期刊文献+
共找到13,530篇文章
< 1 2 250 >
每页显示 20 50 100
气候变暖和物种多样性交互效应对空心莲子草入侵的影响 预览
1
作者 吴昊 张辰 代文魁 《草业学报》 CSCD 北大核心 2020年第3期38-48,共11页
全球变暖加剧了生物入侵进程,而物种多样性对于入侵物种通常具有阻抗作用,探讨二者交互效应对生物入侵的影响有助于预测入侵态势及制定有效的防治措施。通过在我国N 21°-37°设置59个调查样地,探讨外来入侵植物空心莲子草群落... 全球变暖加剧了生物入侵进程,而物种多样性对于入侵物种通常具有阻抗作用,探讨二者交互效应对生物入侵的影响有助于预测入侵态势及制定有效的防治措施。通过在我国N 21°-37°设置59个调查样地,探讨外来入侵植物空心莲子草群落物种多样性与其入侵态势之间的关系;并采用人工构建群落的方式,设置不同温度、物种多样性组合两种因子,研究增温及本土植物多样性对空心莲子草入侵的影响。结果表明:1)样地群落的Shannon-Wiener多样性指数介于0~2.434,空心莲子草入侵盖度(P<0.001)、分枝数(P=0.022)随多样性上升而显著降低,纬度以及纬度×物种多样性交互效应对其入侵态势没有产生显著影响;2)增温导致构建群落中空心莲子草的高度(P=0.004)、最大茎长(P=0.002)以及马唐、苦苣菜和牛筋草3种本土植物的高度(P=0.038)均显著下降,物种多样性上升导致空心莲子草高度、无性分株数、分枝数和最大茎长均显著下降(P<0.001),增温×物种多样性交互效应导致空心莲子草分枝数在“入侵单种”处理中显著升高(P=0.035),而增温×物种属性交互效应显著降低了构建群落中苦苣菜的最大茎长(P<0.001);3)增温并未显著影响空心莲子草及本土植物生物量,物种多样性增加显著削弱了空心莲子草的生物量(P<0.001),但显著提高了其根冠比(P=0.014),即空心莲子草以相对储存更多地下资源的方式应对种间竞争。综上可知,较高水平的物种多样性有助于抵制空心莲子草的入侵,但增温可能会削弱本土物种的抗性;气候变暖背景下应更加重视保护本土植物多样性,以遏制空心莲子草入侵蔓延。 展开更多
关键词 生物入侵 空心莲子草 增温 纬度梯度 物种多样性
在线阅读 下载PDF
全球升温1.5度和2度情景下“一带一路” 区域干燥指数时空演变
2
作者 周建 姜彤 +4 位作者 王艳君 苏布达 陶辉 秦建成 翟建青 《地理学报:英文版》 SCIE CSCD 2020年第1期37-52,共16页
Aridity index reflects the exchanges of energy and water between the land surface and the atmosphere,and its variation can be used to forecast drought and flood patterns,which makes it of great significance for agricu... Aridity index reflects the exchanges of energy and water between the land surface and the atmosphere,and its variation can be used to forecast drought and flood patterns,which makes it of great significance for agricultural production.The ratio of potential evapotranspiration and precipitation is applied to analyse the spatial and temporal distributions of the aridity index in the Belt and Road region under the 1.5℃and 2.0℃global warming scenarios on the basis of outputs from four downscaled global climate models.The results show that:(1)Under the 1.5℃warming scenario,the area-averaged aridity index will be similar to that in 1986-2005(around 1.58),but the changes vary spatially.The aridity index will increase by more than 5%in Central-Eastern Europe,north of West Asia,the monsoon region of East Asia and northwest of Southeast Asia,while it is projected to decrease obviously in the southeast of West Asia.Regarding the seasonal scale,spring and winter will be more arid in South Asia,and the monsoon region of East Asia will be slightly drier in summer compared with the reference period.While,West Asia will be wetter in all seasons,except winter.(2)Relative to 1986-2005,both areal averaged annual potential evapotranspiration and precipitation are projected to increase,and the spatial variation of aridity index will become more obvious as well at the 2.0℃warming level.Although the aridity index over the entire region will be maintained at approximately 1.57 as that in 1.5℃,the index in Central-Eastern Europe,north of West Asia and Central Asia will grow rapidly at a rate of more than 20%,while that in West Siberia,northwest of China,the southern part of South Asia and West Asia will show a declining trend.At the seasonal scale,the increase of the aridity index in Central-Eastern Europe,Central Asia,West Asia,South Asia and the northern part of Siberia in winter will be obvious,and the monsoon region in East Asia will be drier in both summer and autumn.(3)Under the scenario of an additional 0.5℃increase in 展开更多
关键词 1.5℃and 2.0℃global WARMING scenarios ARIDITY index spatial and TEMPORAL VARIATIONS the BELT and Road region
Temperature trends and elevation dependent warming during 1965-2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau
