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An overview of the spatial patterns of land surface processes over arid and semiarid regions 被引量:6
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作者 Jian Zeng Jie Shen Qiang Zhang 《Research in Cold and Arid Regions》 2010年第4期288-297,共10页
With data from the project Collaborative Observation of Semi-arid/Arid Regions in North China, collected during July and September 2008, the spatial patterns of land surface processes over arid and semiarid regions ha... With data from the project Collaborative Observation of Semi-arid/Arid Regions in North China, collected during July and September 2008, the spatial patterns of land surface processes over arid and semiarid regions have been investigated based on the ordinary Kriging interpolation approach. Generally, for the radiation processes, downward and upward short-wave radiation have a uniformly increasing trend with latitude, but the spatial patterns of long-wave radiation present notable regional differences: both upward and downward long-wave radiation increase with latitude in the west of North China, while in the east they vary inversely with latitude, suggesting surface temperature and clouds respectively have feedbacks to the long-wave radiation in the west and east of North China. The surface net radiation basically has a negative latitudinal trend. Long-wave radiation budget plays an important role in the spatial pattern of surface net radiation, particularly in the east of North China, although short-wave radiation budget largely determines the magnitude of surface net radiation. For the energy processes, latent and sensible heat flux varies conversely with latitude: more available land surface energy is consumed by evaporating soil water at lower latitudes while more is used for heating the atmosphere at higher latitudes. A soil heat flux maximum and minimum are found in Loess Plateau and Qinghai Plateau respectively, and a maximum is seen in the northeast China. 展开更多
关键词 land surface radiation processes land surface energy processes spatial pattern arid and semiarid regions
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In-situ experiment investigations of hydrothermal process of highway in deep seasonal frozen soil regions of Inner Mongolia, China 被引量:5
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作者 ZHANG Hong-wei WANG Xue-ying +1 位作者 ZHAO Xin LIU Peng-fei 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第7期2082-2093,共12页
To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years,... To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance. 展开更多
关键词 subgrade engineering hydrothermal process field observation seasonal frozen soil regions freezing-thawing disease
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Role of blowing snow in snow processes in Qilian Mountainous region 被引量:2
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作者 HongYi Li Jian Wang XiaoHua Hao 《Research in Cold and Arid Regions》 CSCD 2014年第2期124-130,共7页
