We proposed a method using latent regression Bayesian network (LRBN) toextract the shared speech feature for the input of end-to-end speech recognition model.The structure of LRBN is compact and its parameter learning...We proposed a method using latent regression Bayesian network (LRBN) toextract the shared speech feature for the input of end-to-end speech recognition model.The structure of LRBN is compact and its parameter learning is fast. Compared withConvolutional Neural Network, it has a simpler and understood structure and lessparameters to learn. Experimental results show that the advantage of hybridLRBN/Bidirectional Long Short-Term Memory-Connectionist Temporal Classificationarchitecture for Tibetan multi-dialect speech recognition, and demonstrate the LRBN ishelpful to differentiate among multiple language speech sets.展开更多
Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosyste...Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.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
On 19 May 2022, an outbreak of 105 red sprites that occurred over South Asia was fortuitously recorded by two amateurs from a site in the southern Tibetan Plateau(TP), marking the highest number captured over a single...On 19 May 2022, an outbreak of 105 red sprites that occurred over South Asia was fortuitously recorded by two amateurs from a site in the southern Tibetan Plateau(TP), marking the highest number captured over a single thunderstorm in South Asia. Nearly half of these events involved dancing sprites, with an additional 16 uncommon secondary jets and at least four extremely rare green emissions called “ghosts” observed following the associated sprites. Due to the absence of the precise timing needed to identify parent lightning, a method based on satellite motion trajectories and star fields is proposed to infer video frame timestamps within an error of less than one second. After verifying 95 sprites from two videos, our method identified the parent lightning for 66 sprites(~70%). The sprite-producing strokes, mainly of positive polarity with peak currents exceeding +50 k A, occurred in the stratiform region of a mesoscale convective complex(MCC)that spanned the Ganges Plain to the southern TP, with a cloud area over 200 000 km2 and a minimum cloud-top black body temperature near 180 K. This observation confirms that thunderstorms in South Asia, akin to mesoscale convective systems(MCSs) in the Great Plains of the United States or coastal thunderstorms in Europe, can produce numerous sprites,including complex species. Our analysis bears important implications for characterizing thunderstorms above the southern TP and examining their physical and chemical effects on the adjacent regions, as well as the nature of the coupling between the troposphere and middle-upper atmosphere in this region.展开更多
Tibetan medical named entity recognition(Tibetan MNER)involves extracting specific types of medical entities from unstructured Tibetan medical texts.Tibetan MNER provide important data support for the work related to ...Tibetan medical named entity recognition(Tibetan MNER)involves extracting specific types of medical entities from unstructured Tibetan medical texts.Tibetan MNER provide important data support for the work related to Tibetan medicine.However,existing Tibetan MNER methods often struggle to comprehensively capture multi-level semantic information,failing to sufficiently extract multi-granularity features and effectively filter out irrelevant information,which ultimately impacts the accuracy of entity recognition.This paper proposes an improved embedding representation method called syllable-word-sentence embedding.By leveraging features at different granularities and using un-scaled dot-product attention to focus on key features for feature fusion,the syllable-word-sentence embedding is integrated into the transformer,enhancing the specificity and diversity of feature representations.The model leverages multi-level and multi-granularity semantic information,thereby improving the performance of Tibetan MNER.We evaluate our proposed model on datasets from various domains.The results indicate that the model effectively identified three types of entities in the Tibetan news dataset we constructed,achieving an F1 score of 93.59%,which represents an improvement of 1.24%compared to the vanilla FLAT.Additionally,results from the Tibetan medical dataset we developed show that it is effective in identifying five kinds of medical entities,with an F1 score of 71.39%,which is a 1.34%improvement over the vanilla FLAT.展开更多
The Tibetan Plateau(TP),known as the“Third Pole of Earth”,and its ecosystem is quite sensitive to climate change(Yao et al.,2012;Qiu,2008).In recent decades,the main TP has experienced warming and humidification(alt...The Tibetan Plateau(TP),known as the“Third Pole of Earth”,and its ecosystem is quite sensitive to climate change(Yao et al.,2012;Qiu,2008).In recent decades,the main TP has experienced warming and humidification(although there has been a drying trend in the southern region),and researchers anticipate that this change will continue in the future(Jiang et al.,2023;Sun et al.,2020;Chen et al.,2015).展开更多
Located in Sakya County,an ancient city nestled at the foot of the Himalayas,the 950-year-old Sakya Monastery majestically spans both the southern and northern banks of the Zhongqu River.Renowned for its distinctive a...Located in Sakya County,an ancient city nestled at the foot of the Himalayas,the 950-year-old Sakya Monastery majestically spans both the southern and northern banks of the Zhongqu River.Renowned for its distinctive architectural style and profound historical significance,the monastery has been academically hailed as the"Dunhuang in the Snowy Land"and sometimes referred to as"The Second Dunhuang".Shagtse Dorje,Executive Chief Editor of the Tibetan version of Tibetan Research and Director of the journal's Editorial Department,spoke in detail about the monastery's rich history and unique features during an interview with East-West Dialogue,a program hosted by China News Service.展开更多
