期刊文献+
共找到249篇文章
< 1 2 13 >
每页显示 20 50 100
A Review of Impacts of Climate Change on Birds:Implications of Long-term Studies 被引量:19
1
作者 石建斌 李迪强 肖文发 《Zoological Research》 CAS CSCD 北大核心 2006年第6期637-646,共10页
It is generally accepted that climate has changed greatly on a global scale, and that the earth's climate has already wanned by some degrees over the past century. Ample evidence shows that there have been apparent c... It is generally accepted that climate has changed greatly on a global scale, and that the earth's climate has already wanned by some degrees over the past century. Ample evidence shows that there have been apparent changes in avian population dynamics, life-history traits and geographic ranges in response to global climate change. This paper briefly reviews the possible effects of climate change on avian biology and ecology all over the world, with emphasis on new findings from several long-term studies in Europe and North America, which provide unique opportunities to investigate how long-term changes in climate affect birds at both individual and population levels. The implications of such long-term studies for future bird studies in China is discussed with hope that this review can contribute to the preparation and plan for studies of climatic effects on birds in China in the future. 展开更多
关键词 Climate change Global wanning Geographic range Phenological change BIRDS
下载PDF
对青少年棒球运动运动员击球动作节奏的分析 被引量:1
2
作者 赵高峰 张凡 《当代体育科技》 2015年第29期50-51,共2页
作者在长时间的棒球专业训练中发现青少年棒球运动员击球时在击投手正式投球时不能很好把握投手投球时的节奏,这样的话严重的影响了击球员的击球节奏,击球员击出的球效果不好不尖锐对防守没有什么威胁。还有青少年棒球运动员不能很好的... 作者在长时间的棒球专业训练中发现青少年棒球运动员击球时在击投手正式投球时不能很好把握投手投球时的节奏,这样的话严重的影响了击球员的击球节奏,击球员击出的球效果不好不尖锐对防守没有什么威胁。还有青少年棒球运动员不能很好的掌握打变化球的技术,在击球时不能很好的控制自己的技术动作,掌握不好击变化球的节奏,影响了击球的能力,这说明击球技术中击球节奏把握起着至关重要的作用。当今日益发展的棒球运动中,青少年棒球运动员是我国棒球未来的希望。 展开更多
关键词 击球员 动作连接 节奏 变化球
下载PDF
垒球投手投球战术在比赛中的运用 被引量:5
3
作者 邵年 蒋立 郑伟 《沈阳体育学院学报》 CSSCI 1995年第3期37-39,共3页
垒球投手投球战术在比赛中的运用邵年,蒋立,郑伟垒球比赛是在激烈对抗的攻守活动中进行的。防中投、攻中击已成为取得比赛胜利的重要条件,只有充分发挥投、击的特长,才能取得比赛的主动权。目前国内外的专家一致认为“垒球比赛的成... 垒球投手投球战术在比赛中的运用邵年,蒋立,郑伟垒球比赛是在激烈对抗的攻守活动中进行的。防中投、攻中击已成为取得比赛胜利的重要条件,只有充分发挥投、击的特长,才能取得比赛的主动权。目前国内外的专家一致认为“垒球比赛的成败,百分之六十取决于投手”。一名好... 展开更多
关键词 击球员 垒球投手 投球技术 变化球 技战术水平 比赛中 上升球 击球动作 下坠球 曲线球
下载PDF
Deformation behavior of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy with two initial microstructures during hot working 被引量:4
4
作者 罗皎 李莲 李淼泉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第2期414-422,共9页
The effects of initial microstructure on the flow stress, strain rate sensitivity (m), strain hardening exponent (n), apparent activation energy (Q) for deformation of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy were investiga... The effects of initial microstructure on the flow stress, strain rate sensitivity (m), strain hardening exponent (n), apparent activation energy (Q) for deformation of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy were investigated using isothermal compression tests. Results show that the alloy with Widmanst-tten alpha plates shows a higher peak stress and flow softening. Additionally, the alloy with equiaxed primary alpha exhibits an early yield drop at or above 810 ℃ and at strain rates of 0.1-5.0 s^-1. In the strain range of 0.5-0.7,m of the alloy with equiaxed primary alpha is found to be larger at 0.01 s^-1 and lower deformation temperatures. This phenomenon could be reasonably explained based on the microstructure evolution. The strain has a significant effect onn of the alloy with Widmanst-tten alpha plates, which is attributed to platelet bending/kinking and dynamic globularization ofα phase. In the strain range of 0.15-0.55,Q of the alloy with Widmanst-tten alpha plates is larger. 展开更多
关键词 titanium alloy isothermal compression flow stress microstructure evolution dynamic globularization
下载PDF
Study on the Water Balance in Three Dominant Plants with Simulated Precipitation Change in Maowusu Sandland 被引量:9
5
作者 肖春旺 周广胜 《Acta Botanica Sinica》 CSCD 2001年第1期82-88,共7页
The distribution pattern and productivity of Maowusu sandland terrestrial ecosystem are greatly affected with the future severe global change, especially global precipitation change. Considering the predicative global... The distribution pattern and productivity of Maowusu sandland terrestrial ecosystem are greatly affected with the future severe global change, especially global precipitation change. Considering the predicative global precipitation change and the appropriate relevant strategy for the sustainable development of the China dry territory, the authors have investigated the response of water balance to global precipitation change by creating an artificial control of four levels of water supply treating 3 dominant plants in Mauwusu sandland. The results showed that the seasonal