3
作者 Naveed AHMED WANG Gen-xu +4 位作者 Adeyeri OLUWAFEMI Sarfraz MUNIR HU Zhao-yong Aamir SHAKOOR Muhammad Ali IMRAN 《山地科学学报:英文版》 SCIE CSCD 2020年第3期556-571,共16页
The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glaci... The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. In this study, climate changes were analyzed based on trends in air temperature variables(Tmax, Tmin, Tmean), and Diurnal Temperature Range(DTR) as well as elevation-dependent warming at annual and seasonal scales in the Headwaters of Yangtze River(HWYZ), Qinghai Tibetan Plateau. The Base Period(1965-2014) was split into two subperiods;Period-Ⅰ(1965-1989) and Period-Ⅱ(1990-2014) and the analysis was constrained over two subbasins;Zhimenda and Tuotuohe. Increasing trends were found in absolute changes in temperature variables during Period-Ⅱ as compared to Period-Ⅰ.Tmax, Tmin, and Tmean had significant increasing trends for both sub-basins. The highest significant trends in annual time scale were observed in Tmin(1.15℃ decade-1) in Tuotuohe and 0.98℃ decade-1 in Zhimenda sub-basins. In Period-Ⅱ, only the winter season had the highest magnitudes of Tmax and Tmin0.58℃ decade-1 and 1.26℃ decade-1 in Tuotuohe subbasin, respectively. Elevation dependent warming analysis revealed that Tmax, Tmin and Tmean trend magnitudes increase with the increase of elevations in the middle reaches(4000 m to 4400 m) of the HWYZ during Period-Ⅱ annually. The increasing trend magnitude during Period-Ⅱ, for Tmax, is 1.77, 0.92, and 1.31℃ decade-1, for Tmin 1.20, 1.32 and 1.59℃ decade-1,for Tmean 1.51, 1.10 and 1.51℃ decade-1 at elevations of4066 m, 4175 m and 4415 m respectively in the winter season. Tmean increases during the spring season for> 3681 m elevations during Period-Ⅱ, with no particular relation with elevation dependency for other variables. During the summer season in Period Ⅱ, Tmax, Tmin, Tmean increases with the increase of elevations(3681 m to 4415 m) in the middle reaches of HWYZ. Elevation dependent warming(EDW), the 展开更多
关键词 Climate change Elevation dependent warming Mann Kendall Temperature trends Yangtze River Qinghai Tibetan Plateau
How does the arthropod-plant system respond to abrupt and gradual increases in atmospheric CO2? 预览
4
作者 ZHENG Xiao-xu WU Gang 《农业科学学报:英文版》 SCIE CAS CSCD 2020年第4期1159-1161,共3页
Global warming caused by elevated carbon dioxide(CO2)is a major environmental and policy issue.The current global average temperature has been elevated by 1℃since the industrial revolution,and it is likely to reach a... Global warming caused by elevated carbon dioxide(CO2)is a major environmental and policy issue.The current global average temperature has been elevated by 1℃since the industrial revolution,and it is likely to reach a temperature increase of 1.5℃between 2030 and 2052(IPCC 2018).Human-caused emission of CO2 is responsible for the greenhouse effect and the atmospheric CO2 concentration is higher now than at any other time in the past 500000 years,and it continues to rise(Lüthi et al.2008).Impacts of arthropod-plant interactions on carbon dynamics and the global climate are important but often ignored.For example,outbreaks of the mountain pine beetle,Dendroctonus ponderosae,in British Columbia during 2000-2020 will cause the release of an estimated 270 Mt carbon and convert the forest from a small carbon sink to a large carbon source(Kurz et al.2008).The annual carbon release due to outbreaks of this beetle is almost equivalent to the annual carbon emission from all forest fires occurring in Canada over 1959-1999(Kurz et al.2008). 展开更多
