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, projectb...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.展开更多
Two important questions are addressed in this paper using the Global Ensemble Forecast System （GEFS） from the National Centers for Environmental Prediction （NCEP）： （1） How many ensemble members are needed to be...Two important questions are addressed in this paper using the Global Ensemble Forecast System （GEFS） from the National Centers for Environmental Prediction （NCEP）： （1） How many ensemble members are needed to better represent forecast uncertainties with limited computational resources？ （2） What is tile relative impact on forecast skill of increasing model resolution and ensemble size？ Two-month experiments at T126L28 resolution were used to test the impact of varying the ensemble size from 5 to 80 members at the 500- hPa geopotential height. Results indicate that increasing the ensemble size leads to significant improvements in the performance for all forecast ranges when measured by probabilistic metrics, but these improvements are not significant beyond 20 members for long forecast ranges when measured by deterministic metrics. An ensemble of 20 to 30 members is the most effective configuration of ensemble sizes by quantifying the tradeoff between ensemble performance and the cost of computational resources. Two representative configurations of the GEFS the T126L28 model with 70 members and the T190L28 model with 20 members, which have equivalent computing costs--were compared. Results confirm that, for the NCEP GEFS, increasing the model resolution is more （less） beneficial than increasing the ensemble size for a short （long） forecast range.展开更多
The Advanced Microwave Sounding Unit-A（AMSU-A） onboard the NOAA satellites NOAA-18 and NOAA-19 and the European Organization for the Exploitation of Meteorological Satellites（EUMETSAT）Met Op-A, the hyperspectral A...The Advanced Microwave Sounding Unit-A（AMSU-A） onboard the NOAA satellites NOAA-18 and NOAA-19 and the European Organization for the Exploitation of Meteorological Satellites（EUMETSAT）Met Op-A, the hyperspectral Atmospheric Infrared Sounder（AIRS） onboard Aqua, the High resolution Infra Red Sounder（HIRS） onboard NOAA-19 and Met Op-A, and the Advanced Technology Microwave Sounder（ATMS） onboard Suomi National Polar-orbiting Partnership（NPP） satellite provide upper-level sounding channels in tropical cyclone environments. Assimilation of these upper-level sounding channels data in the Hurricane Weather Research and Forecasting（HWRF） system with two different model tops is investigated for the tropical storms Debby and Beryl and hurricanes Sandy and Isaac that occurred in 2012. It is shown that the HWRF system with a higher model top allows more upper-level microwave and infrared sounding channels data to be assimilated into HWRF due to a more accurate upper-level background profile. The track and intensity forecasts produced by the HWRF data assimilation and forecast system with a higher model top are more accurate than those with a lower model top.展开更多
The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK...The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.展开更多
In this paper,a way of building an electronic Parity Time(PT)-symmetric dimer without gain material is presented.This is achieved by capacitively coupling a pair of LZC circuits,each combining an inductance L,an imagi...In this paper,a way of building an electronic Parity Time(PT)-symmetric dimer without gain material is presented.This is achieved by capacitively coupling a pair of LZC circuits,each combining an inductance L,an imaginary resistance Z and a positive/negative capacitance C.We derive the effective Hamiltonian of the system,which commutes with the joint PT operator.The eigenspectrum displays spontaneous breaking points,where the system undergoes a transition from real to complex values.The transition points are imposed by the range value of the coupling thanks to the use of a negative capacitance.Temporal charge solutions and energy propagation are also analytically and numerically investigated,and the results are compatible.In the exact phase,these quantities oscillate,whereas in the broken phase,oscillations disappear,giving place to amplification.Our results pave the way to innovative PT-symmetric circuits.Applications could include,among others,optics,metamaterials,photonics and sensitive detection.展开更多
Historically,patients with cancer were told to avoid physical exertion.This dogma has changed over the last 2 decades,with an exponential growth in the number of studies showing not only the safety,but also the benefi...Historically,patients with cancer were told to avoid physical exertion.This dogma has changed over the last 2 decades,with an exponential growth in the number of studies showing not only the safety,but also the benefits of regular physical activity/exercise in the cancer continuum,notably for attenuating treatment-related toxicities and side effects.展开更多
