The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that ...The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that the injected beam has a short bunch length and low emittance,and the preferred injector should offer high stability and low cost.Therefore,an injector based on a booster synchrotron was developed.The proposed injector includes a 250 MeV linac,a booster synchrotron that ramps the beam energy to 3.5 GeV,and two beam transport lines to ensure efficient beam delivery and beam quality preservation.The linac utilizes a thermionic high-voltage DC gun for reliable operation and features a bunching system with an advanced focusing system to preserve the emittance.To meet the injection requirements of the SAPS,a comprehensive design for the booster has been conducted.The booster synchrotron employs a threefold lattice structure,incorporating modified theoretical minimum emittance cells with a small momentum compaction factor and a high voltage to achieve an emittance of 3.98 nm rad and a bunch length of 4.8 mm.The injector has the potential to deliver a high charge,reducing the injection period of the storage ring to less than 1 min.Simulations demonstrated the expected performance,with a transmission efficiency of 90%,confirming its capability to meet the injection requirement of the SAPS storage ring.This design offers a stable and efficient solution for the SAPS.展开更多
Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article ha...Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article has been corrected.展开更多
Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(EN...Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.展开更多
This study provides new evidence for a significant Neoproterozoic tectono-thermal event in the southern Dharwar Craton,based on U-Pb dating of rutile and monazite from metamorphic rocks of the Sargur Group.Trace eleme...This study provides new evidence for a significant Neoproterozoic tectono-thermal event in the southern Dharwar Craton,based on U-Pb dating of rutile and monazite from metamorphic rocks of the Sargur Group.Trace element analysis of rutile in garnet-bearing amphibolite,amphibolite,garnet-bearing staurolite-kyanite schist,and grunerite-garnet schist suggests that their protoliths were primarily basaltic rocks,sediments with mafic component,pelitic sediments,and mixed sediments with both mafic and felsic components,respectively.Rutile U-Pb ages of 625±22 Ma(garnet-bearing amphibolite),752±5.1 Ma(amphibolite),836±4 Ma to 663±26 Ma(garnet-bearing staurolite kyanite schist)and 860±13 Ma(grunerite-garnet schist),along with a monazite U-Pb age of 789±4.4 Ma(garnet-bearing staurolite kyanite schist),record a significant Neoproterozoic(860-625 Ma)tectono-thermal event along the southern margin of the western Dharwar Craton.This event is most likely associated with aborted rift-related alkaline magmatism along the northern margin of the Southern Granulite Terrane(SGT)and the southern margin of the Dharwar Craton.Given the lack of direct evidence for the assembly of the Rodinia supercontinent in the Dharwar Craton and SGT,this Neoproterozoic event is unlikely to be related to the breakup of Rodinia.展开更多
Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and stro...Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and strong heterogeneity.These complex geomechanical conditions lead to pronounced differences in hydraulic fracturing outcomes among wells and sections.To investigate hydraulic fracture propagation and fracturing fluid injection behavior under varying geomechanical settings,true triaxial physical simulation tests were performed on 400×400×400 mm artificial rock samples.The samples were designed with different media properties based on similarity criteria.A sensitivity analysis was conducted to assess the effects of brittleness-ductility characteristics,natural fractures,and in-situ stress conditions.The results reveal that:(i)brittle samples with lower stress difference are favorable for forming complex,perforable fracture networks;(ii)brittle samples with higher stress difference tend to develop simple,planar hydraulic fractures,with natural fractures only slightly activated during very short injection periods;(iii)ductile behavior enhances the activation of natural fractures but reduces fracture complexity compared with brittle samples,even under lower stress difference;and(iv)for typical deep shale formations,larger fluid injection volumes combined with high-density,multi-cluster fracturing techniques are recommended.展开更多
Southern corn rust(SCR)is an airborne fungal disease caused by Puccinia polysora Underw.(P.polysora)that adversely impacts maize quality and yields worldwide.Screening for new elite SCR-resistant maize loci or genes h...Southern corn rust(SCR)is an airborne fungal disease caused by Puccinia polysora Underw.(P.polysora)that adversely impacts maize quality and yields worldwide.Screening for new elite SCR-resistant maize loci or genes has the potential to enhance overall resistance to this pathogen.Using phenotypic SCR resistance-related data collected over two years and three geographical environments,a genome-wide association study was carried out in this work,which eventually identified 91 loci that were substantially correlated with SCR susceptibility.These included 13 loci that were significant in at least three environments and overlapped with 74 candidate genes(B73_RefGen_v4).Comparative transcriptomic analyses were then performed to identify the genes related to SCR infection,with 2,586 and 797 differentially expressed genes(DEGs)ultimately being identified in the resistant Qi319and susceptible 8112 inbred lines following P.polysora infection,respectively,including 306 genes common to both lines.Subsequent integrative multi-omics investigations identified four potential candidate SCR response-related genes.One of these genes is ZmHCT9,which encodes the protein hydroxycinnamoyl transferase 9.This gene was up-regulated in susceptible inbred lines and linked to greater P.polysora resistance as confirmed through cucumber mosaic virus(CMV)-based virus induced-gene silencing(VIGS)system-mediated gene silencing.These data provide important insights into the genetic basis of the maize SCR response.They will be useful for for future research on potential genes related to SCR resistance in maize.展开更多
Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention ha...Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention has been paid to changes in the genesis locations of mesoscale eddies.Here,we provide evidence from three decades of satellite altimetry observations for the heterogeneity of the poleward shift of mesoscale activities,with the largest trend of~0.23°±0.05°(10 yr)^(-1) over the Atlantic sector and a moderate trend of~0.1°±0.03°(10 yr)^(-1) over the Indian sector,but no significant trend in the Pacific sector.The poleward shift of mesoscale eddies is associated with a southward shift of the local westerly winds while being constrained by the major topographies.As the poleward shift of westerly winds is projected to persist,the poleward oceanic heat flux from mesoscale eddies may influence future ice melt.展开更多
On January 7,2025,01:05:15 UTC(9:05 a.m.local time)southern Tibet was rocked by a M_(W)7.1 earthquake(M_(W)=moment magnitude,USGS)centered(28.639°N 87.361°E)in the Lhasa Block north of the India/Eurasia Plat...On January 7,2025,01:05:15 UTC(9:05 a.m.local time)southern Tibet was rocked by a M_(W)7.1 earthquake(M_(W)=moment magnitude,USGS)centered(28.639°N 87.361°E)in the Lhasa Block north of the India/Eurasia Plate boundary,in a remote area about 180 km SW of Xigaze,in Dingri County of Shigatse of the Xizang Autonomous Region(Figure 1).展开更多
Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorl...Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorly understood.In this study,we assessed SRBSDV susceptibility in 20 Xian/indica(XI)and 20 Geng/japonica(GJ)rice varieties.XI-1B accessions in the Xian subgroup displayed higher resistance than GJ accessions.Comparative transcriptome analysis revealed changes in processes like oxidoreductase activity,jasmonic acid(JA)metabolism,and stress response.JA sensitivity assays further linked antiviral defense to the JA pathway.These findings highlight a JA-mediated resistance mechanism in rice and offer insights for breeding SRBSDV-resistant varieties.展开更多
Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale i...Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale irrigation can supply local and sub-regional markets with food in the off-season, it has received little research and its challenges are therefore rarely addressed. In order to contribute to the knowledge of these small-scale irrigation systems, with a view to improving their structure and the management of irrigation water and energy, an assessment of small-scale irrigation in the southern slopes of the Bamboutos Mountains has been done. After direct observations, field measurements, surveys of 100 irrigators with questionnaires and interviews with administrative managers, analyses were carried out using Xlstat software. It was found out that about 226 small-scale irrigation systems designed and managed by producers have been installed on this slope between the end of December 2022 and mid-March 2023. Intended for market garden crops, 84.96% of these irrigation systems use sprinklers and 15.04% surface irrigation (furrow irrigation). Surface or underground water is mobilized using gravity (50%), fossil fuels (34.51%), electricity (14.6%) or solar energy (0.9%). Sprinkler irrigation is mainly carried out using locally manufactured hydraulic turnstiles. There is a lack of formal associations of irrigators in an environment marked by conflicts between water users, when there is not allocation for water withdrawal. Apart from the high cost of pumping energy ($1.32 per liter of fuel), the main constraint identified, which has become more acute over the years, is the lack of irrigation water during the water shortage period (from mid-January to mid-March). These constraints have led to a transition from surface irrigation to sprinkler irrigation, and the adoption of new energy supply and water mobilization technologies. The construction of collective surface and groundwater catchment structures with solar-powered pumping systems, the setting up of formal irrigators’ associations and an irrigation support service, could improve the availability of water throughout the irrigation season, thereby helping to improve the income generated by irrigated market-garden farming on the southern slopes of the Bamboutos Mountains.展开更多
The Baibokoum syenitic pluton(BSP),located in southern Chad,to the NE of the Adamawa-Yadédomain,is one of the few strongly potassic magmatic bodies in the southern part of the Central African Fold Belt(CAFB)in Ch...The Baibokoum syenitic pluton(BSP),located in southern Chad,to the NE of the Adamawa-Yadédomain,is one of the few strongly potassic magmatic bodies in the southern part of the Central African Fold Belt(CAFB)in Chad.It has been previously studied petrologically,but its petrogenesis has remained poorly known.Petrographic and whole-rock geochemical data presented in this article highlight their magma genesis and geodynamic evolution.The BSP consists of medium-to coarse-grained syenites associated with minor microdiorites,which occur as syn-plutonic dikes and mafic microgranular enclaves(MME)coarse-and medium-grained syenites outcrop respectively to the core and the border of the BSP.The syenite displays high-K and alkaline to trans-alkaline affinity.Petrographic and geochemical data suggest that medium-to coarse-grained syenites are from single magma source that evolved and differentiated by fractional crystallization in a magma reservoir.REE profiles show enriched LREEs(La_(N)/Yb_(N)=6.19-45.55)while HREEs show an almost flat profile(Dy_(N)/Yb_(N)=1.0-2.23),and the La/Sm and Sm/Yb ratios have led to propose that the aforementioned rocks derived from the partial melting of a garnet-spinel-lherzolite mantle source.Negative Nb and Ta anomalies indicate that this mantle source was modified by the addition of subduction-related material.Th/Yb ratios associated with high Ba/La ratios indicate that enrichment of the source could be related to slab-derived fluids.The parental magma of the BSP was generated by partial melting of the metasomatized lithospheric mantle that was modified into arc-magmatism material in a subduction setting.Its emplacement took place in two successive stages:a static stage of fractional crystallization and crystal settling in a deep magma source and a dynamic stage in a shear deformation setting during which stratified magma rises towards the upper crust,with evolved syenite magma being emplaced first and diorite later.The emplacement of the BSP was probably controlled by the evolution of the Tcholliré-Banyo Fault and M'BéréShear Zone during the Pan-African orogeny.展开更多
Phytoplankton play a pivotal role in the Southern Ocean ecosystem.This study examines the phytoplankton community structure and the environmental factors driving it in the Cosmonaut Sea,based on samples collected usin...Phytoplankton play a pivotal role in the Southern Ocean ecosystem.This study examines the phytoplankton community structure and the environmental factors driving it in the Cosmonaut Sea,based on samples collected using a net during the summer of 2020/2021.We identified 99 phytoplankton species,predominantly comprising diatoms and dinoflagellates.Among these,diatoms-notably Pseudo-nitzschia,Chaetoceros,and Fragilariopsis,dominated the community in terms of species richness,abundance,and biomass.Endemic species of the Southern Ocean,such as Corethron pennatum,Proboscia alata,and Cylindrotheca closterium,also made significant contributions.Phytoplankton abundance and biomass showed similar spatial distribution patterns,with hotspots in the northern section of the survey area that gradually diminished towards the coastal regions.The oceanic area exhibited low phytoplankton diversity but pronounced regional variations in community distribution,with the northern region emerging as a key zone for abundance,biomass,and diversity.Nutrient distribution was identified as the primary environmental driver shaping the phytoplankton community,with silicate levels having a significant negative impact on overall phytoplankton abundance and the dominant species.展开更多
