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Response of vegetation variation to climate change and human activities in the Shiyang River Basin of China during 2001-2022
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作者 SUN Chao BAI Xuelian +2 位作者 WANG Xinping ZHAO Wenzhi WEI Lemin 《Journal of Arid Land》 SCIE CSCD 2024年第8期1044-1061,共18页
Understanding the response of vegetation variation to climate change and human activities is critical for addressing future conflicts between humans and the environment,and maintaining ecosystem stability.Here,we aime... Understanding the response of vegetation variation to climate change and human activities is critical for addressing future conflicts between humans and the environment,and maintaining ecosystem stability.Here,we aimed to identify the determining factors of vegetation variation and explore the sensitivity of vegetation to temperature(SVT)and the sensitivity of vegetation to precipitation(SVP)in the Shiyang River Basin(SYRB)of China during 2001-2022.The climate data from climatic research unit(CRU),vegetation index data from Moderate Resolution Imaging Spectroradiometer(MODIS),and land use data from Landsat images were used to analyze the spatial-temporal changes in vegetation indices,climate,and land use in the SYRB and its sub-basins(i.e.,upstream,midstream,and downstream basins)during 2001-2022.Linear regression analysis and correlation analysis were used to explore the SVT and SVP,revealing the driving factors of vegetation variation.Significant increasing trends(P<0.05)were detected for the enhanced vegetation index(EVI)and normalized difference vegetation index(NDVI)in the SYRB during 2001-2022,with most regions(84%)experiencing significant variation in vegetation,and land use change was determined as the dominant factor of vegetation variation.Non-significant decreasing trends were detected in the SVT and SVP of the SYRB during 2001-2022.There were spatial differences in vegetation variation,SVT,and SVP.Although NDVI and EVI exhibited increasing trends in the upstream,midstream,and downstream basins,the change slope in the downstream basin was lower than those in the upstream and midstream basins,the SVT in the upstream basin was higher than those in the midstream and downstream basins,and the SVP in the downstream basin was lower than those in the upstream and midstream basins.Temperature and precipitation changes controlled vegetation variation in the upstream and midstream basins while human activities(land use change)dominated vegetation variation in the downstream basin.We concluded that there is a spatial heterogeneity in the response of vegetation variation to climate change and human activities across different sub-basins of the SYRB.These findings can enhance our understanding of the relationship among vegetation variation,climate change,and human activities,and provide a reference for addressing future conflicts between humans and the environment in the arid inland river basins. 展开更多
关键词 vegetation variation climate change land use change normalized difference vegetation index(NDVI) enhanced vegetation index(EVI) Shiyang River Basin
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Impacts of climate change and human activities on vegetation dynamics on the Mongolian Plateau, East Asia from 2000 to 2023
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作者 YAN Yujie CHENG Yiben +3 位作者 XIN Zhiming ZHOU Junyu ZHOU Mengyao WANG Xiaoyu 《Journal of Arid Land》 SCIE CSCD 2024年第8期1062-1079,共18页
The Mongolian Plateau in East Asia is one of the largest contingent arid and semi-arid areas of the world.Under the impacts of climate change and human activities,desertification is becoming increasingly severe on the... The Mongolian Plateau in East Asia is one of the largest contingent arid and semi-arid areas of the world.Under the impacts of climate change and human activities,desertification is becoming increasingly severe on the Mongolian Plateau.Understanding the vegetation dynamics in this region can better characterize its ecological changes.In this study,based on Moderate Resolution Imaging Spectroradiometer(MODIS)images,we calculated the kernel normalized difference vegetation index(kNDVI)on the Mongolian Plateau from 2000 to 2023,and analyzed the changes in kNDVI using the Theil-Sen median trend analysis and Mann-Kendall significance test.We further investigated the impact of climate change on kNDVI change using partial correlation analysis and composite correlation analysis,and quantified the effects of climate change and human activities on kNDVI change by residual analysis.The results showed that kNDVI on the Mongolian Plateau was increasing overall,and the vegetation recovery area in the southern region was significantly larger than that in the northern region.About 50.99%of the plateau showed dominant climate-driven effects of temperature,precipitation,and wind speed on kNDVI change.Residual analysis showed that climate change and human activities together contributed to 94.79%of the areas with vegetation improvement.Appropriate human activities promoted the recovery of local vegetation,and climate change inhibited vegetation growth in the northern part of the Mongolian Plateau.This study provides scientific data for understanding the regional ecological environment status and future changes and developing effective ecological protection measures on the Mongolian Plateau. 展开更多
