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Global precipitation from FY-3 polar orbit satellites

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Science Bulletin 2024年第17期69卷 2688-2692页

作者： Runze Zhao Kaicun Wang Xiangde Xu State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China State Key Laboratory of Severe weather Chinese Academy of Meteorological SciencesBeijing 100081China Institute of Carbon Neutrality Sino-French Institute for Earth System ScienceCollege of Urban and Environmental SciencesPeking UniversityBeijing 100871China

Precipitation provides water resources but can also cause disasters. The amount, intensity, and frequency of precipitation have significant impacts on ecosystems, people’s health, and socioeconomic systems [1]. However, due to its spatiotemporal discontinuity, accurately estimating precipitation remains a great challenge[2]. To estimate global precipitation at the required spatial and temporal resolutions, active microwave and passive microwave(PMW) observations from low-Earth-orbit satellites and infrared observations from geostationary satellites must be *** Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG) product is one of the best such products and provides global precipitation data at 0.1°and half-hour resolutions [3].

关键词： satellites microwave Global

Advancing flood susceptibility modeling using stacking ensemble machine learning: A multi-model approach

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Journal of Geographical Sciences 2024年第8期34卷 1513-1536页

作者： YANG Huilin YAO Rui DONG Linyao SUN Peng ZHANG Qiang WEI Yongqiang SUN Shao AGHAKOUCHAK Amir School of Geography and Tourism Anhui Normal UniversityWuhu 241002AnhuiChina Changjiang River Scientific Research Institute Wuhan 430015China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087GuangdongChina Hunan Institute of Water Resources and Hydropower Research Changsha 410007China State Key Laboratory of Severe weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Civil and Environmental Engineering University of California IrvineIrvineCA 92697USA

Flood susceptibility modeling is crucial for rapid flood forecasting, disaster reduction strategies, evacuation planning, and decision-making. Machine learning(ML) models have proven to be effective tools for assessing flood susceptibility. However, most previous studies have focused on individual models or comparative performance, underscoring the unique strengths and weaknesses of each model. In this study, we propose a stacking ensemble learning algorithm that harnesses the strengths of a diverse range of machine learning models. The findings reveal the following:(1) The stacking ensemble learning, using RF-XGBCB-LR model, significantly enhances flood susceptibility simulation.(2) In addition to rainfall,key flood drivers in the study area include NDVI, and impervious surfaces. Over 40% of the study area, primarily in the northeast and southeast, exhibits high flood susceptibility, with higher risks for populations compared to cropland.(3) In the northeast of the study area,heavy precipitation, low terrain, and NDVI values are key indicators contributing to high flood susceptibility, while long-duration precipitation, mountainous topography, and upper reach vegetation are the main drivers in the southeast. This study underscores the effectiveness of ML, particularly ensemble learning, in flood modeling. It identifies vulnerable areas and contributes to improved flood risk management.

关键词： flood susceptibility assessment machine learning stacking ensemble learning flood drivers XiangjiangRiverBasin

Long-term prognosis and its associated predictive factors in patients with eosinophilic gastroenteritis

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World Journal of Gastroenterology 2024年第2期30卷 146-157页

作者： Kai-Wen Li Ge-Chong Ruan Shuang Liu Tian-Ming Xu Ye Ma Wei-Xun Zhou Wei Liu Peng-Yu Zhao Zhi-Rong Du Ji Li Jing-Nan Li Department of Gastroenterology Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100730China Department of Allergy Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100730China Department of Pathology Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100730China Department of Radiology Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100730China Affairs office Chinese Academy of Medical Sciences and Peking Union Medical College Hospital(West campus)Beijing 100032China