In today's globalized world,cultural diversity has become an essential issue that cannot be overlooked.Tibetan medicine,one of the four major traditional medicines worldwide,carries rich historical and cultural co...In today's globalized world,cultural diversity has become an essential issue that cannot be overlooked.Tibetan medicine,one of the four major traditional medicines worldwide,carries rich historical and cultural connotations.It is a crucial component of the diverse cultures within the Chinese nation,and its preservation and development reflect China's strong commitment to protecting and practicing cultural diversity.展开更多
Group living is widespread across diverse taxa,and the mechanisms underlying collective decision-making in contexts of variable role division are critical for understanding the dynamics of group stability.While studie...Group living is widespread across diverse taxa,and the mechanisms underlying collective decision-making in contexts of variable role division are critical for understanding the dynamics of group stability.While studies on collective behavior in small animals such as fish and insects are well-established,similar research on large wild animals remains challenging due to the limited availability of sufficient and systematic field data.Here,we aimed to explore the collective decision-making pattern and its sexual difference for the dimorphic Tibetan antelopes Pantholops hodgsonii(chiru)in Xizang Autonomous Region,China,by analyzing individual leadership distribution,as well as the joining process,considering factors such as calving stages and joining ranks.The distinct correlations of decision participants’ratio with group size and decision duration underscore the trade-off between accuracy and speed in decision-making.Male antelopes display a more democratic decision-making pattern,while females exhibit more prompt responses after calving at an early stage.This study uncovers a partially shared decision-making strategy among Tibetan antelopes,suggesting flexible self-organization in group decision processes aligned with animal life cycle progression.展开更多
A subducted continental slab is sometimes torn during collision,yet the exact impact of slab-tearing on the overlying lithosphere remains unclear.Here,we image the structure and architecture of the Asian lithosphere a...A subducted continental slab is sometimes torn during collision,yet the exact impact of slab-tearing on the overlying lithosphere remains unclear.Here,we image the structure and architecture of the Asian lithosphere above the Indian slab in the eastern Tibetan Plateau using multiscale seismic tomography models and zircon Hf isotopic mapping,respectively.Our mantle V_(p)model shows that a large low-velocity anomaly extends laterally beneath the thinned Asian lithosphere above the tear zone roughly along the 26°N.The V_(s)images,magmatic records and Hf isotopic mapping indicate that this low-velocity anomaly recorded an asthenosphere flow eastward along the tear zone,which thermally eroded and refertilized the overlying Asian lithosphere,leading to the lithospheric melting,thinning and root delaminating.The vertical tear also generated a tectonic weak zone with associated Cenozoic potassic and carbonatitic magma suites.We argue that such a hot lithosphere discontinuity provided a reasonable mechanism for the abrupt change of crust thickness and the transformation of crust-mantle deformation from coupling to decoupling across the tear zone.展开更多
The position of the South Asian High(SAH)over the Tibetan Plateau(TP)exhibits significant interannual variability.In this study,the criteria for defining the establishment and withdrawal of the SAH,as well as their ac...The position of the South Asian High(SAH)over the Tibetan Plateau(TP)exhibits significant interannual variability.In this study,the criteria for defining the establishment and withdrawal of the SAH,as well as their activities over the TP,are re-evaluated.The SAH is classified as“established over the TP”when the 1660 dagpm geopotential height contour covers 25%or more of the TP,and“withdrawn from the TP”when this contour covers less than 25%.Statistical analysis shows that,on average,the SAH establishes over the TP by the 4th pentad of May(28th pentad)and withdraws from the TP around the 2nd pentad of October(56th pentad).Over the past 50 years(1974–2023),the SAH has tended to establish over the TP earlier and withdraw later,resulting in a longer duration of control over the TP,with the rate of increase accelerating since 2017.The SAH exhibits a long-term linear trend of an eastward shift during both its establishment and withdrawal phases.The anomalous activity of the SAH over the TP is influenced by atmospheric heat sources.When there is anomalous warming(cooling)of atmospheric heating over the Bay of Bengal and the Indochina Peninsula,the SAH tends to establish and withdraw earlier and further westward(later and further eastward),with the westerly trough located over East Asia(the western part of the TP).展开更多
Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of th...Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of the TP,most numerical models exhibit notable uncertainty in simulating snow conditions in this area.This study evaluates historical snow simulations and related climate anomalies over the TP in numerical models from phase 6 of the Coupled Model Intercomparison Project(CMIP6).The CMIP6 model simulations are compared with two observation-based products across different seasons and temporal scales,and the results indicate that the CMIP6 multimodel ensemble(MME)mean reasonably captures the spatial distribution of the annual and seasonal climatological mean TP snow,albeit with weaker magnitudes compared to observations.The CMIP6 MME performs better over the western TP than the eastern regions,showing a higher reproducibility of the long-term warming trends and declining snow cover trends,partly due to the atmospheric circulation anomalies related to global warming.Additionally,some CMIP6 models successfully capture the interannual variability of TPSC and its relationship with associated climate factors.Our work emphasizes the importance of CMIP6 model selection and pays attention to data reliability in interpreting CMIP6 model results across different TP regions when studying snow cover variations and climate effects using numerical models.展开更多
Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carb...Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carbon balance.However,the spatial distribution of regional C_(VEG)is not available remains highly uncertain due to lack of systematic research,especially for different organs.Here,we investigated the spatial distribution patterns and driving factors of C_(VEG)among different plant organs(leaf,branch,trunk and root)by systematically field grid-sampling 2040 field-plots of plant communities over the Tibetan Plateau from 2019 to 2020.The results showed that the carbon content of plant organs ranged from 255.53 to 515.58 g kg^(-1),with the highest in branches and the lowest in roots.Among the different plant functional groups,the highest C_(VEG)was found in evergreen coniferous forests,and the lowest in desert grasslands,with an average C_(VEG)of 1603.98 g m^(-2).C_(VEG)increased spatially from northwest to southeast over the Tibetan Plateau,with MAP being the dominant factor.Furthermore,the total vegetation carbon stock on the Tibetan Plateau was estimated to be 1965.62 Tg for all vegetation types.Based on the comprehensive field survey dataset,the Random Forest model effectively predicted and mapped the spatial distribution of C_(VEG)(including aboveground,belowground,and the total biomass carbon density)over the Tibetan Plateau with notable accuracy(validation R2 values were 71%,56%,and 64%for C_(AGB),C_(BGB),and C_(VEG),respectively)at a spatial resolution of 1 km×1 km.Our findings can help improve the accuracy of regional carbon stock estimations and provide parameters for carbon cycle model optimization and remote sensing calibration in the future.展开更多
This study examines the spatiotemporal evolution of Tibetan villages in western Sichuan through state transition models and predictive simulations to understand their complex dynamics and key driving factors.Using a c...This study examines the spatiotemporal evolution of Tibetan villages in western Sichuan through state transition models and predictive simulations to understand their complex dynamics and key driving factors.Using a combination of multivariate time-series analysis and chaotic attractor identification,the research identifies forest cover,economic growth,employment rates,road density,and communication network coverage as critical determinants of village trajectories.For instance,Molo Village recovers rapidly with a 10%increase in regional economic growth,while Xisuo Village becomes unstable with employment rate fluctuations above 2%.Shenzuo Village benefits from improved road density,and Minzu Village’s stability depends on forest cover.Jiangba Village relies on the growth of irrigated farmland and communication network coverage,whereas Kegeyi Village exhibits periodic dynamics and high sensitivity to employment variations.The findings underscore the inherent complexity and nonlinearity of rural systems,revealed through chaotic attractor analysis,which highlights the system’s sensitivity to initial conditions and external shocks.The article provides actionable insights into resilience mechanisms and offers practical recommendations for the sustainable development of culturally and ecologically sensitive regions.Emphasis on tailored management strategies is essential to meet the challenges faced by these unique systems in the face of modernization and environmental change.展开更多
There was limited knowledge about the flow fluctuations and cycling processes of saline springs in the Nangqen Basin in the Sanjiang tectonic zone.In this work,the flow variations of the saline springs during the wet ...There was limited knowledge about the flow fluctuations and cycling processes of saline springs in the Nangqen Basin in the Sanjiang tectonic zone.In this work,the flow variations of the saline springs during the wet and dry seasons were monitored using volumetric and cross-sectional methods,and the cycling process of the saline springs was quantitatively identified using the integrated hydrochemical and isotopic methods.The results show that most saline springs in the Nangqen Basin had significantly different flow rates,ion concentrations,and TDS concentrations.The ions mainly come from carbonate and sulfate minerals.There is no internal hydraulic connection between these saline springs,and the impact of seasonal changes on the flow is relatively small,indicating that the saline springs originate mainly from deep circulation.The recharge elevation of the saline springs ranges 3661-4990 m a.s.l.,with an average of 4100 m a.s.l.The circulation depth of the saline springs ranges of 240-570 m,with an average of 431 m.The recycle time ranges of 1.15-30.86 years,with an average of 15.66 years.These results could provide a scientific basis for the development and utilization of saline spring resources in the Nangqen Basin.展开更多
Mêdog,located at the entrance of the water vapour channel of the Yarlung Zangbo Grand Canyon,and it has the highest rainfall and lowest elevation on the Tibetan Plateau(TP).The droplet size distribution(DSD)and m...Mêdog,located at the entrance of the water vapour channel of the Yarlung Zangbo Grand Canyon,and it has the highest rainfall and lowest elevation on the Tibetan Plateau(TP).The droplet size distribution(DSD)and microphysical processes associated with rainfall usually exhibit different characteristics under different synoptic patterns.In this study,an objective classification method is used to categorize the synoptic patterns that affect heavy rainfall(daily rainfall amounts>10 mm)in Mêdog into four patterns:southwest airflow(SWA),southern-branch trough(SBT),intense baroclinicity(IBC),and terrain-forced precipitation(TFP).SWA occurs most frequently(approximately 70%)with a mean daily rainfall of~22 mm,while TFP has the lowest occurrence frequency(7.7%)but the highest mean daily rainfall(29 mm).Both SBT and IBC exhibit occurrence frequencies around 12%.Among these patterns,the SWA pattern