The intensification of global warming has led to the continuous outbreak of southern rust(Puccinia polysora Underw.)in major maize-producing regions worldwide.The severe outbreak in the Huang-Huai-Hai summer maize reg...The intensification of global warming has led to the continuous outbreak of southern rust(Puccinia polysora Underw.)in major maize-producing regions worldwide.The severe outbreak in the Huang-Huai-Hai summer maize region of China in 2021 caused yield losses exceeding 50%in some plots,and this disease has been included in the List of Key Crop Pests and Diseases.This paper systematically reviews the molecular resistance mechanisms of maize to southern rust,focusing on the immune mechanisms mediated by NLR family genes and the characteristics of the Bin 10.01 resistance gene cluster;it summarizes the advances in research of molecular breeding technologies such as gene marker development,map-based cloning,and gene editing;combined with the disease characteristics of the spring-sown maize region in Southwest China and the summer-sown maize region in Huang-Huai-Hai,it elaborates on regionally adapted prevention and control strategies;integrating breeding practices of Dunhuang Seed Industry Group(e.g.,Dunyu 810 and Dunyan 616),it proposes a full-chain solution of"precision gene pyramiding-heterotic group utilization-regional promotion".It is expected to provide theoretical and technical references for molecular breeding of maize resistance to southern rust.展开更多
The study of the electrical structure and fluid content of the southern San Andreas Fault(SSAF)plays a significant role in understanding the geological processes and earthquake genesis.The paper analyzes the Bahr skew...The study of the electrical structure and fluid content of the southern San Andreas Fault(SSAF)plays a significant role in understanding the geological processes and earthquake genesis.The paper analyzes the Bahr skew and G-B decomposition from magnetotelluric sounding data in the SSAF to determine the strike direction is north-eastward 135°.Using the Nonlinear Conjugate Gradient algorithm,a reliable 2D electrical structure model was obtained.The Mission Creek and Banning faults,components of the SSAF,exhibit high conductivity within the crust,whereas the Eastern Transverse Ranges to the northeast of the fault show high resistivity characteristics.By integrating the modified Archie's law,the relations between conductivity,temperature,salinity,and fluid content were established,leading to conductivity-temperature and conductivity-fluid content relationships.Combining the results from the electrical structure model and fluid model of the SSAF,it is inferred that the fluid content in the high-conductivity crust reach up to 20%.When the fluid salinity is 10 wt%,the fluid content required to achieve the same high bulk conductivity reduces to 2%.A comparison of the electrical structure and focal depth of the Tan-Lu Fault Zone reveals that the collision between the low-viscosity fluids of the Mission Creek and Banning faults and the rigid Eastern Transverse Ranges contributes to the earthquake in the SSAF.展开更多
Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located ...Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located in the southern Junggar Basin of northwestern China,has geological conditions with rich CBM resources.The 46 Xishanyao coal samples gathered from the drilling cores and coal mines cover 4 types of macrolithotypes(bright coal 1,semi-bright coal 2,semi-dull coal 3,and dull coal 4)and 2 types of coal structures(primary coal I and cataclastic coal II).Based on a range of pore testing experiments and analytical methods,the dual effects of different macrolithotypes and coal structures on pore structures were intensely studied.The results showed that the specific surface area(SSA)and total pore volume(TPV)of coal samples increased gradually from bright to dull coals.For the same macrolithotypes,the SSA and TPV of the primary coals were lower than those of the cataclastic coals.Generally,the pore structures of bright and semi-bright coals are simpler when compared to semi-dull and dull coals with the same coal structure,whereas cataclastic coals have more complicated pore structure systems than primary coals with the same macrolithotypes.The bright and semi-bright coals have higher vitrinite contents and more endogenous fractures,whereas well-developed structural fractures were identified in cataclastic coals.Therefore,bright and semi-bright coals have better pore connectivity than semi-dull and dull coals with the same coal structure,the pore connectivity of cataclastic coals being slightly better than that of primary coals under the same macrolithotypes.In terms of the CBM adsorption conditions,the eight type samples formed a descending order:Ⅱ-4>I-4>Ⅱ-3>Ⅰ-3>Ⅱ-2>Ⅰ-2>Ⅱ-1>Ⅰ-1,while they ranked as follows when consideration was given to the CBM seepage capacities:II-2>Ⅱ-1>Ⅰ-2>Ⅰ-1>Ⅰ-3>Ⅰ-4>Ⅱ-3>Ⅱ-4.As a result,it could be determined that the bright and semi-bright coals had stronger adsorption capacities,whereas the cataclastic coals had better pore connectivity and seepage capacities.Pore structure characteristics should be analysed under the dual control of different macrolithotypes and coal structures,so that they can provide greater value for guiding CBM exploration and exploitation,as along for preventing underground gas accidents.展开更多
This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were ide...This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were identified by Defense Meteorological Satellite Program(DMSP)F16 during the years 2011 to 2022.A temperature ratio of ion/electron temperature(T_(i)/T_(e))<0.68 is recommended to define a hot patch in the Southern Hemisphere,otherwise it is defined as a cold patch.The cold and hot patches have different dependencies on IMF clock angle,while their dependencies on IMF cone angle are similar.Both cold and hot patches appear most often on the duskside,and the distribution of cold patches gradually decreases from the dayside to the nightside,while hot patches have a higher occurrence rate near 14 and 21 magnetic local time(MLT).Moreover,we compared the key plasma characteristics of polar cap cold and hot patches in the Southern and Northern Hemispheres.The intensity of the duskside upward field-aligned current of patches in the Southern Hemisphere(SH)is stronger than that in the Northern Hemisphere(SH),which may be due to the discrepancy in conductivities between the two hemispheres,caused by the tilted dipole.In both hemispheres,the downward soft-electron energy flux of the dawnside patches is significantly greater than that of the duskside patches.展开更多
Utilizing the Standardized Precipitation Evapotranspiration Index(SPEI)and ERA5 reanalysis data,this study investigates the variability of spring drought in southern China from 1979 to 2022 and its associated drivers....Utilizing the Standardized Precipitation Evapotranspiration Index(SPEI)and ERA5 reanalysis data,this study investigates the variability of spring drought in southern China from 1979 to 2022 and its associated drivers.The results indicate that southern China experienced interdecadal changes in SPEI over the past several decades,which can be concluded that drought severity intensified from 1979 to 2010,whereas a transition shift towards increased wetness occurred from 2010 to 2022.The first Empirical Orthogonal Function(EOF1)mode of SPEI variability in southern China accounts for 44.37%of the total variance,reflecting a uniform variation of SPEI across the region.In contrast,the second Empirical Orthogonal Function(EOF2),which explains 24.41%of the total variance,reveals a west-east dipole pattern in SPEI variability.Further analysis indicates that the positive phase of EOF1 is primarily driven by warm sea surface temperature anomalies(SSTAs)in the tropical eastern Pacific.These anomalies induce an anomalous anticyclone over the Philippine Sea,enhancing water vapor transport to southern China during spring.The positive phase of EOF2 is jointly influenced by warm SSTAs in the tropical Indian Ocean and the central Pacific;the latter induces anticyclonic anomalies over the Philippine Sea,which enhance water vapor transport from the western Pacific and increase precipitation in the eastern part of southern China.However,the warm SSTAs in the tropical Indian Ocean trigger an anomalous anticyclone over South Asia,inhibiting water vapor transport from the Bay of Bengal to the western part of southern China and thus reducing precipitation there.展开更多