关键词 ABRUPT GREENHOUSE WARMING
在线阅读 下载PDF
Record-Setting Ocean Warmth Continued in 2019 预览
5
作者 Lijing CHENG John ABRAHAM +11 位作者 Jiang ZHU Kevin E.TRENBERTH John FASULLO Tim BOYER Ricardo LOCARNINI Bin ZHANG Fujiang YU Liying WAN Xingrong CHEN Xiangzhou SONG Yulong LIU Michael E.MANN 《大气科学进展:英文版》 SCIE CAS CSCD 2020年第2期137-142,共6页
Human-emitted greenhouse gases(GHGs)have resulted in a long-term and unequivocal warming of the planet(IPCC,2019).More than 90%of the excess heat is stored within the world's oceans,where it accumulates and causes... Human-emitted greenhouse gases(GHGs)have resulted in a long-term and unequivocal warming of the planet(IPCC,2019).More than 90%of the excess heat is stored within the world's oceans,where it accumulates and causes increases in ocean temperature(Rhein et al.,2013;Abram et al.,2019). 展开更多
关键词 GREENHOUSE WARMING OCEAN
在线阅读 下载PDF
Underestimation of the Warming Trend over the Tibetan Plateau during 1998–2013 by Global Land Data Assimilation Systems and Atmospheric Reanalyses
6
作者 Peng JI Xing YUAN 《气象学报:英文版》 SCIE CSCD 2020年第1期88-100,共13页
Accurate surface air temperature(T2m)data are key to investigating eco-hydrological responses to global warming.Because of sparse in-situ observations,T2m datasets from atmospheric reanalysis or multi-source observati... Accurate surface air temperature(T2m)data are key to investigating eco-hydrological responses to global warming.Because of sparse in-situ observations,T2m datasets from atmospheric reanalysis or multi-source observation-based land data assimilation system(LDAS)are widely used in research over alpine regions such as the Tibetan Plateau(TP).It has been found that the warming rate of T2m over the TP accelerates during the global warming slowdown period of 1998–2013,which raises the question of whether the reanalysis or LDAS datasets can capture the warming feature.By evaluating two global LDASs,five global atmospheric reanalysis datasets,and a high-resolution dynamical downscaling simulation driven by one of the global reanalysis,we demonstrate that the LDASs and reanalysis datasets underestimate the warming trend over the TP by 27%–86%during 1998–2013.This is mainly caused by the underestimations of the increasing trends of surface downward radiation and nighttime total cloud amount over the southern and northern TP,respectively.Although GLDAS2.0,ERA5,and MERRA2 reduce biases of T2m simulation from their previous versions by 12%–94%,they do not show significant improvements in capturing the warming trend.The WRF dynamical downscaling dataset driven by ERA-Interim shows a great improvement,as it corrects the cooling trend in ERA-Interim to an observation-like warming trend over the southern TP.Our results indicate that more efforts are needed to reasonably simulate the warming features over the TP during the global warming slowdown period,and the WRF dynamical downscaling dataset provides more accurate T2m estimations than its driven global reanalysis dataset ERA-Interim for producing LDAS products over the TP. 展开更多
关键词 land data assimilation system(LDAS) REANALYSIS datasets WRF dynamical DOWNSCALING Tibetan Plateau GLOBAL warming SLOWDOWN
Tropical cyclones in a warming climate
7
作者 Liang WU Zhiping WEN Ronghui HUANG 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2020年第3期456-458,共3页