predominantly occurs during the monsoon season with abundant moisture and the lowest concentration of small raindrops.In contrast,the TFP pattern exhibits the highest concentration of large raindrops and the widest DSD spectrum,which can be attributed to the frequent convective activities in this area.As a result,compared with those of the other three synoptic patterns,the TFP pattern exhibits a larger mass-weighted mean diameter(D_(m))and higher rain rate(R).For stratiform rainfall,the difference in D_(m)among the four synoptic patterns can be neglected.The largest(smallest)average lgNW-value is observed in the SWA(IBC)pattern.Regarding convective rainfall,IBC dominated by northerly cold air exhibits mixed-phase processes characterized by larger raindrops and lower concentrations,resembling continental-like rainfall.In contrast,SWA occurring in monsoon season shows high concentrations of small raindrops,deeming it similar to maritime-like rainfall.In terms of the derived relationships,there are significant differences in the D_(m)-R andμ-Λrelationships among the four synoptic patterns.In addition,the diurnal variation in the DSD is analyzed in terms of the four synoptic patterns.These findings can improve the understanding of the microphysical processes of heavy rainfall events under different synoptic patterns and provide a reference for microphysical parameterizations of numerical models.展开更多
Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for...Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for global biodiversity conservation,but its ecosystem is fragile.This study systematically investigated the characteristics,distribution,sources,and ecological risk of microplastics in rivers and lakes across the Tibetan Plateau using the Laser Direct Infrared Imaging Spectroscopy(LDIR).The results indicated that the mean abundances of microplastics in water and sediments were 4250 items/m^(3)(n=50)and 3750 items/kg(n=44),respectively.Microplastics with small sizes(50-200μm),characterized by transparent and white fragments,were predominant.The most common polymers identified were polyamide(PA),polyurethane(PU),polyethylene terephthalate(PET),polyvinyl chloride(PVC),polypropylene(PP),and polyethylene(PE).Water sampling sites near urban/suburban effluent outfalls showed high levels of contamination.Microplastics in water are primarily derived from sewage effluent and atmospheric deposition.No single driver has been identified as the key factor influencing the spatial distribution of microplastics in water.The abundance of microplastics in sediments was significantly negatively correlated with the distance to the nearest city/town(p<0.01,R=-0.56)and significantly positively correlated with precipitation(p<0.01,R=0.60).Discarded or landfilled plastic waste is a major source of microplastics in sediments,which accumulate through transport by stormwater runoff caused by precipitation.Three ecological risk assessment models for microplastics were applied,and the high proportion of hazardous polymers such as PU,PVC,and PA was found to be responsible for the high ecological risk in the study area.This study provides an accurate and detailed exploration of the characteristics,sources,and spatial distribution of microplastic pollution by advanced automatic detection method in rivers and lakes on the Tibetan Plateau.展开更多
In the author list,the corresponding author indicator(*)was inadvertently omitted from HOU Zengqian’s name.This has now been corrected to:“HOU Zengqian¹,*”.The online version of this article was corrected.
The Tibetan Plateau has a large number of hot springs with varying temperatures and hydrochemistry,high elevation,and limited nitrogenous nutrition.Nitrogen-fixing bacteria(NFB)can fix N_(2)to form ammonia and thus pr...The Tibetan Plateau has a large number of hot springs with varying temperatures and hydrochemistry,high elevation,and limited nitrogenous nutrition.Nitrogen-fixing bacteria(NFB)can fix N_(2)to form ammonia and thus provide bioavailable nitrogen.However,there is limited knowledge about the distribution of NFB and its influencing factors in Tibetan hot springs.Here,we measured hydrochemical variables of the hot springs with a wide temperature range(32–77°C)in the Qucai and Daggyai geothermal zones on the Tibetan Plateau and investigated the composition of NFB using high-throughput sequencing of 16SrRNA and nif H genes.The Cl^(-)/SO_(4)^(2-)ratio in Qucai hot springs was higher than that in Daggyai,indicating that Qucai and Daggyai hot springs were more affected by the supply of liquid and gaseous phases,respectively.The NFB communities consisted predominantly of Nirtospirae,Chloroflexi,Deltaproteobacteria and an unidentified clade,with the last three acting as the main NFB with over 42%of the communities(the proportions are significantly larger than those found in hot springs of other geothermal regions).This demonstrates the uniqueness of NFB communities in Tibetan hot springs.NFB richness was limited by temperature in the studied Tibetan hot springs and was significantly lower than in low-elevation geothermal regions.The NFB community was predominantly affected by hydrochemistry,in contrast to the entire prokaryotic community,which was primarily influenced by temperature.This study expands our current understanding of NFB distribution and diversity as well as biogeochemical process in geothermal spring environments.展开更多
Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study uti...Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.展开更多
文摘We proposed a method using latent regression Bayesian network (LRBN) toextract the shared speech feature for the input of end-to-end speech recognition model.The structure of LRBN is compact and its parameter learning is fast. Compared withConvolutional Neural Network, it has a simpler and understood structure and lessparameters to learn. Experimental results show that the advantage of hybridLRBN/Bidirectional Long Short-Term Memory-Connectionist Temporal Classificationarchitecture for Tibetan multi-dialect speech recognition, and demonstrate the LRBN ishelpful to differentiate among multiple language speech sets.