The North American Soil Moisture Database (NASMD) was initiated in 2011 to assemble and homogenize in situ soil moisture measurements from 32 observational networks in the United States and Canada encompassing more th...The North American Soil Moisture Database (NASMD) was initiated in 2011 to assemble and homogenize in situ soil moisture measurements from 32 observational networks in the United States and Canada encompassing more than 1800 stations. Although statistical quality control (QC) procedures have been applied in the NASMD, the soil moisture content tends to be systematically underestimated by in situ sensors in frozen soils, and using a single maximum threshold (i.e., 0.6 m3 m-3) may not be sufficient for robust QC because of the diverse soil textures in North America. In this study, based on the in situ soil porosity and North American Land Data Assimilation System phase 2 (NLDAS-2) Noah soil temperature, the simple automated QC method is revised to supplement the existing QC approach. This revised QC method is first validated based on the assessment at 78 of the Soil Climate Analysis Network (SCAN) stations where the manually checked data are available, and is then applied to all stations in the NASMD to produce a more strict quality-controlled dataset. The results show that the revised automated QC procedure can flag the spurious and erroneous soil moisture measurements for the SCAN stations, especially for those located in high altitudes and latitudes. Relative to station measurements in the original NASMD, the quality-controlled data show a slightly better agreement with the manually checked soil moisture content. It should be noted that this quality-controlled dataset may be over-flagged for some valid soil moisture measurements due to potential errors of the soil temperature and soil porosity data, and validation in this study is limited by the availability of benchmark soil moisture data. The updated QC and additional validation will be desirable to boost confidence in the product when high-quality data become available in the future.展开更多
The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measureme...The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. The Tibetan Plateau, the plains area, and the East China Sea are selected as the focus regions in this study. The average precipitation depths （PD） are about 4.6 km, 5.8 km, and 5.6 km, while convective （stratiform） PDs are about 6.6 （4.5） km, 7.5 （5.7） km, and 6.0 （5.6） km over the plateau, the plains, and the ocean region, respectively. Results demonstrate a prominent PD diurnal cycle, and its diurnal phase is generally a few hours behind the surface precipitation. The spatial variation of the PD diurnal magnitude is weaker near the coastal areas than that of surface precipitation. The height of the PD diurnal peak is around 6 7 km for convective systems and 5-6 km for stratifrom systems. The dominant afternoon diurnal peak for convective PD and the flat diurnal peak for stratiform PD over the Tibetan Plateau indicate that solar diurnal forcing is the key mechanism of the PD diurnal cycle over land. In addition, the diurnal variation is obvious for shallow and deep convective systems, but not for shallow and deep stratiform systems.展开更多
This study presents the real-time performance of the United States(US) National Centers for Environmental Prediction(NCEP) operational Hurricane Weather Research and Forecast(HWRF) model in predicting rapid intensific...This study presents the real-time performance of the United States(US) National Centers for Environmental Prediction(NCEP) operational Hurricane Weather Research and Forecast(HWRF) model in predicting rapid intensification(RI) of typhoons in the North Western Pacific(WPAC) basin in 2013. Examination of all RI cases in WPAC during 2013 shows that the HWRF model captures a consistent vortex structure at the onset of all RI as seen in previous idealized studies with HWRF. However, HWRF has issues with predicting RI when the model vortex is initialized with intensity greater than hurricane strength. Further verification of the probability of detection(POD) and the false alarm rate(FAR) of RI forecasts shows that the HWRF model outperforms all other models used by the US Navy’s Joint Typhoon Warning Center, possessing highest POD and lowest FAR in 2013. Examination of the intensity change forecasts at different forecast lead times also confirms that the HWRF model has superior performance, particularly at the 72-h lead time with the POD index ~0.91 and the FAR index ~0.33. Such unique performance of the HWRF model demonstrates its role in helping operational agencies improve their official intensity(and RI) forecasts for tropical cyclones in the WPAC basin.展开更多
Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in st...Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.展开更多