Blowing snow is an important part of snow hydrologic processes in mountainous region, however the related researches were rare for the Qilian mountainous region where blowing snow is frequent. Using the observation da... Blowing snow is an important part of snow hydrologic processes in mountainous region, however the related researches were rare for the Qilian mountainous region where blowing snow is frequent. Using the observation dataset in 2008 snow season in Binggou wa- tershed in Qilian mountainous region, we systematically studied the energy and mass processes of blowing snow by field observation and model simulation. The results include the analysis of snow observation, the occurrence probability of blowing snow, blowing snow transport and blowing snow sublimation. It was found that blowing snow was obvious in high altitude region (4,146 m), the snow redislribution phenomena was remarkable. In Yakou station in the study region, blowing snow was easily occurred in midwinter and early spring when no snowmelt, the blowing snow transport was dominated in this period; when snowmelt beginning, the occur- rence probability of blowing snow decreased heavily because of the increasing air temperature, melt, and refrozen phenomena. The blowing snow sublimation accounted for 41.5% of total snow sublimation at Yakou station in 2008 snow season. 展开更多
关键词 blowing snow snow sublimation snow processes Qilian mountainous region
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Efects of Crop Growth on Hydrological Processes in River Basins and on Regional Climate in China
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作者 QIN Pei-Hua CHEN Feng XIE Zheng-Hui 《Advances in Climate Change Research》 SCIE 2013年第3期173-181,共9页
The regional climate model RegCM3 incorporating the crop model CERES,called the RegCM3CERES model,was used to study the efects of crop growth and development on regional climate and hydrological processes over seven r... The regional climate model RegCM3 incorporating the crop model CERES,called the RegCM3CERES model,was used to study the efects of crop growth and development on regional climate and hydrological processes over seven river basins in China.A 20-year numerical simulation showed that incorporating the crop growth and development processes improved the simulation of precipitation over the Haihe River Basin,Songhuajiang River Basin and Pearl River Basin.When compared with the RegCM3 control run,RegCM3CERES reduced the negative biases of monthly mean temperature over most of the seven basins in summer,especially the Haihe River Basin and Huaihe River Basin.The simulated maximum monthly evapotranspiration for summer(JJA)was around 100 mm in the basins of the Yangtze,Haihe,Huaihe and Pearl Rivers.The seasonal and annual variations of water balance components(runof,evapotranspiration and total precipitation)over all seven basins indicate that changes of evapotranspiration agree well with total precipitation.Compared to the RegCM3,RegCM3CERES simulations indicate reduced local water recycling rate over most of the seven basins due to lower evapotranspiration and greater water flux into these basins and an increased precipitation in the Heihe River Basin and Yellow River Basin,but reduced precipitation in the other five basins.Furthermore,a lower summer leaf area index(1.20 m2m 2),greater root soil moisture(0.01 m3m 3),lower latent heat flux(1.34 W m 2),and greater sensible heat flux(2.04 W m 2)are simulated for the Yangtze River Basin. 展开更多
关键词 CROP growth regionAL climate EAST ASIAN MONSOON region HYDROLOGICAL process