The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factor...The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factors shaping these variations.This study aimed to investigate the variation in the types and concentrations of elements within the otolith nuclei of three Antarctic fish species,including Pagothenia borchgrevinki,Trematomus hansoni,and Trematomus bernacchii,collected from Prydz Bay,East Antarctica.Nine elements,^(23)Na,^(24)Mg,^(29)Si,^(31)P,^(39)K,^(57)Fe,^(66)Zn,^(88)Sr,and^(137)Ba,were selected for analyses because of their concentrations and ecological significance.Ratios of each element to Ca(Me/Ca)were used for analysis,and Me/Ca in the otolith nuclei of these species were analyzed to explore species-specific variations in element types.Significant differences in element composition,except for Fe/Ca and Ba/Ca,were found in different species.Temperature,salinity,reproduction,pelagic larval lifestyle,and diet composition were considered as key endogenous and exogenous factors influencing these differences.Decision tree discriminant analysis,based on the variation of the types and concentrations of elements,was used to identify P.borchgrevinki,T.hansoni,and T.bernacchii with accuracy rates of 86.54%,82.61%,and 73.33%,respectively.Principal component analysis showed overlapping 95%confidence el-lipses for the three species at 79.96%,67.31%,and 56.71%,respectively.As these species belong to the Nototheniidae family and share a similar hatching period,the accuracy of species discrimination is reduced.Considering the high probability of error in distin-guishing species using otolith nucleus elements,we recommend otolith shape should also be considered to improve identification ac-curacy.展开更多
The oceanic mixed layer in the Southern Ocean is characterized by numerous fronts due to the stirring of freshwater influxes arising from ice melting.The interaction of these fronts with winds modulates the evolution ...The oceanic mixed layer in the Southern Ocean is characterized by numerous fronts due to the stirring of freshwater influxes arising from ice melting.The interaction of these fronts with winds modulates the evolution of the mixed layer and affects atmosphere−ocean energy exchanges.However,the underlying mechanism behind the wind-front interaction remains obscure due to a lack of three-dimensional observations of the ocean,particularly in terms of velocities.To address this issue,this study investigates the dynamics of fronts within the mixed layer during a storm by employing a subset of the global submesoscale-permitting simulation,Northeast Weddell Sea Pre-SWOT Level-4 Hourly MITgcm LLC4320 Native Grid 2km Oceanographic Dataset(ROAM_MIZ).We first compare the ROAM_MIZ data to glider data to assess the performance of the model simulation and find that the ROAM_MIZ can,to a large degree,capture sub-mesoscale features within a mixed layer.Subsequent analyses based on a subset of ROAM_MIZ show that lateral density gradients within the mixed layer rapidly decrease during high winds associated with the storm.Down-front winds accelerate this process as the Ekman buoyancy transport responsible for enhancing the instability of the fronts is primarily dominated by horizontal baroclinic components.After the storm,the fronts strengthen again in the presence of weaker winds due to the frontogenesis by the larger-scale strain.Moreover,the non-geostrophic turbulence induces a modification of the relative vorticity,affecting the instability within the mixed layer.These findings offer valuable guidance for the deployment of observational instruments and subsequent analysis,as well as deepen the understanding of air−sea interactions in the Southern Ocean.展开更多
Sub-seasonal prediction of regional compound heatwaves and their predictability sources remain unclear.In this study,the underlying mechanisms for the long-lasting compound heatwave over Southern China during July 1–...Sub-seasonal prediction of regional compound heatwaves and their predictability sources remain unclear.In this study,the underlying mechanisms for the long-lasting compound heatwave over Southern China during July 1–18,2010,and the major sources of its sub-seasonal prediction skill are identified.The results show that both the development and decay of this compound heatwave are mainly dominated by atmospheric processes(i.e.,adiabatic heating associated with anticyclonic circulation),whereas land-atmosphere coupling processes play an important role in sustaining the heatwave.A further analysis indicates that by inducing anomalous anticyclonic circulations over Southern China,the tropical intraseasonal oscillations with periods of 30–60 days and 10–30 days facilitate the occurrence and maintenance of the heatwave during its entire and second half periods,respectively.The NCEP Climate Forecast System Version 2 shows a low skill in predicting the 2010 compound heatwave over Southern China when the lead time is longer than 2 pentads,which is largely attributed to the model’s bias in representing the intensity and phase of intra-seasonal oscillations.展开更多
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515140007).
文摘The Southern Advanced Photon Source(SAPS)is a diffraction-limited synchrotron light source under design,which employs longitudinal injection as its primary injection scheme.This kind of injection scheme requires that the injected beam has a short bunch length and low emittance,and the preferred injector should offer high stability and low cost.Therefore,an injector based on a booster synchrotron was developed.The proposed injector includes a 250 MeV linac,a booster synchrotron that ramps the beam energy to 3.5 GeV,and two beam transport lines to ensure efficient beam delivery and beam quality preservation.The linac utilizes a thermionic high-voltage DC gun for reliable operation and features a bunching system with an advanced focusing system to preserve the emittance.To meet the injection requirements of the SAPS,a comprehensive design for the booster has been conducted.The booster synchrotron employs a threefold lattice structure,incorporating modified theoretical minimum emittance cells with a small momentum compaction factor and a high voltage to achieve an emittance of 3.98 nm rad and a bunch length of 4.8 mm.The injector has the potential to deliver a high charge,reducing the injection period of the storage ring to less than 1 min.Simulations demonstrated the expected performance,with a transmission efficiency of 90%,confirming its capability to meet the injection requirement of the SAPS storage ring.This design offers a stable and efficient solution for the SAPS.
文摘Correction to:Journal of Forestry Research(2025)36:124 https://doi.org/10.1007/s11676-025-01918-8 In this article the author’s name Yasutomo Hoshika was incorrectly written as Yasutoma Hoshika.The original article has been corrected.
基金supported by the National Natural Science Foundation of China[grant numbers 41975087,U2242212,and 41975085]supported by the National Natural Science Foundation of China[grant number U2242212]。
文摘Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.