Over the past few decades,extreme tropical cyclone(TC)events have become more common.During the 2019 typhoon season in the western North Pacific(WNP),7 super typhoons hit East Asia.Super Typhoon Lekima(2019)caused eco... Over the past few decades,extreme tropical cyclone(TC)events have become more common.During the 2019 typhoon season in the western North Pacific(WNP),7 super typhoons hit East Asia.Super Typhoon Lekima(2019)caused economic loss of at least RMB 51.53 billion yuans and 56 fatalities in the mainland China. 展开更多
关键词 China. TYPHOON WARMING
不同覆盖方式下旱作玉米田土壤呼吸对温度变化的响应
8
作者 解梦怡 商雨晴 +1 位作者 赵发珠 王俊 《应用生态学报》 CAS CSCD 北大核心 2020年第2期467-473,共7页
为探明不同农田管理措施下增温对土壤呼吸及其温度敏感性的影响,基于9年田间定位试验,对秸秆覆盖(SM)、地膜覆盖(FM)和无覆盖对照(CK)3种管理方式下的土壤样品进行了为期60 d的室内恒温培养,培养温度分别为15、25和35℃,对土壤呼吸速率... 为探明不同农田管理措施下增温对土壤呼吸及其温度敏感性的影响,基于9年田间定位试验,对秸秆覆盖(SM)、地膜覆盖(FM)和无覆盖对照(CK)3种管理方式下的土壤样品进行了为期60 d的室内恒温培养,培养温度分别为15、25和35℃,对土壤呼吸速率进行动态监测。结果表明:在整个培养期间,土壤呼吸速率呈单峰型变化,土壤呼吸累积释放量则呈"S"型增长趋势,其中培养前30 d土壤呼吸累积释放量约占整个培养期的75%~85%。与CK相比,SM土壤呼吸累积释放量显著增加了19.4%,而FM差异不显著。与15℃相比,25和35℃条件下土壤平均呼吸速率分别增加了17.0%和36.8%,土壤呼吸累积释放量分别增加了13.1%和33.6%。覆盖方式与温度二者无交互作用。土壤呼吸变异的97.7%~99.9%可以由温度变化解释,且土壤呼吸与有机碳和全氮含量均呈显著正相关。与无覆盖对照和地膜覆盖相比,秸秆覆盖可通过增加土壤中有机质的输入促进土壤呼吸,但同时会降低土壤呼吸温度敏感性,表明在未来气候变暖背景下,黄土高原旱作农业区进行秸秆覆盖较地膜覆盖能更有效地减少土壤CO2排放。 展开更多
关键词 土壤呼吸 秸秆覆盖 地膜覆盖 增温
Preface to the Special Issue on Antarctic Meteorology and Climate:Past,Present and Future 预览
9
作者 Jiping LIU David BROMWICH +5 位作者 Dake CHEN Raul CORDERO Thomas JUNG Marilyn RAPHAEL John TURNER Qinghua YANG 《大气科学进展:英文版》 SCIE CAS CSCD 2020年第5期421-422,共2页
The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studyi... The Antarctic,including the continent of Antarctica and the Southern Ocean,is a critically important part of the Earth system.Research in Antarctic meteorology and climate has always been a challenging endeavor.Studying and predicting weather patterns in the Antarctic are important for understanding their role in local-to-global processes and facilitating field studies and logistical operations in the Antarctic(e.g.,Walsh et al.,2018).Studies of climate change in the Antarctic are comparatively neglected compared to those of the Arctic.However,significant climate changes have occurred in the Antarctic in the past several decades,i.e.,a strong warming over the Antarctic Peninsula even with a recent minor cooling,a deepening of the Amundsen Sea low,a rapid warming of the upper ocean north of the circumpolar current,an increase of Antarctic sea ice since the late 1970s followed by a recent rapid decrease,and an accelerated ice loss from the Antarctic ice shelf/sheet since the late 1970s(e.g.,Turner et al.,2005;Raphael et al.,2016;Sallée,2018;Parkinson,2019;Rignot et al.,2019).Investigating recent climate change in the Antarctic and the underlying mechanisms are important for predicting future climate change and providing information to policymakers. 展开更多
关键词 ANTARCTIC WARMING METEOROLOGY
在线阅读 下载PDF
Characteristics of permafrost degradation in Northeast China and its ecological effects: A review 预览
10
作者 ShanShan Chen ShuYing Zang Li Sun 《寒旱区科学:英文版》 CSCD 2020年第1期1-11,共11页
Latitudinal permafrost in Northern Northeast(NNE)China is located in the southern margin of the Eurasian continent,and is very sensitive to climatic and environmental change.Numerical simulations indicate that air tem... Latitudinal permafrost in Northern Northeast(NNE)China is located in the southern margin of the Eurasian continent,and is very sensitive to climatic and environmental change.Numerical simulations indicate that air temperature in the permafrost regions of Northeast China has been on the rise since the 1950s,and will keep rising in the 21st century,leading to extensive degradation of permafrost.Permafrost