energy(KACARE),grant number“PC-2020-1”.
文摘High-concentration photovoltaic(HCPV)systems present significant thermal management challenges due to the intense heat fluxes generated under concentrated solar irradiation,especially in arid environments.Effective heat dissipation is critical to prevent performance degradation and structural failure.This study investigates the thermal performance and design optimization of an enhanced HCPV module,integrating numerical,analytical,and experimental methods.A coupled optical-thermal-electrical model was developed to simulate ray tracing,heat transfer,and temperature-dependent electrical behaviour,with predictions validated under real-world desert conditions.Compared to a baseline commercial module operating at 106℃,the optimized design achieved a peak temperature reduction of 16℃,lowering the cell temperature to 90℃under a concentration ratio of 961×and direct normal irradiance(DNI)of 950 W/m^(2).The total thermal resistance was reduced from 0.25 to 0.15 K/W(a 40%improvement),and the electrical efficiency increased from 37.5%to 38.6%,representing a relative gain of approximately 3.1%.The system consistently maintained a fill factor exceeding 78%,underscoring stable performance under high thermal load.These findings demonstrate that targeted thermal design,informed by integrated modeling,is essential for unlocking the reliability and efficiency of high-flux solar energy systems.
基金supported by the Natural Science Foundation of Henan Province(252300421290)the National Natural Science Foundation of China(41771438)+1 种基金the Program for Innovative Research Team(in Science and Technology)of Henan University(22IRTSTHN010)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(HNYJS2020JD14).
文摘Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.
基金supported by the National Natural Science Foundation of China(Nos.42271003,42301001)the Fundamental Research Funds for the Central Universities(No.lzujbky-2022-ey09)+1 种基金the China Postdoctoral Science Foundation(No.GZB20230275)Supercomputing Center of Lanzhou University。
文摘Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid region boundary delineated by different indices remain unclear.In this study,the annual precipitation(AP),humidity index(H),and aridity index(K)were calculated for delineating arid region of China using 106 meteorological stations during 1990–2019.The results suggest that AP and H can accurately delineate arid region,because they are consistent with the distribution of typical soil and vegetation in arid region,whereas K is not.Moreover,AP is the best index for delineating arid region in regions with limited meteorological data,especially in studying long-term patterns and mechanisms of area changes.The accuracy of delineating arid region using H is enhanced in regions with abundant meteorological data.Over the past 30 years,influenced by the increase of atmospheric moisture influx and precipitation,the area in arid region of northwestern China decreased by 70×10^(3)–90×10^(3)km^(2),resulting in the present area of approximately 1.55×10^(6)km^(2).This study provides appropriate indices for delineating arid region,contributing to improving our knowledge of regional responses difference to climate change.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program[grant number 2019QZKK0101]。
文摘In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future extreme climate changes in the Asian arid region and Tibetan Plateau,this study applied the NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP-CMIP6)to assess the changes in EHP(Rx5d and R95pTOT)and EHT(TX90p and TXx)under different emission scenarios in the 21st century.Findings suggest that both the frequency and the intensity of the extreme indices will increase,exhibiting accelerated growth under higher emission scenarios,particularly under the SSP5-8.5 emission scenario.It is suggested that the growth of EHT and EHP in the early subperiod of the 21st century(2026-2045)will be relatively moderate,with small differences between different emission scenarios.However,by the middle subperiod of the 21st century(2041-2060),the differences between different emission scenarios will become larger than the 2035s and the growth will become more intense.In western central Asia,TX90p,TXx,Rx5d,and R95pTOT increase by 9.7%-14.2%(13.3%-24.7%),1.3℃-1.7℃(1.6℃-2.7℃),6.5%-8.9%(8.2%-8.8%),and 18.1%-27.0%(25.6%-30.0%)by the early(middle)subperiod;in eastern central Asia,TX90p,TXx,Rx5d,and R95pTOT increase 8.1%-12.0%(11.3%-21.1%),1.4℃-1.8℃(1.9℃-2.9℃),7.4%-9.7%(10.4%-13.8%),and 20.2%-29.3%(32.0%-40.8%)by the early(middle)subperiod;and over the Tibetan Plateau,TX90p,TXx,Rx5d,and R95pTOT increase 12.5%-17.4%(17.0%-31.0%),1.2℃-1.5℃(1.6℃-2.5℃),7.2%-10.0%(9.9%-15.0%),and 26.6%-33.1%(36.1%-55.3%)by the early(middle)subperiod.