基金supported by the National Natural Science Foundations of China(Grant Nos:41890831 and 42172214)the MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest University.
文摘This study provides new evidence for a significant Neoproterozoic tectono-thermal event in the southern Dharwar Craton,based on U-Pb dating of rutile and monazite from metamorphic rocks of the Sargur Group.Trace element analysis of rutile in garnet-bearing amphibolite,amphibolite,garnet-bearing staurolite-kyanite schist,and grunerite-garnet schist suggests that their protoliths were primarily basaltic rocks,sediments with mafic component,pelitic sediments,and mixed sediments with both mafic and felsic components,respectively.Rutile U-Pb ages of 625±22 Ma(garnet-bearing amphibolite),752±5.1 Ma(amphibolite),836±4 Ma to 663±26 Ma(garnet-bearing staurolite kyanite schist)and 860±13 Ma(grunerite-garnet schist),along with a monazite U-Pb age of 789±4.4 Ma(garnet-bearing staurolite kyanite schist),record a significant Neoproterozoic(860-625 Ma)tectono-thermal event along the southern margin of the western Dharwar Craton.This event is most likely associated with aborted rift-related alkaline magmatism along the northern margin of the Southern Granulite Terrane(SGT)and the southern margin of the Dharwar Craton.Given the lack of direct evidence for the assembly of the Rodinia supercontinent in the Dharwar Craton and SGT,this Neoproterozoic event is unlikely to be related to the breakup of Rodinia.
基金the National Natural Science Foundation of China(Nos.52204005,52192622,U20A20265)the Sichuan Science Fund for Young Scholars(23NSFSC4652).
文摘Deep shale gas reservoirs in the southern Sichuan Basin are typically characterized by significant horizontal stress anisotropy(expressed as stress difference),variable brittleness-ductility in rock mechanics,and strong heterogeneity.These complex geomechanical conditions lead to pronounced differences in hydraulic fracturing outcomes among wells and sections.To investigate hydraulic fracture propagation and fracturing fluid injection behavior under varying geomechanical settings,true triaxial physical simulation tests were performed on 400×400×400 mm artificial rock samples.The samples were designed with different media properties based on similarity criteria.A sensitivity analysis was conducted to assess the effects of brittleness-ductility characteristics,natural fractures,and in-situ stress conditions.The results reveal that:(i)brittle samples with lower stress difference are favorable for forming complex,perforable fracture networks;(ii)brittle samples with higher stress difference tend to develop simple,planar hydraulic fractures,with natural fractures only slightly activated during very short injection periods;(iii)ductile behavior enhances the activation of natural fractures but reduces fracture complexity compared with brittle samples,even under lower stress difference;and(iv)for typical deep shale formations,larger fluid injection volumes combined with high-density,multi-cluster fracturing techniques are recommended.
基金supported by the National Key R&D Program of China(2022YFD1201802)the Shandong Key R&D Program,China(2022CXGC010607)+2 种基金the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ZDRW202109)the Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP2017-ICS)the Subproject of the Major Project of Science and Technology in Shanxi Province,China(202201140601025-1-02)。
文摘Southern corn rust(SCR)is an airborne fungal disease caused by Puccinia polysora Underw.(P.polysora)that adversely impacts maize quality and yields worldwide.Screening for new elite SCR-resistant maize loci or genes has the potential to enhance overall resistance to this pathogen.Using phenotypic SCR resistance-related data collected over two years and three geographical environments,a genome-wide association study was carried out in this work,which eventually identified 91 loci that were substantially correlated with SCR susceptibility.These included 13 loci that were significant in at least three environments and overlapped with 74 candidate genes(B73_RefGen_v4).Comparative transcriptomic analyses were then performed to identify the genes related to SCR infection,with 2,586 and 797 differentially expressed genes(DEGs)ultimately being identified in the resistant Qi319and susceptible 8112 inbred lines following P.polysora infection,respectively,including 306 genes common to both lines.Subsequent integrative multi-omics investigations identified four potential candidate SCR response-related genes.One of these genes is ZmHCT9,which encodes the protein hydroxycinnamoyl transferase 9.This gene was up-regulated in susceptible inbred lines and linked to greater P.polysora resistance as confirmed through cucumber mosaic virus(CMV)-based virus induced-gene silencing(VIGS)system-mediated gene silencing.These data provide important insights into the genetic basis of the maize SCR response.They will be useful for for future research on potential genes related to SCR resistance in maize.
基金supported by the National Natural Science Foundation of China(Grant Nos.42230405,42006029)Science and Technology Plan of Liaoning Province(2024JH2/102400061)+1 种基金Dalian Science and Technology Innovation Fund(2024JJ11PT007)Dalian Science and Technology Pro-gram for Innovation Talents of Dalian(2022RJ06).
文摘Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention has been paid to changes in the genesis locations of mesoscale eddies.Here,we provide evidence from three decades of satellite altimetry observations for the heterogeneity of the poleward shift of mesoscale activities,with the largest trend of~0.23°±0.05°(10 yr)^(-1) over the Atlantic sector and a moderate trend of~0.1°±0.03°(10 yr)^(-1) over the Indian sector,but no significant trend in the Pacific sector.The poleward shift of mesoscale eddies is associated with a southward shift of the local westerly winds while being constrained by the major topographies.As the poleward shift of westerly winds is projected to persist,the poleward oceanic heat flux from mesoscale eddies may influence future ice melt.
文摘On January 7,2025,01:05:15 UTC(9:05 a.m.local time)southern Tibet was rocked by a M_(W)7.1 earthquake(M_(W)=moment magnitude,USGS)centered(28.639°N 87.361°E)in the Lhasa Block north of the India/Eurasia Plate boundary,in a remote area about 180 km SW of Xigaze,in Dingri County of Shigatse of the Xizang Autonomous Region(Figure 1).
基金funded by the National Key Research and Development Plan of China(2023YFD1400300)National Natural Science Foundation of China(U23A6006,32270149,32272555)+1 种基金Zhejiang Provincial Natural Science Foundation(LZ22C140001)the Ningbo Major Research and Development Plan Project(2023Z124).
