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1The long-term trend of the sea surface wind speed and the wave height (wind wave, swell, mixed wave) in global ocean during the last 44 a显示文摘Utilizing the 45 a European Centre for Medium-Range Weather Forecasts(ECMWF)reanalysis wave data(ERA-40),the long-term trend of the sea surface wind speed and(wind wave,swell,mixed wave)wave height in the global ocean at grid point 1.5×1.5 during the last 44 a is analyzed.It is discovered that a majority of global ocean swell wave height exhibits a significant linear increasing trend(2–8 cm/decade),the distribution of annual linear trend of the significant wave height(SWH)has good consistency with that of the swell wave height.The sea surface wind speed shows an annually linear increasing trend mainly concentrated in the most waters of Southern Hemisphere westerlies,high latitude of the North Pacific,Indian Ocean north of 30 S,the waters near the western equatorial Pacific and low latitudes of the Atlantic waters,and the annually linear decreasing mainly in central and eastern equator of the Pacific,Juan.Fernandez Archipelago,the waters near South Georgia Island in the Atlantic waters.The linear variational distribution characteristic of the wind wave height is similar to that of the sea surface wind speed.Another find is that the swell is dominant in the mixed wave,the swell index in the central ocean is generally greater than that in the offshore,and the swell index in the eastern ocean coast is greater than that in the western ocean inshore,and in year-round hemisphere westerlies the swell index is relatively low.ZHENG Chongwei ZHOU Lin HUANG Chaofan SHI Yinglong LI Jiaxun LI Jing 2013Acta Oceanologica Sinica2013,32,10:23
2Large-scale Circulation Anomalies Associated with Interannual Variation in Monthly Rainfall over South China from May to August显示文摘Interannual variation in summer rainfall over South China(SC)was investigated on the monthly timescale.It was found that monthly rainfall from May to August exhibits different features of variation,and the amounts are basically independent of each other.There is a significant negative correlation,however,between May and July SC rainfall,which is partially related to the developing phases of ENSO events.It was also found that stronger(weaker)lower-tropospheric winds over SC and the upstream parts are responsible for more(less)SC rainfall in every month from May to August.Despite this monthly consistent enhancement of horizontal winds,the wind anomalies exhibit distinct differences between May–June and July–August,due to the remarkable change in climatological winds between these two periods.More SC rainfall is associated with a lower-tropospheric anticyclonic anomaly over the SCS and the Philippine Sea in May and June,but with a cyclonic anomaly centered over SC in July and August.SU Qin LU Riyu LI Chaofan 2014Advances in Atmospheric Sciences2014,31,2:11
3Optimizing Hotspot Areas for Ecological Planning and Management Based on Biodiversity and Ecosystem Services显示文摘The significance of biodiversity and ecosystem services are gradually recognized by human as an approach towards sustainability, so it is important to understand relationships and congruence between them to support conservation planning, especially in the hotspot areas with a prominent role in conservation. However, the management of most conservation hotspots mainly focused on biodiversity, and rarely concerned with ecosystem services. With the aim of proposing criteria for conservation strategies that contribute to the optimization of biodiversity and ecosystem services, in this study, a Geographic Information System(GIS)-based approach was designed to estimate and map the biodiversity and ecosystem services in Chongqing Municipality of China. Furthermore, the distributions of hotspot areas for biodiversity and ecosystem services were mapped based on the relationship between cumulative ecosystem services and areas. Finally the statistical analysis was processed focused on specific conservation objectives. The results showed that hotspot areas can conserve the most biodiversity but with the least ecosystem services under the conservation plans target