changes of water storage and moisture of different sandland layer depths were affected by different water supply treatments and different plants. The water storage of the three plant growing sandlands and the moisture of different sandland layer depths increased as water supply was increased. The moisture of different water supply treatments and plants increased with the increase of sandland layer depth. The water storage and moisture of the same layer depth of Hedysarum mongolicum Turcz. growing sandland were larger than that of Salix psammophila C. Wang et Ch. Y. Yang growing sandland, which were in turn higher than that of Artemisia ordosica Krasch. growing sandland in the same water supply treatment. Water supply significantly affected the seasonal changes of evaporation and transpiration of the three plant growing sandlands. With the increased levels of water supply, viz. 157.5 mm, 315.0 mm, 472.5 mm and 630.0 mm, the total evaporation was 123.66 mm, 258.68 mm, 376.30 mm, 458.57 mm, respectively, and the total transpiration of A. ordosica was 50.80 mm, 68.93 mm, 108.39 mm, 163.36 mm, respectively, and that of S. psammophila , 47.37 mm, 68.17 mm, 93.65 mm, 135.97 mm, respectively, and that of H. mongolicum 46.73 mm, 67.37 mm, 86.07 mm, 109.64 mm, respectively. Evaporation was significantly higher than transpiration in the experiment. 展开更多
关键词 global change simulated precipitation Maowusu sandland dominant plants water balance
下载PDF
Dynamic globularization kinetics during hot working of TA15 titanium alloy with colony microstructure 被引量:20
6
作者 吴成宝 杨合 +1 位作者 樊晓光 孙志超 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第9期1963-1969,共7页
The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitat... The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitatively studied through isothermal compression tests.It is found that the dynamic globularization kinetics and the kinetics rate of TA15 are sensitive to deformation parameters.The dynamic globularized fraction increases with increasing strain,temperature but decreasing strain rate.The variation of globularized fraction with strain approximately follows an Avrami type equation.Using the Avrami type equation,the initiation and completion strains for dynamic globularization of TA15 were predicted to be 0.34-0.59 and 3.40-6.80.The kinetics rate of dynamic globularization increases with strain at first,then decreases.The peak value of kinetics rate,which corresponds to 20%-33% globularization fraction,increases with increasing temperature and decreasing strain rate. 展开更多
关键词 TA15 titanium alloy dynamic globularization KINETICS STRAIN kinetics rate
下载PDF
Soil carbon dioxide fluxes of a typical broad-leaved/Korean pine mixed forest in Changbai Mountain, China 被引量:3
7
作者 王琛瑞 吴劼 +1 位作者 梁战备 黄国宏 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第4期268-272,共5页
The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static clos... The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static closed chamber technique in a typical broad-leaved/Korean pine mixed forest area on the northern slope of Changbai Mountain, Jilin Province, China. The experiment was carried out through the day and night in the growing season (from June to September) in situ and sample gas was analyzed by a gas chromatograph. Results showed that the forest floor was a large net source of carbon, and soil CO2 fluxes had an obvi-ous law of seasonal and diel variation. The soil CO2 flux of broad-leaved/Korean pine mixed forest was in the range of 0.302.42 mmol穖-2穝-1 with the mean value of 0.98 mmol穖-2穝-1. An examination on the seasonal pattern of soil CO2 emission suggested that the variability in soil CO2 flux could be correlated with variations in soil temperature, and the maximum of mean CO2 flux occurred in July ((1.27±23%) mmol穖-2穝-1) and the minimum was in September ((0.50±28%) mmol穖-2穝-1). The fluctuations in diel soil CO2 flux were also correlated with changes in soil temperature; however, there existed a factor for a time lag. Soil CO2 flux from the forest floor was strongly related to soil temperature and had the highest correlation with temperature at 6-cm depth of soil. Q10 values based on air temperature and soil temperature of different soil depths were at the ranges of 2.09–3.40. 展开更多
关键词 Soil CO2 flux Broad-leaved/Korean pine mixed forest Q10 value Changbai Mountain
下载PDF
Advances of study on atmospheric methane oxidation (consumption) in forest soil 被引量:2
8
作者 王琛瑞 史奕 +2 位作者 杨晓明 吴杰 岳进 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第3期230-238,共9页