基金National Nonprofit Institute Research Grant of CAF,No.CAFYBB2018ZA004,No.CAFYBB2023ZA009Fengyun Application Pioneering Project,No.FY-APP-ZX-2023.02。
文摘Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.
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.
基金supported by the National Natural Science Foundation of China (Grant No.42394122)CAS Project of Stable Support for Youth Team in Basic Research Field (YSRR-018)+1 种基金the National Key R&D Program of China (2023YFC3007703)the Chinese Meridian Project, and the International Partnership Program of Chinese Academy of Sciences (183311KYSB20200003)。
文摘On 19 May 2022, an outbreak of 105 red sprites that occurred over South Asia was fortuitously recorded by two amateurs from a site in the southern Tibetan Plateau(TP), marking the highest number captured over a single thunderstorm in South Asia. Nearly half of these events involved dancing sprites, with an additional 16 uncommon secondary jets and at least four extremely rare green emissions called “ghosts” observed following the associated sprites. Due to the absence of the precise timing needed to identify parent lightning, a method based on satellite motion trajectories and star fields is proposed to infer video frame timestamps within an error of less than one second. After verifying 95 sprites from two videos, our method identified the parent lightning for 66 sprites(~70%). The sprite-producing strokes, mainly of positive polarity with peak currents exceeding +50 k A, occurred in the stratiform region of a mesoscale convective complex(MCC)that spanned the Ganges Plain to the southern TP, with a cloud area over 200 000 km2 and a minimum cloud-top black body temperature near 180 K. This observation confirms that thunderstorms in South Asia, akin to mesoscale convective systems(MCSs) in the Great Plains of the United States or coastal thunderstorms in Europe, can produce numerous sprites,including complex species. Our analysis bears important implications for characterizing thunderstorms above the southern TP and examining their physical and chemical effects on the adjacent regions, as well as the nature of the coupling between the troposphere and middle-upper atmosphere in this region.
基金supported in part by the National Science and Technology Major Project under(Grant 2022ZD0116100)in part by the National Natural Science Foundation Key Project under(Grant 62436006)+4 种基金in part by the National Natural Science Foundation Youth Fund under(Grant 62406257)in part by the Xizang Autonomous Region Natural Science Foundation General Project under(Grant XZ202401ZR0031)in part by the National Natural Science Foundation of China under(Grant 62276055)in part by the Sichuan Science and Technology Program under(Grant 23ZDYF0755)in part by the Xizang University‘High-Level Talent Training Program’Project under(Grant 2022-GSP-S098).
文摘Tibetan medical named entity recognition(Tibetan MNER)involves extracting specific types of medical entities from unstructured Tibetan medical texts.Tibetan MNER provide important data support for the work related to Tibetan medicine.However,existing Tibetan MNER methods often struggle to comprehensively capture multi-level semantic information,failing to sufficiently extract multi-granularity features and effectively filter out irrelevant information,which ultimately impacts the accuracy of entity recognition.This paper proposes an improved embedding representation method called syllable-word-sentence embedding.By leveraging features at different granularities and using un-scaled dot-product attention to focus on key features for feature fusion,the syllable-word-sentence embedding is integrated into the transformer,enhancing the specificity and diversity of feature representations.The model leverages multi-level and multi-granularity semantic information,thereby improving the performance of Tibetan MNER.We evaluate our proposed model on datasets from various domains.The results indicate that the model effectively identified three types of entities in the Tibetan news dataset we constructed,achieving an F1 score of 93.59%,which represents an improvement of 1.24%compared to the vanilla FLAT.Additionally,results from the Tibetan medical dataset we developed show that it is effective in identifying five kinds of medical entities,with an F1 score of 71.39%,which is a 1.34%improvement over the vanilla FLAT.
基金supported by the Basic Science Center for Tibetan Plateau Earth System(No.41988101)the Science and Technology Plan Project of the Xizang Autonomous Region(No.XZ202201ZD0005G01)。
文摘The Tibetan Plateau(TP),known as the“Third Pole of Earth”,and its ecosystem is quite sensitive to climate change(Yao et al.,2012;Qiu,2008).In recent decades,the main TP has experienced warming and humidification(although there has been a drying trend in the southern region),and researchers anticipate that this change will continue in the future(Jiang et al.,2023;Sun et al.,2020;Chen et al.,2015).
文摘Located in Sakya County,an ancient city nestled at the foot of the Himalayas,the 950-year-old Sakya Monastery majestically spans both the southern and northern banks of the Zhongqu River.Renowned for its distinctive architectural style and profound historical significance,the monastery has been academically hailed as the"Dunhuang in the Snowy Land"and sometimes referred to as"The Second Dunhuang".Shagtse Dorje,Executive Chief Editor of the Tibetan version of Tibetan Research and Director of the journal's Editorial Department,spoke in detail about the monastery's rich history and unique features during an interview with East-West Dialogue,a program hosted by China News Service.
文摘In today's globalized world,cultural diversity has become an essential issue that cannot be overlooked.Tibetan medicine,one of the four major traditional medicines worldwide,carries rich historical and cultural connotations.It is a crucial component of the diverse cultures within the Chinese nation,and its preservation and development reflect China's strong commitment to protecting and practicing cultural diversity.