The influences of Tropical Rainfall Measuring Mission （TRMM） precipitation products on the structure and underlying physics of intraseasonal oscillation （ISO） are investigated with the U.S. National Aeronautics an...The influences of Tropical Rainfall Measuring Mission （TRMM） precipitation products on the structure and underlying physics of intraseasonal oscillation （ISO） are investigated with the U.S. National Aeronautics and Space Administration Goddard Earth Observing System model version 3 （GEOS-3） data assimilation system （DAS）. The strong ISO phase in the 1998 summer is apparently located in the Asian monsoon region and the east equatorial Pacific region. The eastward propagation is a dominant feature for the tropical ISO at 20 to 30-day oscillation while the northeastward propagation is the salient ISO at 30 to 60-day oscillation over the 10~N to 25~N belt region. It appears that the Kelvin wave structure is for the tropical 20 to 30-day oscillation. The tropical 30 to 60-day oscillation has the characteristics of the Kelvin-Rossby wave. The impact of satellite-derived precipitation （and its associated latent heating） on the ISO intensity is limited in the GEOS-3 assimilation system. However, its impact on the ISO spatial structures is obvious. Overall, the results demonstrate a better eastward propagation and a northward propagation of ISO with the TRMM precipitation simulation, indicating that latent heating is very important in exciting the equatorial ISO. Key words： 20 to 30-day oscillation; 30 to 60-day oscillation; GEOS data assimilation system; Kelvin wave; TRMM precipitation展开更多
This article is the 13th contribution in the Fungal Diversity Notes series,wherein 125 taxa from four phyla,ten classes,31 orders,69 families,92 genera and three genera incertae sedis are treated,demonstrating worldwi...This article is the 13th contribution in the Fungal Diversity Notes series,wherein 125 taxa from four phyla,ten classes,31 orders,69 families,92 genera and three genera incertae sedis are treated,demonstrating worldwide and geographic distri-bution.Fungal taxa described and illustrated in the present study include three new genera,69 new species,one new com-bination,one reference specimen and 51 new records on new hosts and new geographical distributions.Three new genera,Cylindrotorula(Torulaceae),Scolecoleotia(Leotiales genus incertae sedis)and Xenovaginatispora(Lindomycetaceae)are introduced based on distinct phylogenetic lineages and unique morphologies.Newly described species are Aspergillus lan-naensis,Cercophora dulciaquae,Cladophialophora aquatica,Coprinellus punjabensis,Cortinarius alutarius,C.mammil-latus,C.quercoflocculosus,Coryneum fagi,Cruentomycena uttarakhandina,Cryptocoryneum rosae,Cyathus uniperidiolus,Cylindrotorula indica,Diaporthe chamaeropicola,Didymella azollae,Diplodia alanphillipsii,Dothiora coronicola,Efibula rodriguezarmasiae,Erysiphe salicicola,Fusarium queenslandicum,Geastrum gorgonicum,G.hansagiense,Helicosporium sexualis,Helminthosporium chiangraiensis,Hongkongmyces kokensis,Hydrophilomyces hydraenae,Hygrocybe boertmannii,Hyphoderma australosetigerum,Hyphodontia yunnanensis,Khaleijomyces umikazeana,Laboulbenia divisa,Laboulbenia triarthronis,Laccaria populina,Lactarius pallidozonarius,Lepidosphaeria strobelii,Longipedicellata megafusiformis,Lophiotrema lincangensis,Marasmius benghalensis,M.jinfoshanensis,M.subtropicus,Mariannaea camelliae,Mel-anographium smilaxii,Microbotryum polycnemoides,Mimeomyces digitatus,Minutisphaera thailandensis,Mortierella solitaria,Mucor harpali,Nigrograna jinghongensis,Odontia huanrenensis,O.parvispina,Paraconiothyrium ajrekarii,Par-afuscosporella niloticus,Phaeocytostroma yomensis,Phaeoisaria synnematicus,Phanerochaete hainanensis,Pleopunctum thailandicum,Pleurotheciella dimorphospora,Pseudochaetosphaeronema chiangraiense,Pseudodactylaria albicolonia,Rhex展开更多
This work investigates the dynamics of modulated waves in a coupled nonlinear LC transmission line. By means of a method based on the semi-discrete limit and in suitably scaled coordinates, we derive the two-dimension...This work investigates the dynamics of modulated waves in a coupled nonlinear LC transmission line. By means of a method based on the semi-discrete limit and in suitably scaled coordinates, we derive the two-dimensional NLS equation governing the propagation of slowly modulated waves in the network. The exact transverse solution is found and the analytical criteria of stability of this solution are derived. The condition for which the network can exhibit modulational instability is also determined. The exactness of this analytical analysis is confirmed by numerical simulations performed on the exact equation of the network.展开更多
The tropical cyclone(TC)named Amos(2016)that impacted the Samoan Islands on 23 April 2016 was a particularly dif f icult storm to forecast.Both the intensity changes and the track of Amos represent a signif icant chal...The tropical cyclone(TC)named Amos(2016)that impacted the Samoan Islands on 23 April 2016 was a particularly dif f icult storm to forecast.Both the intensity changes and the track of Amos represent a signif icant challenge for forecasters and this is briefl y summarized in this report.Model forecasts initially indicated that the cyclone would track south of the Samoan Islands.However,the forecasts generally changed to a direct hit over Samoa as a Category 4 storm at approximately 0000 U TC 24April based on model cycles initialized at 0000 UTC 23 April.TC Amos’central pressure dropped from 983 hPa to 957 hPa between 0000 UTC 21 April and 0000 UTC 23April.The models did not pick up on this rapid intensif ication until the intensif ication had already begun around0000 UTC 21 April.The models also struggled to capture the rapid weakening of TC Amos due to vertical wind shear that began 0000 UTC 24 April as the cyclone continued to move north of the islands.Because of the initially ominous track forecasts for TC Amos to hit land,preparations for a Category 3 or Category 4 cyclone were underway in the Samoan islands and the population prepared for the worst.After the center of the storm moved north of the islands as a weaker storm than anticipated,the residents of the Samoan Islands were both surprised and relieved that the cyclone only gave a"glancing blow"to the islands and that the impacts were not as bad as originally feared.An in-depth evaluation of this particular tropical cyclone helps to shed some light on model def iciencies and can be used to help determine future model changes.展开更多
