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Airborne Investigation of Riming: Cloud and Precipitation Microphysics within a Weak Convective System in North China

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ADVANCES IN ATMOSPHERIC SCIENCES 2025年第3期42卷 515-526页

作者： Hu, Xiangfeng Huang, Hao Hou, Shaoyu Zhao, Kun Zhao, Chuanfeng Lu, Yinghui Yang, Jiefang Zhang, Rong Zhao, Delong liu, weiguo Zhang, Dan Xiao, Haixia China Meteorol Adm Key Lab Radar Meteorol Beijing 100044 Peoples R China China Meteorol Adm State Key Lab Severe Weather Beijing 100044 Peoples R China China Meteorol Adm Xiongan Atmospher Boundary Layer Key Lab Xiongan New Area Hebei 071703 Peoples R China Hebei Prov Weather Modificat Ctr Shijiazhuang 051430 Hebei Peoples R China Nanjing Univ Sch Atmospher Sci Key Lab Mesoscale Severe Weather MOE Jiangsu 210023 Peoples R China Nanjing Univ Frontiers Sci Ctr Crit Earth Mat Cycling Jiangsu 210023 Peoples R China Peking Univ Sch Phys Dept Atmospher & Ocean Sci Beijing 100871 Peoples R China Chinese Acad Sci Inst Atmospher Phys Lab Cloud Precipitat Phys & Severe Storms Beijing 100029 Peoples R China China Meteorol Adm Cloud Precipitat Phys & Weather Modificat Key Lab Beijing 100044 Peoples R China Beijing Weather Modificat Ctr Beijing 100089 Peoples R China Nanjing Joint Inst Atmospher Sci Nanjing 210000 Peoples R China

The process of riming significantly impacts the microphysical characteristics of clouds. This study uses aircraft and radar observation data in stratiform clouds with convection embedded that occurred in the central and southern regions of North China on 22 May 2017. The microphysical structural characteristics and processes near the embedded convection core and in the stratiform cloud are analyzed comparatively. Particular attention is given to the effect of riming on the microphysical properties near the upper boundary of the melting layer and to the factors influencing riming efficiency. The collaborative observations reveal that the particle size distributions observed near the convection core and in the stratiform region are close, while the particle properties like habit and riming degree are quite different. Above the melting layer, larger plate-like ice particles and supercooled water droplets (D > 50 mu m) are more abundant near the convective core, leading to higher collision efficiencies between ice particles and supercooled water droplets. Larger fluctuation amplitudes of vertical airflow near the convective core also contribute to the increased riming activity and the formation of more heavily rimed particles, such as graupel. Furthermore, in situ measurements from airborne probes also revealed that above the melting layer, the riming process involves two stages: the mass of snow crystals grows as supercooled droplets merge internally without changing size, followed by external freezing that significantly enlarges the crystals.

关键词： riming collision efficiency airflow fluctuation particle habit aircraft measurement

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Airborne Investigation of Riming: Cloud and Precipitation Microphysics within a Weak Convective System in North China

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Advances in Atmospheric Sciences 2025年第03期 515-526页

作者： Xiangfeng HU Hao HUANG Shaoyu HOU Kun ZHAO Chuanfeng ZHAO Yinghui LU Jiefang YANG Rong ZHANG Delong ZHAO weiguo liu Dan ZHANG Haixia XIAO Key Laboratory of Radar Meteorology and State Key Laboratory of Severe Weather China Meteorology Administration China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory Hebei Provincial Weather Modification Center School of Atmospheric Sciences Key Laboratory of Mesoscale Severe Weather/MOE and Frontiers Science Center for Critical Earth Material Cycling Nanjing University Department of Atmospheric and Oceanic Sciences School of Physics Peking University Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of Sciences Cloud-Precipitation Physics and Weather Modification Key Laboratory China Meteorology Administration Beijing Weather Modification Center Nanjing Joint Institute for Atmospheric Sciences

The process of riming significantly impacts the microphysical characteristics of clouds. This study uses aircraft and radar observation data in stratiform clouds with convection embedded that occurred in the central and southern regions of North China on 22 May 2017. The microphysical structural characteristics and processes near the embedded convection core and in the stratiform cloud are analyzed comparatively. Particular attention is given to the effect of riming on the microphysical properties near the upper boundary of the melting layer and to the factors influencing riming efficiency. The collaborative observations reveal that the particle size distributions observed near the convection core and in the stratiform region are close, while the particle properties like habit and riming degree are quite different. Above the melting layer,larger plate-like ice particles and supercooled water droplets(D > 50 μm) are more abundant near the convective core,leading to higher collision efficiencies between ice particles and supercooled water droplets. Larger fluctuation amplitudes of vertical airflow near the convective core also contribute to the increased riming activity and the formation of more heavily rimed particles, such as graupel. Furthermore, in situ measurements from airborne probes also revealed that above the melting layer, the riming process involves two stages: the mass of snow crystals grows as supercooled droplets merge internally without changing size, followed by external freezing that significantly enlarges the crystals.