关键词 kernel normalized difference vegetation index(kNDVI) human activities climate change partial correlation analysis composite correlation analysis residual analysis Mongolian Plateau
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Interannual Variability of the Normalized Difference Vegetation Index on the Tibetan Plateau and Its Relationship with Climate Change 被引量:24
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作者 周定文 范广洲 +3 位作者 黄荣辉 方之芳 刘雅勤 李洪权 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2007年第3期474-484,共11页
The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly... The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes. In this paper, the interannual variations of the plateau vegetation are investigated using a 21-year normalized difference vegetation index (NDVI) dataset to quantify the consequences of climate warming for the regional ecosystem and its interactions. The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north. On the whole, vegetation activity demonstrates a gradual enhancement in an oscillatory manner during 1982-2002. The temporal variation also exhibits striking regional differences: an increasing trend is most apparent in the west, south, north and southeast, whereas a decreasing trend is present along the southern plateau boundary and in the central-east region. Covariance analysis between the NDVI and surface temperature/precipitation suggests that vegetation change is closely related to climate change. However, the controlling physical processes vary geographically. In the west and east, vegetation variability is found to be driven predominantly by temperature, with the impact of precipitation being of secondary importance. In the central plateau, however, temperature and precipitation factors are equally important in modulating the interannual vegetation variability. 展开更多
关键词 Tibetan Plateau normalized difference vegetation index (NDVI) ECOSYSTEM climate change interannual variability
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Climate-Vegetation Coverage Interactions in the Hengduan Mountains Area, Southeastern Tibetan Plateau, and Their Downstream Effects
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作者 Congxi FANG Jinlei CHEN +4 位作者 Chaojun OUYANG Lu WANG Changfeng SUN Quan ZHANG Jun WEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第4期701-716,共16页
Little is known about the mechanism of climate-vegetation coverage coupled changes in the Tibetan Plateau(TP)region,which is the most climatically sensitive and ecologically fragile region with the highest terrain in ... Little is known about the mechanism of climate-vegetation coverage coupled changes in the Tibetan Plateau(TP)region,which is the most climatically sensitive and ecologically fragile region with the highest terrain in the world.This study,using multisource datasets(including satellite data and meteorological observations and reanalysis data)revealed the mutual feedback mechanisms between changes in climate(temperature and precipitation)and vegetation coverage in recent decades in the Hengduan Mountains Area(HMA)of the southeastern TP and their influences on climate in the downstream region,the Sichuan Basin(SCB).There is mutual facilitation between rising air temperature and increasing vegetation coverage in the HMA,which is most significant during winter,and then during spring,but insignificant during summer and autumn.Rising temperature significantly enhances local vegetation coverage,and vegetation greening in turn heats the atmosphere via enhancing net heat flux from the surface to the atmosphere.The atmospheric heating anomaly over the HMA thickens the atmospheric column and increases upper air pressure.The high pressure anomaly disperses downstream via the westerly flow,expands across the SCB,and eventually increases the SCB temperature.This effect lasts from winter to the following spring,which may cause the maximum increasing trend of the SCB temperature and vegetation coverage in spring.These results are helpful for estimating future trends in climate and eco-environmental variations in the HMA and SCB under warming scenarios,as well as seasonal forecasting based on the connection between the HMA eco-environment and SCB climate. 展开更多