This study shows that the heretofore assumed condition for no temperature-profile (TP)/lapse-rate feedback, for all altitudes z, or , in fact yields a negative feedback. The correct condition for no TP feedback is for...This study shows that the heretofore assumed condition for no temperature-profile (TP)/lapse-rate feedback, for all altitudes z, or , in fact yields a negative feedback. The correct condition for no TP feedback is for all z, where Ts is the surface temperature. This condition translates into a uniform increase (decrease) in lapse rate with altitude for an increase (decrease) in Ts. The temperature changes caused by a change in solar irradiance and/or planetary albedo satisfy the condition for no TP feedback. The temperature changes caused by a change in greenhouse gas concentration do not satisfy the condition for no TP feedback and, instead, yield a positive feedback.展开更多
This paper proposes a method for multi-model ensemble forecasting based on Bayesian model averaging （BMA）, aiming to improve the accuracy of tropical cyclone （TC） intensity forecasts, especially forecasts of minim...This paper proposes a method for multi-model ensemble forecasting based on Bayesian model averaging （BMA）, aiming to improve the accuracy of tropical cyclone （TC） intensity forecasts, especially forecasts of minimum surface pressure at the cyclone center （Pmin）＇ The multi-model ensemble comprises three operational forecast models： the Global Forecast System （GFS） of NCEP, the Hurricane Weather Research and Forecasting （HWRF） models of NCEP, and the Integrated Forecasting System （IFS） of ECMWF. The mean of a predictive distribution is taken as the BMA forecast. In this investigation, bias correction of the minimum surface pressure was applied at each forecast lead time, and the distribution （or probability density function, PDF） of emin was used and transformed. Based on summer season forecasts for three years, we found that the intensity errors in TC forecast from the three models var-ied significantly. The HWRF had a much smaller intensity error for short lead-time forecasts. To demonstrate the proposed methodology, cross validation was implemented to ensure more efficient use of the sample data and more reliable testing. Comparative analysis shows that BMA for this three-model ensemble, after bias correction and distri-bution transformation, provided more accurate forecasts than did the best of the ensemble members （HWRF）, with a 5%-7% decrease in root-mean-square error on average. BMA also outperformed the multi-model ensemble, and it produced ＂predictive variance＂ that represented the forecast uncertainty of the member models. In a word, the BMA method used in the multi-model ensemble forecasting was successful in TC intensity forecasts, and it has the poten-tial to be applied to routine operational forecasting.展开更多
基金Supported by the US Environmental Modeling Center(EMC)Land Surface Modeling Project(granted to Youlong Xia)National Natural Science Foundation of China(51609111,granted to Baoqing Zhang)
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.
文摘Two important questions are addressed in this paper using the Global Ensemble Forecast System （GEFS） from the National Centers for Environmental Prediction （NCEP）： （1） How many ensemble members are needed to better represent forecast uncertainties with limited computational resources？ （2） What is tile relative impact on forecast skill of increasing model resolution and ensemble size？ Two-month experiments at T126L28 resolution were used to test the impact of varying the ensemble size from 5 to 80 members at the 500- hPa geopotential height. Results indicate that increasing the ensemble size leads to significant improvements in the performance for all forecast ranges when measured by probabilistic metrics, but these improvements are not significant beyond 20 members for long forecast ranges when measured by deterministic metrics. An ensemble of 20 to 30 members is the most effective configuration of ensemble sizes by quantifying the tradeoff between ensemble performance and the cost of computational resources. Two representative configurations of the GEFS the T126L28 model with 70 members and the T190L28 model with 20 members, which have equivalent computing costs--were compared. Results confirm that, for the NCEP GEFS, increasing the model resolution is more （less） beneficial than increasing the ensemble size for a short （long） forecast range.