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Hydrogen isotopic composition of plant leaf wax in response to soil moisture in an arid ecosystem of the northeast Qinghai-Tibetan Plateau, China

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Journal of Arid Land 2014年第5期6卷 592-600页

作者： Yuan YAO weiguo liu School of Human Settlements and Civil Engineering Xi'an Jiaotong University State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences

The hydrogen isotopic composition of plant leaf wax（δDwax） is used as an important tool for paleohydrologic reconstruction. However, the understanding of the relative importance of environmental and biological factors in determining δDwax values still remains incomplete. To identify the effects of soil moisture and plant physiology on δDwax values in an arid ecosystem, and to explore the implication of these values for paleoclimatic reconstruction, we measured δD values of soil water（δDwater） and δDwax values in surface soils along two distance transects extending from the lakeshore to wetland to dryland around Lake Qinghai and Lake Gahai on the northeast Qinghai-Tibetan Plateau. The results showed that the δDwater values were negatively correlated with soil water content（SWC）（R^2=0.9166）, and ranged from –67‰ to –46‰ with changes in SWC from 6.2% to 42.1% in the arid areas of the Gangcha（GCh） and Gahai（GH） transects. This indicated that evaporative D-enrichment in soil water was sensitive to soil moisture in an arid ecosystem. Although the shift from grasses to shrubs with increasing aridity occurred in the arid area of the GH transect, the δDwax values in surface soils from the arid areas of the two transects still showed a negative correlation with SWC（R^2=0.6835）, which may be due to the controls of primary evaporative D-enrichment in the soil water and additional transpirational D-enrichment in the leaf water on the δDwaxvalues. Our preliminary research suggested that δDwax values can potentially be applied as a paleo-humidity indicator on the northeast Qinghai-Tibetan Plateau.

关键词： hydrogen isotope D-enrichment soil water content northeast Qinghai-Tibetan Plateau

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n-Alkyl lipid concentrations and distributions in aquatic plants and their individual δD variations

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Science China Earth Sciences 2019年第9期62卷 1441-1452页

作者： Hu liu Zhonghui liu Cheng ZHAO weiguo liu State Key L aboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710061 China University of Chinese Academy of Sciences Beijing 100049 China Department of Earth Sciences The University of Hong Kong Hong Kong 999077 China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China

Aquatic plants are major input sources of autochthonous organic matter in lake sediments, but investigations on fatty acid(FA) and n-alkane distributions in aquatic plants are currently limited, greatly hindering the applications of their isotope geochemistry in lacustrine environments. Here, the reported n-alkyl lipid distributions of aquatic plants in globally studied lakes,together with newly obtained aquatic plant n-alkyl lipid data in Chinese lakes(Yunnan and Inner Mongolia), are used to understand their distribution characteristics. The results show that aquatic plants have predominantly mid-chain lipids(C23–C25 n-alkanes and C22–C24 FAs), differing from that of terrestrial plants(dominant by long-chain lipids), but the long-chain n-alkanes(e.g., C27 and C29) and long-chain FAs(e.g., C26 and C28) also show high abundances in most samples. Submerged plants have high concentrations of long-chain n-alkanes(avg. 47 μg g-1) and long-chain FAs(avg. 170 μg g-1), close to those in terrestrial plants, indicating that submerged plants may make large contributions of long-chain n-alkyl lipids to lake sediments, while the contributions of long-chain n-alkyl lipids derived from algae to lake sediments may be small because of their low concentrations(avg. 2 μg g-1 for n-alkanes and 9 μg g-1 for FAs). We find that lipid molecular proxies(including ACL14-32 and ATR14-18) can be reliably used to distinguish the FAs sourced from algae and other plants, and Paq′ values can be utilized to distinguish the nalkane sources between submerged plants and terrestrial plants. Aquatic plants do not have significant δD differences among different chain-length n-alkanes and FAs for each sample, suggesting that the offset between δD values of different chain-length n-alkyl lipids in lake sediments can help determine sedimentary lipid input sources and infer paleohydrological changes.

