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Similarities in Terms of Humor in Characterization as Seen in Sunshine Sketches of a Little Town andThe Adventures of Huckleberry Finn
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作者 郭勇丽 《阴山学刊》 2013年第4期72-75,共4页
This thesis attempts to investigate the humor in characterization in two novels,Sunshine Sketches of a Little Town by a Canadian writer Stephen Leacock and The Adventures ofHuckleberry Finn by an American writer Mark ... This thesis attempts to investigate the humor in characterization in two novels,Sunshine Sketches of a Little Town by a Canadian writer Stephen Leacock and The Adventures ofHuckleberry Finn by an American writer Mark Twain.Through comparison of characterization inthese two great works,the lively and funny appearances,psychological development and humorousconducts of the characters come to life.It does help readers have a thorough understanding of thehumor created by these two masters of realism in the worldwide literature. 展开更多
关键词 英语 教材 文学作品 文学
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Changes in Spring Snow Cover over the Eastern and Western Tibetan Plateau and Their Associated Mechanism
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作者 Fangchi LIU Xiaojing JIA Wei DONG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第5期959-973,共15页
The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–2020.The current work investigate... The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–2020.The current work investigates the possible mechanisms accounting for these distinct TPSC changes.Our results indicate that the decrease in W_TPSC is primarily attributed to rising temperatures,while the increase in E_TPSC is closely linked to enhanced precipitation.Local circulation analysis shows that the essential system responsible for the TPSC changes is a significant anticyclonic system centered over the northwestern TP.The anomalous descending motion and adiabatic heating linked to this anticyclone leads to warmer temperatures and consequent snowmelt over the western TP.Conversely,anomalous easterly winds along the southern flank of this anticyclone serve to transport additional moisture from the North Pacific,leading to an increase in snowfall over the eastern TP.Further analysis reveals that the anomalous anticyclone is associated with an atmospheric wave pattern that originates from upstream regions.Springtime warming of the subtropical North Atlantic(NA)sea surface temperature(SST)induces an atmospheric pattern resembling a wave train that travels eastward across the Eurasian continent before reaching the TP.Furthermore,the decline in winter sea ice(SIC)over the Barents Sea exerts a persistent warming influence on the atmosphere,inducing an anomalous atmospheric circulation that propagates southeastward and strengthens the northwest TP anticyclone in spring.Additionally,an enhancement of subtropical stationary waves has resulted in significant increases in easterly moisture fluxes over the coastal areas of East Asia,which further promotes more snowfall over eastern TP. 展开更多
关键词 snow cover Tibetan Plateau long-term changes SPRING
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Spatiotemporal landscape pattern changes and their effects on land surface temperature in greenbelt with semi-arid climate:A case study of the Erbil City,Iraq
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作者 Suzan ISMAIL Hamid MALIKI 《Journal of Arid Land》 SCIE CSCD 2024年第9期1214-1231,共18页
Urban expansion of cities has caused changes in land use and land cover(LULC)in addition to transformations in the spatial characteristics of landscape structure.These alterations have generated heat islands and rise ... Urban expansion of cities has caused changes in land use and land cover(LULC)in addition to transformations in the spatial characteristics of landscape structure.These alterations have generated heat islands and rise of land surface temperature(LST),which consequently have caused a variety of environmental issues and threated the sustainable development of urban areas.Greenbelts are employed as an urban planning containment policy to regulate urban expansion,safeguard natural open spaces,and serve adaptation and mitigation functions.And they are regarded as a powerful measure for enhancing urban environmental sustainability.Despite the fact that,the relation between landscape structure change and variation of LST has been examined thoroughly in many studies,but there is a limitation concerning this relation in semi-arid climate and in greenbelts as well,with the