BACKGROUND Eosinophilic gastroenteritis(EGE)is a chronic recurrent disease with abnormal eosinophilic infiltration in the gastrointestinal *** remain the most common treatment ***,disease relapse and glucocorticoid dependence remain notable *** date,few studies have illuminated the prognosis of EGE and risk factors for disease *** To describe the clinical characteristics of EGE and possible predictive factors for disease relapse based on long-term *** This was a retrospective cohort study of 55 patients diagnosed with EGE admitted to one medical center between 2013 and *** records were collected and ***-Meier curves and log-rank tests were conducted to reveal the risk factors for long-term relapse-free survival(RFS).RESULTS EGE showed a median onset age of 38 years and a slight female predominance(56.4%).The main clinical symptoms were abdominal pain(89.1%),diarrhea(61.8%),nausea(52.7%),distension(49.1%)and vomiting(47.3%).Forty-three(78.2%)patients received glucocorticoid treatment,and compared with patients without glucocorticoid treatments,they were more likely to have elevated serum immunoglobin E(IgE)(86.8%vs 50.0%,P=0.022)and descending duodenal involvement(62.8%vs 27.3%,P=0.046)at *** a median follow-up of 67 mo,all patients survived,and 56.4%had at least one *** variables at baseline might have been associated with the overall RFS rate,including age at diagnosis24 kg/m^(2)(HR 0.3922,95%CI:0.1916-0.8027,P=0.014),disease duration from symptom onset to diagnosis>3.5 mo(HR 2.4725,95%CI:1.220-5.0110,P=0.011),vomiting(HR 3.1259,95%CI:1.5246-6.4093,P=0.001),total serum IgE>300 KU/L at diagnosis(HR 0.2773,95%CI:0.1204-0.6384,P=0.022)and glucocorticoid treatment(HR 6.1434,95%CI:2.8446-13.2676,P=0.003).CONCLUSION In patients with EGE,younger onset age,longer disease c

关键词： Eosinophilic gastroenteritis Prognosis Relapse Glucocorticoid Glucocorticoid dependence

TP-PROFILE: Monitoring the Thermodynamic Structure of the Troposphere over the Third Pole

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Advances in Atmospheric Sciences 2024年第6期41卷 1264-1277页

作者： Xuelong CHEN Yajing LIU Yaoming MA Weiqiang MA Xiangde XU Xinghong CHENG Luhan LI Xin XU Binbin WANG Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan College of Atmospheric Science Lanzhou UniversityLanzhou 730000China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Disastrous weather China Academy of Meteorological SciencesBeijing 100081China

Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the *** from some soundings from local meteorological observatories,the tropospheric atmosphere over the Tibetan Plateau(TP)has never been continuously *** part of the Chinese Second Tibetan Plateau Scientific Expedition and Research Program(STEP),the Tibetan Plateau Atmospheric Profile(TPPROFILE)project aims to construct a comprehensive MWR troposphere observation network to study the synoptic processes and environmental changes on the *** initiative has collected three years of data from the MWR *** paper introduces the data information,the data quality,and data *** applications of the data obtained from these MWRs were also *** comparisons of MWR against the nearest radiosonde observation demonstrate that the TP-PROFILE MWR system is adequate for monitoring the thermal and moisture variability of the troposphere over the *** continuous temperature and moisture profiles derived from the MWR data provide a unique perspective on the evolution of the thermodynamic structure associated with the heating of the *** TP-PROFILE project reveals that the low-temporal resolution instruments are prone to large uncertainties in their vapor estimation in the mountain valleys on the TP.

关键词： microwave radiometer thermodynamic structure vertical profile Tibetan Plateau

A Combination Prediction Model for Short Term Travel Demand of Urban Taxi

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Computers, Materials & Continua 2024年第6期79卷 3877-3896页

作者： Mingyuan Li Yuanli Gu Qingqiao Geng Hongru Yu School of Traffic and Transportation Beijing Jiaotong UniversityBeijing100044China Transport Planning and Research Institute Ministry of TransportBeijing100028China