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Association of Genetic Variation in the Promoter Region of OXTR with Differences in Social Affective Neural Processing
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作者 Garret O’Connell Heather C. Whalley +4 位作者 Prerona Mukherjee Andrew C. Stanfield Christian Montag Jeremy Hall Martin Reuter 《Journal of Behavioral and Brain Science》 2012年第1期60-66,共7页
Evidence supports the involvement of oxytocin in social behavior. The oxytocin receptor gene (OXTR) has been associated with differences in social brain function and risk for autism. Motivated by recent work, we inves... Evidence supports the involvement of oxytocin in social behavior. The oxytocin receptor gene (OXTR) has been associated with differences in social brain function and risk for autism. Motivated by recent work, we investigated the effect of variation in the common functional rs2268498 T/C polymorphism in the promoter region of OXTR on neural responses to fear expressions. 46 healthy subjects were divided into genotype groups of C carriers (n = 32) and TT ho-mozygous (n = 14) and neural activity was measured during the recognition of fear and neutral expressions. Results showed that during the recognition of fear expressions, the TT genotype group exhibited increased responding in the inferior occipital gyrus, considered important for face processing, compared to carriers of the C allele (P < 0.005;cluster corrected for whole brain), an effect not found for neutral faces. These results indicate the impact of this OXTR genetic variant on individual differences in social affective neural processing. 展开更多
关键词 OXTR Promoter region INFERIOR OCCIPITAL GYRUS fMRI EMOTIONAL Facial processing
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Fluid Dynamic Response of the Russia Seismically Differing Regions to the Global Geodynamics Processes
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作者 Valera P. Rudakov Pavel P. Firstov Vladislav V. Tsyplakov 《International Journal of Geosciences》 2012年第4期767-771,共5页
The results of the spectral-correlation analysis of the fluid-dynamic (radon and hydrogen) data monitoring obtained in the seismically active region—on Kamchatka and in conditions of Russian platform where compared t... The results of the spectral-correlation analysis of the fluid-dynamic (radon and hydrogen) data monitoring obtained in the seismically active region—on Kamchatka and in conditions of Russian platform where compared to the results of the laser-deformometer measurements obtained on Caucasus. It allowed identify spectral components of the measured parameters, first of all, in the area of the lunar-solar tides. This identification have demonstrated the identical reaction of the mountain and platform regions to the global geodeformation processes of the tidal level and have shown the possibility of the measuring parameters response to the catastrophic events preparation processes. Really the prognostic effects in the investigated fields where indicated in periods of preparation and realization of the catastrophic earthquakes in Indian Ocean on December, 26, 2004 and on March, 28, 2005. 展开更多
关键词 Seismically Active region RUSSIAN PLATFORM Fluid-Dynamic Monitoring GLOBAL processes