lacking of comprehensive research combing both aspects.Accordingly,this study investigated the spatiotemporal changes of landscape pattern of LULC and their relationship with variation of LST within an inner greenbelt in the semi-arid Erbil City of northern Iraq.The study utilized remote sensing data to retrieve LST,classified LULC,and calculated landscape metrics for analyzing spatial changes during the study period.The results indicated that both composition and configuration of LULC had an impact on the variation of LST in the study area.The Pearson's correlation showed the significant effect of Vegetation 1 type(VH),cultivated land(CU),and bare soil(BS)on LST,as increase of LST was related to the decrease of VH and the increases of CU and BS,while,neither Vegetation 2 type(VL)nor built-up(BU)had any effects.Additionally,the spatial distribution of LULC also exhibited significant effects on LST,as LST was strongly correlated with landscape indices for VH,CU,and BS.However,for BU,only aggregation index metric affected LST,while none of VL metrics had a relation.The study provides insights for landscape planners and policymakers to not only develop more green spaces in greenbelt but also optimize the spatial landscape patterns to reduce the influence of LST on the urban environment,and further promote sustainable development and enhance well-being in the cities with semi-arid climate. 展开更多
关键词 land use and land cover change landscape pattern land surface temperature GREENbeLT remote sensing
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Soil Cover in the Eastern Part of the Dried Bed of the Aral Sea
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作者 Galina Stulina Kamaladin Idirisov 《Journal of Geoscience and Environment Protection》 2024年第6期30-37,共8页
The greatest environmental disaster in Central Asiathe drying up of the Aral Seahas led to the formation of a new terrain, extending over 2.7 million hectares in Uzbekistan. This newly formed terrain is dynamically de... The greatest environmental disaster in Central Asiathe drying up of the Aral Seahas led to the formation of a new terrain, extending over 2.7 million hectares in Uzbekistan. This newly formed terrain is dynamically developing, with emerging soil formations replacing bottom sediments. This paper analyzes the results of a study on soil formation in the eastern part of the dried-up seabed, focusing on the influence of natural processes occurring there. 展开更多
关键词 Aral Sea ENVIRONMENTAL Dried Seabed Soil Cover
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The Relationship Between Temperature & Sunshine and Spring-Sown Wheat Quality
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作者 CAOGuang-cai WUDong-bing +7 位作者 SUNQun QIANGXiao-lin CHENHe-qin DONGMei KOUHao WANGJian-lin HOULi-bai LIMeng 《Agricultural Sciences in China》 CAS CSCD 2003年第12期1329-1337,共9页
In order to study the relationship between temperature & sunshine and spring-sown wheat qua lity, a spring-sown experiment with 3 wheat varieties was conducted in Rikaze, Lasa, Linzhi, Beijing and Shenyang from 1... In order to study the relationship between temperature & sunshine and spring-sown wheat qua lity, a spring-sown experiment with 3 wheat varieties was conducted in Rikaze, Lasa, Linzhi, Beijing and Shenyang from 1998 to 2001. The results indicated that significant difference on some quality characteristics of experimental wheat varieties were observed from different locations and different years. The results also showed: protein content was positively correlated with wet gluten content, falling number, the average day temperature and sunshine hours from heading to maturation; and negatively correlated with the growing days and the average diurnal temperature difference from sowing to maturation; wet gluten content was positively correlated with the average day temperature and sunshine hours during the same period. Sedimentation value and falling number were positively correlated with the average sunshine hours from sowing to maturation. The basic way of wheat production in Tibet was as follows: mainly developing medium gluten wheat varieties, suitably planting weak gluten wheat varieties, introducing some inland excellent varieties. 展开更多
关键词 TEMPERATURE sunshine Spring-sown wheat Quality CORRELATION
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THE EVOLUTION OF THE COVERED KARST AND TECTONIC UPLIFT OF HU'NAN, GUANGXI, GUANGZHOU, YUNNAN AND TIBET
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作者 Cui Zhijiu, Li Dewen, Li Hongjiang 《地学前缘》 EI CAS CSCD 2000年第S1期349-350,共2页