This study proposes a prediction model considering external weather and holiday factors to address the issue of accurately predicting urban taxi travel demand caused by complex data and numerous influencing *** model integrates the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)and Convolutional Long Short Term Memory Neural Network(ConvLSTM)to predict short-term taxi travel *** CEEMDAN decomposition method effectively decomposes time series data into a set of modal components,capturing sequence characteristics at different time scales and *** on the sample entropy value of components,secondary processing of more complex sequence components after decomposition is employed to reduce the cumulative prediction error of component sequences and improve prediction *** this basis,considering the correlation between the spatiotemporal trends of short-term taxi traffic,a ConvLSTM neural network model with Long Short Term Memory(LSTM)time series processing ability and Convolutional Neural Networks(CNN)spatial feature processing ability is constructed to predict the travel demand for urban *** combined prediction model is tested on a taxi travel demand dataset in a certain area of *** results show that the CEEMDAN-ConvLSTM prediction model outperforms the LSTM,Autoregressive Integrated Moving Average model(ARIMA),CNN,and ConvLSTM benchmark models in terms of Symmetric Mean Absolute Percentage Error(SMAPE),Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and R2 ***,the SMAPE metric exhibits a remarkable decline of 21.03%with the utilization of our proposed *** results confirm that our study provides a highly accurate and valid model for taxi travel demand forecasting.

关键词： Urban transport taxi travel demand prediction CEEMDAN-ConvLSTM modal components

Quantitative Analysis of Seeing with Height and Time at Muztagh-Ata Site Based on ERA5 Database

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Research in Astronomy and Astrophysics 2024年第1期24卷 87-95页

作者： Xiao-Qi Wu Cun-Ying Xiao Ali Esamdin Jing Xu Ze-Wei Wang Luo Xiao Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Astronomy Beijing Normal UniversityBeijing 100875China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China

Seeing is an important index to evaluate the quality of an astronomical *** estimate seeing at the Muztagh-Ata site with height and time quantitatively,the European Centre for Medium-Range weather Forecasts reanalysis database(ERA5)is *** calculated from ERA5 is compared consistently with the Differential Image Motion Monitor seeing at the height of 12 *** show that seeing decays exponentially with height at the Muztagh-Ata *** decays the fastest in fall in 2021 and most slowly with height in *** seeing condition is better in fall than in *** median value of seeing at 12 m is 0.89 arcsec,the maximum value is1.21 arcsec in August and the minimum is 0.66 arcsec in *** median value of seeing at 12 m is 0.72arcsec in the nighttime and 1.08 arcsec in the *** is a combination of annual and about biannual variations with the same phase as temperature and wind speed indicating that seeing variation with time is influenced by temperature and wind *** Richardson number Ri is used to analyze the atmospheric stability and the variations of seeing are consistent with Ri between *** quantitative results can provide an important reference for a telescopic observation strategy.

关键词： site testing atmospheric effects methods:data analysis telescopes Earth

Statistical Channel Modeling for Indoor VLC Communications Based on Channel Measurements

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China Communications 2024年第1期21卷 131-147页

作者： Shuo Liu Pan Tang Jianhua Zhang Yue Yin Yu Tong Baobao Liu Guangyi Liu Liang Xia State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China China Mobile Research Institute Beijing 100053China

Visible light communication(VLC)has attracted much attention in the research of sixthgeneration(6G)***,channel modeling is the foundation for designing efficient and robust VLC *** this paper,we present extensive VLC channel measurement campaigns in indoor environments,i.e.,an office and a *** on the measured data,the large-scale fading characteristics and multipath-related characteristics,including omnidirectional optical path loss(OPL),K-factor,power angular spectrum(PAS),angle spread(AS),and clustering characteristics,are analyzed and modeled through a statistical *** on the extracted statistics of the above-mentioned channel characteristics,we propose a statistical spatial channel model(SSCM)capable of modeling multipath in the spatial ***,the simulated statistics of the proposed model are compared with the measured *** instance,in the office,the simulated path loss exponent(PLE)and the measured PLE are 1.96and 1.97,***,the simulated medians of AS and measured medians of AS are 25.94°and 24.84°,***,the fact that the simulated results fit well with measured results has demonstrated the accuracy of our SSCM.