基金Supported by the NOAA Hurricane Forecast Improvement Program(HFIP)National Natural Science Foundation of China(91337218)
文摘The Advanced Microwave Sounding Unit-A（AMSU-A） onboard the NOAA satellites NOAA-18 and NOAA-19 and the European Organization for the Exploitation of Meteorological Satellites（EUMETSAT）Met Op-A, the hyperspectral Atmospheric Infrared Sounder（AIRS） onboard Aqua, the High resolution Infra Red Sounder（HIRS） onboard NOAA-19 and Met Op-A, and the Advanced Technology Microwave Sounder（ATMS） onboard Suomi National Polar-orbiting Partnership（NPP） satellite provide upper-level sounding channels in tropical cyclone environments. Assimilation of these upper-level sounding channels data in the Hurricane Weather Research and Forecasting（HWRF） system with two different model tops is investigated for the tropical storms Debby and Beryl and hurricanes Sandy and Isaac that occurred in 2012. It is shown that the HWRF system with a higher model top allows more upper-level microwave and infrared sounding channels data to be assimilated into HWRF due to a more accurate upper-level background profile. The track and intensity forecasts produced by the HWRF data assimilation and forecast system with a higher model top are more accurate than those with a lower model top.
基金supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+22 种基金the CAS Center for Excellence in Particle PhysicsWuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules (IN2P3) in Francethe Istituto Nazionale di Fisica Nucleare (INFN) in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique (F.R.S-FNRS)FWO under the "Excellence of Science-EOS" in Belgiumthe Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo in Chilethe Charles University Research Centrethe Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft (DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+ in Germanythe Joint Institute of Nuclear Research (JINR)Lomonosov Moscow State University in Russiathe joint Russian Science Foundation (RSF)National Natural Science Foundation of China (NSFC) research programthe MOST and MOE in Taiwan,Chinathe Chulalongkorn UniversitySuranaree University of Technology in Thailandthe University of California at Irvine in USA
文摘The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.
文摘In this paper,a way of building an electronic Parity Time(PT)-symmetric dimer without gain material is presented.This is achieved by capacitively coupling a pair of LZC circuits,each combining an inductance L,an imaginary resistance Z and a positive/negative capacitance C.We derive the effective Hamiltonian of the system,which commutes with the joint PT operator.The eigenspectrum displays spontaneous breaking points,where the system undergoes a transition from real to complex values.The transition points are imposed by the range value of the coupling thanks to the use of a negative capacitance.Temporal charge solutions and energy propagation are also analytically and numerically investigated,and the results are compatible.In the exact phase,these quantities oscillate,whereas in the broken phase,oscillations disappear,giving place to amplification.Our results pave the way to innovative PT-symmetric circuits.Applications could include,among others,optics,metamaterials,photonics and sensitive detection.
基金supported by a Sara Borrell(CD21/00138)and Miguel Servet(CP18/00034)postdoctoralcontracts,respectively,granted by Instituto de Salud CarlosⅢfunded by the Spanish Ministry of Economy and Competitiveness and Fondos Feder(Alejandro Lucia,Grant No.PI18/00139+1 种基金Carmen Fiuza-Luces,Grant No.PI20/00645)by"the Wereld Kanker Onderzoek Fonds"(WKOF),as part of the World Cancer Research Fund International grant program(Grant No.IIG_FULL_2021_007)。
文摘Historically,patients with cancer were told to avoid physical exertion.This dogma has changed over the last 2 decades,with an exponential growth in the number of studies showing not only the safety,but also the benefits of regular physical activity/exercise in the cancer continuum,notably for attenuating treatment-related toxicities and side effects.