文摘The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.
基金Supported by Gansu Provincial Key Talent Project(GZTZ20240415)The Central Financial Forestry Science and Technology Promotion Demonstration Fund Project(2024ZYTG04)+1 种基金Gansu Provincial Key Research and Development Program(25YFFA073)"Jiebangguashuai"Project for Key Technology Research and Development of the"Three North"Program of National Forestry and Grassland Administration(202401-05).
文摘[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and tolerance to poor soil,and has strong ecological,landscape and economic value.To provide a theoretical basis for the propagation and application of A.tangutica in Minqin and similar arid sandy areas of Northwest China,this paper explored its introduction and cultivation technology through field experiments,considering the natural geographical conditions of the study area.[Methods]High-quality seeds were introduced from forest farms of Chankou Town,Anding District,Dingxi City,and Dian ga Town,Diebu County,Gannan Prefecture,and the introduction and cultivation experiments of A.tangutica were carried out in the greenhouse of Wuwei Oasis Station.[Results](1)Soaking treatment at different temperatures combined with gibberellin treatment and stratification germination could effectively break the dormancy of A.tangutica seeds,thereby accelerating germination and shortening the germination cycle.The germination peak appeared 15-20 d after sowing,and the final germination rate could reach about 50%.(2)In the introduction and cultivation of A.tangutica in arid areas,large fruit seeds with higher thousand-grain weight should be given priority.The emergence rate of large fruit seeds was significantly higher than that of small fruit seeds,with the highest reaching 57%,while the highest of small fruit seeds was only 20%.Soaking treatment at different temperatures had no significant difference in the germination performance and germination potential of A.tangutica seeds,but the germination index of large fruit seeds was higher than that of small fruit seeds.(3)Under the current conditions,seedling propagation is a reliable way to propagate A.tangutica in arid areas.The cutting propagation technology,particularly hardwood cutting which exhibits an extremely low survival rate,is not yet mature and is currently unsuitable for large-scale production.Consequently,future efforts should prioritize more in-depth research on softwood cutting techniques.[Conclusions]This study provides a theoretical foundation for the propagation and broader application of A.tangutica in Minqin and similar arid sandy areas of Northwest China.
文摘The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.
文摘The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topographical attributes,surface characteristics,soil properties and vegetation patterns vary between alluvial landforms,and(2) define whether morphometric,soil and surface properties influence vegetation patterns along alluvial landscape.Morphometric data were obtained by processing a 5 m digital elevation model.The coverage of rock fragments,fine sediments and mulch was quantified.Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm.Vegetation properties were calculated using a Point Quadrat Method.The relationship between variables was evaluated through multivariate statistical analysis.The main results show the presence of 45 plant species distributed in 19 families,where shrubs are dominant.The wind effect,topographic wetness and dissection of the landscape are limiting factors of diversity.The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater.Furthermore,the different soil textures reveal that the silt content favors an increase in vegetation coverage.The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.
基金The National Natural Science Foundation of China(Grant 42371159)。
文摘Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the evolution of the Shule River in the western Qilian Mountains,China.The results indicate that during the early to mid-Holocene,the river evolution of the Shule River alluvial fan was closely related to regional climate fluctuations.In the late Holocene,flood agriculture began to emerge along the Shule River.During the historical period,population growth and the expansion of arable land led to increased river water usage,resulting in decreased access to the expected distribution of water resources in other regions,which in turn has caused imbalances in the regional hydrological ecosystem.
基金National Natural Science Foundation of China,No.42201170Young Elite Scientists Sponsorship Program by CAST,No.2022QNRC001。
文摘Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.