关键词： channel characteristics channel measurement channel modeling 6G spatial lobe VLC

Recognition of Organizational Morphology of Mesoscale Convective Systems Using Himawari-8 Observations

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Journal of Tropical Meteorology 2024年第3期30卷 289-305页

作者： SHOU Yi-xuan ZHANG Su-zhao LU Feng Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites National Satellite Meteorological Center(National Center for Space Weather)China Meteorological AdministrationBeijing 100081 China Innovation Center for FengYun Meteorological Satellite(FYSIC) Beijing 100081 China Key Laboratory for Meteorological Disaster Monitoring and Early Warning and Risk Management of Characteristic Agriculture in Arid Regions Yinchuan 750002 China Ningxia Key Laboratory of Meteorological Disaster Prevention and Mitigation Yinchuan 750002 China

The onset,evolution,and propagation processes of convective cells can be reflected by the organizational morphology of mesoscale convective systems(MCSs),which are key factors in determining the potential for heavy *** paper proposed a method for objectively classifying and segmenting MCSs using geosynchronous satellite *** of the product relative to the classification in radar composite reflectivity imagery indicates that the algorithm offers skill for discriminating between convective and stratiform areas and matched 65%of convective area identifications in radar imagery with a false alarm rate of 39%and an accuracy of 94%.A quantitative evaluation of the similarity between the structures of 50 MCSs randomly obtained from satellite and radar observations shows that the similarity was as high as 60%.For further testing,the organizational modes of the MCS that caused the heavy precipitation in Northwest China on August 21,2016(hereinafter known as the“0821”rainstorm)were *** was found that the MCS,accompanied by the“0821”rainstorm,successively exhibited modes of the isolated cell,squall line with parallel stratiform(PS)rain,and non-linear system during its life *** them,the PS mode might have played a key role in causing this *** findings are in line with previous studies.

关键词： mesoscale convective system satellite organizational morphology extremely heavy precipitation

Recent Enhanced Deep Troposphere-to-Stratosphere Air Mass Transport Accompanying the Weakening Asian Monsoon

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Journal of Meteorological Research 2024年第4期38卷 708-719页

作者： Bin CHEN Jianzhong MA Wei ZHANG Jianchun BIAN Tianliang ZHAO Xiangde XU State Key Laboratory of Severe weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing100081China Department of Plants Soils and ClimateUtah State UniversityUT84322USA Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological AdministrationNanjing University of Information Science&TechnologyNanjing 210044China

The Asian monsoon(AM) region is a well-known region with prevailing stratosphere–troposphere exchange(STE).However,how the STE across this region changes with the weakening AM remains ***,we particularly diagnose the air mass transport between the planetary boundary layer(PBL) and the stratosphere over the AM region during 1992–2017 using the Lagrangian particle dispersion model FLEXPART based on the ERA-Interim reanalysis *** results show that both the downward and upward deep STEs exhibit a detectable increasing trend,while the latter,namely,the deep troposphere-to-stratosphere transport(DTST),is relatively more *** analysis reveals that the long-term trend of DTST over the AM region could be partly attributed to changes in the Pacific Walker circulation and the air temperature(especially at upper levels).Additionally,it is found that DTST increases markedly over the tropical oceanic regions,while the increasing DTST into the stratosphere can be attributed to the enhanced air masses originated from the PBL over the terrestrial regions,where large amounts of pollutant emissions *** results imply that the influence of the DTST on the chemical composition and the climate of the stratosphere over the AM region is expected to become increasingly important,and is thereby of relevance to climate projection in an evolving climate.

关键词： stratosphere–troposphere exchange(STE) air mass transport deep troposphere-to-stratosphere transport(DTST) Asian monsoon(AM) pollution