to biodiversity conservation. In contrast, depending on the ecosystem services of interest, hotspot areas can conserve the largest ecosystem services but with the least biodiversity. By integrating biodiversity and ecosystem services into conservation plan, we found that the conservation and regeneration of these small areas, would contribute to a conservation of 44% of the biodiversity hotspot and 14%–42% of the ecosystem services hotspot. Moreover, the current nature reserve selection was not maximize the biodiversity and ecosystem services compared to integration strategy, indicating that hotspot areas conservation and selection is vital for optimization protection of biodiversity and ecosystem services, and has practical significance for natural resources and ecosystem management.XIAO Yang OUYANG Zhiyun XU Weihua XIAO Yi ZHENG Hua XIAN Chaofan 2016Chinese Geographical Science2016,26,2:11
4Why Was the Strengthening of Rainfall in Summer over the Yangtze River Valley in 2016 Less Pronounced than that in 1998 under Similar Preceding El Nino Events?Role of Midlatitude Circulation in August显示文摘It is widely recognized that rainfall over the Yangtze River valley(YRV) strengthens considerably during the decaying summer of El Ni ?no,as demonstrated by the catastrophic flooding suffered in the summer of 1998.Nevertheless,the rainfall over the YRV in the summer of 2016 was much weaker than that in 1998,despite the intensity of the 2016 El Nio having been as strong as that in 1998.A thorough comparison of the YRV summer rainfall anomaly between 2016 and 1998 suggests that the difference was caused by the sub-seasonal variation in the YRV rainfall anomaly between these two years,principally in August.The precipitation anomaly was negative in August 2016—different to the positive anomaly of 1998.Further analysis suggests that the weaker YRV rainfall in August 2016 could be attributable to the distinct circulation anomalies over the midlatitudes.The intensified 'Silk Road Pattern' and upper-tropospheric geopotential height over the Urals region,both at their strongest since 1980,resulted in an anticyclonic circulation anomaly over midlatitude East Asia with anomalous easterly flow over the middle-to-lower reaches of the YRV in the lower troposphere.This easterly flow reduced the climatological wind,weakened the water vapor transport,and induced the weaker YRV rainfall in August 2016,as compared to that in 1998.Given the unique sub-seasonal variation of the YRV rainfall in summer 2016,more attention should be paid to midlatitude circulation—besides the signal in the tropics—to further our understanding of the predictability and variation of YRV summer rainfall.chaofan li wei chen xiaowei hong riyu lu 2017Advances in Atmospheric Sciences2017,34,11:10
5Predictability of the Summer East Asian Upper-Tropospheric Westerly Jet in ENSEMBLES Multi-Model Forecasts显示文摘The interannual variation of the East Asian upper-tropospheric westerly jet(EAJ) significantly affects East Asian climate in summer. Identifying its performance in model prediction may provide us another viewpoint,from the perspective of uppertropospheric circulation,to understand the predictability of summer climate anomalies in East Asia. This study presents a comprehensive assessment of year-to-year variability of the EAJ based on retrospective seasonal forecasts,initiated from1 May,in the five state-of-the-art coupled models from ENSEMBLES during 1960–2005. It is found that the coupled models show certain capability in describing the interannual meridional displacement of the EAJ,which reflects the models' performance in the first leading empirical orthogonal function(EOF) mode. This capability is mainly shown over the region south of the EAJ axis. Additionally,the models generally capture well the main features of atmospheric circulation and SST anomalies related to the interannual meridional displacement of the EAJ. Further analysis suggests that the predicted warm SST anomalies in the concurrent summer over the tropical eastern Pacific and northern Indian Ocean are the two main sources of the potential prediction skill of the southward shift of the EAJ. In contrast,the models are powerless in describing the variation over the region north of the EAJ axis,associated with the meridional displacement,and interannual intensity change of the EAJ,the second leading EOF mode,meaning it still remains a challenge to better predict the EAJ and,subsequently,summer climate in East Asia,using current coupled models.LI Chaofan LIN Zhongda 2015Advances in Atmospheric Sciences2015,32,12:9