The Covered Karst, which formed in subsoil environment and distributed in the Tibet Plateau and its eastern district, denuded on the ground surface in different degrees (forming stone pinnacles), but they had the good... The Covered Karst, which formed in subsoil environment and distributed in the Tibet Plateau and its eastern district, denuded on the ground surface in different degrees (forming stone pinnacles), but they had the good consistency in their characteristics. First, some kind of landform, such as stone pinnacles, rock well etc, kept the slippery rock surface. It was believed that they were resulted from the process in soil. Nearer the foot of rock the site was; more clear and integrated the form was. Second, the covered karst often associated with red weathering crust. Based on the character of the red weathering crust of the summit plane of Anduo Mountain, its forming environment was relatively humid and hot. Third, the best geomorphologic position, where the karst was bare, was not on the summit plane but on the slope.The baring degrees and later reworked characteristics of the covered karst made up of an integrated series. They could be divided into three kinds of districts according to their response to the Plateau uplift. (1) The western district, where the uplift was intensive, was mainly Tibet Plateau. For example, in Anduo Mountain, the covered karst was entirely denuded on the ground surface, and the rock surface was turned into mottled rock well because the frost weathering intensively reworked it. The red weathering crust was only kept in the bottom of rock, most of which was observed in the crack of limestone. The present karst process on the ground surface stopped. (2) The middle district, where the uplift degree was moderate, was mainly Yungui Plateau. The covered karst was partly denuded to form the stone pinnacles. Its part, which is baring, is changed to be aciculate and sharp\|pointed, and is active now. (3) The eastern district, where the uplift was weak, was mainly the northern part of Guangxi Province and the southern part of Hunan Province. The covered karst was entirely covered by soil and only observed in the section, which was excavated by human. The form of the covered karst generally had the typical character of the process below the soil. 展开更多
关键词 EVOLUTION covered KARST TECTONIC UPLIFT
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Research on the Development Strategy of Panxi Sunshine Health and Wellness Homestays and Hotels Based on Traditional Chinese Medicine Health Preservation
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作者 Zihui Zhao Zhengnan Wuyu +1 位作者 Sicen Liu Chuibiao Zeng 《Proceedings of Business and Economic Studies》 2024年第3期114-119,共6页
This study is the first phase of research results from the student innovation project“Yunqiao Sunshine Health and Wellness Homestay”group at Chengdu Normal University.By analyzing the current state of the Sunshine H... This study is the first phase of research results from the student innovation project“Yunqiao Sunshine Health and Wellness Homestay”group at Chengdu Normal University.By analyzing the current state of the Sunshine Health and Wellness Tourism Area economy in the Panxi region of Sichuan,local policies,and the current state of Sunshine Health and Wellness homestays and hotels,this paper proposes the possibility of developing Sunshine Health and Wellness homestays and hotels through traditional Chinese medicine(TCM)health preservation methods.It also proposes development strategies for such hotels through a market survey SWOT analysis. 展开更多
关键词 Traditional Chinese medicine health preservation sunshine Health and Wellness Tourism Area Homestays and hotels STRATEGY
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The Relationship between Global Solar Radiation and Sunshine Durations in Cameroon
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作者 R. Mbiaké A. Beya Wakata +5 位作者 E. Mfoumou E. Ndjeuna L. Fotso E. Tiekwe J. R. Kaze Djamen C. Bobda 《Open Journal of Air Pollution》 2018年第2期107-119,共13页