关键词 Hengduan Mountains Area normalized difference vegetation index climate change net heat flux downstream effects
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1991-2020 climate normal in the European Alps:focus on high-elevation environments 被引量:1
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作者 NIGRELLI Guido CHIARLE Marta 《Journal of Mountain Science》 SCIE CSCD 2023年第8期2149-2163,共15页
Alps are an important geographical area of the European continent and,in this area,temperature increase is most evident.However,the 1991-2020 climate normal in the Alps has still not been thoroughly investigated.Aimin... Alps are an important geographical area of the European continent and,in this area,temperature increase is most evident.However,the 1991-2020 climate normal in the Alps has still not been thoroughly investigated.Aiming to fill this gap with a focus on high-elevation environments,minimum and maximum daily air temperature acquired by 23 automatic weather station were used.The results show that the mean annual values of minimum and maximum temperature for the 1991-2020 climate normal in the Alps are-2.4℃ and 4.4℃,respectively,with a warming rate of 0.5℃/10 years.The mean annual temperature comparison between 1961-1990 and 1971-2000,1961-1990 and 1981-2010,1961-1990 and 1991-2020 climate normal show an increase of 0.3℃,0.5℃ and 0.9℃,respectively.The results also confirm that seasonal and annual temperatures are rising through the whole Alpine arc,mainly in summer and autumn.This work highlights that annual minimum and maximum temperature do not seem to be affected by a positive elevation-dependent warming.Instead,a positive elevation-dependent warming in the maximum values of the annual minimum temperature was found.If anthropogenic emissions maintain the trend of the last decades,the expected mean annual temperature of the 2001-2030 climate normal is-0.2℃,with an increase of 0.5℃ if compared to the 1991-2020 climate normal and with an increase of 1.5℃ if compared to the 1961-1990 climate normal.This study highlights the warming rate that is now present in the European Alps,provides indications on the warming rate that will occur in the coming years and highlights the importance of carrying out investigations that consider not only the last 30-year climate normal,but also the most recent 30-year climate normal by comparing them with each other. 展开更多
关键词 Air temperature trend Climate normal Climate change High mountain climate ALPS
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Normal tension glaucoma: from the brain to the eye or the inverse? 被引量:6
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作者 Hui-Jun Zhang Xue-Song Mi Kwok-Fai So 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第11期1845-1850,共6页
Glaucoma is a chronic, progressive optic neuropathy characterized by the loss of peripheral vision first and then central vision. Clinically, normal tension glaucoma is considered a special subtype of glaucoma, in whi... Glaucoma is a chronic, progressive optic neuropathy characterized by the loss of peripheral vision first and then central vision. Clinically, normal tension glaucoma is considered a special subtype of glaucoma, in which the patient’s intraocular pressure is within the normal range, but the patient experiences typical glaucomatous changes. However, increasing evidence has challenged the traditional pathophysiological view of normal tension glaucoma, which is based only on intraocular pressure, and breakthroughs in central nervous system imaging may now greatly increase our knowledge about the mechanisms underlying normal tension glaucoma. In this article, we review the latest progress in understanding the pathogenesis of normal tension glaucoma and in developing imaging techniques to detect it, to strengthen the appreciation for the connection between normal tension glaucoma and the brain. 展开更多
关键词 NERVE REGENERATION normal tension GLAUCOMA open angle GLAUCOMA NEURODEGENERATIVE diseases visual field CEREBROSPINAL fluid pressure IMAGING techniques pathogenesis magnetic resonance IMAGING diffusion tensor IMAGING metabolic changes neural REGENERATION
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Monitoring vegetation drought in the nine major river basins of China based on a new developed Vegetation Drought Condition Index
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作者 ZHAO Lili LI Lusheng +4 位作者 LI Yanbin ZHONG Huayu ZHANG Fang ZHU Junzhen DING Yibo 《Journal of Arid Land》 SCIE CSCD 2023年第12期1421-1438,共18页