6A spatial-explicit dynamic vegetation model that couples carbon,water,and nitrogen processes for arid and semiarid ecosystems显示文摘Arid and semiarid ecosystems,or dryland,are important to global biogeochemical cycles.Dryland's community structure and vegetation dynamics as well as biogeochemical cycles are sensitive to changes in climate and atmospheric composition.Vegetation dynamic models has been applied in global change studies,but the complex interactions among the carbon(C),water,and nitrogen(N) cycles have not been adequately addressed in the current models.In this study,a process-based vegetation dynamic model was developed to study the responses of dryland ecosystems to environmental changes,emphasizing on the interactions among the C,water,and N processes.To address the interactions between the C and water processes,it not only considers the effects of annual precipitation on vegetation distribution and soil moisture on organic matter(SOM) decomposition,but also explicitly models root competition for water and the water compensation processes.To address the interactions between C and N processes,it models the soil inorganic mater processes,such as N mineralization/immobilization,denitrification/nitrification,and N leaching,as well as the root competition for soil N.The model was parameterized for major plant functional types and evaluated against field observations.Chi ZHANG ChaoFan LI Xi CHEN GePing LUO LongHui LI XiaoYu LI Yan YAN Hua SHAO 2013Journal of Arid Land2013,5,1:8
7Two New Fossil Lacewing Species from the Middle Jurassic of Inner Mongolia,China(Neuroptera:Grammolingiidae)显示文摘草蜻蛉的二新种从内部蒙古的 Jiulongshan 形成(中间的侏罗记) 被描述并且说明,中国:Leptolingia calonervis sp。nov。并且 Litholingia ptesa sp。nov。(Grammolingiidae ) 。种类能被下列特征区分:后部的翅膀上的 MP2 的最外面的分支没在 Leptolingia calonervis sp 到达翅膀的边缘。nov;当 R 的另外的分支以后在 Litholingia ptesa sp 很分叉时, R 的第二个分支深深地分叉。nov。SHI Chaofan YANG Qiang REN Dong 2011Acta Geologica Sinica(English Edition)2011,85,2:8
8Seasonal Rainfall Forecasts for the Yangtze River Basin of China in Summer 2019 from an Improved Climate Service显示文摘Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rainfall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon(EASM) index, seasonal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin regions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is significant in May–June–July(MJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August(JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both MJJ and JJA. The forecasts issued in 2019 gave good guidance for the enhanced rainfall in the MJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.Philip E.BETT Nicola MARTIN Adam A.SCAIFE Nick DUNSTONE Gill M.MARTIN Nicola GOLDING Joanne CAMP Peiqun ZHANG Chris D.HEWITT Leon HERMANSON Chaofan LI Hong-Li REN Ying LIU Min LIU 2020Journal of Meteorological Research2020,34,5:7
9Object-based classification approach for greenhouse mapping using Landsat-8 imagery显示文摘Suburban greenhouses with intensive agricultural productivity have increasingly influenced the daily diet and vegetable supply in Chinese cities.With their enormous input of fertilizers and pesticides,greenhouses have considerably changed the local soil quality and environmental risk factors.The ability to obtain timely and accurate information regarding the spatial distribution of greenhouses could make an important contribution to local agricultural management and soil protection.This paper attempts to present a practical framework for extracting suburban greenhouses,integrating remote sensing data from Landsat-8 and object-oriented classification.Inheritance classification was implemented,and various properties,including texture and neighborhood features in addition to spectral information,were investigated through the popular random forest technique for feature selection prior