基金Supported by the National Key Research and Development Program of China(2017YFA0604300)National Natural Science Foundation of China(51779278,51379224,and 41671398)NOAA/CPO Modeling,Analyses,Predictions,and Projections(MAP) Program
文摘The North American Soil Moisture Database (NASMD) was initiated in 2011 to assemble and homogenize in situ soil moisture measurements from 32 observational networks in the United States and Canada encompassing more than 1800 stations. Although statistical quality control (QC) procedures have been applied in the NASMD, the soil moisture content tends to be systematically underestimated by in situ sensors in frozen soils, and using a single maximum threshold (i.e., 0.6 m3 m-3) may not be sufficient for robust QC because of the diverse soil textures in North America. In this study, based on the in situ soil porosity and North American Land Data Assimilation System phase 2 (NLDAS-2) Noah soil temperature, the simple automated QC method is revised to supplement the existing QC approach. This revised QC method is first validated based on the assessment at 78 of the Soil Climate Analysis Network (SCAN) stations where the manually checked data are available, and is then applied to all stations in the NASMD to produce a more strict quality-controlled dataset. The results show that the revised automated QC procedure can flag the spurious and erroneous soil moisture measurements for the SCAN stations, especially for those located in high altitudes and latitudes. Relative to station measurements in the original NASMD, the quality-controlled data show a slightly better agreement with the manually checked soil moisture content. It should be noted that this quality-controlled dataset may be over-flagged for some valid soil moisture measurements due to potential errors of the soil temperature and soil porosity data, and validation in this study is limited by the availability of benchmark soil moisture data. The updated QC and additional validation will be desirable to boost confidence in the product when high-quality data become available in the future.
基金supportedby the National Natural Science Foundation of China with research Grant Nos.40428002,40633018,and 40775058
文摘The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. The Tibetan Plateau, the plains area, and the East China Sea are selected as the focus regions in this study. The average precipitation depths （PD） are about 4.6 km, 5.8 km, and 5.6 km, while convective （stratiform） PDs are about 6.6 （4.5） km, 7.5 （5.7） km, and 6.0 （5.6） km over the plateau, the plains, and the ocean region, respectively. Results demonstrate a prominent PD diurnal cycle, and its diurnal phase is generally a few hours behind the surface precipitation. The spatial variation of the PD diurnal magnitude is weaker near the coastal areas than that of surface precipitation. The height of the PD diurnal peak is around 6 7 km for convective systems and 5-6 km for stratifrom systems. The dominant afternoon diurnal peak for convective PD and the flat diurnal peak for stratiform PD over the Tibetan Plateau indicate that solar diurnal forcing is the key mechanism of the PD diurnal cycle over land. In addition, the diurnal variation is obvious for shallow and deep convective systems, but not for shallow and deep stratiform systems.
文摘This study presents the real-time performance of the United States(US) National Centers for Environmental Prediction(NCEP) operational Hurricane Weather Research and Forecast(HWRF) model in predicting rapid intensification(RI) of typhoons in the North Western Pacific(WPAC) basin in 2013. Examination of all RI cases in WPAC during 2013 shows that the HWRF model captures a consistent vortex structure at the onset of all RI as seen in previous idealized studies with HWRF. However, HWRF has issues with predicting RI when the model vortex is initialized with intensity greater than hurricane strength. Further verification of the probability of detection(POD) and the false alarm rate(FAR) of RI forecasts shows that the HWRF model outperforms all other models used by the US Navy’s Joint Typhoon Warning Center, possessing highest POD and lowest FAR in 2013. Examination of the intensity change forecasts at different forecast lead times also confirms that the HWRF model has superior performance, particularly at the 72-h lead time with the POD index ~0.91 and the FAR index ~0.33. Such unique performance of the HWRF model demonstrates its role in helping operational agencies improve their official intensity(and RI) forecasts for tropical cyclones in the WPAC basin.
基金Sponsored by Science and Technology Plan Projects of Tianjin of China(07ZCKFGX03800)Science and Technology Plan Projects for CAS Supporting Tianjin Construction of China(TJZX1-YW-09)
文摘Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.
