Expanding urbanization and agricultural intensification across neighboring South Asia and East Asia have substantially threatened atmospheric condition over the Third Pole(TP)during the past few decades.Whether the at...Expanding urbanization and agricultural intensification across neighboring South Asia and East Asia have substantially threatened atmospheric condition over the Third Pole(TP)during the past few decades.Whether the atmospheric condition over the TP is still as clean as a representative of the regional background draws great concern.In this work,great differences in levoglucosan concentration within/above the atmospheric boundary layer height are revealed.Levoglucosan results support the hypothesis that atmospheric pollutants in the mid-troposphere over the TP are mainly affected by long-range transport,although there are some local biomass burning emissions in residential areas.In addition,levoglucosan concentration in the midtroposphere over the TP is at the same magnitude as marine and polar regions,but about 2–3 magnitudes lower than neighboring densely-populated Asian regions.With insights of levoglucosan records,this work therefore proves that the high-altitude TP still has largely pristine atmospheric conditions,and is one of the cleanest remote regions on the Earth.展开更多
To understand the spatio-temporal variability of precipitation(P)in the Third Pole region(centered on the Tibetan Plateau-TP),it is necessary to quantify the interannual periodicity of P and its relationship with larg...To understand the spatio-temporal variability of precipitation(P)in the Third Pole region(centered on the Tibetan Plateau-TP),it is necessary to quantify the interannual periodicity of P and its relationship with large-scale circulations.In this study,Morlet wavelet transform was used to detect significant(p<0.05)periodic characteristics in P data from meteorological stations in four climate domains in the Third Pole,and to reveal the major large-scale circulations that triggered the variability of periodic P,in addition to bringing large amounts of water vapour.The wavelet transform results were as follows.(1)Significant quasiperiodicity varied from 2 to 11 years.The high-frequency variability mode(2 to 6 years quasi-periods)was universal,and the low-frequency variability mode(7 to 11 years quasi-periods)was rare,occurring mainly in the westerlies and Indian monsoon domains.(2)The majority of periods were base periods(53%),followed by two-base periods.Almost all stations in the Third Pole(95%)showed one or two periods.(3)Periodicity was widely detected in the majority of years(84%).(4)The power spectra of P in the four domains were dominated by statistically significant high-frequency oscillations(ie.,with short periodicity).(5)Large-scale circulations directly and indirectly influenced the periodic P variability in the different domains.The mode of P variability in the different domains was influenced by interactions between large-scale circulation features and not only by the dominant circulation and its control of water vapour transport.The results of this study will contribute to better understanding of the causal mechanisms associated with P variability,which is important for hydrological science and waterresourcemanagement.展开更多
The diverse climates,distribution of snow and glaciers,and geographic locations directly affect the runoff response to climate change in the upper basins of the Third Pole.At present,a comprehensive analysis of runoff...The diverse climates,distribution of snow and glaciers,and geographic locations directly affect the runoff response to climate change in the upper basins of the Third Pole.At present,a comprehensive analysis of runoff variations and their distinct responses to climate change in the westerlies-and monsoon-dominated upper basins is still lacking.This study comprehensively analyzed annual runoff variations in westerlies-dominated basins(the upper basins of the Aksu(UAKS),Syr Darya(USRD),Yarkant(UYK),Hotan(UHT),Amu Darya(UAMD),and Indus(UI))and monsoon-dominated basins(the upper basins of the Yangtze(UYA),Yellow(UYE),Lancang(ULC),Nujiang(UNJ),and Yarlung Zangbo(UYZ))of the Third Pole from 1961 to2015.Using multi-source meteorological data and large-scale circulation factors,this study investigated the divergent responses of runoff in the upper basins to climate change,and explored the large-scale circulation mechanisms underlying runoff variations in these upper basins.The results showed that:(1)The annual runoff in the majority of upper basins(except for the UYE and UYZ)exhibited an increasing trend,and the annual runoff in the UAKS,UYK,and UI showed a significant increasing trend from1961 to 2015.The annual runoff in the upper basins of the Third Pole changed abruptly from decreasing to increasing between the 1980s and 2000s,with the exception of the UYE.(2)The runoff in the monsoon-dominated upper basins has been controlled primarily by changes in precipitation over the past 55 years.In contrast,the runoff in the westerlies-dominated upper basins exhibited three distinct long-term responses to climate change:temperature-dominated(UYK and UHT),precipitation-dominated(USRD and UAMD),and the combined influence of precipitation and temperature(UAKS and UI).Since the 1960s,the sensitivity of runoff to warm season temperature changes in the most westerlies-dominated upper basins has decreased,while the response of runoff to precipitation changes has intensified.(3)The study revealed the connection between large-scale circulation,climate,and runoff in the upper basins of the Third Pole.The Atlantic Multidecadal Oscillation,the Westerly Index,and the El Ni?o-Southern Oscillation predominantly impact the precipitation or temperature in the upper basins of the Third Pole,which in turn affect the runoff variations in the upper basins dominated by either the westerlies or the monsoon.This study will be a valuable scientific reference for water resource management and climate change adaptation for both the westerlies-and monsoon-dominated upper basins in the Third Pole.展开更多