关键词： n-Alkanes Fatty acids Hydrogen isotopes Algae Submerged plants

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Distributions and hydrogen isotopic compositions of plant leaf wax from Orinus kokonorica along a general aridity gradient around Lake Qinghai, China

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Chinese Journal Of Geochemistry 2014年第3期33卷 236-243页

作者： YAO Yuan liu weiguo School of Human Settlements and Civil Engineering Xi'an Jiaotong University State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences

To quantitatively analyze the response of distributions and hydrogen isotopic compositions(δD) of plant leaf wax to moisture, and to better understand their implications for paleoclimatic reconstruction, we measured average chain length(ACL) and δD values of n-alkanes and n-fatty acids(n-FAs) from Orinus kokonorica, a typical and representative plant in Lake Qinghai area, along a distance transect extending from lakeshore to wetland to dryland in the arid ecosystem. The results showed that the ACL values of n-alkanes and n-FAs were negatively correlated with soil water content(SWC) with R2=0.593 and R2=0.924, respectively. This is as a result of plant's response to water loss with more abundance in long-chain n-alkyl lipids under increasing aridity by analyzing relationships between the molecular ratios of long-chain n-alkyl lipids(n-alkanes and n-FAs) from O. kokonorica and SWC. The δD values of C29 n-alkane and C28 n-FA were also negatively correlated with SWC with R2=0.778 and R2=0.760, respectively, which may due to enhanced D-enrichment in leaf water by evapotranspiration(soil water evaporation and leaf water transpiration) with increasing aridity. Our results demonstrated that moisture exerts a significant control on the ACL and δD values from O. kokonorica in an arid ecosystem. This preliminary study on a modern single plant(O. kokonorica) sets a foundation for comprehending these values as quantitative proxies for paleo-humidity reconstruction.

关键词：同位素组成青海湖地区植物叶干旱土壤水分蒸发访问控制列表正构烷烃梯度

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Influence factors of methane hydrate formation from ice:Temperature,pressure and SDS surfactant

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Chinese Journal of Chemical Engineering 2019年第2期27卷 405-410页

作者： weiguo liu Yanghui Li Xiaohu Xu Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology

A series of experiments of forming hydrate from ice powders in different conditions have been carried out with constant volume method to evaluate the influence factors such as pressure, temperature, and SDS surfactant. The change of temperature and pressure were collected as a function of elapsed time, which were used to calculate the gas consumption and hydrate saturation during hydrate formation(pVT method). Based on the experimental results and the analysis, it is concluded that:(1) Both initial pressure and temperature have effect on the hydrate formation and temperature plays a more important role in the process;(2) heating and secondary pressurization will promote the gas hydrate formation and enhance the hydrate saturation as a result. Meanwhile, the promotion of heating seems to be more obvious than that of secondary pressurization;(3) different concentrations of SDS surfactant have clearly influence on the saturation of gas hydrate and there is an optimal concentration to promote the hydrate formation.

关键词： Methane hydrate Ice Heating Secondary pressurization Surfactant

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A Comparison of Different Preservation Methods for Nitrogen Isotopes of Soil Extractable NO3^-

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Pedosphere 2018年第6期28卷 943-951页

作者： liu Junchi liu weiguo HU Jing State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710075(China) Key Laboratory of Vertebrate Evolution and Human Origin of Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044(China) University of Chinese Academy of Sciences Beijing 100049(China) School of Human Settlement and Civil Engineering Xi'an Jiaotong UniversityXi'an 710049(China)

Nitrogen(N) isotope ratio(δ^(15)N) of soil extractable NO_3^- plays a pivotal role in the study of N biogeochemical circulation in ecosystems. However, the NO_3^-concentration and its isotope composition of soil samples are unstable, making sample storage critical for preserving the N isotope composition of extracted soil NO_3^-. Nevertheless, studies on the appropriate selection of storage methods after soil sampling are scarce. In this study, we compared two commonly used methods for storing soil samples and investigated the stability of N isotopes of soil NO_3^-. The results demonstrated that no significant changes in the NO_3^-concentration and δ^(15)N value occurred in the samples stored at-18?C. However, the soil NO_3^-concentration markedly increased, and NO_3^-δ^(15)N value significantly changed after air-drying storage. Meanwhile, we also found that NO_3^-and its δ^(15)N were well preserved in the filtered soil extracts after 1 month. In contrast, the NO_3^-concentration gradually decreased and the^(15)N in NO_3^-was gradually enriched in the bactericidal agent-containing soil mixture solution during the storage period. Overall, our results indicated that N isotopes of NO_3^-could be effectively preserved in frozen-stored soil samples or filtered soil extracts. For field investigations conducted in remote areas and continued for a long-time period(and lacking a refrigerant supply), soil extraction/filtration using a CaSO_4-saturated solution may be a superior preparation and storage method for analyzing N isotopes of soil NO_3^-.