The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecolo... The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecological environments.In this study,we constructed a new drought index(i.e.,Vegetation Drought Condition Index(VDCI))based on precipitation,potential evapotranspiration,soil moisture and Normalized Difference Vegetation Index(NDVI)data,to monitor vegetation drought in the nine major river basins(including the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin,Yangtze River Basin,Southeast River Basin,Pearl River Basin,Southwest River Basin and Continental River Basin)in China at 1-month–12-month(T1–T12)time scales.We used the Pearson's correlation coefficients to assess the relationships between the drought indices(the developed VDCI and traditional drought indices including the Standardized Precipitation Evapotranspiration Index(SPEI),Standardized Soil Moisture Index(SSMI)and Self-calibrating Palmer Drought Severity Index(scPDSI))and the NDVI at T1–T12 time scales,and to estimate and compare the lag times of vegetation response to drought among different drought indices.The results showed that precipitation and potential evapotranspiration have positive and major influences on vegetation in the nine major river basins at T1–T6 time scales.Soil moisture shows a lower degree of negative influence on vegetation in different river basins at multiple time scales.Potential evapotranspiration shows a higher degree of positive influence on vegetation,and it acts as the primary influencing factor with higher area proportion at multiple time scales in different river basins.The VDCI has a stronger relationship with the NDVI in the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin and Yangtze River Basin at T1–T4 time scales.In general,the VDCI is more sensitive(with shorter lag time of vegetation response to drought)than the traditional drought indices(SPEI,scPDSI and SSMI)in monitoring vegetation drought,and thus it could be applied to monitor short-term vegetation drought.The VDCI developed in the study can reveal the law of unclear mechanisms between vegetation and climate,and can be applied in other fields of vegetation drought monitoring with complex mechanisms. 展开更多
关键词 vegetation drought Vegetation Drought Condition Index(VDCI) normalized Difference Vegetation Index(NDVI) vegetation dynamics climate change China
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A primitive approach to Ou MC decrescendo phenomenon with a hands-on therapy—The relation between human bilateral symmetry and disease 被引量:1
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作者 Ming Cheh Ou Dennis Ou Chung Chu Pang 《Natural Science》 2014年第2期88-98,共11页
The Ou MC decrescendo phenomenon (OuDP) involves the placing of the contralateral hand of the examiner on the acute abdomen of female patients (Ou MC manipulation), which results in an alleviation of pain [1]. Two fro... The Ou MC decrescendo phenomenon (OuDP) involves the placing of the contralateral hand of the examiner on the acute abdomen of female patients (Ou MC manipulation), which results in an alleviation of pain [1]. Two front-end observations showed that placement of the contralateral hand on the acute abdomen of women alleviated pain (78 of 81 women or 96.3%), while placement of the ipsilateral hand did not (0 of 39 women or 0%). This method named as Ou MC handing remedy (HR) was used to observe the immediate and cumulative effects of OuDP on 38 cases, of which 27 were self-administered and 11 were administered by the therapist. The mean age of the patients was 55.8 years (standard deviation, 22.9 years). Five minutes after initial self-administered HR, there was pain alleviation in 14 cases and symptoms or signs beyond pain improved for another 6 cases while 7 cases unevaluated. Final results showed 9 cured, 5 with partial remission and the remaining 13 with complete remission. Five minutes after initial therapist-administered HR, pain alleviation was found with 10 cases while 1 case unevaluated. The final results showed 7 cases cured, 2 with partial remission, and 2 with complete remission. The resolution of non-infectious conditions (23/ 38) with OuDP is consistent with the restoration of normal tissue function, which seems to contribute to pain alleviation and defense against infections and tumors. Interestingly, the OuDP is capable of being invoked by either the patient or the therapist. These findings warrant further investigation. 展开更多
关键词 OU MC Decrescendo Phenomenon PAIN Inflammation Oncological change HANDS-ON Treatment Restoration of normal Tissue Function
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Vegetation Change of Ecotone in West of Northeast China Plain Using Time-series Remote Sensing Data 被引量:10
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作者 HUANG Fang WANG Ping 《Chinese Geographical Science》 SCIE CSCD 2010年第2期167-175,共9页