The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibratio...The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibrations of traffic, and we listed successive scientific confirmations to indicate the rotation of the planet in a regular movement around its axis once every 24 hours, and it is running in another second movement around the sun once every 365¼ days, so are they only two movements, no more?! Is it possible for him to run at a regular speed in an additional direction?展开更多
Microorganisms are unique among all of the living organisms because of their high population size, advanced genetic diversity, short generation time, and quick response to the small change in environmental conditions....Microorganisms are unique among all of the living organisms because of their high population size, advanced genetic diversity, short generation time, and quick response to the small change in environmental conditions. Remote alpine lakes of the Third Pole region provide the unique habitat for microorganisms acting as a natural laboratory and offering the information about the ecological roles of microorganisms. Many researchers focused on microbial communities as well as the impact of physicochemical, biological and hydrological parameters in lakes of this region since decades but the comprehensive review focusing on bacterial diversity and the role of environmental parameters still lacks. Here we reviewed bacterial diversity in lakes of the Third Pole region by analyzing 16 S rRNA clone libraries accessed from previous research findings. A total of 5 388 bacterial 16 S rRNA gene sequences were analyzed and classified into different phylogenetic groups. The average relative abundance of dominant taxa includes Betaproteobacteria(19%), Bacteroidetes(18%), Gammaproteobacteria(16%), Actinobacteria(15%), Alphaproteobacteria(14%), Cyanobacteria(7%), and Firmicutes(5%). Several adaptational strategies were adopted by these dominant bacterial groups in order to accommodate in the respective habitat. Nevertheless, lake water properties like temperature, pH, salinity, incident UV radiation, turbidity, and nutrients also played role in bacterial diversity.展开更多
基金the Youth Innovation Promotion Association CAS(2020071)Chinese Academy of Sciences(YIPA-2020071,XDA20060200)+1 种基金the National Natural Science Foundation of China(41701078,41805127)the Second Tibetan Plateau Scientific Expedition and Research(2019QZKK0201).
文摘Expanding urbanization and agricultural intensification across neighboring South Asia and East Asia have substantially threatened atmospheric condition over the Third Pole(TP)during the past few decades.Whether the atmospheric condition over the TP is still as clean as a representative of the regional background draws great concern.In this work,great differences in levoglucosan concentration within/above the atmospheric boundary layer height are revealed.Levoglucosan results support the hypothesis that atmospheric pollutants in the mid-troposphere over the TP are mainly affected by long-range transport,although there are some local biomass burning emissions in residential areas.In addition,levoglucosan concentration in the midtroposphere over the TP is at the same magnitude as marine and polar regions,but about 2–3 magnitudes lower than neighboring densely-populated Asian regions.With insights of levoglucosan records,this work therefore proves that the high-altitude TP still has largely pristine atmospheric conditions,and is one of the cleanest remote regions on the Earth.
基金National Natural Science Foundation of China,No.42271141,No.42071129National Key Basic Research and Development Project,No.2022YFF1300902。
文摘To understand the spatio-temporal variability of precipitation(P)in the Third Pole region(centered on the Tibetan Plateau-TP),it is necessary to quantify the interannual periodicity of P and its relationship with large-scale circulations.In this study,Morlet wavelet transform was used to detect significant(p<0.05)periodic characteristics in P data from meteorological stations in four climate domains in the Third Pole,and to reveal the major large-scale circulations that triggered the variability of periodic P,in addition to bringing large amounts of water vapour.The wavelet transform results were as follows.(1)Significant quasiperiodicity varied from 2 to 11 years.The high-frequency variability mode(2 to 6 years quasi-periods)was universal,and the low-frequency variability mode(7 to 11 years quasi-periods)was rare,occurring mainly in the westerlies and Indian monsoon domains.(2)The majority of periods were base periods(53%),followed by two-base periods.Almost all stations in the Third Pole(95%)showed one or two periods.(3)Periodicity was widely detected in the majority of years(84%).(4)The power spectra of P in the four domains were dominated by statistically significant high-frequency oscillations(ie.,with short periodicity).(5)Large-scale circulations directly and indirectly influenced the periodic P variability in the different domains.The mode of P variability in the different domains was influenced by interactions between large-scale circulation features and not only by the dominant circulation and its control of water vapour transport.The results of this study will contribute to better understanding of the causal mechanisms associated with P variability,which is important for hydrological science and waterresourcemanagement.