Based on the well-known modified Angstrom formula on the relationship between the sunshine duration and the global solar radiation, this paper aimed to estimate the value of the constant a and b in Cameroon. Only five... Based on the well-known modified Angstrom formula on the relationship between the sunshine duration and the global solar radiation, this paper aimed to estimate the value of the constant a and b in Cameroon. Only five cities (Maroua, Garoua, NGaoundéré, Yaoundé and Douala) had the both available in-situ data recorded during the period of eleven years (1996-2006) beside which four others cities (Dschang, Koundja, Yoko and Manfé) had only the in-situ sunshine duration available data recorded during the period of twenty years (1986-2006). The 9 cities were grouped in 3 different climate regions. Based on the data of the 5 first cities belonging the 3 regions, the follow constant values a1 = -0.05, a2 = -0.02, a3 = -0.14 and b1 = 0.94, b2 = 0.74, b3 = 1.12 were obtained. The Root Mean Square Error (RMSE) Mean Bias Error (MBE) and correlation coefficient (r) were also determined. Then we used these values to estimate the global solar radiation for the other four remain cities. The constants a and b obtained values are in accordance with those of the West Africa region which Cameroon belongs to. So they can be employed in estimating global solar radiation of location in Cameroon paying attention only to the geographical location information. 展开更多
关键词 Solar Radiation sunshine DURATION ANGSTROM CONSTANTS CLIMATIC Region
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A comparative study of the land-atmosphere energy and water exchanges over the Tibetan Plateau and the Yangtze River Region
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作者 Nan Yao Yaoming Ma +3 位作者 Binbin Wang Jun Zou Jianning Sun Zhipeng Xie 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第2期52-59,共8页
正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8... 正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8个不同地表类型(包括高山荒漠,高山草地,(平原)城市和(平原)草地等)观测站点的地表辐射和能量通量数据.结果显示:(1)TP由于高原大气层稀薄且空气洁净,年平均入射短波辐射为251.3W m^(-2),是YRR的1.7倍.加之高原地表反照率高导致反射辐射(59.6 W m^(-2))是YRR的2.87倍.入射及出射的长波辐射为231.5和338.0 W m^(-2),分别为YRR的0.64和0.83.而两个区域的净辐射差异不大;(2)草地站更多的潜热释放使得地表总加热效率高于城市和高山荒漠,TP和YRR的草地站的年平均潜热分别为35.0和38.8 W m^(-2),而植被稀疏且土壤干燥的高山荒漠地区感热最大,年平均感热为42.1 W m^(-2);其次是城市下垫面,其年平均感热为37.7 W m^(-2).研究结果揭示了不同气候背景下典型下垫面地气相互作用特征,为地气相互作用过程深入分析奠定了基础. 展开更多
关键词 能量和水分交换 辐射分量 地表能量通量 青藏高原 长江流域 不同地表类型
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Analysis on the Change Law and Meteorological Factor of Sunshine Duration in Dalian City in Recent 60 Years 被引量:3
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作者 蔡冬梅 《Meteorological and Environmental Research》 CAS 2010年第12期49-51,62,共4页
[Objective] The change law and meteorological factor of sunshine duration in Dalian in recent 60 years were studied.[Method] Based on the statistical data of sunshine duration from base station in Dalian City from 195... [Objective] The change law and meteorological factor of sunshine duration in Dalian in recent 60 years were studied.[Method] Based on the statistical data of sunshine duration from base station in Dalian City from 1951 to 2009,the annual,seasonal,and monthly variation of sunshine duration in recent 60 years were analyzed,as well as its relationship with meteorological factors,and sunshine duration was detected by means of climate mutation theory.[Result] Annual sunshine duration in Dalian in recent 60 years showed decrease trend on the whole,and its climatic variation rate was-3.31 h/a,with larger annual variation,namely the difference between maximum value(1978) and minimum value(2003) reached 681 h;there was obvious seasonal variation in sunshine duration,with the order of autumn>summer>winter>spring,and their climatic variation rate were-1.18,-1.15,-0.91 and-0.62 h/a;except for March,sunshine duration in each month went down,especially October,while there was slight increase in March;sunshine percentage had inverse correlation relationship with total cloudiness,relative humidity and heavy fog days;annual sunshine duration reduced abruptly around 1983.[Conclusion] Our study could provide scientific foundation for the development of agriculture and forestry in Dalian City. 展开更多
关键词 sunshine duration Abrupt change TENDENCY DALIAN China
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Study on the Changes of Precipitation and Sunshine in Shenyang from 1951 to 2009
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作者 康敏 姜晓艳 +1 位作者 杨黎黎 赵凤 《Meteorological and Environmental Research》 CAS 2010年第9期22-24,28,共4页
Based on the data of precipitation in Shenyang from 1951 to 2009,the variation characteristics of precipitation and sunshine hours in Shenyang in recent 59 years were analyzed and studied comprehensively from differen... Based on the data of precipitation in Shenyang from 1951 to 2009,the variation characteristics of precipitation and sunshine hours in Shenyang in recent 59 years were analyzed and studied comprehensively from different time scales of annual,seasonal and monthly,etc..And the relationship between the precipitation and sunshine duration was analyzed.It was concluded that the changes of precipitation between years is big,the distribution of the precipitation among four seasons is uneven,and the overall change trend of the precipitation is in downward from 1951 to 2009.It was also found that the sunshine duration changes are generally in decreased trend. 展开更多
