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Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China
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作者 Limei YANG Jun GE +4 位作者 Yipeng CAO Yu LIU Xing LUO Shiyao WANG Weidong GUO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第11期2259-2275,共17页
Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter d... Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter days.These results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming. 展开更多
关键词 urban trees cooling efficiency China's cities EVAPOTRANSPIRATION SUMMER hot days
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Days Matter软件预警功能在口腔专科医院物品效期管理的应用 被引量:5
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作者 杨冬叶 侯明娇 +1 位作者 刘晓刚 林丽婷 《护理学杂志》 CSCD 北大核心 2019年第23期62-64,共3页
目的探讨Days Matter软件预警功能对口腔专科医院物品效期自动化管理的效果。方法将科室物品分成仪器设备、耗材(常用和不常用类)两大类物品,运用Days Matter软件导入仪器设备及不常用耗材物品有效期并设置提醒功能。比较使用前后3个月... 目的探讨Days Matter软件预警功能对口腔专科医院物品效期自动化管理的效果。方法将科室物品分成仪器设备、耗材(常用和不常用类)两大类物品,运用Days Matter软件导入仪器设备及不常用耗材物品有效期并设置提醒功能。比较使用前后3个月每月护士检查该类物品效期所需平均时间。结果使用前,护士每月检查物品效期所需时间为(97.03±3.63)min,使用后为(26.73±1.19)min,使用前后比较,差异有统计学意义(P<0.01)。结论Days Matter软件操作简单,能精准监控物品效期,实现数据共享,节省检查时间。 展开更多
关键词 days Matter软件 医疗物品 仪器设备 医疗耗材 有效期 自动化管理
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Analysis of Causes for An Unusual Cloudy-rainy Weather for Several Days in Autumn 被引量:1
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作者 张景珍 张莉 +1 位作者 李建明 李静 《Meteorological and Environmental Research》 CAS 2010年第10期20-24,共5页
Cloudy-rainy weather for several days in 2007 was featured with the longest duration and the most serious extent of injury since the time from which there was meteorology observation record in Shandong.The causes of t... Cloudy-rainy weather for several days in 2007 was featured with the longest duration and the most serious extent of injury since the time from which there was meteorology observation record in Shandong.The causes of this process were analyzed in this article in terms of general circulation,character of physical quantity and tropical cyclone.The result showed that the precipitation process was a long wave adjustment process and it took place during the transformation process of general circulation turning from the zonal to the radial.During the cloudy-rainy weather process,the Ural mountain ridge and the Western Pacific subtropical high were more abnormally strong and in the further north than that in any other years.The tropical cyclone in the south of the subtropical cyclone activity was more frequent.There was more shortwave in middle latitudes of Asian.The cold air masses Siberia went down south.The cold air masses joined with the current of air in the Lower Yellow River.This led to the lasting cloudy-rainy weather for several days in Shandong. 展开更多
关键词 Cloudy-rainy weather for several days General circulation Physics characteristics Analysis of the causes China
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混合方法:教育游戏评价研究的理想范式——以80Days教育游戏项目为例 被引量:1
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作者 庄科君 贺宝勋 《软件导刊》 2013年第3期189-191,共3页
教育游戏评价是教育游戏设计开发过程中的核心环节之一,是一项综合的、多准则、多因素的复杂工程。评价过程应该采用科学的评价研究范式,以避免信度与效度的缺失。在目前国内教育游戏评价研究几乎空白的境遇下,以欧盟委员会FP7框架计划... 教育游戏评价是教育游戏设计开发过程中的核心环节之一,是一项综合的、多准则、多因素的复杂工程。评价过程应该采用科学的评价研究范式,以避免信度与效度的缺失。在目前国内教育游戏评价研究几乎空白的境遇下,以欧盟委员会FP7框架计划下的科研项目———80Days教育游戏项目为例,介绍了混合方法下的教育游戏评价研究范式,以期对我国教育游戏评价研究与实践有所帮助。 展开更多
关键词 教育游戏 混合方法 研究范式 80days
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The Absurdity of Happy Days
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作者 杨樱 《英语广场(学术研究)》 2012年第8期36-38,共3页
Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure an... Happy Days,one of Samuel Beckett's renowned works,is remarkable for its absurdity.The paper approaches the predominant feature from such aspects as fragmented characters,disconnected language,peculiar structure and grotesque stagecraft. 展开更多
关键词 Happy days ABSURDITY fragmented characters disconnected language peculiar structure grotesque stagecraft
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On Aesthetic Representation at Phonological Level in English Versions of Zhu Ziqing's Lyric Prose Transient Days
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作者 孔令会 《海外英语》 2012年第13期176-177,共2页