关键词： air-drying freezing ion exchange isotopic fractionation nitrogen isotope tracing soil extraction soil storage

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Compound-specific δD and its hydrological and environmental implication in the lakes on the Tibetan Plateau

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Science China Earth Sciences 2018年第6期61卷 765-777页

作者： Hu liu Hong YANG Yunning CAO weiguo liu State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi 'an 710061 China University of Chinese Academy of Sciences Beijing 100049 China Laboratory for Terrestrial Environments Department of Science and Technology College of Arts and Sciences Bryant University Smithfield Rhode Island 02917 USA

The hydrogen isotopic composition(δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges for the interpretation of the increasing dataset as an environment and climatic proxy. We systematically investigated n-alkane δD values from 51 submerged plants(39 Potamogeton, 1 Myriophyllum, and 11 Ruppia), 13 algae(5 Chara, 3 Cladophora, and 5 Spirogyra) and 20 terrestrial plants(10 grasses and 10 shrubs) in and around 15 lakes on the Tibetan Plateau. Our results demonstrate that δD values of C_(29) nalkane are correlated significantly with the lake water δD values both for algae(R^2=0.85, p0.05), suggesting that the n-alkane δD values of the algae and submerged plants record the signal of D enrichment in lake water relative to precipitation only in closed lakes in arid and semi-arid area. For each algae and submerged plant sample, we find uniformed δD values of different chain length n-alkanes, implying that, in combination with other proxies such as Paq and Average Chain Length, the offset between the δD values of different chain length n-alkanes can help

关键词： n-Alkane Hydrogen isotope composition Submerged plant Algae Tibetan Plateau

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Effects of neurotrophin-3 on the differentiation of neural stem cells into neurons and oligodendrocytes

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Neural Regeneration Research 2012年第19期7卷 1483-1487页

作者： Guowei Zhu Chongran Sun weiguo liu Department of Neurosurgery Second Affiliated Hospital of Zhejiang University Medical CollegeHangzhou 310009Zhejiang ProvinceChina

In this study, cells from the cerebral cortex of fetal rats at pregnant 16 days were harvested and cultured with 20 μg/L neurotrophin-3. After 7 days of culture, immunocytochemical staining showed that, 22.4% of cells were positive for nestin, 10.5% were positive for 18-111 tubulin （neuronal marker）, and 60.6% were positive for glial fibrillary acidic protein, but no cells were positive for 04 （oligodendrocytic marker）. At 14 days, there were 5.6% nestin-, 9.6% 13-111 tubulin-, 81.1% glial fibrillary acidic protein-, and 2.2% O4-positive cells. In cells not treated with neurotrophin-3, some were nestin-positive, while the majority showed positive staining for glial fibdllary acidic protein. Our experimental findings indicate that neurotrophin-3 is a crucial factor for inducing neural stem cells differentiation into neurons and oligodendrocytes.

关键词： neurotrophin-3 neural stem cells differentiation neuron oligodendrocytes stem cells neuralregeneration

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Efect of operating parameters on sulfide biotransformation to sulfur

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Journal of Environmental Sciences 2013年第12期25卷 2417-2421页

作者： weiguo liu Cunzhen Liang Jiaqing Chen Ling Zhu College of Resources and Environmental Engineering Wuhan University of Technology Department of Environmental Engineering Beijing Institute of Petrochemical Technology

A laboratory-scale bioreactor with polyethylene semi-soft packing was constructed and utilized to determine the efficlency of sulfide biotransformation to sulfur under various operating parameters. Sodium sulfide dissolved in tap water was pumped into the bioreactor as sulfide for biological desulfurization. The sulfide, sulfur and sulfate-S in the effluent and the sulfide purged as gas-phase HzS were determined to investigate the effects of operating parameters, such as pH, DO, hydraulic retention time （HRT）, temperature and salinity, on the sulfide oxidation products. The activity of bacteria was highest at pH 7.8-8.2. The maximal sulfide removal load was 7.25 kg/（m^3·day）, with a 322.07 mg/L influent sulfide concentration and 4.80 mg/L DO. The increase of DO value corresponds to a decrease in the sulfur yield. The reactor had the highest sulfide removal load and sulfur yield at 2.55 mg/L DO. HRT had little effect on desulfurization efficiency when the sulfide removal load was kept constant. The most effective desulfurization temperature was 33℃. The sulfide removal load decreased from 2.85 to 0.51 kg/（m^***） with increasing salinity from 0.5% to 2.5% （m/m）.

关键词： sulfide sulfur biotransformation operating parameters

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