关键词 Precipitation change sunshine duration Shenyang City China
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Study on the Remote Sensing of Surface Albedo in the Horqin Sand Land
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作者 李荣平 张建平 《Meteorological and Environmental Research》 CAS 2010年第3期21-24,28,共5页
The surface albedo which is affected by the earth surface coverage or other surface characteristics is one of the important factors impacting remote sensing image information and therefore it can be calculated by inte... The surface albedo which is affected by the earth surface coverage or other surface characteristics is one of the important factors impacting remote sensing image information and therefore it can be calculated by integrating land coverage types with information of remote sensing images.Horqin sand land which was taken as an experimental area for study on Landsat-TM topography and atmospheric correction,then the Landsat-TM data inversion formula established by Liang was used to calculate the experimental zone albedo map;correlation analysis was performed to the surface albedo map and the land-use maps which was acquired by supervision and classification.The results revealed significant relations between land-use types and the surface albedo of study area.Additionally,the surface albedo and NDVI of the study area were statistically analyzed to obtain the study area's surface albedo and NDVI dependent equation. 展开更多
关键词 Surface albedo Land cover types Distribution characteristics NDVI China
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The relationship between NDVI and precipitation on the Tibetan Plateau 被引量:50
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作者 DING Mingjun ZHANG Yili LIU Linshan ZHANG Wei WANG Zhaofeng BAI Wanqi 《Journal of Geographical Sciences》 SCIE CSCD 2007年第3期259-268,共10页
The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data f... The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to 1999. Monthly maximum NDVI and monthly rainfall were used to analyze the seasonal changes, and annual maximum NDVI, annual effective precipitation and growing season precipitation (from April to August) were used to discuss the interannual changes. The dynamic change of NDVI and the corre- lation coefficients between NDVI and rainfall were computed for each pixel. The results are as follows: (1) The NDVI reached the peak in growing season (from July to September) on the Tibetan Plateau. In the northern and western parts of the plateau, the growing season was very short (about two or three months); but in the southern, vegetation grew almost all the year round. The correlation of monthly maximum NDVI and monthly rainfall varied in different areas. It was weak in the western, northern and southern parts, but strong in the central and eastern parts. (2) The spatial distribution of NDVI interannual dynamic change was different too. The increase areas were mainly distributed in southern Tibet montane shrub-steppe zone western part of western Sichuan-eastern Tibet montane coniferous forest zone, western part of northern slopes of Kunlun montane desert zone and southeastern part of southern slopes of Himalaya montane evergreen broad-leaved forest zone; the decrease areas were mainly distributed in the Qaidam montane desert zone, the western and northern parts of eastern Qinghai-Qilian montane steppe zone, southern Qinghai high cold meadow steppe zone and Ngari montane desert-steppe and desert zone. The spatial distribution of correlation coeffi- cient between annual effective rainfall and annual maximum NDVI was similar to the growing season rainfall and annual maximum NDVI, and there was good relationship between NDVI and rainfall in the meadow and grassland with medium vegetation cover, and the effect of rainfall on vegetation was small in the forest and desert area. 展开更多
关键词 Tibetan Plateau land cover change NDVI PRECIPITATION CORRELATION
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The Summer Snow Cover Anomaly over the Tibetan Plateau and Its Association with Simultaneous Precipitation over the Mei-yu–Baiu region 被引量:15
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作者 LIU Ge WU Renguang +1 位作者 ZHANG Yuanzhi NAN Sulan 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第4期755-764,共10页