The paper analyses aesthetic message at phonological level of Zhu Ziqing's lyric prose Transient Days and explores how such message is represented in English versions respectively translated by Zhang Peiji and Zhu... The paper analyses aesthetic message at phonological level of Zhu Ziqing's lyric prose Transient Days and explores how such message is represented in English versions respectively translated by Zhang Peiji and Zhu Chunshen. 展开更多
关键词 ZHU Ziqing TRANSIENT days PHONOLOGICAL LEVEL aesth
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On the Main Characters in“Days of the Butterfly”
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作者 李伟娟 《海外英语》 2016年第24期169-170,共2页
"Days of the Butterfly"was one of Alice Munro's short stories written in 1950 s, when she was still a new hand. This paper will mainly focus on the development of the main characters in the story, includ... "Days of the Butterfly"was one of Alice Munro's short stories written in 1950 s, when she was still a new hand. This paper will mainly focus on the development of the main characters in the story, including Myra, the black girl who was the heroine, the teacher Miss Darling, and the Narrator"I". In portraying these characters, Munro adopted several writing techniques including conversation, detailed description, psychological description and so on. She vividly transferred those characters into paper. 展开更多
关键词 Munro "days of the Butterfly" main characters Myra Miss Darling
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青年职场“Gap day”现象探究
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作者 张良驯 付成梅 《中国青年社会科学》 CSSCI 北大核心 2024年第4期11-22,共12页
青年职场“Gap day”现象引起了社会的广泛关注和热烈讨论。青年职场“Gap day”现象的典型特征是:通过语言上的拼贴与再造,表达部分职业青年的困顿疲倦情绪;通过行为上的放空与逃离,排解青年在工作中积攒的情绪和压力;通过价值上的戏... 青年职场“Gap day”现象引起了社会的广泛关注和热烈讨论。青年职场“Gap day”现象的典型特征是:通过语言上的拼贴与再造,表达部分职业青年的困顿疲倦情绪;通过行为上的放空与逃离,排解青年在工作中积攒的情绪和压力;通过价值上的戏谑与自嘲,赋予青年的短暂休息以正向意义。青年职场“Gap day”现象的深层原因是:青年在高压生存环境中的“弹性姿态”、在加速社会运行中的“精神逃离”和在社会时钟齿轮下的“自我审视”。对青年职场“Gap day”现象的有效治理,既要着眼于青年发展,运用公共政策实现青年发展的普遍性诉求,又要立足于青年就业,采取切实措施促进青年实现高质量充分就业。 展开更多
关键词 Gap day 青年现象 青年就业 青年职业发展
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水仙花日(Daffodil Days)简介
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作者 窦剑 《花卉》 2019年第9期47-48,共2页
Daffodil为石蒜科水仙属(Narcissus)植物的统称,它们是一类具膜质有皮鳞茎的多年生草本,通常于春季开花。万物萧飒的冬季,水仙的叶片破土而出(图1)。待到早春时节,水仙花儿迸放(图2),拉开春色满园的序幕。而当春夏交替之季,地上的绿叶... Daffodil为石蒜科水仙属(Narcissus)植物的统称,它们是一类具膜质有皮鳞茎的多年生草本,通常于春季开花。万物萧飒的冬季,水仙的叶片破土而出(图1)。待到早春时节,水仙花儿迸放(图2),拉开春色满园的序幕。而当春夏交替之季,地上的绿叶逐渐枯黄倒伏(图3),地下鳞茎进入休眠。水仙如此般,一岁一枯荣、周而复始。 展开更多
关键词 水仙花 days 多年生草本 石蒜科 鳞茎 早春 倒伏 枯黄
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Changes of heating and cooling degree days over China in response toglobal warming of 1.5℃, 2℃, 3℃ and 4℃ 被引量:8
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作者 SHI Ying ZHANG Dong-Feng +1 位作者 XU Ying ZHOU Bo-Tao 《Advances in Climate Change Research》 SCIE CSCD 2018年第3期192-200,共9页
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 Ea... 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. 展开更多
关键词 REGIONAL CLIMATE model Global WARMING of 1.5 2℃ 3℃ and 4℃ Heating DEGREE days Cooling DEGREE days China
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An Abrupt Increase in the Summer High Temperature Extreme Days across China in the mid-1990s 被引量:23
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作者 魏科 陈文 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第5期1023-1029,共7页
Based on the daily maximum surface air temperature records from an updated homogenized temperature dataset for 549 Chinese stations during 1960-2008,we reveal that there is an abrupt increase in the number of days wit... Based on the daily maximum surface air temperature records from an updated homogenized temperature dataset for 549 Chinese stations during 1960-2008,we reveal that there is an abrupt increase in the number of days with high temperature extremes (HTEs,an HTE day is defined when the maximum temperature exceeds the 95th percentile of the daily maximum temperature distributions) across China in the mid-1990s.Before this regime shift,the average number of HTE days is about 2.9 d yr 1 during the period from the 1970s to the early 1990s,while it rocketed to about 7.2 d yr 1 after the mid-1990s.We show that the significant HTE day increase occurs uniformly across the whole of China after the regime shift.The observational evidence raises the possibility that this change in HTE days is associated with global-scale warming as well as circulation adjustment.Possible causes for the abrupt change in the HTE days are discussed,and the circulation adjustment is suggested to play a crucial role in the increase in HTE days in this region. 展开更多