degradation in NNE China has its own characteristics,such as northward shifts in the shape of a"W"for the permafrost southern boundary(SLP),discontinuous permafrost degradation into islandlike frozen soil,and gradually disappearing island permafrost.Permafrost degradation leads to deterioration of the ecological environment in cold regions.As a result,the belt of larch forests dominated by Larix gmelinii has shifted northwards and wetland areas with symbiotic relationships with permafrost have decreased significantly.With rapid retreat and thinning of permafrost and vegetation change,the CO2 and CH4 flux increases with mean air temperature from continuous to sporadic permafrost areas as a result of activity of methanogen enhancement,positively feeding back to climate warming.This paper reviews the features of permafrost degradation,the effects of permafrost degradation on wetland and forest ecosystem structure and function,and greenhouse gas emissions on latitudinal permafrost in NNE China.We also put forward critical questions about the aforementioned effects,including:(1)establish long-term permafrost observation systems to evaluate the distribution of permafrost and SLP change,in order to study the feedback of permafrost to climate change;(2)carry out research about the effects of permafrost degradation on the wetland ecosystem and the response of Xing'an larch to global change,and predict ecosystem dynamics in permafrost degradation based on long-term field observation;(3)focus intensively on the dynamics of greenhouse gas flux in permafrost degradation of Northeast China and the feedback of greenhouse gas emi 展开更多
关键词 climate warming permafrost degradation greenhouse gas emissions ecosystem impact
在线阅读 下载PDF
Surface warming patterns dominate the uncertainty in global water vapor plus lapse rate feedback 预览
11
作者 Jingchun Zhang Jian Ma +2 位作者 Jing Che Zhenqiang Zhou Guoping Gao 《海洋学报:英文版》 SCIE CAS CSCD 2020年第3期81-89,共9页
Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surfac... Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surface temperature increase. In projections by global climate models, it has been demonstrated that the geographical variation of sea surface temperature change brings significant uncertainties into atmospheric circulation and precipitation responses at regional scales. Here we show that the spatial pattern of surface warming is a major contributor to uncertainty in the combined water vapour-lapse rate feedback. This is demonstrated by computing the global-mean radiative effects of changes in air temperature and relative humidity simulated by 31 climate models using a methodology based on radiative kernels. Our results highlight the important contribution of regional climate change to the uncertainty in climate feedbacks, and identify the regions of the world where constraining surface warming patterns would be most effective for higher skill of climate projections. 展开更多
关键词 surface warming patterns UNCERTAINTY water vapor feedback lapse rate feedback relative humidity air temperature radiative kernels
在线阅读 下载PDF
增温与氮添加对杉木幼苗细根化学计量学的影响
12
作者 姜琦 陈光水 +5 位作者 郭润泉 宋涛涛 陈廷廷 陈宇辉 贾林巧 熊德成 《生态学杂志》 CAS CSCD 北大核心 2020年第3期723-732,共10页
全球气候变暖与氮沉降是两个同时存在的全球变化主要因素,但目前关于二者的研究多以单因子为主。细根碳(C)、氮(N)、磷(P)浓度影响着森林生态系统生产力与碳汇,然而目前关于气候变暖与N沉降对细根化学组成元素的影响尚不清楚。本研究在... 全球气候变暖与氮沉降是两个同时存在的全球变化主要因素,但目前关于二者的研究多以单因子为主。细根碳(C)、氮(N)、磷(P)浓度影响着森林生态系统生产力与碳汇,然而目前关于气候变暖与N沉降对细根化学组成元素的影响尚不清楚。本研究在福建三明森林生态系统与全球变化研究站陈大观测点开展增温(W,+4℃)与N添加(N,+40 kg N·hm-2·a-1)双因子试验,探讨增温与N添加对杉木细根C、N、P化学计量学的影响。结果表明:(1)增温提高了春季细根N浓度,对细根C与P浓度则无显著影响;增温降低了春季细根C∶N,对细根N∶P无显著影响。(2)N添加提高了细根C浓度与春季细根N浓度,对细根P浓度则无显著影响;N添加降低了春季细根C∶N,提高了春季细根N∶P。(3)增温与N添加的交互作用对春季1~2 mm径级细根C浓度有显著影响,但对0~1 mm径级细根C浓度无显著影响,并且增温与N添加的交互作用对细根N与P浓度均无显著影响。本研究表明,增温与N添加会促进亚热带森林生态系统养分循环,N添加并未改变亚热带杉木人工林N限制现状;增温与N添加的交互作用对细根C、N、P元素的影响并不一致,受苗木C投资权衡与生长稀释效应所调节。 展开更多