The summer snow anomalies over the Tibetan Plateau (TP) and their effects on climate variability are often overlooked,possibly due to the fact that some datasets cannot properly capture summer snow cover over high t... The summer snow anomalies over the Tibetan Plateau (TP) and their effects on climate variability are often overlooked,possibly due to the fact that some datasets cannot properly capture summer snow cover over high terrain.The satellite-derived Equal-Area Scalable Earth grid (EASE-grid) dataset shows that snow still exists in summer in the western part and along the southem flank of the TP.Analysis demonstrates that the summer snow cover area proportion (SCAP) over the TP has a significant positive correlation with simultaneous precipitation over the mei-yu-baiu (MB) region on the interannual time scale.The close relationship between the summer SCAP and summer precipitation over the MB region could not be simply considered as a simultaneous response to the Silk Road pattern and the SST anomalies in the tropical Indian Ocean and tropical central-eastern Pacific.The SCAP anomaly has an independent effect and may directly modulate the land surface heating and,consequently,vertical motion over the western TP,and concurrently induce anomalous vertical motion over the North Indian Ocean via a meridional vertical circulation.Through a zonal vertical circulation over the tropics and a Kelvin wave-type response,anomalous vertical motion over the North Indian Ocean may result in an anomalous high over the western North Pacific and modulate the convective activity in the western Pacific warm pool,which stimulates the East Asia-Pacific (EAP) pattern and eventually affects summer precipitation over the MB region. 展开更多
关键词 snow cover Tibetan Plateau MEI-YU baiu PRECIPITATION
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Trends in sunshine duration and atmospheric visibility in the Yunnan-Guizhou Plateau,1961-2005 被引量:4
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作者 XiaoBo Zheng TianLiang Zhao +2 位作者 YuXiang Luo ChangChun Duan Juan Chen 《Research in Cold and Arid Regions》 2011年第2期179-184,共6页
Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005, the long-term trends in sunshine duration, cloud amount, dry visibility (Vd), dry extinction, and water vapor over... Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005, the long-term trends in sunshine duration, cloud amount, dry visibility (Vd), dry extinction, and water vapor over the YGP are analyzed. The results show that 85% of the stations recorded shortening annual sunshine duration, with the decrease rates between -12.2 and -173.7 h/10yr. Results of Mann-Kendall tests indicate that, among the stations with decreasing sunshine duration, 63.7% of them experienced an abrupt change that started in the 1970s and peaked in the 1980s. This decreasing trend has reversed in the early years of the 21st century. The cloud cover and water vapor content in the mid and lower levels over the YGP had no obvious changes during the study period. The annual averages of Vd declined from 34 km in the 1960s to 27 km at present. The annual mean dry extinction coefficient trended upward, from 0.176 to 0.190, on the YGP from 1980 to 2005. Analyses of cloud cover, water vapor, atmospheric visibility, and dry extinction coefficient revealed that emitted tropospheric aerosols (including air pollutants) resulting from increased energy consumption over the YGP could be a major Factor influencing the reductions of sunshine duration and atmospheric visibility. 展开更多
关键词 Yunnan-Guizhou Plateau climatic change sunshine duration VISIBILITY cloudy cover
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Interannual Variability of Atmospheric Heat Source/ Sink over the Qinghai-Xizang (Tibetan) Plateau and its Relation to Circulation 被引量:26
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作者 赵平 陈隆勋 +1 位作者 Zhao Ping Chen Longxun 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2001年第1期106-116,共11页