基金supported by the National Natural Science Foundation of China(Grant no.32101237)the China Postdoctoral Science Foundation(Grant no.2021M691522)+1 种基金the National Key Research and Development Program(Grant no.2022YFC3202104)the Tibet Major Science and Technology Project(Grant no.XZ201901-GA-06).
文摘Group living is widespread across diverse taxa,and the mechanisms underlying collective decision-making in contexts of variable role division are critical for understanding the dynamics of group stability.While studies on collective behavior in small animals such as fish and insects are well-established,similar research on large wild animals remains challenging due to the limited availability of sufficient and systematic field data.Here,we aimed to explore the collective decision-making pattern and its sexual difference for the dimorphic Tibetan antelopes Pantholops hodgsonii(chiru)in Xizang Autonomous Region,China,by analyzing individual leadership distribution,as well as the joining process,considering factors such as calving stages and joining ranks.The distinct correlations of decision participants’ratio with group size and decision duration underscore the trade-off between accuracy and speed in decision-making.Male antelopes display a more democratic decision-making pattern,while females exhibit more prompt responses after calving at an early stage.This study uncovers a partially shared decision-making strategy among Tibetan antelopes,suggesting flexible self-organization in group decision processes aligned with animal life cycle progression.
基金supported by the National Natural Science Foundation of China(92462304)National Key Technologies R&D Program(2022YFF0800903)。
文摘A subducted continental slab is sometimes torn during collision,yet the exact impact of slab-tearing on the overlying lithosphere remains unclear.Here,we image the structure and architecture of the Asian lithosphere above the Indian slab in the eastern Tibetan Plateau using multiscale seismic tomography models and zircon Hf isotopic mapping,respectively.Our mantle V_(p)model shows that a large low-velocity anomaly extends laterally beneath the thinned Asian lithosphere above the tear zone roughly along the 26°N.The V_(s)images,magmatic records and Hf isotopic mapping indicate that this low-velocity anomaly recorded an asthenosphere flow eastward along the tear zone,which thermally eroded and refertilized the overlying Asian lithosphere,leading to the lithospheric melting,thinning and root delaminating.The vertical tear also generated a tectonic weak zone with associated Cenozoic potassic and carbonatitic magma suites.We argue that such a hot lithosphere discontinuity provided a reasonable mechanism for the abrupt change of crust thickness and the transformation of crust-mantle deformation from coupling to decoupling across the tear zone.
基金supported by the National Natural Science Foundation of China(Grant Nos.41930972 and 42475015)the Financial Meteorology Scientific and Technological Innovation Group of the China Meteorological Administration(Grant No.CMA2024ZD03).
文摘The position of the South Asian High(SAH)over the Tibetan Plateau(TP)exhibits significant interannual variability.In this study,the criteria for defining the establishment and withdrawal of the SAH,as well as their activities over the TP,are re-evaluated.The SAH is classified as“established over the TP”when the 1660 dagpm geopotential height contour covers 25%or more of the TP,and“withdrawn from the TP”when this contour covers less than 25%.Statistical analysis shows that,on average,the SAH establishes over the TP by the 4th pentad of May(28th pentad)and withdraws from the TP around the 2nd pentad of October(56th pentad).Over the past 50 years(1974–2023),the SAH has tended to establish over the TP earlier and withdraw later,resulting in a longer duration of control over the TP,with the rate of increase accelerating since 2017.The SAH exhibits a long-term linear trend of an eastward shift during both its establishment and withdrawal phases.The anomalous activity of the SAH over the TP is influenced by atmospheric heat sources.When there is anomalous warming(cooling)of atmospheric heating over the Bay of Bengal and the Indochina Peninsula,the SAH tends to establish and withdraw earlier and further westward(later and further eastward),with the westerly trough located over East Asia(the western part of the TP).
基金funded by the Natural Science Foundation of China(Grant No.W2412145,42275031)the Natural Science Foundation of Yunnan Province(Grant No.202302AN360006)。
文摘Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of the TP,most numerical models exhibit notable uncertainty in simulating snow conditions in this area.This study evaluates historical snow simulations and related climate anomalies over the TP in numerical models from phase 6 of the Coupled Model Intercomparison Project(CMIP6).The CMIP6 model simulations are compared with two observation-based products across different seasons and temporal scales,and the results indicate that the CMIP6 multimodel ensemble(MME)mean reasonably captures the spatial distribution of the annual and seasonal climatological mean TP snow,albeit with weaker magnitudes compared to observations.The CMIP6 MME performs better over the western TP than the eastern regions,showing a higher reproducibility of the long-term warming trends and declining snow cover trends,partly due to the atmospheric circulation anomalies related to global warming.Additionally,some CMIP6 models successfully capture the interannual variability of TPSC and its relationship with associated climate factors.Our work emphasizes the importance of CMIP6 model selection and pays attention to data reliability in interpreting CMIP6 model results across different TP regions when studying snow cover variations and climate effects using numerical models.
基金supported by CAS Project for Young Scientists in Basic Research(YSBR-037)the National Natural Science Foundation of China(42141004,32430067)by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP,2019QZKK060602).