Multi-temporal series of satellite SPOT-VEGETATION normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data from 1998 to 2007 were used for analyzing vegetation change of the eco... Multi-temporal series of satellite SPOT-VEGETATION normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data from 1998 to 2007 were used for analyzing vegetation change of the ecotone in the west of the Northeast China Plain. The yearly and monthly maximal values,anomalies and change rates of NDVI and NDWI were calculated to reveal the interannual and seasonal changes in vegetation cover and vegetation water content. Linear regression method was adopted to characterize the trends in vegetation change. The yearly maximal NDVI decreased from 0.41 in 1998 to 0.37 in 2007,implying the decreasing trend of vegetation activity. There was a significant decrease of maximal NDVI in spring and summer over the study period,while an increase trend was observed in autumn. The vegetation-improved regions and vegetation-degraded regions occupied 17.03% and 20.30% of the study area,respectively. The maximal NDWI over growing season dropped by 0.027 in 1998–2007,and about 15.15% of the study area showed a decreasing trend of water content. Vegetation water stress in autumn was better than that in spring. Vegetation cover and water content variations were sensitive to annual precipitation,autumn precipitation and summer temperature. The vegetation degradation trend in this ecotone might be induced by the warm-drying climate especially continuous spring and summer drought in the recent ten years. 展开更多
关键词 东北平原西部 农牧交错带 植被变化 遥感数据 时间序列 中国 归一化植被指数 NDWI
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Spatial-temporal Changes of Vegetation Cover in Guizhou Province, Southern China 被引量:22
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作者 TIAN Yichao BAI Xiaoyong +2 位作者 WANG Shijie QIN Luoyi LI Yue 《Chinese Geographical Science》 SCIE CSCD 2017年第1期25-38,共14页
Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different character... Guizhou Province is an important karst area in the world and a fragile ecological area in China. Ecological risk assessment is very necessary to be conducted in this region. This study investigates different characteristics of the spatial-temporal changes of vegetation cover in Guizhou Province of Southern China using the data set of SPOT VEGETATION(1999–2015) at spatial resolution of 1-km and temporal resolution of 10-day. The coefficient of variation, the Theil-Sen median trend analysis, and the Mann-Kendall test are used to investigate the spatial-temporal change of vegetation cover and its future trend. Results show that: 1) the spatial distribution pattern of vegetation cover in Guizhou Plateau is high in the east whereas low in the west. The average annual normalized difference vegetation index(NDVI) from west to east is higher than that from south to north. 2) Average annual NDVI improved obviously in the past 17 years. The growth rate of average annual NDVI is 0.028/10 yr, which is slower than that of vegetation in the country(0.048/10 yr) from 1998 to 2007. Average annual NDVI in karst area is lower than that in non-karst area. However, the growing rate of average annual NDVI in karst area(0.030/10 yr) is faster than that in non-karst area(0.023/10 yr), indicating that vegetation coverage increases more rapidly in karst area. 3) Vegetation coverage in the study area is stable overall, but fluctuates in the local scales. 4) Vegetation coverage presents a continuous increasing trend. The Hurst exponent of NDVI in different vegetation types has an obvious threshold in various elevations. 5) The proportion of vegetation cover with sustainable increase is higher than that of vegetation cover with sustainable decrease. The improvement in vegetation cover may expand to most parts of the study area. 展开更多
关键词 植被覆盖度 时空变化 贵州省 VEGETATION数据 华南 喀斯特地区 归一化植被指数 HURST指数
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Spatiotemporal changes of typical glaciers and their responses to climate change in Xinjiang,Northwest China
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作者 HUANG Xiaoran BAO Anming +7 位作者 GUO Hao MENG Fanhao ZHANG Pengfei ZHENG Guoxiong YU Tao QI Peng Vincent NZABARINDA DU Weibing 《Journal of Arid Land》 SCIE CSCD 2022年第5期502-520,共19页
Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes.In this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in... Glaciers are highly sensitive to climate change and are undergoing significant changes in mid-latitudes.In this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990-2015 in 4 different mountainous sub-regions in Xinjiang Uygur Autonomous Region of Northwest China:the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains;the Yinsugaiti Glacier sub-region in the Karakorum Mountains;and the Youyi Peak sub-region in the Altay Mountains.The standardized snow cover index(NDSI)and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to 2015.Glacial areas in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions in the period of 1990-2015 decreased by 57.7,369.1,369.1,and 170.4 km^(2),respectively.Analysis of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the origin.Glacier area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect,while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south aspect.Increased precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain extent.However,glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased precipitation.On a seasonal time scale,glacier area changes in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season;on an annual time scale,the correlation coefficient between glacier area and annual average temperature was-0.72 and passed the significance test at P<0.05 level in the Karlik Mountain sub-region.The findings of this study can provide a scientific basis for water resources management in the arid and semi-arid regions of Northwest China in the context of global warming. 展开更多
关键词 glacier area change normalized snow cover index(NDSI) climate change remote sensing Altay Mountains Tianshan Mountains Karakorum Mountains
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Impact of climatic factors on vegetation dynamics in the upper Yangtze River basin in China 被引量:3
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作者 ZHANG Yu-xin WANG Yu-kuan +3 位作者 FU Bin DIXIT Amod Mani CHAUDHARY Suresh WANG Shan 《Journal of Mountain Science》 SCIE CSCD 2020年第5期1235-1250,共16页
It is necessary to understand vegetation dynamics and their climatic controls for sustainable ecosystem management.This study examines the vegetation dynamics and the effect of climate change on vegetation growth in t... It is necessary to understand vegetation dynamics and their climatic controls for sustainable ecosystem management.This study examines the vegetation dynamics and the effect of climate change on vegetation growth in the pristine conditions of 58 woodland National Nature Reserves(NNRs)located in the upper Yangtze River basin(UYRB)in China which are little influenced by human activities.Changes in the normalized difference vegetation index(NDVI),precipitation,and temperature in the selected NNRs were observed and analyzed for the period between 1999 and 2015.The relationship between time-lag effect of climate and changes in the NDVI were assessed using Pearson correlations.The results showed three major trends.1)The NDVI increased during the study period;this indicates an increase in the amount of green vegetation,especially due to the warmer climate during the growing season.The NDVIs in March and September were significantly affected by the temperature of the previous months.Spring temperatures increased significantly(P<0.05)and there was a delay between climatic factors and their effect on vegetation,which depended on the previous season.In particular,the spring temperature had a delayed effect on the NDVI in summer.2)The way in which vegetation responds to climatic factors varied significantly across the seasons.Temperature had a greater effect on the NDVI in spring and summer and the effect was greater at higher altitudes.A similar trend was observed for precipitation,except for altitudes of 1000–2000 m.3)Temperature had a greater effect on the NDVI in spring and autumn at higher altitudes.The same trend was observed for precipitation in summer.These findings suggest that the vegetation found in NNRs in the upper reaches of the Yangtze River was in good condition between 1999 and 2015 and that the growth and development of vegetation in the region has not been adversely affected by climate change.This demonstrates the effectiveness of nature reserves in protecting regional ecology and minimizing anthropogenic effects. 展开更多
关键词 National Nature Reserves Upper Yangtze River basin normalized difference vegetation index Climate change Correlation analysis
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Seasonal Responses of Net Primary Productivity of Vegetation to Phenological Dynamics in the Loess Plateau, China 被引量:2
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作者 HAN Hongzhu BAI Jianjun +4 位作者 MA Gao YAN Jianwu WANG Xiaohui TA Zhijie WANG Pengtao 《Chinese Geographical Science》 SCIE CSCD 2022年第2期340-357,共18页