文摘Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorly understood.In this study,we assessed SRBSDV susceptibility in 20 Xian/indica(XI)and 20 Geng/japonica(GJ)rice varieties.XI-1B accessions in the Xian subgroup displayed higher resistance than GJ accessions.Comparative transcriptome analysis revealed changes in processes like oxidoreductase activity,jasmonic acid(JA)metabolism,and stress response.JA sensitivity assays further linked antiviral defense to the JA pathway.These findings highlight a JA-mediated resistance mechanism in rice and offer insights for breeding SRBSDV-resistant varieties.
文摘Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale irrigation can supply local and sub-regional markets with food in the off-season, it has received little research and its challenges are therefore rarely addressed. In order to contribute to the knowledge of these small-scale irrigation systems, with a view to improving their structure and the management of irrigation water and energy, an assessment of small-scale irrigation in the southern slopes of the Bamboutos Mountains has been done. After direct observations, field measurements, surveys of 100 irrigators with questionnaires and interviews with administrative managers, analyses were carried out using Xlstat software. It was found out that about 226 small-scale irrigation systems designed and managed by producers have been installed on this slope between the end of December 2022 and mid-March 2023. Intended for market garden crops, 84.96% of these irrigation systems use sprinklers and 15.04% surface irrigation (furrow irrigation). Surface or underground water is mobilized using gravity (50%), fossil fuels (34.51%), electricity (14.6%) or solar energy (0.9%). Sprinkler irrigation is mainly carried out using locally manufactured hydraulic turnstiles. There is a lack of formal associations of irrigators in an environment marked by conflicts between water users, when there is not allocation for water withdrawal. Apart from the high cost of pumping energy ($1.32 per liter of fuel), the main constraint identified, which has become more acute over the years, is the lack of irrigation water during the water shortage period (from mid-January to mid-March). These constraints have led to a transition from surface irrigation to sprinkler irrigation, and the adoption of new energy supply and water mobilization technologies. The construction of collective surface and groundwater catchment structures with solar-powered pumping systems, the setting up of formal irrigators’ associations and an irrigation support service, could improve the availability of water throughout the irrigation season, thereby helping to improve the income generated by irrigated market-garden farming on the southern slopes of the Bamboutos Mountains.
文摘The Baibokoum syenitic pluton(BSP),located in southern Chad,to the NE of the Adamawa-Yadédomain,is one of the few strongly potassic magmatic bodies in the southern part of the Central African Fold Belt(CAFB)in Chad.It has been previously studied petrologically,but its petrogenesis has remained poorly known.Petrographic and whole-rock geochemical data presented in this article highlight their magma genesis and geodynamic evolution.The BSP consists of medium-to coarse-grained syenites associated with minor microdiorites,which occur as syn-plutonic dikes and mafic microgranular enclaves(MME)coarse-and medium-grained syenites outcrop respectively to the core and the border of the BSP.The syenite displays high-K and alkaline to trans-alkaline affinity.Petrographic and geochemical data suggest that medium-to coarse-grained syenites are from single magma source that evolved and differentiated by fractional crystallization in a magma reservoir.REE profiles show enriched LREEs(La_(N)/Yb_(N)=6.19-45.55)while HREEs show an almost flat profile(Dy_(N)/Yb_(N)=1.0-2.23),and the La/Sm and Sm/Yb ratios have led to propose that the aforementioned rocks derived from the partial melting of a garnet-spinel-lherzolite mantle source.Negative Nb and Ta anomalies indicate that this mantle source was modified by the addition of subduction-related material.Th/Yb ratios associated with high Ba/La ratios indicate that enrichment of the source could be related to slab-derived fluids.The parental magma of the BSP was generated by partial melting of the metasomatized lithospheric mantle that was modified into arc-magmatism material in a subduction setting.Its emplacement took place in two successive stages:a static stage of fractional crystallization and crystal settling in a deep magma source and a dynamic stage in a shear deformation setting during which stratified magma rises towards the upper crust,with evolved syenite magma being emplaced first and diorite later.The emplacement of the BSP was probably controlled by the evolution of the Tcholliré-Banyo Fault and M'BéréShear Zone during the Pan-African orogeny.
基金funded by National Science Foundation of China(Grant no.42276238)Impact and Response of Antarctic Seas to Climate Change(Grant nos.IRASCC 01-02-01D,01-01-02A)Taishan Scholars Program.
文摘Phytoplankton play a pivotal role in the Southern Ocean ecosystem.This study examines the phytoplankton community structure and the environmental factors driving it in the Cosmonaut Sea,based on samples collected using a net during the summer of 2020/2021.We identified 99 phytoplankton species,predominantly comprising diatoms and dinoflagellates.Among these,diatoms-notably Pseudo-nitzschia,Chaetoceros,and Fragilariopsis,dominated the community in terms of species richness,abundance,and biomass.Endemic species of the Southern Ocean,such as Corethron pennatum,Proboscia alata,and Cylindrotheca closterium,also made significant contributions.Phytoplankton abundance and biomass showed similar spatial distribution patterns,with hotspots in the northern section of the survey area that gradually diminished towards the coastal regions.The oceanic area exhibited low phytoplankton diversity but pronounced regional variations in community distribution,with the northern region emerging as a key zone for abundance,biomass,and diversity.Nutrient distribution was identified as the primary environmental driver shaping the phytoplankton community,with silicate levels having a significant negative impact on overall phytoplankton abundance and the dominant species.
基金Supported by Central Government Funds for Guiding Local Scientific and Technological Development(24ZYQF002)Major Science and Technology Project of Gansu Province(24ZDNF001)+1 种基金National Key R&D Program"Exploration and Utilization of Disease-and Pest-Resistant and High-Yield Gene Resources in Maize"(2022YDF1201800)Key Laboratory of Mechanized Maize Variety Creation,Ministry of Agriculture and Rural Affairs.
文摘The intensification of global warming has led to the continuous outbreak of southern rust(Puccinia polysora Underw.)in major maize-producing regions worldwide.The severe outbreak in the Huang-Huai-Hai summer maize region of China in 2021 caused yield losses exceeding 50%in some plots,and this disease has been included in the List of Key Crop Pests and Diseases.This paper systematically reviews the molecular resistance mechanisms of maize to southern rust,focusing on the immune mechanisms mediated by NLR family genes and the characteristics of the Bin 10.01 resistance gene cluster;it summarizes the advances in research of molecular breeding technologies such as gene marker development,map-based cloning,and gene editing;combined with the disease characteristics of the spring-sown maize region in Southwest China and the summer-sown maize region in Huang-Huai-Hai,it elaborates on regionally adapted prevention and control strategies;integrating breeding practices of Dunhuang Seed Industry Group(e.g.,Dunyu 810 and Dunyan 616),it proposes a full-chain solution of"precision gene pyramiding-heterotic group utilization-regional promotion".It is expected to provide theoretical and technical references for molecular breeding of maize resistance to southern rust.