Based on the 1961-1995 atmospheric apparent heat source/sink and the 1961-1990 snow-cover days and depth over the Qinghai-Xizang Plateau (QXP) and the 1961-1995 reanalysis data of NCEP/NCAR and the 1975-1994 OLR data,... Based on the 1961-1995 atmospheric apparent heat source/sink and the 1961-1990 snow-cover days and depth over the Qinghai-Xizang Plateau (QXP) and the 1961-1995 reanalysis data of NCEP/NCAR and the 1975-1994 OLR data, this paper discusses the interannual variability of the heat regime and its relation to atmospheric circulation It is shown that the interannual variability is pronounced, with maximal variability in spring and autumn, and the variability is heterogeneous horizontally. In the years with the weak (or strong) winter cold source, the deep trough over East Asia is to the east (or west) of its normal, which corresponds to strong (or weak) winter monsoon in East Asia. In the years with the strong (or weak) sum mer heat source, there exists an anomalous cyclone (or anticyclone) in the middle and lower troposphere over the QXP and ifs neighborhood and anomalous southwest (or northeast) winds over the Yangtze River valley of China, corresponding to strong (or weak) summer monsoon in East Asia. The summer heat source of the QXP is related to the intensity and position of the South Asia high. The QXP snow cover condition of April has a close relation to the heating intensity of summer. There is a remarkable negative correlation between the summer heat source of the QXP and the convection over the southeastern QXP, the Bay of Bengal, the Indo-China Peninsula, the southeastern Asia, the southwest part of China and the lower reaches of the Yangtze River and in the area from the Yellow Sea of China to the Sea of Japan. 展开更多
关键词 Qinghai-Xizang Plateau apparent heat source/sink snow cover OLR
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Spatial pattern of impervious surfaces and their impacts on land surface temperature in Beijing,China 被引量:48
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作者 XIAO Rong-bo OUYANG Zhi-yun +3 位作者 ZHENG Hua LI Wei-feng SCHIENKE Erich W WANG Xiao-ke 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第2期250-256,共7页
Land surface temperature (LST), which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces (IS) spatial ... Land surface temperature (LST), which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces (IS) spatial patterns have on LST in Beijing, China. A classification and regression tree model (CART) was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird. LST was retrieved from the Landsat Thematic Mapper (TM) image to examine the relationships between IS and LST. The results revealed that CART was capable of consistently predicting LST with acceptable accuracy (correlation coefficient of 0.94 and the average error of 8.59%). Spatial patterns of IS exhibited changing gradients across the various urban-rural transects, with LST values showing a concentric shape that increased as you moved from the outskirts towards the downtown areas. Transect analysis also indicated that the changes in both IS and LST patterns were similar at various resolution levels, which suggests a distinct linear relationship between them. Results of correlation analysis further showed that IS tended to be positively correlated with LST, and that the correlation coefficients increased from 0.807 to 0.925 with increases in IS pixel size. The findings identified in this study provide a theoretical basis for improving urban planning efforts to lessen urban temperatures and thus dampen urban heat island effects. 展开更多
关键词 urban heat islands urban land cover normalized difference vegetation index (NDVI) climate mitigation regression tree
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Land cover change along the Qinghai-Tibet Highway and Railway from 1981 to 2001 被引量:15
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作者 DING Mingkun ZHANG Yili +5 位作者 SHEN Zhenx LIU Linshan ZHANG Wei WANG Zhaofeng BAI Wanqi ZHENG Du 《Journal of Geographical Sciences》 SCIE CSCD 2006年第4期387-395,共9页
Based on the NOAA AVHRR-NDVI monthly data from 1981 to 2001, the spatial distribution and dynamic change of land cover along the Qinghai-Tibet Highway and Railway were studied. The results of the analytical data indic... Based on the NOAA AVHRR-NDVI monthly data from 1981 to 2001, the spatial distribution and dynamic change of land cover along the Qinghai-Tibet Highway and Railway were studied. The results of the analytical data indicate that the NDVI values in July, August and September are rather high during a year, and a linear trend by calculating NDVI of each pixel computed based on the average values of NDVI in July, August and September were obtained. The results are as follows: 1) Land cover of the study area by NDVI displays high at two sides of the area and low in the center, and agriculture area 〉 alpine meadow 〉 alpine grassland 〉 desert grassland. 2) In the study area, the amount ofpixels with high increase, slight increase, no change, slight decrease and high decrease account for 0.29%, 14.86%, 67.61%, 16.7% and 0.57% of the whole area, respectively. The increase of land cover pixels is mainly in the agriculture and alpine meadow and the decrease pixels mainly in the alpine grassland, desert grassland and hungriness. Grassland and hungriness contribute to the decrease mostly and artificial land and meadow contribute to the increase mostly. 3) In the area where human beings live, the changing trend is obvious, such as the valleys of Lhasa River and Huangshui River and area along the Yellow River; in the high altitude area with fewer people living, the changing trend is relatively low, like the area of Hoh Xil. 4) Human being's behaviors are a key factor followed by the climate changes affecting land cover. 展开更多