关键词 增温 氮添加 交互作用 细根 化学组成
Climatic suitability and spatial distribution for summer maize cultivation in China at 1.5 and 2.0℃ global warming
13
作者 Qijin He Guangsheng Zhou +1 位作者 Xiaomin Lü Mengzi Zhou 《科学通报:英文版》 SCIE EI CSCD 2019年第10期690-697,共8页
Evaluating climatic suitability of crop cultivation lays a foundation for agriculture coping with climate change scientifically. Herein, we analyse changes in the climatically suitable distribution of summer maize cul... Evaluating climatic suitability of crop cultivation lays a foundation for agriculture coping with climate change scientifically. Herein, we analyse changes in the climatically suitable distribution of summer maize cultivation in China at 1.5℃(GW1.5) and 2.0℃(GW2.0) global warming in the future according to the temperature control targets set by the Paris Agreement. Compared with the reference period (1971- 2000), the summer maize cultivation climatically suitable region (CSR) in China mainly shifts eastwards, and its acreage significantly decreases at both GW1.5 and GW2.0. Despite no dramatic changes in the CSR spatial pattern, there are considerable decreases in the acreages of optimum and suitable regions (the core of the main producing region), indicating that half-a-degree more global warming is unfavourable for summer maize production in China's main producing region. When the global warming threshold increases from GW1.5 to GW2.0, the centres-of-gravity of optimum areas shift northeastward under RCP4.5 and RCP8.5, the centres-of-gravity of both suitable and less suitable areas shift northwestward, though the northward trend is more prominent for the less suitable areas, and the centre-of-gravity of unsuitable areas shifts southeastward. Generally, half-a-degree more global warming drives the cultivable areas of summer maize to shift northward in China, while the west region shows a certain potential for expansion of summer maize cultivation. 展开更多
关键词 Summer maize CULTIVATION distribution CLIMATIC SUITABILITY 1.5℃ GLOBAL WARMING 2.0℃ GLOBAL WARMING
Permafrost warming along the Mo’he-Jiagedaqi section of the China-Russia crude oil pipeline
14
作者 WANG Fei LI Guo-yu +4 位作者 MA Wei MAO Yun-cheng MU Yan-hu SERBAN Mihaela CAI Yong-jun 《山地科学学报:英文版》 SCIE CSCD 2019年第2期285-295,共11页
The permafrost along the China-Russia Crude Oil Pipeline(CRCOP) is degrading since the pipeline operation in 2011. Heat dissipated from the pipeline, climate warming and anthropogenic activities leads to permafrost wa... The permafrost along the China-Russia Crude Oil Pipeline(CRCOP) is degrading since the pipeline operation in 2011. Heat dissipated from the pipeline, climate warming and anthropogenic activities leads to permafrost warming. The processes of permafrost warming along the CRCOP were studied based on the monitoring of air and soil temperatures, and electrical resistivity tomography(ERT) surveys. Results show that:(1) the mean annual air temperature(MAAT) in permafrost regions along the CRCOP increased with a rate of 0.21°C/10a–0.40°C/10 a during the past five decades;(2) the mean annual ground temperature(MAGT, at-15 m depth) of undisturbed permafrost increased by 0.2°C and the natural permafrost table remained unchanged due to the zero-curtain effect;(3) permafrost