关键词 high temperature extremes hot days long-term trend regime shift
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Analysis of China's Haze Days in the Winter Half-Year and the Climatic Background during 1961–2012 被引量:6
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作者 SONG Lian-Chun GAO Rong +1 位作者 LI Ying WANG Guo-Fu 《Advances in Climate Change Research》 SCIE 2014年第1期1-6,共6页
The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The r... The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The results show that haze days occur significantly more often in eastern China than in western China.The annual number of haze days is 5–30 d in most parts of central-eastern China,with some areas experiencing more than 30 d,while less than 5 d are averagely occurring in western China.Haze days are mainly concentrated in the winter half-year,with most in winter,followed by autumn,spring,and then summer.Nearly 20%of annual haze days are experienced in December.The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961–2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was also significant abrupt changes of haze days in the early 1970s and 2000s.From 1961 to 2012,haze days in the winter half-year increased in South China,the middle-lower reaches of the Yangtze River,and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China.The number of persistent haze is rising.The Longer the haze,the greater the proportion to the number persistent haze.Certain climatic conditions exacerbated the occurrence of haze.The correlation coefficient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China.The precipitation days show a decreasing trend in most parts of China,with a rate of around–4.0 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During the period of 1961–2012,the correlation coefficients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China,while there exists positive correlation between haze days and breeze days in the winter half-year.The mean wind speed and strong wind days are decreasing,while breeze days are increasing in most parts of China,which is benefitial to the reduction of the pollutants diffusion capacity.As a result,haze occurs more easily. 展开更多
关键词 HAZE winter half-year precipitation days wind speed
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Quantifying the attribution of model bias in simulating summer hot days in China with IAP AGCM 4.1 被引量:4
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作者 LIN Zhao-Hui YU Zheng +1 位作者 ZHANG He WU Cheng-Lai 《Atmospheric and Oceanic Science Letters》 CSCD 2016年第6期436-442,共7页
Using lAP AGCM simulation results for the period 1961-2005, summer hot days in China were calculated and then compared with observations. Generally, the spatial pattern of hot days is reasonably reproduced, with more ... Using lAP AGCM simulation results for the period 1961-2005, summer hot days in China were calculated and then compared with observations. Generally, the spatial pattern of hot days is reasonably reproduced, with more hot days found in northern China, the Yangtze and Huaihe River basin, the Chuan-Yu region, and southern Xinjiang. However, the model tends to overestimate the number of hot days in the above-mentioned regions, particularly in the Yangtze and Huaihe River basin where the simulated summer-mean hot days is 13 days more than observed when averaged over the whole region, and the maximum overestimation of hot days can reach 23 days in the region. Analysis of the probability distribution of daily maximum temperature (Trnax) suggests that the warm bias in the model-simulated Tmax contributes largely to the overestimation of hot days in the model. Furthermore, the discrepancy in the simulated variance of the Tmax distribution also plays a non- negligible role in the overestimation of hot days. Indeed, the latter can even account for 22% of the total bias of simulated hot days in August in the Yangtze and Huaihe River basin. The quantification of model bias from the mean value and variability can provide more information for further model improvement. 展开更多
关键词 Hot days variance inprobability distribution bias attribution modelevaluation IAP AGCM