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Key regions where land surface processes shape the East Asian climate
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作者 Haishan Chen 《Atmospheric and Oceanic Science Letters》 CSCD 2022年第3期64-66,共3页
Land-atmosphere interaction,as one of the key processes affecting the atmosphere and climate over East Asia,has drawn increasing attention during the past few decades.However,the current level of understanding regardi... Land-atmosphere interaction,as one of the key processes affecting the atmosphere and climate over East Asia,has drawn increasing attention during the past few decades.However,the current level of understanding regarding the mechanisms through which land surface processes impact the East Asian climate needs to be improved.Based on existing studies,six key regions where land surface processes affect the East Asian climate are proposed in this study,which can provide a valuable reference for future research into land-atmosphere interaction in East Asia. 展开更多
关键词 Land surface process East Asian climate Key regions
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Design and Research on Virtual Display of Whole Process Mechanization for Rice Production in Cold Region
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作者 Na WANG 《Asian Agricultural Research》 2017年第3期106-109,共4页
With the development of society,the virtual reality technology and multimedia technology have been applied to modern large-scale agriculture. The paper describes the design ideas for animation display of mechanized ri... With the development of society,the virtual reality technology and multimedia technology have been applied to modern large-scale agriculture. The paper describes the design ideas for animation display of mechanized rice production in cold region,and elaborates the design of major part of each scene. By animation display,we can know about the whole process of rice production,as well as the benefits of mechanized operation. 展开更多
关键词 Rice in cold region Whole process mechanization Virtual display
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MESOZOIC-CENOZOIC VOLCANISM AND THE SIGNIFICANCE OF DEEP PROCESSES IN THE BOHAI REGION
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作者 Gu Li Dai Tagen and Fan Weiming(Dept of Geology, Central Soulh Universily of Technology, Changsha 410083, China )(Changsha Inslilute Of Geolectonics, Academia Sinica, Changsha 410013, China ) 《Geotectonica et Metallogenia》 1999年第1期44-50,共7页
Based on data from petrochemistry, trace element geochemistry and isotopic compositions of Mesozoic-Cenozoic volcanic rocks in three basins in the Bohai region, some conclusions can be drawn. In the region. there are ... Based on data from petrochemistry, trace element geochemistry and isotopic compositions of Mesozoic-Cenozoic volcanic rocks in three basins in the Bohai region, some conclusions can be drawn. In the region. there are three major voIcanic eruption stages with corresponding volcanic rocks in the Mesozoic-Cenozoic. i. e., early Mesozoic dacite (228. 8~ 226. 9 Ma). late Mesozoic basaltic-trachy-andesite, lamprophyre and rhyolite (136. 0~90. 9 Ma). and Cenozoic basa1t (61.0~29. 7 Ma). All the volcanics have undergone different fractional crystallization. Trace elements and isotopic compositions characteristics of the Cenozoic volcanics suggest that they are derived from the asthenosphere, and those of the Mesozoic volcanics show that they are derived from the enriched lithosphere. A model is proposed indicating that the lithosphere-asthenosphere boundary was uplifted, then fell back in the Mesozoic-Cenozoic with the thinning of lithosphere. 展开更多