文摘Tibetan Plateau,as one of the most carbon intensive regions in China,is crucial in the carbon cycle,and accurately estimating its vegetation carbon density(C_(VEG))is essential for assessing regional and national carbon balance.However,the spatial distribution of regional C_(VEG)is not available remains highly uncertain due to lack of systematic research,especially for different organs.Here,we investigated the spatial distribution patterns and driving factors of C_(VEG)among different plant organs(leaf,branch,trunk and root)by systematically field grid-sampling 2040 field-plots of plant communities over the Tibetan Plateau from 2019 to 2020.The results showed that the carbon content of plant organs ranged from 255.53 to 515.58 g kg^(-1),with the highest in branches and the lowest in roots.Among the different plant functional groups,the highest C_(VEG)was found in evergreen coniferous forests,and the lowest in desert grasslands,with an average C_(VEG)of 1603.98 g m^(-2).C_(VEG)increased spatially from northwest to southeast over the Tibetan Plateau,with MAP being the dominant factor.Furthermore,the total vegetation carbon stock on the Tibetan Plateau was estimated to be 1965.62 Tg for all vegetation types.Based on the comprehensive field survey dataset,the Random Forest model effectively predicted and mapped the spatial distribution of C_(VEG)(including aboveground,belowground,and the total biomass carbon density)over the Tibetan Plateau with notable accuracy(validation R2 values were 71%,56%,and 64%for C_(AGB),C_(BGB),and C_(VEG),respectively)at a spatial resolution of 1 km×1 km.Our findings can help improve the accuracy of regional carbon stock estimations and provide parameters for carbon cycle model optimization and remote sensing calibration in the future.
文摘This study examines the spatiotemporal evolution of Tibetan villages in western Sichuan through state transition models and predictive simulations to understand their complex dynamics and key driving factors.Using a combination of multivariate time-series analysis and chaotic attractor identification,the research identifies forest cover,economic growth,employment rates,road density,and communication network coverage as critical determinants of village trajectories.For instance,Molo Village recovers rapidly with a 10%increase in regional economic growth,while Xisuo Village becomes unstable with employment rate fluctuations above 2%.Shenzuo Village benefits from improved road density,and Minzu Village’s stability depends on forest cover.Jiangba Village relies on the growth of irrigated farmland and communication network coverage,whereas Kegeyi Village exhibits periodic dynamics and high sensitivity to employment variations.The findings underscore the inherent complexity and nonlinearity of rural systems,revealed through chaotic attractor analysis,which highlights the system’s sensitivity to initial conditions and external shocks.The article provides actionable insights into resilience mechanisms and offers practical recommendations for the sustainable development of culturally and ecologically sensitive regions.Emphasis on tailored management strategies is essential to meet the challenges faced by these unique systems in the face of modernization and environmental change.
基金supported by the National Natural Science Foundation of China(Nos.42007169,U20A2088)the Natural Science Foundation of Qinghai Province(No.2020-ZJ-932Q)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0805-02)。
文摘There was limited knowledge about the flow fluctuations and cycling processes of saline springs in the Nangqen Basin in the Sanjiang tectonic zone.In this work,the flow variations of the saline springs during the wet and dry seasons were monitored using volumetric and cross-sectional methods,and the cycling process of the saline springs was quantitatively identified using the integrated hydrochemical and isotopic methods.The results show that most saline springs in the Nangqen Basin had significantly different flow rates,ion concentrations,and TDS concentrations.The ions mainly come from carbonate and sulfate minerals.There is no internal hydraulic connection between these saline springs,and the impact of seasonal changes on the flow is relatively small,indicating that the saline springs originate mainly from deep circulation.The recharge elevation of the saline springs ranges 3661-4990 m a.s.l.,with an average of 4100 m a.s.l.The circulation depth of the saline springs ranges of 240-570 m,with an average of 431 m.The recycle time ranges of 1.15-30.86 years,with an average of 15.66 years.These results could provide a scientific basis for the development and utilization of saline spring resources in the Nangqen Basin.
基金funded by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program,Grant No.2019QZKK0105Basic Research Fund of CAMS(2023Z009)Science and Technology Development Fund of Chinese Academy of Meteorological Sciences(2023KJ041).
