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The uniaxial compressive strength of the Arctic summer sea ice

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Acta oceanologica Sinica 2015年第1期34卷 129-136页

作者： HAN Hongwei LI Zhijun HUANG Wenfeng LU Peng LEI Ruibo State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology school of Environmental Science and Engineering Chang'an University Polar Research Institute of china State Oceanic Administration

The results on the uniaxial compressive strength of Arctic summer sea ice are presented based on the sam- ples collected during the fifth Chinese National Arctic Research Expedition in 2012 （chinaRE-2012）. Exper- imental studies were carried out at different testing temperatures （-3, -6 and -9℃）, and vertical samples were loaded at stress rates ranging from 0.001 to 1 MPa/s. The temperature, density, and salinity of the ice were measured to calculate the total porosity of the ice. In order to study the effects of the total porosity and the density on the uniaxial compressive strength, the measured strengths for a narrow range of stress rates from 0.01 to 0.03 MPa/s were analyzed. The results show that the uniaxial compressive strength decreases linearly with increasing total porosity, and when the density was lower than 0.86 g/cm3, the uniaxial com- pressive strength increases in a power-law manner with density. The uniaxial compressive behavior of the Arctic summer sea ice is sensitive to the loading rate, and the peak uniaxial compressive strength is reached in the brittle-ductile transition range. The dependence of the strength on the temperature shows that the calculated average strength in the brittle-ductile transition range, which was considered as the peak uniaxial compressive strength, increases steadily in the temperature range from -3 to -9℃.

关键词： Arctic sea ice compressive strength porosity density temperature

Nighttime peroxy radicals chemistry at Rishiri Island during the campaign RISFEX 2003

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Science china Chemistry 2012年第11期55卷 2450-2461页

作者： LIU Yan WANG JiangTao WANG ZhuQing GONG XiaoDong YANG Bing TAN LiJu QI Bin Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationOcean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of ocean Environment Monitoring Technology Shandong Academy of Sciences Institute of Oceanographic InstrumentationQingdao 266001China Key Laboratory of Applied Surface and Colloid Chemistry(Shaanxi Normal university) Ministry of EducationSchool of Chemistry and Materials ScienceXi'an 710062China

Peroxy radicals (ROx) concentrations were measured by Peroxy Radical Chemical Amplifier (PERCA) technique during the field campaign RISFEX 2003 (RiShiri Fall Experiment 2003), which was performed in September 2003 at Rishiri island (45.07 N, 141.12 E, and 35 m asl) in the sea of Japan. The concentrations of nighttime ROx radicals had temporal variations around an average of 7.9±5.8 (1σ) pptv and showed a positive correlation with the summed mixing ratio of four monoterpene species. Model calculations suggested that local nighttime ROx radicals were dominated by the reactions of monoterpene with ozone (O 3 ) and nitrate radical (NO 3 ), contributing ca. 76% and 19%, respectively. The comparisons between the observed ROx and ones modeled had implied that the current model may be overestimated the yields of peroxy radicals from the reactions of monoterpenes with ozone and an important source of peroxy radicals was possibly missed. Abnormal high concentrations of observed ROx radicals were found during high relative humidity (RH) period (especially > 95%), and the possible explanation was that the humidity correction of ROx radicals under high RH conditions may be inaccurate and overestimates ROx concentrations.

关键词：自由基化学过氧化浓度测定氧自由基单萜烯时空变化相对湿度湿度修正

40 YEARS OF THE RULE OF ADMINISTRATIVE LAW:ENHANCEMENTS, EXPERIENCE,AND EXPECTATIONS

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Frontiers of Law in china-Selected publications from Chinese Universities 2018年第4期13卷 497-537页

作者：马怀德孔祥稳 school of Law China University of Political Science and LawBeijing China school of Law-Based Government China University of Political Science and LawBeijing 100088China school of Law University of International Business and EconomicsBeijing 100029China

Based on major landmark events and the rule of law development, the administrative rule-of-law construction in china, over 40 years since the initiation of the reform and opening up policy, can be divided into four stages: the “recovery” stage; the “rapid development by focusing on administrative legislation” stage; the “implementing the basic policy of law-based governance of the country and focusing on law-based administration of government” stage; and the “simultaneous advancement and integrated construction in building the rule of law in china” stage. Over the past 40 years, china’s administrative rule-of-law construction has achieved fruitful results in terms of theoretical shaping, system construction, and concept popularization. The future construction of the administrative rule of law should promptly respond to the theoretical needs put forward by state governance, administrative changes, emerging science, and technology development, and it should continue to improve the theoretical system of administrative law with Chinese characteristics; we should strengthen legislation in key areas, solve practical problems in the construction of a government under the rule of law, and promote the effect of law enforcement and system implementation. We should also focus on improving the awareness and qualities of the rule of law at all levels of leading cadres and form a good rule of law atmosphere in the entire society.