Next to CO2, methane (CH4) is the second important contributor to global warming in the atmosphere and global atmospheric CH4 budget depends on both CH4 sources and sinks. Unsaturated soil is known as a unique sink fo... Next to CO2, methane (CH4) is the second important contributor to global warming in the atmosphere and global atmospheric CH4 budget depends on both CH4 sources and sinks. Unsaturated soil is known as a unique sink for atmospheric CH4 in terrestrial ecosystem. Many comparison studies proved that forest soil had the biggest capacity of oxidizing atmospheric CH4 in various unsaturated soils. However, up to now, there is not an overall review in the aspect of atmospheric CH4 oxidation (consumption) in forest soil. This paper analyzed advances of studies on the mechanism of atmospheric CH4 oxidation, and re-lated natural factors (Soil physical and chemical characters, temperature and moisture, ambient main greenhouse gases con-centrations, tree species, and forest fire) and anthropogenic factors (forest clear-cutting and thinning, fertilization, exogenous aluminum salts and atmospheric deposition, adding biocides, and switch of forest land use) in forest soils. It was believed that CH4 consumption rate by forest soil was limited by diffusion and sensitive to changes in water status and temperature of soil. CH4 oxidation was also particularly sensitive to soil C/N, Ambient CO2, CH4 and N2O concentrations, tree species and forest fire. In most cases, anthropogenic disturbances will decrease atmospheric CH4 oxidation, thus resulting in the elevating of atmos-pheric CH4. Finally, the author pointed out that our knowledge of atmospheric CH4 oxidation (consumption) in forest soil was insufficient. In order to evaluate the contribution of forest soils to atmospheric CH4 oxidation and the role of forest played in the process of global environmental change, and to forecast the trends of global warming exactly, more researchers need to studies further on CH4 oxidation in various forest soils of different areas. 展开更多
关键词 Atmospheric methane Oxidation Global warming Forest soil SINK
下载PDF
太公雪耻篇
9
作者 杨晖 《棋艺(象棋)》 1999年第6期3-6,共4页
关键词 白方 太公 马晓春 下法 理由很简单 变化球 烟雾弹 开拆 无法忍受 仔细研究
下载PDF
Obsevation for Epidermal Ultrastructure of Nostoc sphaeroides Kutzing under Scanning Electron Microscope 被引量:1
10
作者 李莉 《Agricultural Science & Technology》 CAS 2009年第1期1-3,共3页
[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild an... [Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing. 展开更多
关键词 Nostoc sphaeroides Kutzing Epidermal ultrastructure Scanning electron microscope
下载PDF
Pedosphere and Its Effect on Global Changes 被引量:5
11
作者 ZHAO QIGUO and CAO HUI(Institute of Soil Science, the Chinese Academy of Sciences, P.O. Box 821, Nauling 210008 China) 《Pedosphere》 SCIE CAS CSCD 2000年第2期97-106,共10页
With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. Soil is not onlya certain subst... With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. Soil is not onlya certain substance or a certain independent natural historical body but also a spheric layer with peculiarstructure and functions in the earth system. From the viewpoint of the geo-biosphere system of earth, soilscience does deal not only with the soil substances per se but also more importantly with the relationshipsamong soil, the other spheres and the human survival environment in view of the "pedosphere". This is thenew orientation of soil science today and will affect profoundly the studies on the human survival environmentand global changes. To throw more light on this subject, the present paper intends to address the conceptionof pedosphere and its role in global changes. Also addressed are series of environmental issues in China andtheir relations to the global changes. Moreover, research orientation and priorities are indicated, includingexploitation and protection of the soil resources, soil fertility and sustainable agricultural development, construction of the ecological environment, and the material cycling in pedosphere and its relation to globalchanges. 展开更多
关键词 EARTH ecological environment global changes PEDOSPHERE soil science
下载PDF
Effect of Climate Variability and Human Activities on Runoff in the Jinghe River Basin, Northwest China 被引量:4
12
作者 YAO Jun-qiang ZHAO Qiu-dong LIU Zhi-hui 《Journal of Mountain Science》 SCIE CSCD 2015年第2期358-367,共10页
Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB)... Much attention has recently been focused on the effects of climate variability and human activities on the runoff. In this study, we analyzed 56-yr(1957–2012) runoff change and patterns in the Jinghe River Basin(JRB) in the arid region of northwest China. The nonparametric Mann–Kendall test and the precipitation-runoff double cumulative curve(PRDCC) were used to identify change trend and abrupt change points in the annual runoff. It was found that the runoff in the JRB has periodically fluctuated in the past 56 yr. Abrupt change point in annual runoff was identified in the JRB, which occurred in the years around 1964 and 1996 dividing the long-term hydrologic series into a natural period(1957 – 1964) and a climate and man-induced period(1965 – 1996 and 1997 – 2012). In the 1965 – 1996 period, human activities were the main factor that decreased runoff with contribution of 88.9%, while climate variability only accounted for 11.1%. However,the impact of climate variability has been increased from 11.1% to 47.5% during 1997 – 2012, showing that runoff in JRB is more sensitive to climate variability during global warming. This study distinguishes theeffect of climate variability from human activities on runoff, which can do duty for a reference for regional water resources assessment and management. 展开更多
关键词 Water resource RUNOFF Climate variability Precipitation Jinghe River Basin
下载PDF
Regional Summer Temperature Decrease against Global Warming in China, Landform Effect? 被引量:1
13
作者 LU Aigang PANG Deqian +3 位作者 HE Yuanqing PANG Hongxi WANG Tianming GE Jianping 《Journal of Mountain Science》 SCIE CSCD 2007年第1期86-90,共5页
The data of 16o national meteorological observatory (NMO) stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global ... The data of 16o national meteorological observatory (NMO) stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global warming in the past half century. The summer and winter isotherm structures of 1950s and 1990s worked out by interpolation show the isotherm structure variations: the isotherm structure generally moves northward in winter, but in summer it is characterized with separate high-temperature and low-temperature centers and the isotherm structure moves inward the centers with global warming, indicating that the temperature in the highland areas increases but that in the lowland areas decreases in the summer of the duration. The possible mechanism of the basin-centered temperature decrease in summer is discussed in this paper. 展开更多
关键词 Isotherm structure seasonal variation summer temperature decrease plateau-basin effect China
下载PDF
Global Water Vapor Content Decreases from 2003 to 2012: An Analysis Based on MODIS Data 被引量:6
14
作者 MAO Kebiao CHEN Jingming +4 位作者 LI Zhaoliang MA Ying SONG Yang TAN Xuelan Yang Kaixian 《Chinese Geographical Science》 SCIE CSCD 2017年第1期1-7,共7页
Water vapor in the earth′s upper atmosphere plays a crucial role in the radiative balance, hydrological process, and climate change. Based on the latest moderate-resolution imaging spectroradiometer(MODIS) data, this... Water vapor in the earth′s upper atmosphere plays a crucial role in the radiative balance, hydrological process, and climate change. Based on the latest moderate-resolution imaging spectroradiometer(MODIS) data, this study probes the spatio-temporal variations of global water vapor content in the past decade. It is found that overall the global water vapor content declined from 2003 to 2012(slope b = –0.0149, R = 0.893, P = 0.0005). The decreasing trend over the ocean surface(b = –0.0170, R = 0.908, P = 0.0003) is more explicit than that over terrestrial surface(b = –0.0100, R = 0.782, P = 0.0070), more significant over the Northern Hemisphere(b = –0.0175, R = 0.923, P = 0.0001) than that over the Southern Hemisphere(b = –0.0123, R = 0.826, P = 0.0030). In addition, the analytical results indicate that water vapor content are decreasing obviously between latitude of 36°N and 36°S(b = 0.0224, R = 0.892, P = 0.0005), especially between latitude of 0°N and 36°N(b = 0.0263, R = 0.931, P = 0.0001), while the water vapor concentrations are increasing slightly in the Arctic regions(b = 0.0028, R = 0.612, P = 0.0590). The decreasing and spatial variation of water vapor content regulates the effects of carbon dioxide which is the main reason of the trend in global surface temperatures becoming nearly flat since the late 1990 s. The spatio-temporal variations of water vapor content also affect the growth and spatial distribution of global vegetation which also regulates the global surface temperature change, and the climate change is mainly caused by the earth's orbit position in the solar and galaxy system. A big data model based on gravitational-magmatic change with the solar or the galactic system is proposed to be built for analyzing how the earth's orbit position in the solar and galaxy system affects spatio-temporal variations of global water vapor content, vegetation and temperature at large spatio-temporal scale. This comprehensive examination of water vapor changes promises a holistic understanding of the global climate change and potential underlying mechanisms. 展开更多
关键词 water vapor content climate change moderate-resolution imaging spectroradiometer(MODIS)