关键词 Tibetan Plateau Qinghai-Tibet Highway Qinghai-Tibet Railway land cover change NDVI
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A Modeling Study of the Effects of Anomalous Snow Cover over the Tibetan Plateau upon the South Asian Summer Monsoon 被引量:10
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作者 刘华强 孙照渤 +1 位作者 王举 闵锦忠 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第6期964-975,共12页
The e?ect of anomalous snow cover over the Tibetan Plateau upon the South Asian summer monsoon is investigated by numerical simulations using the NCAR regional climate model (RegCM2) into which gravity wave ... The e?ect of anomalous snow cover over the Tibetan Plateau upon the South Asian summer monsoon is investigated by numerical simulations using the NCAR regional climate model (RegCM2) into which gravity wave drag has been introduced. The simulations adopt relatively realistic snow mass forcings based on Scanning Multi-channel Microwave Radiometer (SMMR) pentad snow depth data. The physical mechanism and spatial structure of the sensitivity of the South Asian early summer monsoon to snow cover anomaly over the Tibetan Plateau are revealed. The main results are summarized as follows. The heavier than normal snow cover over the Plateau can obviously reduce the shortwave radiation absorbed by surface through the albedo e?ect, which is compensated by weaker upward sensible heat ?ux associated with colder surface temperature, whereas the e?ects of snow melting and evaporation are relatively smaller. The anomalies of surface heat ?uxes can last until June and become unobvious in July. The decrease of the Plateau surface temperature caused by heavier snow cover reaches its maximum value from late April to early May. The atmospheric cooling in the mid-upper troposphere over the Plateau and its surrounding areas is most obvious in May and can keep a fairly strong intensity in June. In contrast, there is warming to the south of the Plateau in the mid-lower troposphere from April to June with a maximum value in May. The heavier snow cover over the Plateau can reduce the intensity of the South Asian summer monsoon and rainfall to some extent, but this in?uence is only obvious in early summer and almost disappears in later stages. 展开更多
关键词 snow cover Tibetan Plateau South Asian monsoon numerical simulation
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The Effects of Anomalous Snow Cover of the Tibetan Plateau on the Surface Heating 被引量:7
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作者 李国平 卢敬华 +1 位作者 靳冰凌 布尼玛 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2001年第6期1207-1214,共8页
On the basis of snow data and AWS (Automatic Weather Station) data obtained from the Tibetan Plateau in recent years (1993 to 1999), the features of sensible heat, latent heat and net long-wave radiations are estimate... On the basis of snow data and AWS (Automatic Weather Station) data obtained from the Tibetan Plateau in recent years (1993 to 1999), the features of sensible heat, latent heat and net long-wave radiations are estimated, and their variations in more-snow year (1997/ 1998) and less-snow year (1996/ 1997) are analyzed comparatively. The relationships between snow cover of the Tibetan Plateau and plateau’s surface heating to the atmospheric heating are also discussed. The difference between more-snow and less-snow year in spring is remarkably larger than that in winter. Therefore, the effect of anomalous snow cover of the Tibetan Plateau in winter on the plateau heating appears more clearly in the following spring of anomalous snow cover. Key words Tibetan Plateau - Snow cover - Effects - Surface heat fluxes This research was supported by the National Key Programme for Developing Basic Sciences G1998040900 (I), National Natural Science Foundation of China (40075018) and Sichuan Youth Science and Technology Fund. 展开更多
关键词 Tibetan Plateau Snow cover EFFECTS Surface heat fluxes
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