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Weakening of Winter North Atlantic Oscillation Signal in Spring Precipitation over Southern China

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Atmospheric and Oceanic Science Letters 2013年第5期6卷 248-252页

作者： zhou bo-tao National Climate Center Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences

In this study,the relationship between the North Atlantic Oscillation （NAO） in winter （DecemberFebruary） and the precipitation over southem China （SCP） in the following spring （March-May） was *** showed an interdecadal change,from strong to weak connection,in their *** the early 1980s,they were highly correlated,with a strong （weak） winter NAO followed by an increased （decreased） spring ***,after the early 1980s,their relationship was weakened *** unstable relationship may be linked to the climatological change of East Asian *** the early 1980s,the wave train along the Asian jet propagated the NAO signal eastward to East Asia and affected local upper-tropospheric atmospheric circulation.A strong NAO in winter led to an anomalous anticyclonic circulation at the south side of 30°N in East Asia in spring,resulting in an increase of *** contrast,after the early 1980s,the wave train pattern along the Asian jet extended eastward due to strengthening of the climatological East Asian ***,the NAO-related East Asian atmospheric circulations in the upper troposphere shifted eastward,thereby weakening the linkage between the spring SCP and the winter NAO.

关键词： North Atlantic Oscillation precipitation over southern China interdecadal change

CMIP5 analysis of the interannual variability of the Pacific SST and its association with the Asian-Pacific oscillation

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Atmospheric and Oceanic Science Letters 2017年第2期10卷 138-145页

作者： zhou bo-tao XU Ying National Climate Center China Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

This study analyzed the interannual variability of sea surface temperature （SST） over the Pacific in the historical simulation and under the Representative Concentration Pathways （RCPs, including RCP4.5 and RCPS.5） from 27 models archived in the Coupled Model Intercomparison Project Phase 5 （CMIPS）. Its association with the Asian-Pacific oscillation （APO） was also *** evaluation results showed that the multi-model ensemble mean （MME） and most of the individual models perform well in reproducing the relatively stronger interannual variability of SST over the North Pacific and tropical eastern Pacific. They can also capture reasonably well the observed in-phase and out-of-phase relationships of the APO with the SST in the above two regions, respectively. Under the RCP4.5 and RCPS.5 scenarios, the interannual variability of the SST over the North Pacific and the tropical eastern Pacific is projected by the MME to be weakened during 2050-99 compared to 1950-99. The majority of the CMIP5 models show the same projection as the MME. Besides, the MME projection indicates that the present relationship between the APO and the SST over those two regions would still be dominant under both RCPs. However, considerable discrepancies exist in the changes of the relationships among the individual models.

关键词： Interannual variability Pacific SST CMIPS evaluation projection

Model Evaluation and Projection on the Linkage between Hadley Circulation and Atmospheric Background Related to the Tropical Cyclone Frequency over the Western North Pacific

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Atmospheric and Oceanic Science Letters 2012年第6期5卷 473-477页

作者： zhou bo-tao National Climate Center Beijing 100081 China Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The performance of climate models in simulating the linkage of the spring Hadley circulation (HC) to the vertical zonal wind shear and atmospheric divergence in the lower and upper troposphere, which are related to the tropical cyclone frequency over the western North Pacific (WNPTCF) during June-September (JJAS), is evaluated on the basis of the 20th century climate simulations (20C3M). It is found that four models can simulta-neously reproduce the pattern revealed in the observation, with the spring HC in the Northern Hemisphere being positively correlated to the vertical zonal wind shear in the major tropical cyclone (TC) genesis region and negatively (positively) correlated to the atmospheric diver- gence in the upper (lower) troposphere over the western North Pacific (WNP) in the following JJAS. These four models are further used to project their relationship in the late 21st century under the A1B scenario. The results show that the association of spring HC with the vertical zonal wind shear and the upper-and lower-tropospheric divergence over the WNP will weaken in the late 21st century, thereby resulting in a weak relationship between the spring HC and the JJAS WNPTCF.

关键词： Hadley circulation atmospheric circulation tropical cyclone assessment projection

Changes of heating and cooling degree days over China in response toglobal warming of 1.5℃, 2℃, 3℃ and 4℃

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Advances in Climate Change Research 2018年第3期9卷 192-200页

作者： SHI Ying ZHANG Dong-Feng XU Ying zhou bo-tao National Climate Center China Meteorological Administration Beijing 100081 China Shanxi Climate Center Shanxi Meteorological Service Taiyuan 030006 China