to SVM classification to improve the mapping accuracy.The results demonstrated that object-based classification incorporating non-spectral features yielded a significant improvement compared with the classification results obtained using only the spectral information in traditional per-pixel classification.Both the producer’s and user’s accuracy were higher than 85%for greenhouse identification.Although it remained a challenge to completely distinguish greenhouses from sparse plants,the final greenhouse map indicated that the proposed object-based classification scheme,providing multiple feature selections and multi-scale analysis,yielded worthwhile information when applied to a continuous series of the freely available Landsat-8 imagery data.Wu Chaofan Deng Jinsong Wang Ke Ma Ligang Amir Reza Shah Tahmassebi 2016International Journal of Agricultural and Biological Engineering2016,9,1:7
10Robust superhydrophobic polyurethane sponge functionalized with perfluorinated graphene oxide for efficient immiscible oil/water mixture, stable emulsion separation and crude oil dehydration显示文摘In recent years, graphene oxide(GO), prepared by the modified Hummers’ method, and its derivatives have become a focus of research owing to their outstanding physical and chemical properties and low cost. Drawing inspiration from the mussel protein,a facile and environmentally-friendly method was employed to fabricate superhydrophobic/superoleophilic reduced graphene oxide(rGO) derivative. The preparation comprises two steps: coating GO nanosheets with polydopamine(PDA) and subsequent reaction with 1H,1H,2H,2H-perfluorodecanethiol. Due to the excellent adhesive ability of PDA, the resulting f PDA modified rGO nanosheets(rGO-f PDA) were firmly immobilized onto polyurethane(PU) sponge skeleton by a simple drop-coating method. The as-prepared rGO-f PDA functionalized sponge exhibited superhydrophobic behavior with a water contact angle of 162°±2°, high organic adsorption capacity, recyclability and stable oil/water separation behavior under different acidic/alkaline conditions. Due to its facile fabrication technique and outstanding properties, the superhydrophobic-superoleophilic PU-rGOf PDA sponge holds great promise as an oil adsorbent for cleaning up large-scale pollution of oil and organic solvents, and dehydrating crude oil.CAO Ning GUO JingYu BOUKHERROUB Rabah SHAO QingGuo ZANG XiaoBei LI Jin LIN XueQiang JU Hong LIU EnYang ZHOU ChaoFan LI HuiPing 2019Science China(Technological Sciences)2019,62,9:6
11Characterization of a Putative New Semi-Dominant Reduced Height Gene, Rht_NM9, in Wheat(Triticum aestivum L.)显示文摘Plant height is an important agronomic trait in cereal crops, and can affect both plant architecture and grain yield. New dwarfing genes are required for improving the genetic diversity of wheat. In this study, a novel dwarf mutant, NM9, was created by treating seeds of the wheat variety NAU9918 with ethyl methanesulfonate(EMS). NM9 showed obvious phenotypic changes, which were distinct from those caused by other dwarfing genes, especially the reduced plant height, increased effective tiller number, and elongated spike and grain length. The reduced plant height in NM9 was attributable to a semi-dominant dwarfing gene Rht_NM9, which was flanked by two closely linked SNP markers, SNP34 and SNP41, covering an 8.86-Mb region on the chromosome arm 2AS. The results of gibberellic acid(GA) sensitivity evaluation, comparative genomics analysis and allelism test indicated that Rht_NM9 was neither allelic to Rht7 and Rht21 nor homoeoallelic to Rht8, so Rht_NM9 was proposed to be a new dwarfing locus on the homoeologous group 2 chromosomes of wheat. Rht_NM9has a negative effect on plant height and positive effects on effective tiller number and grain size, thus, Rht_NM9 could be used for elucidating the mechanisms underlying plant architecture and grain development.Yuan Lu Liping Xing Shujuan Xing Ping Hu Chaofan Cui Mingyi Zhang Jin Xiao Haiyan Wang Ruiqi Zhang Xiue Wang Peidu Chen Aizhong Cao 2015Journal of Genetics and Genomics2015,42,12:6