下载PDF
Hot tensile deformation behavior and globularization mechanism of bimodal microstructured Ti-6Al-2Zr-1Mo-1V alloy 被引量:10
15
作者 Hui-jun ZHAO Bao-yu WANG +1 位作者 Dong-ying JU Guo-jin CHEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第12期2449-2459,共11页
The hot deformation behavior,microstructure evolution and fracture characteristics of bimodal microstructured Ti-6Al-2Zr-1Mo-1V alloy were investigated by isothermal tensile tests.Results reveal that flow softening is... The hot deformation behavior,microstructure evolution and fracture characteristics of bimodal microstructured Ti-6Al-2Zr-1Mo-1V alloy were investigated by isothermal tensile tests.Results reveal that flow softening is caused by dynamic globularization of the bimodal microstructure,which also results in a relatively high stress exponent and thermal activation energy.The corresponding SEM,EBSD and TEM observations indicate that the dynamic globularization at750and800℃is accomplished by the formation ofα/αsub-grain boundary and penetration of theβphase.However,dynamic recrystallization(DRX)is the main globularization mechanism at850℃,which was proved by the generation of fine grains with a necklace-like character due to the transformation of low-angle boundaries(LABs)into high-angle boundaries(HABs).With an increase in the deformation temperature or a decrease in the strain rate,the fracture mechanism changes from microvoid coalescence to intergranular fracture. 展开更多
关键词 titanium alloy bimodal microstructure deformation behavior globularization mechanism fracture morphology
下载PDF
Weathering and soils formation on different parent materials in Golestan Province,Northern Iran 被引量:6
16
作者 Maryam MAHMOODI Farhad KI-IORMALI +1 位作者 Arash AMINI Shamsollah AYOUBI 《Journal of Mountain Science》 SCIE CSCD 2016年第5期870-881,共12页
Geochemical, mineralogical, and micromorphologieal characteristics of soils and their relevant parent rocks including loess, ignimbrite, sandstone and limestone were investigated to identify the soil-parent material u... Geochemical, mineralogical, and micromorphologieal characteristics of soils and their relevant parent rocks including loess, ignimbrite, sandstone and limestone were investigated to identify the soil-parent material uniformity and the weathering degree of soils in Golestan Province, northern Iran. Highly developed Caleixerolls and moderately developed Haploxerepts were formed on loess and limestone, respectively. In contrast, the soils formed on ignimbrite and sandstone were non- developed Entisols. Illite was the dominant clay mineral found in ignimbrite and sandstone in both the A horizon and parent material. In loess derived soils however, smectite was dominant especially in the Bt horizon compared to its parent material indicating partly to its pedogenic formation. In limestone, illite and vermiculite were dominant both in the A and C horizons. Ti/Zr ratio proved that the studied soils were closely related to their underlying parent materials geochemically. Chemical index of alteration (CIA), micromorphological index of soil development (MISECA), smectite/illite+chlorite ratio and magnetic susceptibility were applied to investigate the degree of soil development. Results showed that the most and the least developed soils were those formed on loess deposits and limestone,respectively. Application of the different geochemical and pedogenetic approaches was proved to be useful in identifying the relevance of soils to their underlying parent materials and also their degree of development. 展开更多
关键词 Parent material Soil formation Weathering index LOESS Iran
下载PDF
Detecting Global Vegetation Changes Using Mann-Kendal(MK) Trend Test for 1982–2015 Time Period 被引量:10
17
作者 GUO Meng LI Jing +2 位作者 HE Hongshi XU Jiawei JIN Yinghua 《Chinese Geographical Science》 SCIE CSCD 2018年第6期907-919,共13页
Vegetation is the main component of the terrestrial ecosystem and plays a key role in global climate change. Remotely sensed vegetation indices are widely used to detect vegetation trends at large scales. To understan... Vegetation is the main component of the terrestrial ecosystem and plays a key role in global climate change. Remotely sensed vegetation indices are widely used to detect vegetation trends at large scales. To understand the trends of vegetation cover, this research examined the spatial-temporal trends of global vegetation by employing the normalized difference vegetation index(NDVI) from the Advanced Very High Resolution Radiometer(AVHRR) Global Inventory Modeling and Mapping Studies(GIMMS) time series(1982–2015). Ten samples were selected to test the temporal trend of NDVI, and the results show that in arid and semi-arid regions, NDVI showed a deceasing trend, while it showed a growing trend in other regions. Mann-Kendal(MK) trend test results indicate that 83.37% of NDVI pixels exhibited positive trends and that only 16.63% showed negative trends(P < 0.05) during the period from 1982 to 2015. The increasing NDVI trends primarily occurred in tree-covered regions because of forest growth and re-growth and also because of vegetation succession after a forest disturbance. The increasing trend of the NDVI in cropland regions was primarily because of the increasing cropland area and the improvement in planting techniques. This research describes the spatial vegetation trends at a global scale over the past 30+ years, especially for different land cover types. 展开更多