surrounding the uninsulated pipeline right-of-way warmed significantly compared with that in a natural site. During 2012–2017, the MAGT and the artificial permafrost table, 2 m away from the pipeline centerline, increased at rates of 0.063°C/a and 1.0 m/a. The thaw bulb developed around the pipe and exhibits a faster lateral expansion;(4) 80-mm-thick insulation could reduce the heat exchange between the pipeline and underlying permafrost and then keep the permafrost and pipe stable. The MAGT and the artificial permafrost table, 4.8 m away from the center line of the pipeline, increased by 0.3°C/a and 0.43 m/a, respectively. Due to the heat disturbance caused by warm oil, the degradation of wetland, controlled burn each autumn and climate warming, the permafrost extent reduced and warmed significantly along the CRCOP route. Field observations provide basic data to clarify the interactions between CRCOP and permafrost degradation and environmental effects in the context of climate change. 展开更多
关键词 PERMAFROST WARMING China-Russia CRUDE Oil PIPELINE Air TEMPERATURE Soil TEMPERATURE Climate WARMING
放牧和模拟增温对藏北高寒草地植物群落特征及生产力的影响
15
作者 吴红宝 高清竹 +6 位作者 干珠扎布 李钰 闫玉龙 胡国铮 王学霞 严俊 何世丞 《植物生态学报》 CAS CSCD 北大核心 2019年第10期853-862,共10页
气候变化和放牧活动对草地植物物种多样性和生产力具有重要影响。为探索藏北高寒草地植物物种多样性和生产力对增温、放牧及其交互作用的响应,于2011年在藏北高原开始建立增温实验平台,2016年起增设放牧、增温+放牧实验,连续2年(2016–2... 气候变化和放牧活动对草地植物物种多样性和生产力具有重要影响。为探索藏北高寒草地植物物种多样性和生产力对增温、放牧及其交互作用的响应,于2011年在藏北高原开始建立增温实验平台,2016年起增设放牧、增温+放牧实验,连续2年(2016–2017年)观测了植物群落特征、群落组成、生产力和物种多样性。结果表明,增温和放牧对高寒草地植物高度和净初级生产力具有显著交互作用。在放牧条件下,增温对植物高度无显著影响;但在不放牧条件下,增温却显著增加了植物高度。在放牧条件下,增温对净初级生产力的影响存在年际差异,2016年增温对生产力无显著影响,2017年增温显著降低了植物净初级生产力;但在不放牧条件下,增温对植物净初级生产力无显著影响。增温和放牧对高寒草地植物物种丰富度、盖度、重要值及多样性均无显著交互作用。植物盖度在增温和放牧条件下显著降低,杂类草物种比例显著增加,但物种多样性均无显著变化。研究表明,增温和放牧显著改变高寒草地群落结构。未来气候变化条件下,放牧活动加剧有可能导致高寒草地生产力降低。 展开更多
关键词 增温 放牧 增温+放牧 物种多样性 净初级生产力
增温对南亚热带混交林4个树种养分含量及化学计量的影响 预览
16
作者 李旭 列志旸 +5 位作者 吴婷 黄楚敏 刘世忠 刘菊秀 傅松玲 李义勇 《生态环境学报》 CSCD 北大核心 2019年第5期890-897,共8页
为了解南亚热带针阔叶混交林不同树种的养分元素含量及其计量比对增温的响应情况,基于鼎湖山森林生态系统定位站的模拟增温研究平台,选取混交林中红枝蒲桃(Syzygium rehderianum)、红锥(Castanopsis hystrix)、马尾松(Pinus massoniana... 为了解南亚热带针阔叶混交林不同树种的养分元素含量及其计量比对增温的响应情况,基于鼎湖山森林生态系统定位站的模拟增温研究平台,选取混交林中红枝蒲桃(Syzygium rehderianum)、红锥(Castanopsis hystrix)、马尾松(Pinus massoniana)和木荷(Schima superba)4个树种为研究对象,采用沿海拔梯度垂直移位模拟增温的方法,研究了4个树种叶、枝和根中主要元素含量及计量比对增温的响应情况。结果显示,增温降低了各树种各器官的C和N含量,升高了P含量。增温条件下,各树种C含量变化幅度不大,叶的N和P含量大于枝和根,不同树种对增温的响应有所差异,红锥和木荷的C、N和P含量对增温的响应大于红枝蒲桃。增温显著降低了各树种各器官的C/P和N/P,各树种在化学计量比上对增温的响应表现为红锥>木荷>马尾松>红枝蒲桃。增温升高了各树种叶的Ca含量,其他养分在不同器官没有表现出一致的规律。研究结果揭示了南亚热带针阔叶混交林主要树种养分含量及化学计量学特征对增温的响应特征,发现增温对南亚热带主要乡土树种的影响存在一定的种间差异性,这种差异可能会影响不同树种生长,进而影响森林群落结构和功能。 展开更多
关键词 垂直位移 植物器官 养分含量 化学计量比 南亚热带
在线阅读 免费下载
Why would sea-level rise for global warming and polar ice-melt? 预览
17
作者 Aftab Alam Khan 《地学前缘:英文版》 CAS CSCD 2019年第2期481-494,共14页
Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other cli... Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise. 展开更多
关键词 Global warming POLAR ice-melt EQUATORIAL BULGE POLAR FLATTENING GEOLOGIC events Sea level rise
在线阅读 下载PDF
京津冀干旱时空演变规律分析(英文)
18
作者 章杰 孙福宝 +2 位作者 刘文彬 刘家宏 王红 《地理学报:英文版》 SCIE CSCD 2019年第6期863-876,共14页
