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Atmospheric and Oceanic Science Letters 2025年第1期18卷 6-11页

作者： Haoyu Zhou Pang-Chi Hsu Lin Chen Yitian Qian Key Laboratory of meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjingChina

During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis *** elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget *** findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern *** increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective *** a process is pivotal in amplifying intraseasonal convection *** observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.

关键词： Boreal summer intraseasonal oscillation Interannual variability Pacific Meridional Mode Moisture budget analysis

Homogenization of Surface Pressure Data in tianjin, China

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Journal of meteorological Research 2019年第6期33卷 1131-1142页

作者： Peng SI Chuanjun LUO Min WANG tianjin meteorological Information center Tianjin Meteorological BureauTianjin 300074

Based on a hydrostatic check,a preliminary quality control procedure was applied to the hourly surface air pressure(SAP)and sea level pressure(SLP)data from 13 surface observation stations in tianjin,*** daily and monthly series of the two pressures were tested for homogeneity with the RHtestsV5 software package and corrected by using the surface air temperature data as a *** results showed that 5 and 3 of the 13 stations had significant breakpoints in their SAP and SLP data,respectively,mainly caused by station *** matching adjustments showed that both pressures were dominated by positive deviation corrections and adjustments,with probability densities>0.2 concentrated in the ranges 0.02 to 1.80 and-0.02 to 1.64 *** of the variances and trends of the two pressures before and after adjustment showed that homogeneity correction can greatly reduce the influence of abnormal discrete pressure data and make the long-term trends of the series more *** Baodi station(54525),which has the most significant correction results,as an example,the trend amplitude of the adjusted SAP and SLP was increased by 0.316 and 0.294 hPa(10 yr)-1(95%confidence level),respectively,clearly weakening the sudden reduction induced in the two pressure series by the relocation of this *** with similar products showed that the adjusted data were better than those from the China meteorological ***,the reliability of the surface pressure data and the processing techniques have been improved.

关键词： tianjin station surface air pressure sea level pressure homogenization usability assessment

Effects of rainfall on the weekday traffic flow in major cities of the Beijing-tianjin-Hebei region, China, in 2021

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Advances in Climate Change Research 2022年第6期13卷 858-867页

作者： Ming-Ming XIONG Zhen-Yu HAN Bo LU Jun GUO Shu XU Yan-Juan YANG He HUANG tianjin Climate center Tianjin Meteorological ServiceTianjin 300074China National Climate center China Meteorological AdministrationBeijing 100081China tianjin meteorological Observatory Tianjin Meteorological ServiceTianjin 300074China

Rainfall can bring uncertainties to the traffic flow and influence the normal function of urban transportation *** impact of precipitation on the urban traffic flow,especially the different impacts among cities and areas within a city,is worth ***,we analysed the impact of precipitation on the traffic flow in the urban areas of the Beijing-tianjin-Hebei region by comparing the traffic flow in non-precipitation and rainy weather with different hourly precipitation intensities in *** increase in the travel time index(TTI)is chosen to represent the influence of precipitation on the transportation *** results show that the maximum of the average TTI increases on the city scale under various rainfall intensities by 3.3%,6.6%and 10.8%in Beijing,tianjin and Shijiazhuang,*** general,the increase in the TTI contributed by precipitation is the greatest at morning and afternoon peak hours,and the traffic congestion degree increases with the rainfall ***,in the morning peak,afternoon peak and midday hours in Beijing and tianjin,the influences of the weak rainfall intensity on the traffic flow are generally great,whereas the traffic congestion degree caused by heavy precipitation is relatively ***,in morning peak hours,the congestion reduction reaches approximately 2%,which may be related to the spatial difference in the impacts of precipitation on the traffic flow and the changes in people's travel intention under different rainfall *** findings can help better understand the relationship between rainfall and urban traffic flow characteristics and also potentially contribute to the development of impact-oriented climate predictions.

关键词： Rainfall intensity Urban traffic flow Beijing-tianjin-Hebei region Auto Navi map road condition data

Simulation and Projection of Near-Surface Wind Speeds in China by BCC-CSM Models

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Journal of meteorological Research 2019年第1期33卷 149-158页

作者： Yajun XIONG Xiaoge XIN Xingxia KOU Institute of Urban Meteorology China Meteorological Administration environmental Meteorology Forecast center of Beijing–tianjin–Hebei Region National Climate center China Meteorological Administration

We evaluated the ability of the Beijing Climate center models on different horizontal resolutions(BCC-CSM1.1 on approximately 280-km resolution and BCC-CSM1.1 m on approximately 110-km resolution) in simulating the nearsurface wind speeds(NWS) in China during 1961–2005. The spatial distribution of the annual mean NWS over China is better captured by BCC-CSM1.1 m than by BCC-CSM1.1 due to the finer resolution. The weakened NWS over China during 1961–2005 cannot be reproduced by BCC-CSM1.1, whereas BCC-CSM1.1 m is able to simulate the decreasing trend of the autumn NWS in North China, although the magnitude is about 1/3 of the observed *** is attributed to the better performance of this finer-resolution model in reproducing the increase in sea level pressure over Mongolia and North China over the past 45 years. The results suggest that increasing the horizontal resolution of the BCC-CSM model has improved its ability in reproducing the spatial distribution and long-term changes of NWS over China. Future projections by BCC-CSM1.1 m under different Representative Concentration Pathway(RCP) scenarios demonstrate that the autumn NWS in North China will decrease during the 21 st century under both the middle(RCP4.5) and high(RCP8.5) emission scenarios, with a higher decreasing rate under RCP8.5.