基金supported by the National Natural Science Foundation of China(Grant No.41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0201)the National Science Foundation for Young Scientists of China(Grant No.42201140)。
文摘The diverse climates,distribution of snow and glaciers,and geographic locations directly affect the runoff response to climate change in the upper basins of the Third Pole.At present,a comprehensive analysis of runoff variations and their distinct responses to climate change in the westerlies-and monsoon-dominated upper basins is still lacking.This study comprehensively analyzed annual runoff variations in westerlies-dominated basins(the upper basins of the Aksu(UAKS),Syr Darya(USRD),Yarkant(UYK),Hotan(UHT),Amu Darya(UAMD),and Indus(UI))and monsoon-dominated basins(the upper basins of the Yangtze(UYA),Yellow(UYE),Lancang(ULC),Nujiang(UNJ),and Yarlung Zangbo(UYZ))of the Third Pole from 1961 to2015.Using multi-source meteorological data and large-scale circulation factors,this study investigated the divergent responses of runoff in the upper basins to climate change,and explored the large-scale circulation mechanisms underlying runoff variations in these upper basins.The results showed that:(1)The annual runoff in the majority of upper basins(except for the UYE and UYZ)exhibited an increasing trend,and the annual runoff in the UAKS,UYK,and UI showed a significant increasing trend from1961 to 2015.The annual runoff in the upper basins of the Third Pole changed abruptly from decreasing to increasing between the 1980s and 2000s,with the exception of the UYE.(2)The runoff in the monsoon-dominated upper basins has been controlled primarily by changes in precipitation over the past 55 years.In contrast,the runoff in the westerlies-dominated upper basins exhibited three distinct long-term responses to climate change:temperature-dominated(UYK and UHT),precipitation-dominated(USRD and UAMD),and the combined influence of precipitation and temperature(UAKS and UI).Since the 1960s,the sensitivity of runoff to warm season temperature changes in the most westerlies-dominated upper basins has decreased,while the response of runoff to precipitation changes has intensified.(3)The study revealed the connection between large-scale circulation,climate,and runoff in the upper basins of the Third Pole.The Atlantic Multidecadal Oscillation,the Westerly Index,and the El Ni?o-Southern Oscillation predominantly impact the precipitation or temperature in the upper basins of the Third Pole,which in turn affect the runoff variations in the upper basins dominated by either the westerlies or the monsoon.This study will be a valuable scientific reference for water resource management and climate change adaptation for both the westerlies-and monsoon-dominated upper basins in the Third Pole.
文摘The idea of research started with a crazy imaginary theory in the field of astrogeography, saying: We often taught ourselves and then convinced the students that the planet Earth moves despite not feeling the vibrations of traffic, and we listed successive scientific confirmations to indicate the rotation of the planet in a regular movement around its axis once every 24 hours, and it is running in another second movement around the sun once every 365¼ days, so are they only two movements, no more?! Is it possible for him to run at a regular speed in an additional direction?
基金financially supported by the National Natural Science Foundation of China (No. 41425004)
文摘Microorganisms are unique among all of the living organisms because of their high population size, advanced genetic diversity, short generation time, and quick response to the small change in environmental conditions. Remote alpine lakes of the Third Pole region provide the unique habitat for microorganisms acting as a natural laboratory and offering the information about the ecological roles of microorganisms. Many researchers focused on microbial communities as well as the impact of physicochemical, biological and hydrological parameters in lakes of this region since decades but the comprehensive review focusing on bacterial diversity and the role of environmental parameters still lacks. Here we reviewed bacterial diversity in lakes of the Third Pole region by analyzing 16 S rRNA clone libraries accessed from previous research findings. A total of 5 388 bacterial 16 S rRNA gene sequences were analyzed and classified into different phylogenetic groups. The average relative abundance of dominant taxa includes Betaproteobacteria(19%), Bacteroidetes(18%), Gammaproteobacteria(16%), Actinobacteria(15%), Alphaproteobacteria(14%), Cyanobacteria(7%), and Firmicutes(5%). Several adaptational strategies were adopted by these dominant bacterial groups in order to accommodate in the respective habitat. Nevertheless, lake water properties like temperature, pH, salinity, incident UV radiation, turbidity, and nutrients also played role in bacterial diversity.