关键词 vegetation trend NDVI3g.v1 Mann-Kendall (MK) trend test land cover types
下载PDF
Advancing Climate Dynamics Toward Reliable Regional Climate Projections 被引量:1
18
作者 XIE Shang-Ping 《Journal of Ocean University of China》 SCIE CAS 2013年第2期191-200,共10页
With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national projec... With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national project was launched in China in 2012 to study ocean's role in regional climate change. This paper starts with a review of recent advances in the study of regional climate re-sponse to global warming, followed by a description of the Chinese project including the rationale, objectives, and plan for field ob-servations. The 15 research articles that follow in the special issue are highlighted, representing some of the initial results from the project. 展开更多
关键词 global warming regional climate change ocean-atmosphere interaction
下载PDF
Global Trend of Low-carbon Economy and China's Responses 被引量:1
19
作者 He Jiankun Zhou Jian +1 位作者 Liu Bin Sun Zhenqing 《Chinese Journal of Population,Resources and Environment》 2011年第2期3-17,共15页
Based on the analysis on the global economic crisis,climate change crisis and their mutual underlying reasons,the authors believe that low-carbon economy has become an inevitable choice to break through the dual crise... Based on the analysis on the global economic crisis,climate change crisis and their mutual underlying reasons,the authors believe that low-carbon economy has become an inevitable choice to break through the dual crises,coordinate the economic development,and protect the global climate.The global trend of low-carbon economy finds expression in Green Recovery currently,while,in a long run,it will give rise to a new pattern of world competition in politics,economy,technology,trade and finance.The impact of the global trend of low-carbon economy on China can not be overlooked,and it is both a challenge and an opportunity for China's future development.Based on comparative studies on the low-carbon economy of China,the U.S.,EU and Japan,the authors conclude that China should blaze a new path of lowcarbon economy development with Chinese characteristics,and the authors have put forward relevant countermeasures for China to address the global trend of low-carbon economy from angles of countries,enterprises and the public 展开更多
关键词 global trend of low-carbon economy Green NewDeal low-carbon development economic development address-ing global climate change
下载PDF
Impact of Climatic Change on Agricultural Production and Response Strategies in China 被引量:1
20
作者 Liu Yansui Liu Yu Guo Liying 《Chinese Journal of Population,Resources and Environment》 2011年第4期16-23,共8页
A number of studies indicate that global climate warming has been increasing, especially in recent decades. Climate warming greatly affects global agro-production and food security-- becoming a hotspot of global envir... A number of studies indicate that global climate warming has been increasing, especially in recent decades. Climate warming greatly affects global agro-production and food security-- becoming a hotspot of global environmental change. This paper proposes a structural and orientational framework for scientifically addressing climatic change impact on agroroduction. Through literature reviews and comparative studies, the paper systematically summarizes influencing mechanisms and impact of climate warming on such agro-production factors as light, temperature, soil quality and water environment. The impact of climate warm- ing on cultivation regions, cropping systems, crop pests, agro- production capacity, agro-economy and farm management is analyzed. Then, suitable climate-adapting agro-development strategies are put forward for different regions in China. The strategies are carefully selected from a repository of international tested climatic change countermeasures in agriculture at national or district level. 展开更多
关键词 agro-production food security climatic change response strategy China
下载PDF
上一页 1 2 13 下一页 到第
使用帮助 返回顶部