关键词： rule of administrative law law-based administration of government strengthening the rule of law in government 40 years of reform and opening up

Nonlinear Measurement Function in the Ensemble Kalman Filter

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Advances in Atmospheric Sciences 2014年第3期31卷 551-558页

作者： Youmin TANG Jaison AMBANDAN Dake CHEN Environmental Science and Engineering University of Northern BritishColumbiaPrince GeorgeCanadaV2N 4Z9 State Key Laboratory of Satellite ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration international Max Planck Research school on Earth System Modelling Max Planck Institute for MeteorologyHamburgGermany 20146

ABSTRACT The optimal Kalman gain was analyzed in a rigorous statistical framework. Emphasis was placed on a comprehensive understanding and interpretation of the current algorithm, especially when the measurement function is nonlinear. It is argued that when the measurement function is nonlinear, the current ensemble Kalman Filter algorithm seems to contain implicit assumptions： the forecast of the measurement function is unbiased or the nonlinear measurement function is linearized. While the forecast of the model state is assumed to be unbiased, the two assumptions are actually equivalent. On the above basis, we present two modified Kalman gain algorithms. Compared to the current Kalman gain algorithm, the modified ones remove the above assumptions, thereby leading to smaller estimated errors. This outcome was confirmed experimentally, in which we used the simple Lorenz 3-component model as the test-bed. It was found that in such a simple nonlinear dynamical system, the modified Kalman gain can perform better than the current one. However, the application of the modified schemes to realistic models involving nonlinear measurement functions needs to be further investigated.

关键词： ensemble Kalman filter measurement function data assimilation.

Ephemeral gully recognition and accuracy evaluation using deep learning in the hilly and gully region of the Loess Plateau in china

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international Soil and Water Conservation Research 2022年第3期10卷 371-381页

作者： Boyang Liu Biao Zhang Hao Feng Shufang Wu Jiangtao Yang Yufeng Zou Kadambot H.M.Siddique Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling712100China Institute of Water Saving Agriculture in Arid Areas of china Northwest A&F UniversityYangling712100China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling712100China Department of Foreign Languages Northwest A&F UniversityYangling712100China The UWA Institute of Agriculture and school of Agriculture&Environment The University of Western AustraliaPerthWA6001Australia

Ephemeral gullies are widely distributed in the hilly and gully region of the Loess Plateau and play a unique role in the slope gully erosion *** and accurate identification of ephemeral gullies impacts the distribution law and development trend of soil erosion on the Loess *** learning algorithms can quickly and accurately process large data samples that recognize ephemeral gullies from remote sensing ***,we investigated ephemeral gullies in the Zhoutungou watershed in the hilly and gully region of the Loess Plateau in china using satellite and unmanned aerial vehicle images and combined a deep learning image semantic segmentation model to realize automatic recognition and feature *** Accuracy,Precision,Recall,F1value,and AUC,we compared the ephemeral gully recognition results and accuracy evaluation of U-Net,R2U-Net,and SegNet image semantic segmentation *** SegNet model was ranked first,followed by the R2U-Net and U-Net models,for ephemeral gully recognition in the hilly and gully region of the Loess *** ephemeral gully length and width between predicted and measured values had RMSE values of 6.78 m and 0.50 m,respectively,indicating that the model has an excellent recognition *** study identified a fast and accurate method for ephemeral gully recognition in the hilly and gully region of the Loess Plateau based on remote sensing images to provide an academic reference and practical guidance for soil erosion monitoring and slope and gully management in the Loess Plateau region.