12Light absorption properties and potential sources of brown carbon in Fenwei Plain during winter 2018–2019显示文摘A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.Wenyu Zhang Weigang Wang Jie Li Shuangliang Ma Chaofan Lian Kun Li Bo Shi Mingyuan Liu Yanyu Li QingQing Wang Yele Sun Shengrui Tong Maofa Ge 2021Journal of Environmental Sciences2021,33,4:6
13The Seasonal Prediction of the Exceptional Yangtze River Rainfall in Summer 2020显示文摘During June and July of 2020,the Yangtze River basin suffered from extreme mei-yu rainfall and catastrophic flooding.This study explores the seasonal predictability and associated dynamical causes for this extreme Yangtze River rainfall event,based on forecasts from the Met Office GloSea5 operational forecast system.The forecasts successfully predicted above-average rainfall over the Yangtze River basin,which arose from the successful reproduction of the anomalous western North Pacific subtropical high(WNPSH).Our results indicate that both the Indian Ocean warm sea surface temperature(SST)and local WNP SST gradient were responsible for the westward extension of the WNPSH,and the forecasts captured these tropical signals well.We explore extratropical drivers but find a large model spread among the forecast members regarding the meridional displacements of the East Asian mid-latitude westerly jet(EAJ).The forecast members with an evident southward displacement of the EAJ favored more extreme Yangtze River rainfall.However,the forecast Yangtze River rainfall anomaly was weaker compared to that was observed and no member showed such strong rainfall.In observations,the EAJ displayed an evident acceleration in summer 2020,which could lead to a significant wind convergence in the lower troposphere around the Yangtze River basin,and favor more mei-yu rainfall.The model forecast failed to satisfactorily reproduce these processes.This difference implies that the observed enhancement of the EAJ intensity gave a large boost to the Yangtze River rainfall,hindering a better forecast of the intensity of the event and disaster mitigation.Chaofan LI Riyu LU Nick DUNSTONE Adam ASCAIFE Philip EBETT Fei ZHENG 2021Advances in Atmospheric Sciences2021,38,12:5
14Modeling grassland net primary productivity and water-use efficiency along an elevational gradient of the Northern Tianshan Mountains显示文摘Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and climatic changes.Therefore,quantifying the effects of elevation on grassland productivity to understand ecosystem-climate interactions is vital for mountainous ecosystems.Water-use efficiency(WUE)provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands.This paper explored net primary productivity(NPP)and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin(TMJB),Xinjiang of China,using the Biome-BGC model.The results showed that:1)the NPP increased by 0.05 g C/(m2·a)with every increase of 1-m elevation,reached the maximum at the mid-high elevation(1,600 m asl),and then decreased by 0.06 g C/(m2·a)per 1-m increase in elevation;2)the grassland NPP was positively correlated with temperature in alpine meadow(AM,2,700-3,500 m asl),mid-mountain forest meadow(MMFM,1,650-2,700 m asl)and low-mountain dry grassland(LMDG,650-1,650 m asl),while positive correlations were found between NPP and annual precipitation in plain desert grassland(PDG,lower than 650 m asl);3)an increase(from 0.08 to 1.09 g C/(m2·a))in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009;and 4)remarkable differences in WUE were found among different elevations.In general,WUE increased with decreasing elevation,because water availability is lower at lower elevations;however,at elevations lower than 540 m asl,we did observe a decreasing trend of WUE with decreasing elevation,which may be due to the sharp changes in canopy cover over this gradient.Our research suggests that the NPP simulated by Biome-BGC is consistent with field data,and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.QiFei HAN GePing LUO ChaoFan LI Hui YE YaoLiang CHEN 2013Journal of Arid Land2013,5,3:5