关键词 VOLCANISM Mesozoic-Cenozoic Era LITHOSPHERE ASTHENOSPHERE Bohai region deep process
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Development of dangerous geological processes in the Hankaisky Region of Primorskiy Krai (Russian Far East)
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作者 Tatiana V.Selivanova 《Global Geology》 2006年第2期176-179,共4页
Hankaisky Region is the mest densely populated and economic developed part of the Primorskiy Krai. It is promoting development of dangerous geological processes there. In the article.the reasons of formation and inten... Hankaisky Region is the mest densely populated and economic developed part of the Primorskiy Krai. It is promoting development of dangerous geological processes there. In the article.the reasons of formation and intensive development in Hankaisky Region of the following dangerous geological processes lateral, winder and ground erosive, sill, floods, taluses, bogging, slope wash, karts, rebound of ground are considered. 展开更多
关键词 Hankaisky region dangerous geological processes EROSIVE slope wash rebound of ground
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Fusion of Region Extraction and Cross-Entropy SVM Models for Wheat Rust Diseases Classification
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作者 Deepak Kumar Vinay Kukreja +2 位作者 Ayush Dogra Bhawna Goyal Talal Taha Ali 《Computers, Materials & Continua》 SCIE EI 2023年第11期2097-2121,共25页
Wheat rust diseases are one of the major types of fungal diseases that cause substantial yield quality losses of 15%–20%every year.The wheat rust diseases are identified either through experienced evaluators or compu... Wheat rust diseases are one of the major types of fungal diseases that cause substantial yield quality losses of 15%–20%every year.The wheat rust diseases are identified either through experienced evaluators or computerassisted techniques.The experienced evaluators take time to identify the disease which is highly laborious and too costly.If wheat rust diseases are predicted at the development stages,then fungicides are sprayed earlier which helps to increase wheat yield quality.To solve the experienced evaluator issues,a combined region extraction and cross-entropy support vector machine(CE-SVM)model is proposed for wheat rust disease identification.In the proposed system,a total of 2300 secondary source images were augmented through flipping,cropping,and rotation techniques.The augmented images are preprocessed by histogram equalization.As a result,preprocessed images have been applied to region extraction convolutional neural networks(RCNN);Fast-RCNN,Faster-RCNN,and Mask-RCNN models for wheat plant patch extraction.Different layers of region extraction models construct a feature vector that is later passed to the CE-SVM model.As a result,the Gaussian kernel function in CE-SVM achieves high F1-score(88.43%)and accuracy(93.60%)for wheat stripe rust disease classification. 展开更多