关键词： wind speed simulation projection BCC-CSM Representative Concentration Pathway(RCP)

Impact of meteorological conditions on a nine-day particulate matter pollution event observed in December 2013,Shanghai,China

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Particuology 2015年第3期13卷 69-79页

作者： Jianming Xu Fengxia Yan Ying Xie Fengyun Wang Jianbin Wu Qingyan Fu Shanghai meteorological Bureau meteorological center of Traffic Management Bureau of East China Shanghai environmental Monitoring center

A severe particulate matter pollution event occurred in Shanghai from 1 to 9 December 2013. The mean hourly mass concentrations of PM2.5 and PM10 were 211.9 and 249.0 μg/m3, respectively. Reanalysis data, in situ, and remote-sensing measurements were used to examine the impacts of meteorological conditions on this event. It was found that the synoptic pattern of weak pressure, the reduced planetary boundary layer height, and the passage of two cold fronts were key factors causing the event. Four stages were identified during this event based on the evolution of its PM2.5 levels and weather conditions. The highest concentration of PM2.5 （602 μg/m3） was observed in stage 3. High PM2.5 concentrations were closely associated with a low local ventilation index, with an average of 505 m2/s, as well as with the influx of pollutants from upstream, transported by the cold fronts.

关键词： Particulate matterPM2.5Pollution eventPlanetary boundary layerCold frontUrban air pollution

Seasonal variations and size distributions of water-soluble ions in atmospheric aerosols in Beijing, 2012

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Journal of environmental Sciences 2015年第8期27卷 197-205页

作者： Yongjie Yang Rui Zhou Jianjun Wu Yue Yu Zhiqiang Ma Lejian Zhang Yi'an Di National Research center for environmental Analysis and Measurement Jiangsu Institute of meteorological Sciences Beijing Urban meteorological Engineering Technology Research center meteorological Observation center China Meteorological Administration

The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7 ± 48.9 μg/m3 in spring, 54.0 ± 17.0 μg/m3 in summer, 54.1 ± 42.9 μg/m3 in autumn, and 88.8 ± 47.7 μg/m3 in winter, respectively. Furthermore, out of all the ions, NO3-,SO42-and NH4＋accounted for 81.2% in spring, 78.5% in summer, 74.6% in autumn, and 76.3%in winter. Mg2＋and Ca2＋were mainly associated with coarse particles, with a peak that ranged from 5.8 to 9.0 μm. Na＋, NH4＋and Cl-had a multi-mode distribution with peaks that ranged from 0.43 to 1.1 μm and 4.7 to 9.0 μm. K＋, NO3-, and SO42-were mainly associated with fine particles, with a peak that ranged from 0.65 to 2.1 μm. The concentrations of Na＋, K＋,Mg2＋, Ca2＋, NH4＋, Cl-, NO3-and SO42-were 2.69, 2.32, 1.01, 4.84, 16.9, 11.8, 42.0, and 44.1 μg/m3 in particulate matter（PM） on foggy days, respectively, which were 1.4 to 7.3 times higher than those on clear days. The concentrations of these ions were 2.40, 1.66, 0.92, 4.95, 17.5,7.00, 32.6, and 34.7 μg/m3 in PM on hazy days, respectively, which were 1.2–5.7 times higher than those on clear days.

关键词： Water-soluble ions Size distribution Hazy day Foggy day Beijing

Spatiotemporal characteristics and influencing factors of vegetation water use efficiency on the Tibetan Plateau in 2001–2020

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Journal of Geographical Sciences 2025年第1期 39-64页

作者： HE Chenyang WANG Yanjiao YAN Feng LU Qi School of Ecological and environmental Science East China Normal University Institute of Ecological Conservation and Restoration Chinese Academy of Forestry National Climate center China Meteorological Administration

Water use efficiency （WUE）,as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ***,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain *** study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–*** indicated an annual mean WUE of 0.8088 gC/mm·m2across the plateau,with a spatial gradient reflecting decrease from the southeast toward the *** manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,***,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of *** factors accounted for 70.79%of the variability in *** leaf area index and temperature served as the major driving forces of WUE variation.