关键词： Deep learning Remote sensing image Ephemeral gully recognition Loess plateau Image semantic segmentation Accuracy evaluation

Record-Setting ocean Warmth Continued in 2019

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Advances in Atmospheric Sciences 2020年第2期37卷 137-142页

作者： Lijing CHENG John ABRAHAM Jiang ZHU Kevin ETRENBERTH John FASULLO Tim BOYER Ricardo LOCARNINI Bin ZHANG Fujiang YU Liying WAN Xingrong CHEN Xiangzhou SONG Yulong LIU Michael EMANN international Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Center for ocean Mega-Science Chinese Academy of SciencesQingdao 266071China university of St.Thomas School of EngineeringMinnesota 55105USA National Center for Atmospheric Research BoulderColorado 80307USA National oceanic and Atmospheric administration National Centers for Environmental InformationSilver SpringMaryland 20910USA Institute of oceanology Chinese Academy of SciencesQingdao 266071China National Marine Environmental Forecasting Center Ministry of Natural Resources of ChinaBeijing 100081China College of oceanography Hohai UniversityNanjing 210098China National Marine Data and Information Service Tianjin 300171China Department of Meteorology&Atmospheric Science The Pennsylvania State UniversityUniversity ParkPennsylvania 16802USA State Key Laboratory of Satellite ocean Environment Dynamics Second Institute of OceanographyHangzhou 310012China

Human-emitted greenhouse gases(GHGs)have resulted in a long-term and unequivocal warming of the planet(IPCC,2019).More than 90%of the excess heat is stored within the world's oceans,where it accumulates and causes inc... 详细信息

关键词： greenhouse warming ocean

Impacts of Steering Flows with Different Timescales on the Track of Typhoon Sanba(2012)

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Journal of Meteorological Research 2021年第2期35卷 343-357页

作者： Qiao LIU Melinda PENG Weican ZHOU Tim LI Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)Nanjing University of Information Science&TechnologyNanjing 210044China university of Colorado Colorado SpringColorado 80918USA international Pacific Research Center and Department of Atmospheric Sciences School of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHawaii 96822USA

Typhoon Sanba(2012),the strongest tropical cyclone(TC)of the year worldwide,moved northward almost along130°longitude during its lifetime and passed through different background flows from low to high *** steering flows with different timescales for Sanba are retrieved by using the NCEP reanalysis data with the total wind field separated into:a mean state,an interannual component,an intraseasonal component,and a synoptic *** analysis indicates that the intraseasonal timescale wave train(WT)with east–west oriented circulations made the largest contribution to the movement of *** effects of the environmental steering with different timescales on Sanba’s movement are investigated with numerical simulations using the Weather Research and Forecasting(WRF)*** the control simulation,total fields from the NCEP reanalysis are used as initial and boundary conditions,and the northward motion of Sanba is well *** sensitivity experiments,each of the intraseasonal and interannual components is removed one at a *** steering vectors associated with these timescales can explain their influences on the movement of Sanba in the *** budget analyses indicate that the horizontal vorticity advection made the largest contribution to the movement of the storm.

关键词： intraseasonal interannual mean state steering flow

In situ observation of transmission and reflection of dislocations at twin boundary in CoCrNi alloys

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Science china(Technological Sciences) 2021年第2期64卷 407-413页

作者： LIANG YanXiang YANG XiaoFang MING KaiSheng XIANG ShiHua LIU Qing international Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The deformation mechanism of CoCrNi alloy with high density of annealing twins was studied by in situ transmission electron microscopy. Dislocation transmission and reflection at the twin boundary were observed during in situ loading. We characterized these reaction processes by combining TEM, dislocation theory and crystallography of twin. Twin boundary not only strengthens the material by impeding the motion of dislocation, but also acts as dislocation source to produce large of slip bands. These processes generate large of slip bands to accommodate the plastic deformation or strengthening material.

关键词： dislocation transmission reflection TEM CoCrNi alloys

The china Multi-Model Ensemble Prediction System and Its Application to Flood-Season Prediction in 2018

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Journal of Meteorological Research 2019年第3期33卷 540-552页

作者： Hong-Li REN Yujie WU Qing BAO Jiehua MA Changzheng LIU Jianghua WAN Qiaoping LI Xiaofei WU Ying LIU Ben TIAN Joshua-Xiouhua FU Jianqi SUN Laboratory for Climate Studies & china Meteorological administration-Nanjing university Joint Laboratory for Climate Prediction Studies National Climate Center China Meteorological Administration Beijing 100081 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Nansen-Zhu international Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 National Climate Center China Meteorological Administration Beijing 100081 school of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Chengdu 610225 Institute of Atmospheric Sciences Fudan University Shanghai 200433

Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the china Meteorological administration has established the china multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of china, while the JJA precipitation exhibits some skills only in northwestern and eastern china. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern china and captured the primary rainbelt over northern china,

关键词： multi-model ensemble china multi-model ensemble prediction system (CMME) real-time forecast skill assessment