关键词 Wheat rust diseases AGRICULTURAL region extraction models INTERCROPPING image processing feature extraction precision agriculture
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近62 a三峡地区区域性暴雨过程气候特征及长期变化规律 被引量:1
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作者 王荣 叶殿秀 +3 位作者 肖潺 赵珊珊 陈鲜艳 李威 《水利水电技术(中英文)》 北大核心 2024年第2期16-26,共11页
【目的】充分认识三峡地区区域暴雨过程的气候特征及长期变化规律对于科学防汛以及合理利用水资源具有重要意义。【方法】基于三峡地区33个国家级气象观测站1961—2022年逐日降水量资料和目前重庆市气候中心业务采用的区域性暴雨过程监... 【目的】充分认识三峡地区区域暴雨过程的气候特征及长期变化规律对于科学防汛以及合理利用水资源具有重要意义。【方法】基于三峡地区33个国家级气象观测站1961—2022年逐日降水量资料和目前重庆市气候中心业务采用的区域性暴雨过程监测指标,对三峡地区区域性暴雨过程进行客观识别,并利用多种数理统计方法分析区域性暴雨过程的气候特征和长期变化规律。【结果】结果表明:(1)三峡地区近三分之二的暴雨以区域性过程形式出现,平均每年区域性暴雨过程有8.4次,主要出现在5—9月,尤以6—7月为集中发生时段。区域性暴雨过程首次开始日期多年平均为5月8日,末次结束日期为9月17日。平均每次过程的暴雨覆盖范围为8.6站,持续时间1.3 d,平均暴雨强度为74.7 mm/d。(2)三峡地区区域性暴雨过程年频次存在2~3 a和8 a左右的变化周期,年平均区域性暴雨过程覆盖范围存在4~6 a和8~11 a周期变化。(3)近62 a三峡地区区域性暴雨过程的首次开始日期显著提前,末次结束日期无明显变化,发生期显著变长;发生频次没有明显变化趋势、平均持续时间、平均覆盖范围、平均综合强度也均没有明显变化趋势,但平均暴雨强度呈增强趋势。(4)近62 a,三峡地区区域性暴雨过程的各项指标均未发生突变现象。【结论】研究成果为三峡地区防汛减灾、水资源管理以及回应三峡工程对局地气候影响的社会关切等提供科学支撑。 展开更多
关键词 区域性暴雨过程 气候特征 变化趋势 变化周期 三峡地区 极端降雨 降水 三峡水库
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中国实现碳中和:进程评估与实践困境 被引量:1
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作者 袁晓玲 金中国 李朝鹏 《北京工业大学学报(社会科学版)》 北大核心 2024年第4期90-106,共17页
中国实现碳中和目标面临经济结构转型与能源结构调整等严峻挑战。根据2020年中国30个省市自治区的能源消费数据与土地利用数据核算得到其CO_(2)排放量与吸收量,对碳中和进程进行评估。研究认为,2020年中国30个省市自治区平均碳中和进程... 中国实现碳中和目标面临经济结构转型与能源结构调整等严峻挑战。根据2020年中国30个省市自治区的能源消费数据与土地利用数据核算得到其CO_(2)排放量与吸收量,对碳中和进程进行评估。研究认为,2020年中国30个省市自治区平均碳中和进程为5.45%,区域碳中和进程差异较大,呈现出“阶梯状”特征;其中9个高碳中和进程型省市自治区平均碳中和进程为16.66%,而11个低碳中和进程型省市自治区平均进程仅为1.32%。目前,中国实现碳中和面临碳赤字严重、碳汇量缩减以及区域协同不足的实践困境,应根据区域CO_(2)排放与吸收特征,由经济与科研水平具有比较优势的省市自治区研发新型低碳技术,通过区域内部产业承接转移实现结构性减排,同时完善碳汇自然资源价值实现机制推进增汇,配合国家重大区域战略实现区域协同的碳中和。 展开更多
关键词 碳中和进程 区域特征 实践困境 碳中和路径 区域协同
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中国农业区划发展的历史回溯与未来展望
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作者 孙凯 丁晓蕾 《农业考古》 北大核心 2024年第3期73-81,共9页
农业区划作为指导农业因地制宜生产和因势利导合理配置资源的有效手段,对于优化要素利用、提振乡村产业和加快农业农村现代化建设具有重要意义。中国农业区划有着深厚的历史积淀和发展根基,按其思想演变、学术研究和实践历程可以划分为... 农业区划作为指导农业因地制宜生产和因势利导合理配置资源的有效手段,对于优化要素利用、提振乡村产业和加快农业农村现代化建设具有重要意义。中国农业区划有着深厚的历史积淀和发展根基,按其思想演变、学术研究和实践历程可以划分为古代早期农业分区思想萌芽与涉农土地利用实践、近代农业区划科学发轫与起步探索和新中国成立后政府工作实务及体系化建设三个发展阶段。针对目前农业生产资源环境和社会经济条件出现的新变化,未来中国农业区划需要与时俱进,围绕全球气候变暖、城乡地理空间格局变化、农业新生产要素发展、农业废弃物资源化利用、农业生产组织方式转变等内容,为国家宏观农业发展计划的实施提供前瞻性战略支撑。 展开更多
关键词 农业区划 发展历程 历史回溯 未来展望
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2022年末安徽一次大气重污染过程特征及成因分析
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作者 张浩 于彩霞 +1 位作者 杨关盈 石春娥 《环境监测管理与技术》 CSCD 北大核心 2024年第5期20-26,共7页
综合利用多源数据,应用HYSPLIT4轨迹分析、颗粒物区域传输分析等方法对2022年末安徽一次大气重污染过程变化特征及成因进行分析。结果表明:污染前期,受弱冷空气影响,有利于污染物输送至安徽地区;污染期间,地面处于弱气压场,混合层厚度较... 综合利用多源数据,应用HYSPLIT4轨迹分析、颗粒物区域传输分析等方法对2022年末安徽一次大气重污染过程变化特征及成因进行分析。结果表明:污染前期,受弱冷空气影响,有利于污染物输送至安徽地区;污染期间,地面处于弱气压场,混合层厚度较低,存在持续性逆温,且地面风速小、相对湿度较高、基本无降水,不利于污染物的扩散和清除,受区域输送叠加本地污染排放累积共同影响,污染程度加剧;2023年1月2日地面以东北、偏东风为主,风速增大、相对湿度下降、混合层厚度抬升,扩散条件转好,污染程度减轻。在此次污染过程中,山东、江苏、河南对安徽累积的区域输送贡献率占比为48.5%,高于安徽本地污染的贡献率(21.4%)。 展开更多
关键词 PM_(2.5) 重污染过程 成因分析 气象条件 区域输送 安徽
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我国区域典型城市国际化水平的定量分析及对策思考
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作者 汪来喜 赵梦娟 李世杰 《区域经济评论》 北大核心 2024年第3期114-124,共11页