15A Post-domestication Mutation, Dt2, Triggers Systemic Modification of Divergent and Convergent Pathways Modulating Multiple Agronomic Traits in Soybean显示文摘The semi-determinate stem growth habit in leguminous crops,similar to the“green revolution”semi-dwarf trait in cereals,is a key plant architecture trait that affects several other traits determining grain yield.In soybean semi-determinacy is modulated by a post-domestication gain-of-function mutation in the gene,Dt2,which encodes an MADS-box transcription factor.However,its role in systemic modification of stem growth and other traits is unknown.In this study,we show that Dt2 functions not only as a direct repressor of Dt1,which prevents terminal flowering,but also as a direct activator of putative floral integrator/identity genes including GmSOC1,GmAP1,and GmFUL,which likely promote flowering.We also demonstrate that Dt2 functions as a direct repressor of the putative drought-responsive transcription factor gene GmDREB1D,and as a direct activator of GmSPCH and GmGRP7,which are potentially associated with asymmetric division of young epidermal cells and stomatal opening,respectively,and may affect the plant's water-use efficiency(WUE).Intriguingly,Dt2 was found to be a direct activator or repressor of the precursors of eight microRNAs targeting genes potentially associated with meristem maintenance,flowering time,stomatal density,WUE,and/or stress responses.This study thus reveals the molecular basis of pleiotropy associated with plant productivity,adaptability,and environmental resilience.Dajian Zhang Xutong Wang Shuo Li Chaofan Wang Michael JGosney Michael VMickelbart Jianxin Ma 2019Molecular Plant2019,12,10:4
16Thymosin Alpha-1 Inhibits Complete Freund’s Adjuvant-Induced Pain and Production of Microglia-Mediated Pro-inflammatory Cytokines in Spinal Cord显示文摘Activation of inflammatory responses regulates the transmission of pain pathways through an integrated network in the peripheral and central nervous systems.The immunopotentiator thymosin alpha-1(Tal)has recently been reported to have anti-inflammatory and neuroprotective functions in rodents.However,how Tα1 affects inflammatory pain remains unclear.In the present study,intraperitoneal injection of Tal attenuated complete Freund's adjuvant(CFA)-induced pain hypersensitivity,and decreased the up-regulation of pro-inflammatory cytokines(TNF-α,IL-1β,and IL-6)in inflamed skin and the spinal cord.We found that CFA-induced peripheral inflammation evoked strong microglial activation,but the effect was reversed by Tα1.Notably,Tα1 reversed the CFA-induced up-regulation of vesicular glutamate transporter(VGLUT)and down-regulated the vesicular γ-aminobutyric acid transporter(VGAT)in the spinal cord.Taken together,these results suggest that Tα1 plays a therapeutic role in inflammatory pain and in the modulation of microgliainduced pro-inflammatory cytokine production in addition to mediation of VGLUT and VGAT expression in the spinal cord.Yunlong Xu Yanjun Jiang Lin Wang Jiahua Huang Junmao Wen Hang Lv Xiaoli Wu Chaofan Wan Chuanxin Yu Wenjie Zhang Jiaying Zhao Yinqi Zhou Yongjun Chen 2019Neuroscience Bulletin2019,35,4:4
17温拌添加剂对沥青结合料PG分级的影响研究显示文摘采用室内试验量化分析了不同温拌添加剂对基质沥青和SBS改性沥青结合料PG分级的影响。结果表明:温拌添加剂对沥青结合料的PG分级影响程度取决于沥青和添加剂种类、添加剂含量和RTFOT老化温度等。石蜡基添加剂Sasobit对沥青结合料PG分级产生强化作用,在其典型掺量3%时,沥青结合料的PG分级上限、下限和中间温度可分别提高13.5、6.9和5.0℃。在正常掺量范围内,Aspha-min温拌添加剂对沥青结合料的PG分级上限、下限和中间温度影响不大。剔除个别异常数据,RTFOT老化温度163~133℃的变化对沥青结合料PG分级无显著影响。刘克非 Chaofan Wu Menglan Zeng 2015中外公路2015,35,4:4
18A vacuum ultraviolet laser with a submicrometer spot for spatially resolved photoemission spectroscopy显示文摘Vacuum ultraviolet(VUV)lasers have demonstrated great potential as the light source for various spectroscopies,which,if they can be focused into a small beam spot,will not only allow investigation of mesoscopic materials and structures but also find application in the manufacture of nano-objects with excellent precision.In this work,we report the construction of a 177 nm VUV laser that can achieve a record-small(〜0.76 μm)focal spot at a long focal length(~45 mm)by using a flat lens without spherical aberration.The size of the beam spot of this VUV laser was tested using a metal grating and exfoliated graphene flakes,and we demonstrated its application in a fluorescence spectroscopy study on pure and Tm3+-doped NaYF4 microcrystals,revealing a new emission band that cannot be observed in the traditional up-conversion process.In addition,this laser system would be an ideal light source for spatially and angleresolved photoemission spectroscopy.Yuanhao Mao Dong Zhao Shen Yan Hongjia Zhang Juan Li Kai Han Xiaojun Xu Chuan Guo Lexian Yang Chaofan Zhang Kun Huang Yulin Chen 2021Light(Science & Applications)2021,10,3:3
