| 1 | Regional and Global Land Data Assimilation Systems: Innovations,Challenges, and Prospects显示文摘Since the North American and Global Land Data Assimilation Systems(NLDAS and GLDAS) were established in2004, significant progress has been made in development of regional and global LDASs. National, regional, projectbased, and global LDASs are widely developed across the world. This paper summarizes and overviews the development, current status, applications, challenges, and future prospects of these LDASs. We first introduce various regional and global LDASs including their development history and innovations, and then discuss the evaluation, validation, and applications(from numerical model prediction to water resources management) of these LDASs. More importantly, we document in detail some specific challenges that the LDASs are facing: quality of the in-situ observations, satellite retrievals, reanalysis data, surface meteorological forcing data, and soil and vegetation databases; land surface model physical process treatment and parameter calibration; land data assimilation difficulties; and spatial scale incompatibility problems. Finally, some prospects such as the use of land information system software, the unified global LDAS system with nesting concept and hyper-resolution, and uncertainty estimates for model structure,parameters, and forcing are discussed. | Youlong XIA Zengchao HAO Chunxiang SHI Yaohui LI Jesse MENG Tongren XU Xinying WU Baoqing ZHANG | 2019 | Journal of Meteorological Research2019，33，2： | 7 |
| 3 | Crystallography of low Z material at ultrahigh pressure:Case study on solid hydrogen显示文摘Diamond anvil cell techniques have been improved to allow access to the multimegabar ultrahigh-pressure region for exploring novel phenomena in condensedmatter.However,the onlyway to determine crystal structures of materials above 100 GPa,namely,X-ray diffraction(XRD),especially for lowZ materials,remains nontrivial in the ultrahigh-pressure region,even with the availability of brilliant synchrotron X-ray sources.In thiswork,we performa systematic study,choosing hydrogen(the lowest X-ray scatterer)as the subject,to understand how to better perform XRD measurements of low Z materials at multimegabar pressures.The techniques that we have developed have been proved to be effective in measuring the crystal structure of solid hydrogen up to 254GPa at room temperature[C.Ji et al.,Nature 573,558–562(2019)].Wepresent our discoveries and experienceswith regard to several aspects of thiswork,namely,diamond anvil selection,sample configuration for ultrahigh-pressure XRDstudies,XRDdiagnostics for low Z materials,and related issues in data interpretation and pressure calibration.Webelieve that these methods can be readily extended to other low Z materials and can pave the way for studying the crystal structure of hydrogen at higher pressures,eventually testing structural models of metallic hydrogen. | Cheng Ji Bing Li Wenjun Liu Jesse S.Smith Alexander Bjoorling Arnab Majumdar Wei Luo Rajeev Ahuja Jinfu Shu Junyue Wang Stanislav Sinogeikin Yue Meng Vitali B.Prakapenka Eran Greenberg Ruqing Xu Xianrong Huang Yang Ding Alexander Soldatov Wenge Yang Guoyin Shen Wendy L.Mao Ho-Kwang Mao | 2020 | Matter and Radiation at Extremes2020，5，3： | 0 |
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