采用层次分析法,从经济开放、科技创新、国际影响和城市宜居四个层面构建准则层,选取18个指标评价14个区域典型城市的国际化水平,结果表明:(1)区域典型城市的国际化水平总体评分及经济开放指标评价呈现东部最优、西部次优,而中部最靠后;... 采用层次分析法,从经济开放、科技创新、国际影响和城市宜居四个层面构建准则层,选取18个指标评价14个区域典型城市的国际化水平,结果表明:(1)区域典型城市的国际化水平总体评分及经济开放指标评价呈现东部最优、西部次优,而中部最靠后;(2)科技创新上,东部科技创新实力强劲,中部城市的武汉处于第二位次城市组别,西部城市成都处于第一层次城市群里;(3)国际影响上,第一层次东部占据前三城市,中部4个城市均居于第三层次,西部城市成都处于第一层次里第四位次;(4)城市宜居上,东中西部典型城市分值差别不大。 展开更多
关键词 城市国际化 区域典型城市 层次分析法
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1961—2022年四川省区域性干旱过程识别及时空演变特征
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作者 邓彪 孙蕊 +1 位作者 邢开瑜 张顺谦 《高原山地气象研究》 2024年第1期85-93,共9页
利用四川142个国家气象站1961—2022年逐日气温、降水资料,基于气象干旱综合指数(MCI)及其区域性干旱过程识别方法,分析四川区域性干旱时空变化特征。结果表明:(1)1961—2022年四川识别239次区域性干旱过程,平均3.9次/a,综合强度为较强... 利用四川142个国家气象站1961—2022年逐日气温、降水资料,基于气象干旱综合指数(MCI)及其区域性干旱过程识别方法,分析四川区域性干旱时空变化特征。结果表明:(1)1961—2022年四川识别239次区域性干旱过程,平均3.9次/a,综合强度为较强等级以上占比49.4%;过程开始11月最多,9月最少;过程频次1960年代和1990年代偏少,1970年代、1980年代和21世纪以来相对偏多。(2)四川省区域性干旱过程的综合强度呈显著增强趋势,主要是过程影响范围增加趋势明显,平均每10 a增加3.7站,而过程强度和持续天数的变化趋势均不明显。(3)四川省各地干旱日数变化趋势各异,盆地及攀西地区干旱频发态势明显,常见4种区域干旱分型,分别是盆西南型、盆东北型、盆西北型和攀西型。(4)2022年四川省发生4次区域性干旱过程,过程频次接近常年水平,年度干旱综合评价为近10年来偏强。区域性干旱过程识别结果与业务实际和灾情验证比较吻合,综合强度指标对干旱事件的影响有一定表征能力,可本地化业务应用于四川区域性干旱过程监测评估。 展开更多
关键词 区域性干旱过程识别 MCI监测评估 时空变化特征 四川省
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榆林野生地被植物资源的园林绿化应用评价
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作者 白晓霞 姚亮 +1 位作者 纪晓玲 张静 《草业科学》 CAS CSCD 北大核心 2024年第10期2284-2294,共11页
为了扩充陕北旱区园林绿化地被植物种类,采用样方法对榆林市横山县、绥德县、佳县野生地被植物资源展开调查,采用层次分析法构建了野生地被植物评价体系。结果表明,榆林市黄土旱区共有野生地被植物47种,以禾本科(14种)与菊科(7种)居多;... 为了扩充陕北旱区园林绿化地被植物种类,采用样方法对榆林市横山县、绥德县、佳县野生地被植物资源展开调查,采用层次分析法构建了野生地被植物评价体系。结果表明,榆林市黄土旱区共有野生地被植物47种,以禾本科(14种)与菊科(7种)居多;评价体系准则层由园林观赏价值(权重值为0.334)、生态适应性(权重值为0.525)和防护功能(权重值为0.141)组成,要素层包括17个评价指标,其中权重值较高的分别是抗逆性(0.219)、繁殖难易度(0.141)、生长势(0.101)、生育期(0.077)、根系生长(0.071)、分布范围(0.064);最终评选出Ⅰ级优等地被植物9种,Ⅱ级良好地被植物12种,Ⅲ级一般地被植物13种,Ⅳ级较差地被植物13种。该评价体系能够准确反映榆林野生地被植物资源特点,为当地地被植物资源的筛选应用提供参考。 展开更多
关键词 黄土旱区 野生地被 资源调查 层次分析法 园林应用
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新疆南部暴雨研究:科学认知与主要进展
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作者 姚俊强 陈静 +1 位作者 周桂香 毛炜峄 《沙漠与绿洲气象》 2024年第5期1-8,共8页
新疆南部(简称“南疆”)是典型的干旱区,地形和下垫面复杂,生态环境脆弱,对气候变化异常敏感。在全球变暖背景下,近年来南疆暴雨发生频率和强度明显增加,引起社会广泛关注。通过综述南疆干旱区暴雨的科学认知、研究进程和最新研究进展,... 新疆南部(简称“南疆”)是典型的干旱区,地形和下垫面复杂,生态环境脆弱,对气候变化异常敏感。在全球变暖背景下,近年来南疆暴雨发生频率和强度明显增加,引起社会广泛关注。通过综述南疆干旱区暴雨的科学认知、研究进程和最新研究进展,得出南疆暴雨具有降水集中度高、相对强度大、极端性强、空间分布不均匀等特点。南疆暴雨研究经过了从大降水个例到多尺度相互作用机理和数值模拟发展应用的阶段,目前在南疆暴雨的重要影响天气系统和水汽输送等方面取得新的科学认识。 展开更多
关键词 暴雨 科学认知 研究进展 发展历程 新疆南部 干旱区
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云南区域性暴雨过程时空变化特征
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作者 杨鹏武 周德丽 +3 位作者 吉文娟 马思源 罗蒙 李蒙 《气象与环境学报》 2024年第3期83-90,共8页
针对中国气象局发布的《区域性重要过程(暴雨)监测和评价业务规定》确定了云南本地化区域性暴雨过程识别阈值,经灾害数据检验客观有效。进一步应用气候趋势分析、M-K检验、小波分析、EOF分析及REOF分析等方法研究了1961—2022年云南区... 针对中国气象局发布的《区域性重要过程(暴雨)监测和评价业务规定》确定了云南本地化区域性暴雨过程识别阈值,经灾害数据检验客观有效。进一步应用气候趋势分析、M-K检验、小波分析、EOF分析及REOF分析等方法研究了1961—2022年云南区域性暴雨过程的时空分布特征。结果表明:云南历次区域性暴雨过程综合强度波动较大,年平均综合强度呈减小趋势,但不显著,月平均综合强度呈波动分布,峰值出现在1月,雨季各旬平均综合强度变化较小。云南区域性暴雨过程年均4次,1977年以后呈减少趋势,但不显著,没有明显突变点,2008—2022年过程频次有6~8 a周期,但不稳定,云南区域性暴雨过程夏季最多,冬季最少,6月中旬至8月下旬过程数约占全年近7成。云南区域性暴雨过程呈南多北少分布,北部边缘虽然频次较少,但过程降水强度较大。云南区域性暴雨过程呈现全省大部一致型、东北-西南反向型及南北反向型等5个主要模态,进一步可分为5个典型区,即南区、西区、中东部区、北区及西北区,过去62 a,南区、西区和中东部区波动较大,变化趋势不明显,北区平稳少变,西北区前期以偏少为主,后期增加明显。 展开更多
关键词 区域性暴雨过程 EOF分析 REOF分析
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