With global warming, the great changes in the patterns of plant growth have occurred. The conditions in early spring and late autumn have changed the process of vegetation photosynthesis, which are expected to have a ... With global warming, the great changes in the patterns of plant growth have occurred. The conditions in early spring and late autumn have changed the process of vegetation photosynthesis, which are expected to have a significant impact on net primary productivity(NPP) and affect the global carbon cycle. Currently, the seasonal response characteristics of NPP to phenological changes in dryland ecosystems are still not well defined. This article calibrated and analyzed the normalized difference vegetation index(NDVI)time series of Advanced Very-High-Resolution Radiometer(AVHRR) data from 1982 to 2015 in the Loess Plateau, China. The spatial and temporal distributions of vegetation phenology and NPP in the Loess Plateau under semihumid and semiarid conditions were investigated. The seasonal variation in the NPP response to vegetation phenology under the climate change was also analyzed. The results showed that, different from the northern forest, there was distinct spatial heterogeneity in the effect of climate change on the dynamic change in vegetation growth in the Loess Plateau: 1) an advance of the start of the growing season(SOS) and a delay of the end of the growing season(EOS) significantly increased the NPP in spring and autumn, respectively, in the humid southeast;2) in the arid northwest, the NPP did not significantly increase in spring and autumn but significantly decreased in summer. 展开更多
关键词 climate change normalized difference vegetation index PHENOLOGY net primary productivity Loess Plateau China
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Assessment of Vegetation Productivity in the Northern Part of Nigeria 被引量:1
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作者 Sadiq Abdullahi Yelwa Umar Usman 《American Journal of Climate Change》 2017年第2期360-373,共14页
Climate change is one of the greatest threats facing the global community and has been mainly induced by increasing atmospheric concentrations of greenhouse gases resulting from fossil fuel energy use and change in ve... Climate change is one of the greatest threats facing the global community and has been mainly induced by increasing atmospheric concentrations of greenhouse gases resulting from fossil fuel energy use and change in vegetation cover. This study used modelling techniques to determine how changes in climate could affect vegetation productivity in the northern part of Nigeria. Climatic parameters (Rainfall, Minimum and Maximum Temperatures) as well as coarse Normalised Difference Vegetation Index (NDVI) data for the growing seasons of 1981-2009 were utilised. Because of the relationship between climatic parameters and vegetation, Spatial method of data interpolation was tested. Results from the prediction elevation values ranged from -3e-9 to 2e-9. It was observed from prediction variance map that the values were higher in the upper portion of the study area which comprised Gusau (GS), Jos (JS), Katsina (KT), Minna (MN) and Zaria (ZR) and lower in the middle and lower parts of the study area which comprised mainly Funtua, Kano, Maiduguri and Sokoto. Further studies are encouraged with high resolution imageries and more meteorological data to cover the montane and forest zone of the country to determine the level of climatic impacts particularly on vegetation productivity in general. 展开更多
关键词 Climate change Regression-Kriging (RK) and normalized Difference VEGETATION Index (NDVI) Linear MODEL Digital ELEVATION MODEL (DEM)
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Knowing Changes and Seeking Changes
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作者 Dong Fangxiao a Senior Research Fellow and Director of Division for International Relations at Institute of West Asian and African Studies, China Academy of Social Sciences. 《Contemporary International Relations》 2003年第6期37-43,共7页
In the report of the 16th Party Congress, the first two decades of the 21st century are seen as "the period of important strategic opportunities which we must seize tightly and which offers bright prospects."... In the report of the 16th Party Congress, the first two decades of the 21st century are seen as "the period of important strategic opportunities which we must seize tightly and which offers bright prospects." How to seize this period of strategic opportunities and get something done is a major task for every decision-maker of every region, department, and industry and even for every ordinary Chinese. 展开更多
关键词 that in HAVE knowing changes and Seeking changes of for WTO very BE
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Climate change:Australia fires will be ’normal’ in warmer world
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《数理天地(初中版)》 2020年第2期47-48,共2页
UK scientists say the recent fires in Australia are a taste of what the world will experience as temperatures rise.Prof Richard Betts from the Met Office Hadley Centre said we are"seeing a sign of what would be n... UK scientists say the recent fires in Australia are a taste of what the world will experience as temperatures rise.Prof Richard Betts from the Met Office Hadley Centre said we are"seeing a sign of what would be normal conditions under a future warming world of 3C". 展开更多