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A Novel Fusion Forecast Model for Hail Weather in Plateau Areas Based on Machine Learning

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Journal of meteorological Research 2021年第5期35卷 896-910页

作者： Yan ZHANG Zhong JI Bing XUE Ping WANG School of Electrical and Information Engineering Tianjin UniversityTianjin 300072 Public meteorological Service center China Meteorological AdministrationBeijing 100081

In order to improve the accuracy of hail forecasting for mountainous and plateau areas in China,this study presents a novel fusion forecast model based on machine learning ***,known mechanisms of hail formation and two newly proposed elevation features calculated from radar data,sounding data,automatic station data,and terrain data,are firstly combined,from which a hail/short-duration heavy rainfall(SDHR)classification model based on the random forest(RF)algorithm is built ***,we construct a hail/SDHR probability identification(PI)model based on the Bayesian minimum error decision and principal component analysis ***,an"and"fusion strategy for coupling the RF and PI models is *** addition to the mechanism features,the new elevation features improve the models’performance *** results show that the fusion strategy is particularly notable for reducing the number of false alarms on the premise of ensuring the hit rate.A comparison with two classical hail indexes shows that our proposed algorithm has a higher forecasting accuracy for hail in mountainous and plateau *** 19 hail cases used for testing could be identified,and our algorithm is able to provide an early warning for 89.5%(17 cases)of hail cases,among which 52.6%(10 cases)receive an early warning of more than 42 minutes in *** PI model sheds new light on using Bayesian classification approaches for highdimensional solutions.

关键词： hail identification hail warning random forest Bayesian minimum error decision fusion strategy

Revisiting the variations of precipitation and water vapour budget over the Tibetan Plateau

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Advances in Climate Change Research 2023年第1期14卷 77-84页

作者： Ping WU Yan-Ju LIU Jing WANG Yi-Hui DING National Climate center China Meteorological AdministrationBeijing 100081China tianjin Key Laboratory for Oceanic Meteorology Tianjin Institute of Meteorological ScienceTianjin 300074China

Owing to the scarcity of observation data in the western Tibetan Plateau(TP),the knowledge of precipitation changes over the entire plateau based only on the limited data in eastern TP is not ***,the alternative high-resolution precipitation data of the China Meteorological Forcing Dataset(CMFD)are used for the comprehensive analysis of precipitation changes over the whole TP(including western and northern TP)to fill in the lack of understanding of precipitation in the western *** with observations,CMFD can broadly capture the spatial distributions and identify the temporal variabilities of precipitation over the *** with CMFD data suggested that the annual precipitation over the whole TP did not show a uniform humidification trend in 1979-2018 and featured wetting and drying trends in the northern(NTP)and southern TP(STP),***,the four seasonal regimes of precipitation over the northern TP(NTP,including most areas of western TP)all experienced a noticeable interdecadal shift around the late 1990s,followed by above-normal precip*** for spring,the seasonal precipitation over the southern TP(STP)showed interannual *** precipitation over the STP has undergone moistening since the late 1990s,which was consistent with that over the *** different reanalysis datasets,namely JRA55,MERRA2,ERA5 and CRA40,were used to compare the water vapour budget of each boundary over the *** increase in spring precipitation over the NTP and STP was found to be related to the decrease in water vapour outflow from the north *** interdecadal increase in summer precipitation over the NTP was mainly due to the reduction of outflow from the east ***,the increase in autumn precipitation was related to the increase in inflow from the west boundary.

关键词： Tibetan Plateau Precipitation Water vapour budget Reanalysis data

Validation of the Modified Becker's Split-Window Approach for Retrieving Land Surface Temperature from AVHRR

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Journal of meteorological Research 2015年第5期29卷 823-836页

作者：权维俊陈洪滨韩秀珍马志强 Key Laboratory for Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences environmental Meteorology Forecast center of Beijing-tianjin-Hebei Beijing Meteorological Bureau National Satellite meteorological center China Meteorological Administration

To further verify the modified Becker＇s split-window approach for retrieving land surface temperature （LST） from long-term Advanced Very High Resolution Radiometer （AVHRR） data, a cross-validation and a radiance-based （R-based） validation are performed and examined in this paper. In the cross-validation, 3481 LST data pairs are extracted from the AVttRR LST product retrieved with the modified Becker＇s approach and compared with the Moderate Resolution Imaging Spectroradiometer （MODIS） LST product （MYDllA1） for the period 2002-2008, relative to the positions of 548 weather stations in China. The results show that in most cases, the AVHRR LST values are higher than the MYDllA1. When the AVHRR LSTs are adjusted with a linear regression, the values are close to the MYDllA1, showing a good linear relationship between the two datasets （R2 = 0.91）. In the R-based validation, comparison is made between AVHRR LST retrieved from the modified Becker＇s approach and the inversed LST from the Moderate Resolution Transmittance Model （MODTRAN） consolidated with observed temperature and humidity profiles at four radiosonde stations. The results show that the retrieved AVHRR LST deviates from the MODTRAN inversed LST by -1.3 （-2.5） K when the total water vapor amount is less （larger） than 20 mm. This provides useful hints for further improvement of the LST retrieval algorithms＇ accuracy and consistency.

关键词： LST split-window approach MODTRAN AVHRR validation