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A Distinguishing Method and Distribution Characteristics of Fog and Haze Days in Fuzhou 被引量:1
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作者 Wang Hong Zheng Qiuping +1 位作者 Sui Ping Yu Hua 《Meteorological and Environmental Research》 CAS 2014年第4期1-4,共4页
For data of atmospheric composition missing, fog and haze days were distinguished based on the standard of meteorological industry Observation and Forecasting Levels of Haze (QX/T113-2010) and four user-defined stan... For data of atmospheric composition missing, fog and haze days were distinguished based on the standard of meteorological industry Observation and Forecasting Levels of Haze (QX/T113-2010) and four user-defined standards, and using data of surface meteorological factors in Fuzhou City, China from 2005 to 2011, temporal distributions of fog and haze days were analyzed respectively to provide methods for fog and haze forecast. The results showed that there were 28.9 fog days and 89.7 haze days per year in Fuzhou. Both fog and haze days were variable, and there might be a day difference of twice to thrice among the years. They were the most in 2007, and then decreased in recent years. Both fog and haze days were more in winter and spring, accounted for 94.1% and 70.1% respectively, while in summer and autumn, they only accounted for 5.9% and 29.9% respectively. In a day, fog mainly occurred from night to early morning, while haze occurred mainly at about noon, which demonstrated that fog and haze are different synoptic phenomena. The mass concentration of PM2.5 in fog days was 34 μg/m^3, while it was 61 μg/m^3 in haze days, and in 22% of haze days it was larger than 75 μg/m3, which was above the national second-grade ambient air quality standard. 展开更多
关键词 Fog day Haze day Distinguishing method Temporal distribution Fuzhou China
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Load-forecasting method for IES based on LSTM and dynamic similar days with multi-features 被引量:3
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作者 Fan Sun Yaojia Huo +3 位作者 Lei Fu Huilan Liu Xi Wang Yiming Ma 《Global Energy Interconnection》 EI CSCD 2023年第3期285-296,共12页
To fully exploit the rich characteristic variation laws of an integrated energy system(IES)and further improve the short-term load-forecasting accuracy,a load-forecasting method is proposed for an IES based on LSTM an... To fully exploit the rich characteristic variation laws of an integrated energy system(IES)and further improve the short-term load-forecasting accuracy,a load-forecasting method is proposed for an IES based on LSTM and dynamic similar days with multi-features.Feature expansion was performed to construct a comprehensive load day covering the load and meteorological information with coarse and fine time granularity,far and near time periods.The Gaussian mixture model(GMM)was used to divide the scene of the comprehensive load day,and gray correlation analysis was used to match the scene with the coarse time granularity characteristics of the day to be forecasted.Five typical days with the highest correlation with the day to be predicted in the scene were selected to construct a“dynamic similar day”by weighting.The key features of adjacent days and dynamic similar days were used to forecast multi-loads with fine time granularity using LSTM.Comparing the static features as input and the selection method of similar days based on non-extended single features,the effectiveness of the proposed prediction method was verified. 展开更多
关键词 Integrated energy system Load forecast Long short-term memory Dynamic similar days Gaussian mixture model
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Impacts of Sea Surface Temperature on the Interannual Variability of Winter Haze Days in Guangdong Province 被引量:3
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作者 刘晴晴 李春晖 +3 位作者 谷德军 郑彬 林爱兰 彭冬冬 《Journal of Tropical Meteorology》 SCIE 2023年第2期168-178,共11页