关键词 CLIMATE change:Australia fires WILL BE in WARMER world normal
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Regulatory mode selection and legal governance of China's response to climate change risk
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作者 HAN Kang-ning SHEN Ran-ran 《Ecological Economy》 2023年第4期381-400,共20页
The regulation of climate change risk is an important measure for China to achieve the goal of"carbon neutrality and carbon peak".Although China has built a legal regulation system for environmental risk at ... The regulation of climate change risk is an important measure for China to achieve the goal of"carbon neutrality and carbon peak".Although China has built a legal regulation system for environmental risk at the macro level,and normative and functionalism have constructed different paths for regulating climate change risk,it is necessary to analysis the two paths at the micro level,in order to examine its adaptability to climate change risk.The normative mode of climate change risk regulation emphasizes the clarity of the legal regulation system,controls the regulatory subject formally,and pays attention to the role of judicial review;The functionalist mode of climate change risk regulation emphasizes the authorization of regulatory subjects,and identifies and manages climate change risks in the way of administrative self-control.In order to regulate climate change risk,in addition to the traditional way of solving the problem of"normalization"and"functionalism",there is also a third regulatory mode,that is,to overcome the inherent shortcomings and defects of both functionalism and normalization,and to integrate the two necessary:not only pay attention to the legal normative requirements of the normative mode,but also mobilize the initiative of administrative regulation under functionalism,and strengthen the judicial prevention function,and then improve the effe ctiveness of China’s participation in global climate change governance. 展开更多
关键词 climate change risk normalISM FUNCTIONALISM environmental risk China mode
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京大戟醋制前后对正常大鼠毒性的研究
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作者 邵霞 曹睿贞 +2 位作者 姚芳 张丽 曹雨诞 《环球中医药》 CAS 2024年第7期1306-1312,共7页
目的比较京大戟醋制前后对正常大鼠肝、胃、肠、肾毒性的差异。方法采用雄性SD大鼠56只,随机分为7组:空白组、京大戟低、中、高剂量组和醋京大戟低、中、高剂量组。给药组大鼠分别灌胃0.253 g/kg、0.506 g/kg、1.012 g/kg京大戟、醋京... 目的比较京大戟醋制前后对正常大鼠肝、胃、肠、肾毒性的差异。方法采用雄性SD大鼠56只,随机分为7组:空白组、京大戟低、中、高剂量组和醋京大戟低、中、高剂量组。给药组大鼠分别灌胃0.253 g/kg、0.506 g/kg、1.012 g/kg京大戟、醋京大戟粉末,空白组灌胃等量的0.5%羧甲基纤维素钠,连续7天。考察给药后各组大鼠各脏器的组织病理形态学变化,测定血清中的肝肾功能指标及血清和组织中的氧化损伤指标。结果与空白组比较,各给药组大鼠肝、胃、肠病理切片可见不同程度的组织损伤,京大戟各剂量组的大鼠血清中谷丙转氨酶(alanine aminotransferase,ALT)与谷草转氨酶(aspartate transaminase,AST)活性显著升高(P<0.01,P<0.05),肌酐(creatinine,CRE)与尿素氮(blood urea nitrogen,BUN)活性略有升高;血清和肝、胃、肠组织中的超氧化歧化酶(superoxide dismutase,SOD)和谷胱甘肽(glutathione,GSH)含量明显降低,丙二醛(malondialdehyde,MDA)含量显著升高(P<0.01,P<0.05)。与京大戟组比较,醋京大戟组的大鼠肝、胃、肠组织损伤较轻,血清中AST、ALT活性显著降低;血清和肝、胃、肠组织中的MDA含量明显降低,SOD和GSH含量明显升高(P>0.05),但两组间无显著性差异。结论京大戟对正常大鼠肝、胃、肠毒性明显,对肾无明显损伤,醋制后毒性均下降,其毒性作用与氧化损伤相关。 展开更多
关键词 京大戟 醋制 正常大鼠 毒性 病理变化 肝肾功能 氧化损伤指标
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基于归一化原理的流量计群在线核查方法
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作者 方修睦 杨大易 《暖通空调》 2024年第1期81-88,9,共9页
目前供热系统中的流量计带病工作较多、流量测量数据可信度低、判断流量计工作情况难。本文研究了利用归一化方法解决流量计群的测量数据不闭合问题,给出了流量及热量的修正方法;分析了总流量变化时各热力站的流量比变化率,以及正常运... 目前供热系统中的流量计带病工作较多、流量测量数据可信度低、判断流量计工作情况难。本文研究了利用归一化方法解决流量计群的测量数据不闭合问题,给出了流量及热量的修正方法;分析了总流量变化时各热力站的流量比变化率,以及正常运行的流量计的流量比变化率的区间,证明了利用流量比变化率可实现流量计的云在线核查,为保障智慧供热系统中的数据正确及完整提供了简单、实用的方法。 展开更多
关键词 流量计 在线运行核查 归一化方法 智慧供热 流量比变化率
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山东半岛南部海域鱼类群落生物量粒径谱季节变化
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作者 曲耀琦 刘淑德 +4 位作者 薛莹 张崇良 纪毓鹏 任一平 徐宾铎 《中国海洋大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第3期51-59,共9页
为了解山东半岛南部海域鱼类群落粒径结构特征,本文根据2016—2017年渔业资源底拖网季度调查数据,构建了山东半岛南部海域鱼类生物量粒径谱,分析了该海域鱼类群落的粒径结构特征及其季节变化。研究表明,山东半岛南部海域Sheldon型鱼类... 为了解山东半岛南部海域鱼类群落粒径结构特征,本文根据2016—2017年渔业资源底拖网季度调查数据,构建了山东半岛南部海域鱼类生物量粒径谱,分析了该海域鱼类群落的粒径结构特征及其季节变化。研究表明,山东半岛南部海域Sheldon型鱼类生物量粒径谱呈双峰模式,鱼类粒径范围为2~12粒径级,粒径分布相对均匀,出现波峰的粒径区间存在季节差异,春、夏季第一个波峰出现在3~4粒径级,主要由细纹狮子鱼(Liparis tanakae)、方氏云鳚(Pholis fangi)和大泷六线鱼(Hexagrammos otakii)等种类组成。秋、冬季第一个波峰出现在5~6粒径级,主要由小眼绿鳍鱼(Chelidonichthys spinosus)、长蛇鲻(Saurida elongata)和斑鰶(Konosirus punctatus)等种类组成。四个季节的第二个波峰均由细纹狮子鱼、黄鮟鱇(Lophius litulon)和大头鳕(Gadus macrocephalus)等鱼类个体组成。全部鱼类群落标准化生物量粒径谱的斜率和截距存在季节差异,其中夏季粒径谱陡峭,截距值显著高于其他季节,而冬季粒径谱最平缓,截距值最小,粒径谱斜率和截距的变化主要受当年生幼鱼群体的影响。在山东半岛南部海域,底层鱼类群落与全部鱼类群落的标准化生物量粒径谱的变化趋势相似。在同一季节,底层鱼类群落与全部鱼类群落的标准化生物量粒径谱斜率和截距之间无显著性差异(P>0.05),而暖温性鱼类群落与全部鱼类群落之间存在显著性差异(P<0.05)。山东半岛南部海域的全部鱼类群落粒径结构以小粒径鱼类为主,大型鱼种和大个体较少。鱼类的种类组成有明显的季节变化,当年生幼鱼及洄游性鱼类的个体数量变化是影响该海域鱼类群落粒径结构的主要因素。 展开更多
关键词 生物量粒径谱 鱼类资源 粒径结构 季节变化 山东半岛南部海域
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