19Seasonal Forecasts of the Summer 2016 Yangtze River Basin Rainfall显示文摘The Yangtze River has been subject to heavy flooding throughout history,and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods.Dams along the river help to manage flood waters,and are important sources of electricity for the region.Being able to forecast high-impact events at long lead times therefore has enormous potential benefit.Recent improvements in seasonal forecasting mean that dynamical climate models can start to be used directly for operational services.The teleconnection from El Ni ?no to Yangtze River basin rainfall meant that the strong El Ni ?no in winter 2015/16 provided a valuable opportunity to test the application of a dynamical forecast system.This paper therefore presents a case study of a real-time seasonal forecast for the Yangtze River basin,building on previous work demonstrating the retrospective skill of such a forecast.A simple forecasting methodology is presented,in which the forecast probabilities are derived from the historical relationship between hindcast and observations.Its performance for2016 is discussed.The heavy rainfall in the May–June–July period was correctly forecast well in advance.August saw anomalously low rainfall,and the forecasts for the June–July–August period correctly showed closer to average levels.The forecasts contributed to the confidence of decision-makers across the Yangtze River basin.Trials of climate services such as this help to promote appropriate use of seasonal forecasts,and highlight areas for future improvements.Philip E. BETT Adam A. SCAIFE Chaofan LI Chris HEWITT Nicola GOLDING Peiqun ZHANG Nick DUNSTONE Doug M. SMITH Hazel E. THORNTON Riyu LU Hong-Li REN 2018Advances in Atmospheric Sciences2018,35,8:3
20Continuous and comprehensive atmospheric observations in Beijing:a station to understand the complex urban atmospheric environment显示文摘Due to profound impact on climate and human health,air quality has attracted attention from all levels of the civil society.The key step in the provision of required tools for the society to tackle the complex air quality problem is to characterize it in a comprehensive manner with a long-term perspective.Here,we describe a continuous and comprehensive observation station and its accompanying state-ofthe-art instrumentation that was established to investigate the complex urban atmospheric environment in a rapidly developing Chinese Megacity.The station,located in downtown Beijing,aims to study air quality by identifying the major atmospheric pollutants and key processes determining their formation and loss mechanisms.A few hundreds of parameters are continuously measured with the state-of-the-art instruments,including trace gas concentrations,aerosol particle size distributions,and mass concentrations,covering aerosol particle chemical composition from molecules to micrometer-sized aerosol particles.This produced long-term,comprehensive big data with around 1�10^(11)bytes per year.In this paper,we provide an overview on the facilities of the station,the instrumentation used,the workflow of continuous observations and examples of results from 2018 to 2019 and a basis for establishing a modern long-term,comprehensive atmospheric urban observation station in other megacities.Yongchun Liu Chao Yan Zemin Feng Feixue Zheng Xiaolong Fan Yusheng Zhang Chang Li Ying Zhou Zhuohui Lin Yishou Guo Ying Zhang Li Ma Wenshuo Zhou Zhikun Liu Lubna Dada Kaspar Dallenbach Jenni Kontkanen Runlong Cai Tommy Chan Biwu Chu Wei Du Lei Yao Yonghong Wang Jing Cai Juha Kangasluoma Tom Kokkonen Joni Kujansuu Anton Rusanen Chenjuan Deng Yueyun Fu Rujing Yin Xiaoxiao Li Yiqun Lu Yiliang Liu Chaofan Lian Dongsen Yang Weigang Wang Maofa Ge Yuesi Wang Douglas R.Worsnop Heikki Junninen Hong He Veli-Matti Kerminen Jun Zheng Lin Wang Jingkun Jiang Tuukka Petaja Federico Bianchi Markku Kulmala 2020Big Earth Data2020,4,3:3
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