基金supported by the National Natural Science Foundation of China(42167023)the China Postdoctoral Science Foundation(2024MD753947)+1 种基金the National Natural Science Foundation of Inner Mongolia(2023QN04007,2022MS04009)the Basic Scientific Research Project of Institutions of Higher Learning in Inner Mongolia(JY20230090).
文摘The study of the electrical structure and fluid content of the southern San Andreas Fault(SSAF)plays a significant role in understanding the geological processes and earthquake genesis.The paper analyzes the Bahr skew and G-B decomposition from magnetotelluric sounding data in the SSAF to determine the strike direction is north-eastward 135°.Using the Nonlinear Conjugate Gradient algorithm,a reliable 2D electrical structure model was obtained.The Mission Creek and Banning faults,components of the SSAF,exhibit high conductivity within the crust,whereas the Eastern Transverse Ranges to the northeast of the fault show high resistivity characteristics.By integrating the modified Archie's law,the relations between conductivity,temperature,salinity,and fluid content were established,leading to conductivity-temperature and conductivity-fluid content relationships.Combining the results from the electrical structure model and fluid model of the SSAF,it is inferred that the fluid content in the high-conductivity crust reach up to 20%.When the fluid salinity is 10 wt%,the fluid content required to achieve the same high bulk conductivity reduces to 2%.A comparison of the electrical structure and focal depth of the Tan-Lu Fault Zone reveals that the collision between the low-viscosity fluids of the Mission Creek and Banning faults and the rigid Eastern Transverse Ranges contributes to the earthquake in the SSAF.
基金supported by the National Natural Science Foundation of China(Grant No.42102223)the Chinese Postdoctoral Science Foundation(Grant Nos.2021M693844,2022T150284)+1 种基金the Chinese Geological Survey Project(Grant No.DD20160204-3)the discipline innovation team of Liaoning Technical University(Grant Nos.LNTU20TD-14,LNTU20TD-30)。
文摘Coal pore parameters are closely related to macrolithotypes and coal structures,having a large influence over the gas potential and productivity of coalbed methane(CBM).The Middle Jurassic Xishanyao Formation,located in the southern Junggar Basin of northwestern China,has geological conditions with rich CBM resources.The 46 Xishanyao coal samples gathered from the drilling cores and coal mines cover 4 types of macrolithotypes(bright coal 1,semi-bright coal 2,semi-dull coal 3,and dull coal 4)and 2 types of coal structures(primary coal I and cataclastic coal II).Based on a range of pore testing experiments and analytical methods,the dual effects of different macrolithotypes and coal structures on pore structures were intensely studied.The results showed that the specific surface area(SSA)and total pore volume(TPV)of coal samples increased gradually from bright to dull coals.For the same macrolithotypes,the SSA and TPV of the primary coals were lower than those of the cataclastic coals.Generally,the pore structures of bright and semi-bright coals are simpler when compared to semi-dull and dull coals with the same coal structure,whereas cataclastic coals have more complicated pore structure systems than primary coals with the same macrolithotypes.The bright and semi-bright coals have higher vitrinite contents and more endogenous fractures,whereas well-developed structural fractures were identified in cataclastic coals.Therefore,bright and semi-bright coals have better pore connectivity than semi-dull and dull coals with the same coal structure,the pore connectivity of cataclastic coals being slightly better than that of primary coals under the same macrolithotypes.In terms of the CBM adsorption conditions,the eight type samples formed a descending order:Ⅱ-4>I-4>Ⅱ-3>Ⅰ-3>Ⅱ-2>Ⅰ-2>Ⅱ-1>Ⅰ-1,while they ranked as follows when consideration was given to the CBM seepage capacities:II-2>Ⅱ-1>Ⅰ-2>Ⅰ-1>Ⅰ-3>Ⅰ-4>Ⅱ-3>Ⅱ-4.As a result,it could be determined that the bright and semi-bright coals had stronger adsorption capacities,whereas the cataclastic coals had better pore connectivity and seepage capacities.Pore structure characteristics should be analysed under the dual control of different macrolithotypes and coal structures,so that they can provide greater value for guiding CBM exploration and exploitation,as along for preventing underground gas accidents.
基金supported by the National Natural Science Foundation of China(Grants 42325404,42120104003,42204164,42474219 and U22A2006)the Chinese Meridian Project,the International Partnership Program of Chinese Academy of Sciences(Grant 183311KYSB20200003)+7 种基金Shandong Provincial Natural Science Foundation(Grants ZR2022QD077,ZR2022MD034)the Stable-Support Scientific Project of China Research Institute of Radiowave Propagation(Grant A132312191)the foundation of the National Key Laboratory of Electromagnetic Environment(Grant 6142403180204)the Chongqing Natural Science Foundation(Grants cstc2021ycjh-bgzxm0072,CSTB2023NSCQ-LZX0082)National Program on Key Basic Research Project(Grant 2022173-SD-1)The work in Norway is supported by the Research Council of Norway Grant 326039Work at UCLA has been supported by NSF grant AGS-2055192This research was supported by the International Space Science Institute(ISSI)in Bern and Beijing,through ISSI International Team project#511(Multi-Scale Magnetosphere-Ionosphere-Thermosphere Interaction).
文摘This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were identified by Defense Meteorological Satellite Program(DMSP)F16 during the years 2011 to 2022.A temperature ratio of ion/electron temperature(T_(i)/T_(e))<0.68 is recommended to define a hot patch in the Southern Hemisphere,otherwise it is defined as a cold patch.The cold and hot patches have different dependencies on IMF clock angle,while their dependencies on IMF cone angle are similar.Both cold and hot patches appear most often on the duskside,and the distribution of cold patches gradually decreases from the dayside to the nightside,while hot patches have a higher occurrence rate near 14 and 21 magnetic local time(MLT).Moreover,we compared the key plasma characteristics of polar cap cold and hot patches in the Southern and Northern Hemispheres.The intensity of the duskside upward field-aligned current of patches in the Southern Hemisphere(SH)is stronger than that in the Northern Hemisphere(SH),which may be due to the discrepancy in conductivities between the two hemispheres,caused by the tilted dipole.In both hemispheres,the downward soft-electron energy flux of the dawnside patches is significantly greater than that of the duskside patches.