文摘Mêdog,located at the entrance of the water vapour channel of the Yarlung Zangbo Grand Canyon,and it has the highest rainfall and lowest elevation on the Tibetan Plateau(TP).The droplet size distribution(DSD)and microphysical processes associated with rainfall usually exhibit different characteristics under different synoptic patterns.In this study,an objective classification method is used to categorize the synoptic patterns that affect heavy rainfall(daily rainfall amounts>10 mm)in Mêdog into four patterns:southwest airflow(SWA),southern-branch trough(SBT),intense baroclinicity(IBC),and terrain-forced precipitation(TFP).SWA occurs most frequently(approximately 70%)with a mean daily rainfall of~22 mm,while TFP has the lowest occurrence frequency(7.7%)but the highest mean daily rainfall(29 mm).Both SBT and IBC exhibit occurrence frequencies around 12%.Among these patterns,the SWA pattern predominantly occurs during the monsoon season with abundant moisture and the lowest concentration of small raindrops.In contrast,the TFP pattern exhibits the highest concentration of large raindrops and the widest DSD spectrum,which can be attributed to the frequent convective activities in this area.As a result,compared with those of the other three synoptic patterns,the TFP pattern exhibits a larger mass-weighted mean diameter(D_(m))and higher rain rate(R).For stratiform rainfall,the difference in D_(m)among the four synoptic patterns can be neglected.The largest(smallest)average lgNW-value is observed in the SWA(IBC)pattern.Regarding convective rainfall,IBC dominated by northerly cold air exhibits mixed-phase processes characterized by larger raindrops and lower concentrations,resembling continental-like rainfall.In contrast,SWA occurring in monsoon season shows high concentrations of small raindrops,deeming it similar to maritime-like rainfall.In terms of the derived relationships,there are significant differences in the D_(m)-R andμ-Λrelationships among the four synoptic patterns.In addition,the diurnal variation in the DSD is analyzed in terms of the four synoptic patterns.These findings can improve the understanding of the microphysical processes of heavy rainfall events under different synoptic patterns and provide a reference for microphysical parameterizations of numerical models.
基金supported by the National Natural Science Foundation of China(42322105)Outstanding Youth Fund of Gansu Province(23JRRA612)Postdoctoral Fellowship Program of CPSF(GZC20232952).
文摘Microplastics have emerged as one of the most significant threats to the Earth's ecosystems due to their persistence,ability to carry high loads of contaminants,and biotoxicity.The Tibetan Plateau is a hotspot for global biodiversity conservation,but its ecosystem is fragile.This study systematically investigated the characteristics,distribution,sources,and ecological risk of microplastics in rivers and lakes across the Tibetan Plateau using the Laser Direct Infrared Imaging Spectroscopy(LDIR).The results indicated that the mean abundances of microplastics in water and sediments were 4250 items/m^(3)(n=50)and 3750 items/kg(n=44),respectively.Microplastics with small sizes(50-200μm),characterized by transparent and white fragments,were predominant.The most common polymers identified were polyamide(PA),polyurethane(PU),polyethylene terephthalate(PET),polyvinyl chloride(PVC),polypropylene(PP),and polyethylene(PE).Water sampling sites near urban/suburban effluent outfalls showed high levels of contamination.Microplastics in water are primarily derived from sewage effluent and atmospheric deposition.No single driver has been identified as the key factor influencing the spatial distribution of microplastics in water.The abundance of microplastics in sediments was significantly negatively correlated with the distance to the nearest city/town(p<0.01,R=-0.56)and significantly positively correlated with precipitation(p<0.01,R=0.60).Discarded or landfilled plastic waste is a major source of microplastics in sediments,which accumulate through transport by stormwater runoff caused by precipitation.Three ecological risk assessment models for microplastics were applied,and the high proportion of hazardous polymers such as PU,PVC,and PA was found to be responsible for the high ecological risk in the study area.This study provides an accurate and detailed exploration of the characteristics,sources,and spatial distribution of microplastic pollution by advanced automatic detection method in rivers and lakes on the Tibetan Plateau.
文摘In the author list,the corresponding author indicator(*)was inadvertently omitted from HOU Zengqian’s name.This has now been corrected to:“HOU Zengqian¹,*”.The online version of this article was corrected.
基金supported by the National Natural Science Foundation of China(Nos.31300430,42172339,91951205)Key Scientific Research Project Plan of Colleges and Universities in Henan Province(No.18A180002)Science and Technology Research Project of Henan Province(No.152102310352)。
文摘The Tibetan Plateau has a large number of hot springs with varying temperatures and hydrochemistry,high elevation,and limited nitrogenous nutrition.Nitrogen-fixing bacteria(NFB)can fix N_(2)to form ammonia and thus provide bioavailable nitrogen.However,there is limited knowledge about the distribution of NFB and its influencing factors in Tibetan hot springs.Here,we measured hydrochemical variables of the hot springs with a wide temperature range(32–77°C)in the Qucai and Daggyai geothermal zones on the Tibetan Plateau and investigated the composition of NFB using high-throughput sequencing of 16SrRNA and nif H genes.The Cl^(-)/SO_(4)^(2-)ratio in Qucai hot springs was higher than that in Daggyai,indicating that Qucai and Daggyai hot springs were more affected by the supply of liquid and gaseous phases,respectively.The NFB communities consisted predominantly of Nirtospirae,Chloroflexi,Deltaproteobacteria and an unidentified clade,with the last three acting as the main NFB with over 42%of the communities(the proportions are significantly larger than those found in hot springs of other geothermal regions).This demonstrates the uniqueness of NFB communities in Tibetan hot springs.NFB richness was limited by temperature in the studied Tibetan hot springs and was significantly lower than in low-elevation geothermal regions.The NFB community was predominantly affected by hydrochemistry,in contrast to the entire prokaryotic community,which was primarily influenced by temperature.This study expands our current understanding of NFB distribution and diversity as well as biogeochemical process in geothermal spring environments.
基金supported by the National Key R&D Program of China[grant number 2022YFF0801603]the Natural Science Foundation of China[grant number 41905074].
文摘Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.
