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| 1 | A continuous simulation of Holocene effective moisture change represented by variability of virtual lake level in East and Central Asia显示文摘The fluctuation of a single lake level is a comprehensive reflection of water balance within the basin, while the regional consistent fluctuations of lake level can indicate the change of regional effective moisture. Previous researches were mainly focused on reconstructing effective moisture by multiproxy analyses of lake sediments. We carried out a series of experiments, including a transient climate evolution model, a lake energy balance model and a lake water balance model to simulate continuous Holocene effective moisture change represented by variability of virtual lake level in East and Central Asia.The virtual lake level, area, water depth and salinity are not equivalent to actual values, but we estimated relative changes of the regional effective moisture. We also explored the driving mechanisms of effective moisture change in different geographical regions. Our results indicated that gradually falling effective moisture during the Holocene in northern China was due to the combined effects of high lake evaporation caused by longwave and shortwave radiation, and low precipitation caused by reductions of summer solar insolation. A decline in effective moisture through the Holocene in the Tibetan Plateau and southern Central Asia resulted from decreased precipitation because of the weakening of the Asian summer monsoon. Increased precipitation induced by the strengthening of the westerly circulation contributed to the effective moisture rise during the Holocene in northern Central Asia. | Yu LI Yuxin ZHANG Xinzhong ZHANG Wangting YE Lingmei XU Qin HAN Yichan LI Hebin LIU Simin PENG | 2020 | Science China Earth Sciences2020，63，8： | 1 |
| 2 | A Molecular Dynamics Study on the (1120) Domain Boundary Structures in Epitaxial Wurtzite GaN显示文摘A computer program has been developed for the moIlcular dynamics calculation of ionic orstrong-ionic covalent systems. Ewald summation algorithm and Keating potentiaI model areadopted to calculate the long-range Coulomb interaction and the short-range bonding forces,respectively. A theoretical study on the domain boundary structures in epitaxial wurtzite GaN film is accomplished with the program. The calculation result is used in the structure formationexplanation of an interesting defect observed by HREM experiment. | Shaoqing WANGt Yuanming WANG and Hengqiang YE(Laboratory of Atomic Imaging of Solids, Institute of Metal Research, Chinese Academy of Sciences,Shenyang 110015, China)To whom correspondence should be addressedE-mail: sqwang@imr.ac.cn | 1999 | Journal of Materials Science & Technology1999，15，4： | 0 |
| 3 | A paleo-hydrological simulation experiment and its verification in an inland basin显示文摘Hydrological circulation,as the most basic material cycle and active natural phenomenon on earth,exerts a significant in fluence on climate change.The mid-Holocene is an important period to better understand modern environmental change;however,little research has focused on its quantitative simulation of paleo-hydrological process.In this research,we first collected chronological evidence and sediment records from six Holocene sedimentary sections in the Shiyang River Ba sin to reconstruct the mid-Holocene environment and terminal paleo-lake area.Secondly,we comprehensively analyzed modern pollen combinations and their propagation characteristics in surface soil,air,river and lacustrine sediments in the Shiyang River Basin,and combined the pollen records,as well as quantitatively reconstructed the millennial-scale vegeta tion zones.Finally,based on the land-cover adjustment results during the mid-Holocene,we successfully used the Soil and Water Assessment Tool(SWAT)model,a modern distributed hydrological watershed model,to simulate mid-Holocene runoff in the basin.Results show that the reconstructed climate in the basin was warmer and moister than that in recent times.Vegetation types in the mid-Holocene mainly consisted of sub-alpine shrub distributed between 2,550 m and 2,750 m,forest at an elevation of 2,550 2,750 m,steppe at an elevation of 1,550 2,150 m and desert steppe below 1,550 m.The up stream,midstream,downstream and average annual runoff of the mid-Holocene in the basin were 16.76×10^8 m^3,22.86×10^8 m^3,9.00×10^8 m^3 and 16.20×10^8 m^3 respectively,compared to 15.61×10^8 m^3 of modern annual runoff.Also,the area of terminal paleo-lake in the mid-Holocene was 628 km^2.Thus,this study provides a new quantitative method for paleo-hy drological simulation. | YuXin Zhang Yu Li XinZhong Zhang ChengQi Zhang WangTing Ye Yuan Liu | 2019 | Research in Cold and Arid Regions2019，11，4： | 0 |
| 4 | Holocene lake carbon sequestration, hydrological status and vegetation change, China显示文摘Lakes have received considerable attention as long-term sinks for organic carbon(C)at regional and global scales.Previ ous studies have focused on assessment and quantification of carbon sinks,and few have worked on the relationship be tween millennial-scale lake C sequestration,hydrological status and vegetation,which has important scientific signifi cance in improving our understanding of lake C stocks and storage mechanisms.Here,we present a comprehensive study of pollen records,organic geochemical proxies,lake-level records,sediment accumulation rate(SAR)and organic C accu mulation rate(CAR)in China since the Holocene.We also include numerical climate classification and lake-level simula tions,to investigate variations of lake C sequestration,hydrological status and vegetation during the Holocene.Results in dicate that the evolution of lake C accumulation showed an out-of-phase relationship with hydrological status and vegeta tion in China.Lake C accumulation exhibited an overall trend of increasing from the early to late Holocene in response to gradually increasing terrestrial organic matter input.However,China as a whole experienced the densest vegetation cover in the middle Holocene,corresponding to the mid-Holocene optimum of a milder and wetter climate.Optimal hydrologi cal conditions were asynchronous in China;for example,early Holocene in Asian monsoon dominated areas,and middle Holocene in westerlies controlled regions.Our synthesis indicated that climate change was the main factor controlling the long-term variability in lake C accumulation,hydrologic conditions,as well as vegetation,and human influences were usu ally superimposed on the natural trends. | LingMei Xu Yu Li WangTing Ye XinZhong Zhang YiChan Li YuXin Zhang | 2019 | Research in Cold and Arid Regions2019，11，4： | 0 |
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