Spatio-temporal patterns of drought from 1961 to 2013 over the Beijing-Tianjin-Hebei(BTH) region of China were analyzed using the Palmer Drought Severity index(PDSI) based on 21 meteorological stations. Overall, chang... Spatio-temporal patterns of drought from 1961 to 2013 over the Beijing-Tianjin-Hebei(BTH) region of China were analyzed using the Palmer Drought Severity index(PDSI) based on 21 meteorological stations. Overall, changes in the mean-state of drought detected in recent decades were due to decreases in precipitation and potential evapotranspiration. The Empirical Orthogonal Functions(EOF) method was used to decompose drought into spatio-temporal patterns, and the first two EOF modes were analyzed. According to the first leading EOF mode(48.5%), the temporal variability(Principal Components, PC1) was highly positively correlated with annual series of PDSI(r=+0.99). The variance decomposition method was further applied to explain the inter-decadal temporal and spatial variations of drought relative to the total variation. We find that 90% of total variance was explained by time variance, and both total and time variance dramatically decreased from 1982 to 2013. The total variance was consistent with extreme climate events at the inter-decadal scale(r=0.71, p<0.01). Comparing the influence of climate change on the annual drought in two different long-term periods characterized by dramatic global warming(P1: 1961–1989 and P2: 1990–2013), we find that temperature sensitivity in the P2 was three times more than that in the P1. 展开更多
关键词 PDSI SPATIAL and TEMPORAL PATTERNS sensitivity analysis GLOBAL WARMING
Global warming weakening the inherent stability of glaciers and permafrost
19
作者 Yongjian Ding Shiqiang Zhang +2 位作者 Lin Zhao Zhongqin Li Shichang Kang 《科学通报:英文版》 SCIE EI CSCD 2019年第4期245-253,共9页
The Cryosphere has been undergoing a worldwide retreat, as seen in the decrease in the areal extent and volume of glaciers and in the areal extent of permafrost. This paper prese nts a systematic exami nation of the i... The Cryosphere has been undergoing a worldwide retreat, as seen in the decrease in the areal extent and volume of glaciers and in the areal extent of permafrost. This paper prese nts a systematic exami nation of the inherent stability changes of glaciers and permafrost caused by warming. Various study results suggest that over the past 30 years, the internal temperature of glaciers and permafrost exhibits an overall accelerating warming trend. The warming rate peaked in the mid-2000s and slowed slightly for several years afterward. In recent years, however, the warming rate has seemed to pick up again. The warming of glaciers and permafrost has exerted great impact on their stability, displayed as intensified melting, increased glacier surging, enlargement of supraglacial lakes, and increased permafrost degradation. Even without a future temperature increase, some glaciers will continue to shrink, and the number of surging glaciers will increase. The transition from low-temperature to high-temperature permafrost is a noticeable warning sign of a comprehensive degradation of permafrost. These results indicate that "warming” glaciers and permafrost will exert significant impacts on the hydrology, ecology, and stability of engineering in cold regions. 展开更多
关键词 WARMING Englacial temperature PERMAFROST INTERNAL thermal state STABILITY
气候变化对西藏农业生产的影响 预览
20
作者 刘国一 《西藏农业科技》 2019年第1期49-54,共6页
气候变化已成为全球公认的环境问题,主要因人类活动温室气体排放增加导致,青藏高原是气候变化的敏感区,生态环境和农业生产受气候变化的影响较大,研究气候变化对西藏农业的应对意义重大。文章综述了当前西藏气候变化方面的研究进展,分... 气候变化已成为全球公认的环境问题,主要因人类活动温室气体排放增加导致,青藏高原是气候变化的敏感区,生态环境和农业生产受气候变化的影响较大,研究气候变化对西藏农业的应对意义重大。文章综述了当前西藏气候变化方面的研究进展,分析气候变化对西藏农业产生的影响,西藏的温度增加趋势比较明显,高于全球同纬度的平均增温速率。降水量也呈增加趋势,增温与降水在空间上具有不一致性,西藏的气候将朝着暖湿化方向发展,对农业的生产形成较大的挑战。冬春季的增温趋势使得作物的物候期提前,使得播期提前,作物的布局向高纬度和高海拔地区推移,有利于套复种。温度增加使土壤中微生物的活性增加,加速对土壤有机质的分解,土壤有机质含量呈下降趋势。气候变化对西藏的农业生产带来了影响,严重威胁到西藏的粮食生产安全问题,需要积极探寻应对策略。 展开更多
关键词 青藏高原 气候变化 增温 降水
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