Future changes of heating degree days （HDD） and cooling degree days （CDD） in the 21st century with and without considering populationfactor are investigated based on four sets of climate change simulations over East Asia using the regional climate model version 4.4 （RegCM4.4）driven by the global models of CSIRO-Mk3-6-0, EC-EARTH, HadGEM2-ES, and MPI-ESM-MR. Under global warming of 1.5℃, 2℃, 3℃,and 4℃, significant decrease of HDD can be found over China without considering population factor, with greater decrease over high elevationand high latitude regions, including the Tibetan Plateau, the northern part of Northeast China, and Northwest China; while population-weightedHDD increased in areas where population will increase in the future, such as Beijing, Tianjin, parts of southern Hebei, northern Shandong andHenan provinces. Similarly, the CDD projections with and without considering population factor are largely different. Specifically, withoutconsidering population, increase of CDD were observed over most parts of China except the Tibetan Plateau where the CDD remained zerobecause of the cold climate even under global warming; while considering population factor, the future CDD decreases in South China andincreases in North China, the Sichuan Basin, and the southeastern coastal areas, which is directly related to the population changes. The differentfuture changes of HDD and CDD when considering and disregarding the effects of population show that population distribution plays animportant role in energy consumption, which should be considered in future research.

关键词： Regional climate model Global warming of 1.5 ℃ 2℃ 3℃ and 4℃ Heating degree days Cooling degree days China

A Simulation of the Upper-Tropospheric Temperature Pattern in BCC_CSM1.1

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Atmospheric and Oceanic Science Letters 2012年第6期5卷 478-482页

作者： zhou bo-tao ZHANG Li National Climate Center Beijing 100081China Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

A simulation of the upper-tropospheric temperature (UTT) by the Beijing Climate Center Climate System Model version 1.1 (BCC_CSM1.1) model is evaluated through a comparison with NCEP/NCAR reanalysis data. It is shown that this model has the ability to simulate the climate pattern of the UTT in all four seasons. The spatial correlation on the climatological distribution between the simulation and the observation is 0.92, 0.93, 0.90, and 0.93 for spring, summer, autumn, and winter, respectively. The first leading mode of the UTT in the simulation agrees with that in the observation, except that the simulated second leading mode corresponds to the observed first leading mode in spring. The standard deviation distribution of the simulation is also roughly consistent with the observation, with a pattern coefficient of 0.82, 0.78, 0.82, and 0.82 in spring, summer, autumn, and winter, respectively. The potential UTT change in the second half of the 21st century under the Representative Concentration Pathway 8.5 (RCP8.5) scenario is examined. The prominent change is that the summer UTT will increase over Eurasia and decrease over the North Pacific compared with the present, indicating that the zonal thermal contrast between Asia and the North Pacific will be strengthened within the context of future global warming. The intensity of the interannual variability of the UTT over the Asian-Pacific region is also generally increased. The zonal thermal contrast between Asia and the North Pacific will tend to be enhanced in winter, concurrent with the intensified interannual variability.

关键词： model assessment projection upper-tropospheric temperature

Future changes of cluster high temperature events over China from RegCM4 ensemble under RCP4.5 scenario

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Advances in Climate Change Research 2020年第4期11卷 349-359页

作者： zhou bo-tao CHENG Yang HAN Zhen-Yu XU Ying WANG Xiao-Long Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment ChangeNanjing University of Information Science and TechnologyNanjing210044China School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu610225China National Climate Center China Meteorological AdministrationBeijing100081China Zhengzhou Meteorological Service Zhengzhou450000China

Using the daily maximum temperature of the RegCM4 dynamical downscaling from four global climate models under the historical and RCP4.5 simulations,this study firstly identified the cluster high temperature event(CHTE)occurring in China through a simplified objective method,and then projected its change during the 21st century in terms of the CHTE metrics including frequency,duration,extreme intensity,cumulative intensity,maximum influential area,average influential area,and comprehensive *** ensemble projection indicates that all the CHTE metrics tend to increase toward the end of the 21st century on the national ***,the occurrence of CHTE shows a longer month span during the middle and the end of the 21st century(from April to October)compared to the present(from April to September),accompanied with the peaks of the frequency,duration,and cumulative intensity shifting from the present July ahead to *** to 1986-2005,the projected slight,moderate,and extreme CHTEs increase by 55%,50%,and 50%(58%,43%,and 60%)during 2046-2065(2080-2099),respectively;the projected severe CHTE increases by 11%during 2046-2065 while decreases by 11% during ***,the CHTE frequency,duration,and cumulative intensity are projected to increase in a widespread *** largest increase appears in southern China for the frequency and in Xinjiang and Southeast China for the duration and cumulative *** further divided China into five sub-regions to examine the regional features of CHTE *** is found that in addition to the increase of CHTEs in each single subregion,a pronounced enhancement is also projected for the occurrence of cross-regional CHTEs,particularly for that across more than two subregions.