基金Natural Science Foundation of Guangdong Province,China(2024A1515011352)National Natural Science Founda-tion of China(42275020)+2 种基金Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhu-hai)(311021001)Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(2020B1212060025)Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction(FDAOS-OP202401)。
文摘Utilizing the Standardized Precipitation Evapotranspiration Index(SPEI)and ERA5 reanalysis data,this study investigates the variability of spring drought in southern China from 1979 to 2022 and its associated drivers.The results indicate that southern China experienced interdecadal changes in SPEI over the past several decades,which can be concluded that drought severity intensified from 1979 to 2010,whereas a transition shift towards increased wetness occurred from 2010 to 2022.The first Empirical Orthogonal Function(EOF1)mode of SPEI variability in southern China accounts for 44.37%of the total variance,reflecting a uniform variation of SPEI across the region.In contrast,the second Empirical Orthogonal Function(EOF2),which explains 24.41%of the total variance,reveals a west-east dipole pattern in SPEI variability.Further analysis indicates that the positive phase of EOF1 is primarily driven by warm sea surface temperature anomalies(SSTAs)in the tropical eastern Pacific.These anomalies induce an anomalous anticyclone over the Philippine Sea,enhancing water vapor transport to southern China during spring.The positive phase of EOF2 is jointly influenced by warm SSTAs in the tropical Indian Ocean and the central Pacific;the latter induces anticyclonic anomalies over the Philippine Sea,which enhance water vapor transport from the western Pacific and increase precipitation in the eastern part of southern China.However,the warm SSTAs in the tropical Indian Ocean trigger an anomalous anticyclone over South Asia,inhibiting water vapor transport from the Bay of Bengal to the western part of southern China and thus reducing precipitation there.
基金supported by the Impact and Response of Antarctic Seas to Climate Change(No.IRASCC 2020-2025)from the Ministry of Natural Resources of the Peo-ple’s Republic of China.
文摘The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factors shaping these variations.This study aimed to investigate the variation in the types and concentrations of elements within the otolith nuclei of three Antarctic fish species,including Pagothenia borchgrevinki,Trematomus hansoni,and Trematomus bernacchii,collected from Prydz Bay,East Antarctica.Nine elements,^(23)Na,^(24)Mg,^(29)Si,^(31)P,^(39)K,^(57)Fe,^(66)Zn,^(88)Sr,and^(137)Ba,were selected for analyses because of their concentrations and ecological significance.Ratios of each element to Ca(Me/Ca)were used for analysis,and Me/Ca in the otolith nuclei of these species were analyzed to explore species-specific variations in element types.Significant differences in element composition,except for Fe/Ca and Ba/Ca,were found in different species.Temperature,salinity,reproduction,pelagic larval lifestyle,and diet composition were considered as key endogenous and exogenous factors influencing these differences.Decision tree discriminant analysis,based on the variation of the types and concentrations of elements,was used to identify P.borchgrevinki,T.hansoni,and T.bernacchii with accuracy rates of 86.54%,82.61%,and 73.33%,respectively.Principal component analysis showed overlapping 95%confidence el-lipses for the three species at 79.96%,67.31%,and 56.71%,respectively.As these species belong to the Nototheniidae family and share a similar hatching period,the accuracy of species discrimination is reduced.Considering the high probability of error in distin-guishing species using otolith nucleus elements,we recommend otolith shape should also be considered to improve identification ac-curacy.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42406241,42325604,42227901)the Ministry of Science and Technology of China (No. 2021YFC2803304)+2 种基金the Program of Shanghai Academic/Technology Research Leader (22XD1403600)supported by the Swedish Research Council (Nos. 2020–03190 and 2024-04209)the Swedish Research Council for the Environment, Agricultural Sciences and Spatial Planning (No. 202400375)
文摘The oceanic mixed layer in the Southern Ocean is characterized by numerous fronts due to the stirring of freshwater influxes arising from ice melting.The interaction of these fronts with winds modulates the evolution of the mixed layer and affects atmosphere−ocean energy exchanges.However,the underlying mechanism behind the wind-front interaction remains obscure due to a lack of three-dimensional observations of the ocean,particularly in terms of velocities.To address this issue,this study investigates the dynamics of fronts within the mixed layer during a storm by employing a subset of the global submesoscale-permitting simulation,Northeast Weddell Sea Pre-SWOT Level-4 Hourly MITgcm LLC4320 Native Grid 2km Oceanographic Dataset(ROAM_MIZ).We first compare the ROAM_MIZ data to glider data to assess the performance of the model simulation and find that the ROAM_MIZ can,to a large degree,capture sub-mesoscale features within a mixed layer.Subsequent analyses based on a subset of ROAM_MIZ show that lateral density gradients within the mixed layer rapidly decrease during high winds associated with the storm.Down-front winds accelerate this process as the Ekman buoyancy transport responsible for enhancing the instability of the fronts is primarily dominated by horizontal baroclinic components.After the storm,the fronts strengthen again in the presence of weaker winds due to the frontogenesis by the larger-scale strain.Moreover,the non-geostrophic turbulence induces a modification of the relative vorticity,affecting the instability within the mixed layer.These findings offer valuable guidance for the deployment of observational instruments and subsequent analysis,as well as deepen the understanding of air−sea interactions in the Southern Ocean.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)National Natural Science Foundation of China(42105015)+3 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515010659)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP209)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021001)Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(2020B1212060025)。
文摘Sub-seasonal prediction of regional compound heatwaves and their predictability sources remain unclear.In this study,the underlying mechanisms for the long-lasting compound heatwave over Southern China during July 1–18,2010,and the major sources of its sub-seasonal prediction skill are identified.The results show that both the development and decay of this compound heatwave are mainly dominated by atmospheric processes(i.e.,adiabatic heating associated with anticyclonic circulation),whereas land-atmosphere coupling processes play an important role in sustaining the heatwave.A further analysis indicates that by inducing anomalous anticyclonic circulations over Southern China,the tropical intraseasonal oscillations with periods of 30–60 days and 10–30 days facilitate the occurrence and maintenance of the heatwave during its entire and second half periods,respectively.The NCEP Climate Forecast System Version 2 shows a low skill in predicting the 2010 compound heatwave over Southern China when the lead time is longer than 2 pentads,which is largely attributed to the model’s bias in representing the intensity and phase of intra-seasonal oscillations.