基金Qing Lan Project and a Special Public Sector Research (GYHY200806009)The second author was funded by the NASA Global Water and Energy Cycle project with a grant NNG04G098G
文摘The influences of Tropical Rainfall Measuring Mission （TRMM） precipitation products on the structure and underlying physics of intraseasonal oscillation （ISO） are investigated with the U.S. National Aeronautics and Space Administration Goddard Earth Observing System model version 3 （GEOS-3） data assimilation system （DAS）. The strong ISO phase in the 1998 summer is apparently located in the Asian monsoon region and the east equatorial Pacific region. The eastward propagation is a dominant feature for the tropical ISO at 20 to 30-day oscillation while the northeastward propagation is the salient ISO at 30 to 60-day oscillation over the 10~N to 25~N belt region. It appears that the Kelvin wave structure is for the tropical 20 to 30-day oscillation. The tropical 30 to 60-day oscillation has the characteristics of the Kelvin-Rossby wave. The impact of satellite-derived precipitation （and its associated latent heating） on the ISO intensity is limited in the GEOS-3 assimilation system. However, its impact on the ISO spatial structures is obvious. Overall, the results demonstrate a better eastward propagation and a northward propagation of ISO with the TRMM precipitation simulation, indicating that latent heating is very important in exciting the equatorial ISO. Key words： 20 to 30-day oscillation; 30 to 60-day oscillation; GEOS data assimilation system; Kelvin wave; TRMM precipitation
基金the Thailand Research Fund(Grant No.TRG6180001)the Mae Fah Luang University Fund(Grant No.631C15001)+14 种基金Plant Genetic Conserva-tion Project under the Royal Initiation of Her Royal Highness Princess Maha Chakri Sirindhorn-Mae Fah Luang Universitythe Mushroom Research Foundation.Kevin D.Hyde thanks the 2019 high-end foreign expert introduction plan to Kunming Institute of Botany(Granted by the Ministry of Science and Technology of the People’s Republic of China,Grant No.G20190139006)the future of specialist fungi in a changing climate:baseline data for generalist and specialist fungi associated with ants,Rhododendron species and Dra-caena species(Grant No.DBG6080013)Impact of climate change on fungal diversity and biogeography in the Greater Mekong Subregion(Grant No.RDG6130001)Dhanushka Wanasinghe thanks CAS President’s International Fellowship Initiative(PIFI)for funding his postdoctoral research(Grant No.2021FYB0005)the Postdoctoral Fund from Human Resources and Social Security Bureau of Yunnan Province.the National Natural Science Foundation of China(Nos.31870011,31750001,31770028 and 31970017).CAS President’s International Fellowship Initiative(PIFI)for young staff(Grant No.Y9215811Q1)Provincial Science and Tech-nology Department(grant no.202003AD150004)Yunnan Provincial Key Programs of Yunnan Eco-friendly Food International Cooperation Research Center(Grant No.2019ZG00908)Key Research Program of Frontier Sciences“Response of Asian mountain ecosystems to global change”,CAS,Grant No.QYZDY-SSWSMC014”the Agreement ENDESA and San Ignacio de Huinay Foundations and Consejo Superior de Investiga-ciones Científicas,CSIC(Projects No.2011HUIN10,2013CL0012)and DGICYT projects CGL2005-01192/BOS,CGL2009-07231,CGL2015-67459-P,CSIC project PIE202030E059the Polish Ministry of Science and Higher Education(grant No.N N305299640)the support from UIDB/04046/2020 and UIDP/04046/2020 Centre grants from FCT,Portugal(to BioISI).the University of Southern Queensland and the Grains Research and Development Corp
文摘This article is the 13th contribution in the Fungal Diversity Notes series,wherein 125 taxa from four phyla,ten classes,31 orders,69 families,92 genera and three genera incertae sedis are treated,demonstrating worldwide and geographic distri-bution.Fungal taxa described and illustrated in the present study include three new genera,69 new species,one new com-bination,one reference specimen and 51 new records on new hosts and new geographical distributions.Three new genera,Cylindrotorula(Torulaceae),Scolecoleotia(Leotiales genus incertae sedis)and Xenovaginatispora(Lindomycetaceae)are introduced based on distinct phylogenetic lineages and unique morphologies.Newly described species are Aspergillus lan-naensis,Cercophora dulciaquae,Cladophialophora aquatica,Coprinellus punjabensis,Cortinarius alutarius,C.mammil-latus,C.quercoflocculosus,Coryneum fagi,Cruentomycena uttarakhandina,Cryptocoryneum rosae,Cyathus uniperidiolus,Cylindrotorula indica,Diaporthe chamaeropicola,Didymella azollae,Diplodia alanphillipsii,Dothiora coronicola,Efibula rodriguezarmasiae,Erysiphe salicicola,Fusarium queenslandicum,Geastrum gorgonicum,G.hansagiense,Helicosporium sexualis,Helminthosporium chiangraiensis,Hongkongmyces kokensis,Hydrophilomyces hydraenae,Hygrocybe boertmannii,Hyphoderma australosetigerum,Hyphodontia yunnanensis,Khaleijomyces umikazeana,Laboulbenia divisa,Laboulbenia triarthronis,Laccaria populina,Lactarius pallidozonarius,Lepidosphaeria strobelii,Longipedicellata megafusiformis,Lophiotrema lincangensis,Marasmius benghalensis,M.jinfoshanensis,M.subtropicus,Mariannaea camelliae,Mel-anographium smilaxii,Microbotryum polycnemoides,Mimeomyces digitatus,Minutisphaera thailandensis,Mortierella solitaria,Mucor harpali,Nigrograna jinghongensis,Odontia huanrenensis,O.parvispina,Paraconiothyrium ajrekarii,Par-afuscosporella niloticus,Phaeocytostroma yomensis,Phaeoisaria synnematicus,Phanerochaete hainanensis,Pleopunctum thailandicum,Pleurotheciella dimorphospora,Pseudochaetosphaeronema chiangraiense,Pseudodactylaria albicolonia,Rhex
基金grateful to the Journal of Modern Physics for financial support in publication.