The impact of sea surface temperature(SST)on winter haze in Guangdong province(WHDGD)was analyzed on the interannual scale.It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading... The impact of sea surface temperature(SST)on winter haze in Guangdong province(WHDGD)was analyzed on the interannual scale.It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading role in the variation of WHDGD.Cold(warm)SST anomalies over the northern Indian Ocean and the Northwest Pacific stimulate the eastward propagation of cold(warm)Kelvin waves through the Gill forced response,causing Ekman convergence(divergence)in the western Pacific,inducing abnormal cyclonic(anticyclonic)circulation.It excites the positive(negative)Western Pacific teleconnection pattern(WP),which results in the temperature and the precipitation decrease(increase)in Guangdong and forms the meteorological variables conditions that are conducive(not conducive)to the formation of haze.ENSO has an asymmetric influence on WHDGD.In El Niño(La Niña)winters,there are strong(weak)coordinated variations between the northern Indian Ocean,the northwest Pacific,and the eastern Pacific,which stimulate the negative(positive)phase of WP teleconnection.In El Niño winters,the enhanced moisture is attributed to the joint effects of the horizontal advection from the surrounding ocean,vertical advection from the moisture convergence,and the increased atmospheric apparent moisture sink(Q2)from soil evaporation.The weakening of the atmospheric apparent heat source(Q1)in the upper layer is not conducive to the formation of inversion stratification.In contrast,in La Niña winters,the reduced moisture is attributed to the reduced upward water vapor transport and Q2 loss.Due to the Q1 increase in the upper layer,the temperature inversion forms and suppresses the diffusion of haze. 展开更多
关键词 Guangdong province winter haze days interannual variability sea surface temperature ENSO
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Research on Optimal Delivery Days and Customer Satisfaction Based on Quality Costs 被引量:3
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作者 薛伟 周宏彤 陈亚绒 《Journal of China University of Mining and Technology》 2004年第1期82-85,共4页
Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lo... Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lowest costs and the highest manufacturing speed. Regarding the delivery days of a coach company as a design variable, this paper builds up an optimization model of customer satisfaction, and suggests an effective method to reduce costs and increase customer satisfaction based on analysis and research. 展开更多
关键词 quality costs customer satisfaction delivery days optimization design
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Seasonal Prediction of Extreme High-Temperature Days in Southwestern China Based on the Physical Precursors 被引量:1
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作者 Zhiyi ZHOU Juan LI +1 位作者 Haishan CHEN Zhiwei ZHU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第7期1212-1224,共13页
Extreme high temperatures frequently occur in southwestern China,significantly impacting the local ecological system and economic development.However,accurate prediction of extreme high-temperature days(EHDs)in this r... Extreme high temperatures frequently occur in southwestern China,significantly impacting the local ecological system and economic development.However,accurate prediction of extreme high-temperature days(EHDs)in this region is still an unresolved challenge.Based on the spatiotemporal characteristics of EHDs over China,a domain-averaged EHD index over southwestern China(SWC-EHDs)during April-May is defined.The simultaneous dynamic and thermodynamic fields associated with the increased SWC-EHDs are a local upper-level anticyclonic(high-pressure)anomaly and wavy geopotential height anomaly patterns over Eurasia.In tracing the origins of the lower boundary anomalies,two physically meaningful precursors are detected for SWC-EHDs.They are the tripolar SST change tendency from December-January to February-March in the northern Atlantic and the February-March mean snow depth in central Asia.Using these two selected predictors,a physics-based empirical model prediction was applied to the training period of 1961–2005 to obtain a skillful prediction of the EHDs index,attaining a correlation coefficient of 0.76 in the independent prediction period(2006–19),suggesting that 58%of the total SWC-EHDs variability is predictable.This study provides an estimate for the lower bound of the seasonal predictability of EHDs as well as for the hydrological drought over southwestern China. 展开更多
关键词 extreme high-temperature days southwestern China seasonal prediction PREDICTABILITY
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Decadal Variations of Winter Extreme Cold Days in Northern China 被引量:2