关键词： Cluster high temperature event Regional climate model Dynamical downscaling Ensemble projection

Application of a neural network model with multimodal fusion for fluorescence spectroscopy

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NUCLEAR SCIENCE AND TECHNIQUES 2024年第10期35卷 1-14页

作者： Tang, Lin zhou, Shuang Shi, Kai-bo Shen, Hong-tao You, Lei Chengdu Univ Coll Elect Informat & Elect Engn Chengdu 610106 Peoples R China Guangxi Normal Univ Guangxi Key Lab Nucl Phys & Nucl Technol Guilin 541004 Peoples R China Anhui Univ Natl Engn Res Ctr Agroecol Big Data Anal & Applica Hefei 230039 Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Panzhihua Univ Vanadium & Titanium Resource Comprehens Utilizat K Panzhihua 617000 Peoples R China Chengdu Normal Univ Inst Higher Educ Sichuan Prov Key Lab Interior Layout Optimizat & Secur Chengdu 611130 Peoples R China

In energy-dispersive X-ray fluorescence spectroscopy, the estimation of the pulse amplitude determines the accuracy of the spectrum measurement. The error generated by the amplitude estimation of the pulse output distorted by the measurement system leads to false peaks in the measured spectrum. To eliminate these false peaks and achieve an accurate estimation of the distorted pulse amplitude, a composite neural network model is proposed, which embeds long and short-term memory (LSTM) into the UNet structure. The UNet network realizes the fusion of pulse sequence features and the LSTM model realizes pulse amplitude estimation. The model is trained using simulated pulse datasets with different amplitudes and distortion times. For the pulse height estimation, the average relative error of the trained model on the test set was approximately 0.64%, which is 27.37% lower than that of the traditional trapezoidal shaping algorithm. Offline processing of a standard iron source further validated the pulse height estimation performance of the UNet-LSTM model. After estimating the amplitude of the distorted pulses using the model, the false peak area was reduced by approximately 91% over the full spectrum and was corrected to the characteristic peak region of interest (ROI). The corrected peak area accounted for approximately 1.32% of the characteristic peak ROI area. The results indicate that the model can accurately estimate the height of distorted pulses and has substantial corrective effects on false peaks.

关键词： UNet Long- and short-term memory Pulse distortion Pulse height estimation Fluorescent spectroscopy

Change in Extreme Climate Events over China Based on CMIP5

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Atmospheric and Oceanic Science Letters 2015年第4期8卷 185-192页

作者： XU Ying WU Jie SHI Ying zhou bo-tao LI Rou-Ke WU Jia National Climate Center China Meteorological Administration Chinese Academy of Meteorological Sciences China Meteorological Administration

The changes in a selection of extreme climate indices(maximum of daily maximum temperature(TXx),minimum of daily minimum temperature(TNn),annual total precipitation when the daily precipitation exceeds the 95th percentile of wet-day precipitation(very wet days,R95p),and the maximum number of consecutive days with less than 1 mm of precipitation(consecutive dry days,CDD))were projected using multi-model results from phase 5 of the Coupled Model Intercomparison Project in the early,middle,and latter parts of the 21st century under different Representative Concentration Pathway(RCP)emissions *** results suggest that TXx and TNn will increase in the future and,moreover,the increases of TNn under all RCPs are larger than those of TXx.R95p is projected to increase and CDD to decrease *** changes in TXx,TNn,R95p,and CDD in eight sub-regions of China are different in the three periods of the 21st century,and the ranges of change for the four indices under the higher emissions scenario are projected to be larger than those under the lower emissions *** multi-model simulations show remarkable consistency in their projection of the extreme temperature indices,but poor consistency with respect to the extreme precipitation *** substantial inconsistency is found in those regions where high and low temperatures are likely to happen for TXx and TNn,*** extreme precipitation events(R95p),greater uncertainty appears in most of the southern regions,while for drought events(CDD)it appears in the basins of *** uncertainty in the future changes of the extreme climate indices increases with the increasing severity of the emissions scenario.

关键词： CMIP5 extreme climate index climate projection uncertainty

Catalyst-free and Reprocessable Aromatic Polydithiourethanes

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Chinese Journal of Polymer Science 2024年第10期42卷 1435-1441,I0007页

作者： bo Yang Hai-Jun Feng Tian-Tian Ni Xiao-Rui zhou tao Xie Ning Zheng State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310058China Department of Colorectal Surgery and Oncology Key Laboratory of Cancer Prevention and InterventionMinistry of EducationThe Second Affiliated HospitalZhejiang University School of MedicineHangzhou310009China

The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer ***,the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing *** this work,we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst,enabling the efficient reprocessing of the corresponding *** a consequence,the mechanical properties of the polydithiourethane can be largely preserved after *** discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.

关键词： Reprocessing Polydithiourethane Dynamic covalent bond