文摘This work investigates the dynamics of modulated waves in a coupled nonlinear LC transmission line. By means of a method based on the semi-discrete limit and in suitably scaled coordinates, we derive the two-dimensional NLS equation governing the propagation of slowly modulated waves in the network. The exact transverse solution is found and the analytical criteria of stability of this solution are derived. The condition for which the network can exhibit modulational instability is also determined. The exactness of this analytical analysis is confirmed by numerical simulations performed on the exact equation of the network.
文摘The tropical cyclone(TC)named Amos(2016)that impacted the Samoan Islands on 23 April 2016 was a particularly dif f icult storm to forecast.Both the intensity changes and the track of Amos represent a signif icant challenge for forecasters and this is briefl y summarized in this report.Model forecasts initially indicated that the cyclone would track south of the Samoan Islands.However,the forecasts generally changed to a direct hit over Samoa as a Category 4 storm at approximately 0000 U TC 24April based on model cycles initialized at 0000 UTC 23 April.TC Amos’central pressure dropped from 983 hPa to 957 hPa between 0000 UTC 21 April and 0000 UTC 23April.The models did not pick up on this rapid intensif ication until the intensif ication had already begun around0000 UTC 21 April.The models also struggled to capture the rapid weakening of TC Amos due to vertical wind shear that began 0000 UTC 24 April as the cyclone continued to move north of the islands.Because of the initially ominous track forecasts for TC Amos to hit land,preparations for a Category 3 or Category 4 cyclone were underway in the Samoan islands and the population prepared for the worst.After the center of the storm moved north of the islands as a weaker storm than anticipated,the residents of the Samoan Islands were both surprised and relieved that the cyclone only gave a"glancing blow"to the islands and that the impacts were not as bad as originally feared.An in-depth evaluation of this particular tropical cyclone helps to shed some light on model def iciencies and can be used to help determine future model changes.
文摘This study shows that the heretofore assumed condition for no temperature-profile (TP)/lapse-rate feedback, for all altitudes z, or , in fact yields a negative feedback. The correct condition for no TP feedback is for all z, where Ts is the surface temperature. This condition translates into a uniform increase (decrease) in lapse rate with altitude for an increase (decrease) in Ts. The temperature changes caused by a change in solar irradiance and/or planetary albedo satisfy the condition for no TP feedback. The temperature changes caused by a change in greenhouse gas concentration do not satisfy the condition for no TP feedback and, instead, yield a positive feedback.
基金Supported by the National Natural Science Foundation of China(40830957)China Meteorological Administration Special Public Welfare Research Fund(GYHY201106018)+2 种基金National Basic Research and Development(973)Program of China(2011CB421504)National Science and Technology Support Program of China(2010BAC51B05)Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-YW-Q1-02)
文摘This paper proposes a method for multi-model ensemble forecasting based on Bayesian model averaging （BMA）, aiming to improve the accuracy of tropical cyclone （TC） intensity forecasts, especially forecasts of minimum surface pressure at the cyclone center （Pmin）＇ The multi-model ensemble comprises three operational forecast models： the Global Forecast System （GFS） of NCEP, the Hurricane Weather Research and Forecasting （HWRF） models of NCEP, and the Integrated Forecasting System （IFS） of ECMWF. The mean of a predictive distribution is taken as the BMA forecast. In this investigation, bias correction of the minimum surface pressure was applied at each forecast lead time, and the distribution （or probability density function, PDF） of emin was used and transformed. Based on summer season forecasts for three years, we found that the intensity errors in TC forecast from the three models var-ied significantly. The HWRF had a much smaller intensity error for short lead-time forecasts. To demonstrate the proposed methodology, cross validation was implemented to ensure more efficient use of the sample data and more reliable testing. Comparative analysis shows that BMA for this three-model ensemble, after bias correction and distri-bution transformation, provided more accurate forecasts than did the best of the ensemble members （HWRF）, with a 5%-7% decrease in root-mean-square error on average. BMA also outperformed the multi-model ensemble, and it produced ＂predictive variance＂ that represented the forecast uncertainty of the member models. In a word, the BMA method used in the multi-model ensemble forecasting was successful in TC intensity forecasts, and it has the poten-tial to be applied to routine operational forecasting.