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作者 Wenmao Li Chaoxia Yuan 《Journal of Geoscience and Environment Protection》 2019年第8期241-250,共10页
Weather and climate extremes often lead to dramatic losses in our society and warrant improvement of their understanding. In this study, the decadal variations in the first two dominant empirical orthogonal function (... Weather and climate extremes often lead to dramatic losses in our society and warrant improvement of their understanding. In this study, the decadal variations in the first two dominant empirical orthogonal function (EOF) modes of winter extreme cold days (WECDs) in northern China (NC) have been investigated. Results show that both EOF modes show distinct decadal variations that together explain around 24% of total variances. At the decadal time scale, the EOF1 is closely related to the decadal Arctic Oscillation (AO);the negative AO can lead to spatially consistent increase of WECDs in NC. On the other hand, the decadal EOF2 can be influenced by the decadal El Ni&#241;o-Southern Oscillation (ENSO). The decadal El Ni&#241;o can result in the large-scale negative sea level pressure (SLP) anomalies in the Eurasian continent west of the western NC and the positive ones over western China. The anomalous southwesterlies between the contrasted SLP anomalies can advect the warmer air from the lower latitudes to the western NC, decrease the WECDs there, and contribute to the east-west asymmetric WECD anomalies in NC. The impacts of El Ni&#241;o are confirmed by the numerical simulations in the Atmospheric Model 2.1 (AM2.1) when forced by the El Ni&#241;o-related sea surface temperature (SST) anomalies in the tropical Pacific. 展开更多
关键词 WINTER EXTREME COLD day ARCTIC Oscillation ENSO
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Long-Term Trends in the Probability of Different Grades of Haze Days in China from 1960 to 2013 被引量:1
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作者 FU Chuan-bo DAN Li 《Journal of Tropical Meteorology》 SCIE 2020年第2期199-207,共9页
The number of haze days and daily visibility data for 543 stations in China were used to define the probabilities of four grades of haze days:slight haze(SLH)days;light haze(LIH)days;moderate haze(MOH)days;and severe ... The number of haze days and daily visibility data for 543 stations in China were used to define the probabilities of four grades of haze days:slight haze(SLH)days;light haze(LIH)days;moderate haze(MOH)days;and severe haze(SEH)days.The change trends of the four grades of haze were investigated and the following results were obtained.The highest probability was obtained for SLH days(95.138%),which showed a decreasing trend over the last54 years with the fastest rate of decrease of-0.903%·(10 years)-1 and a trend coefficient of-0.699,passing the 99.9%confidence level.The probabilities of LIH and MOH days increased steadily,whereas the probability of SEH days showed a slight downward trend during that period.The increasing probability of SLH days was mainly distributed to the east of 105°E and the south of 42°N and the highest value of the trend coefficient was located in the Pearl River Delta and Yangtze River Delta regions.The increasing probability of LIH days was mainly distributed in eastern China and the southeastern coastal region.The probabilities of MOH and SEH days was similar to the probability of LIH days.An analysis of the four grades of haze days in cities with different sizes suggested that the probability of SLH days in large cities and medium cities clearly decreased during the last 54 years.However,the probabilities of LIH days was<10%and increased steadily.The probability of MOH days showed a clear interdecadal fluctuation and the probability of SEH days showed a weak upward trend.The probability of SLH days in small cities within 0.8°of large or medium cities decreased steadily,but the probability of LIH and MOH days clearly increased,which might be attributed to the impact of large and medium cities.The probability of SLH days in small cities>1.5°from a large or medium city showed an increasing trend and reached 100%after 1990;the probability of the other three grades was small and decreased significantly. 展开更多
关键词 haze days long-term trends PROBABILITY VISIBILITY China
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