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Ecological Regionalization of Suitable Trees, Shrubs and Herbages for Vegetation Restoration in the Farming-Pastoral Zone of Northern China 被引量:5
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作者 康慕谊 董世魁 +3 位作者 黄晓霞 熊敏 陈海 张新时 《Acta Botanica Sinica》 CSCD 2003年第10期1157-1165,共9页
To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-far... To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail. 展开更多
关键词 farming-pastoral zone ecological regionalization suitable species for vegetation restoration northern china
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Changes and spatial patterns of eco-environment in the farming-pastoral region of northern China 被引量:2
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作者 JIANG Weiguo LI Jing +2 位作者 LI Jiahong CHEN Yunhao WU Yongfeng 《Journal of Geographical Sciences》 SCIE CSCD 2005年第3期329-336,共8页
This paper firstly selects 10 kinds of indexes to reflect eco-environment background condition and builds the multi-subject spatial database by using ground meteorological data, remote sensing data and DEM. It then di... This paper firstly selects 10 kinds of indexes to reflect eco-environment background condition and builds the multi-subject spatial database by using ground meteorological data, remote sensing data and DEM. It then discusses in detail the methods about evaluating eco-environment background condition and analyzing eco-environment change. The eco-environment background conditions of 1989 and 1999 are synthetically appraised. Finally, the paper analyzes the spatial distribution, quantitative change, the trend of change, the areas of change and the dynamic spatial pattern of eco-environment. The results are as follows: (1) The eco-environment background condition becomes worse from southeast to northwest in the fanning-pastoral region of northern China. (2) The eco-environment background condition deteriorates from 1989 to 1999. (3) In the adjacent areas of Shanxi-Shaanxi-Inner Mongolia-Gansu-Ningxia, Horqin Sandy Land and its peripheries, and eastern Qinghai orovince, eco-environmental deterioration is very serious. 展开更多
关键词 fanning-pastoral region ECO-ENVIRONMENT spatial pattern northern china
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Study on the growth of wind wave frequency spectra generated by cold waves in the northern East China Sea 被引量:3
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作者 MO Dongxue HOU Yijun +1 位作者 LIU Yahao LI JiaJn 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第5期1509-1526,共18页
The growth of frequency spectra and spectral parameters of wind waves generated by cold waves, a kind of severe weather system, in the northern East China Sea is studied in this paper. Based on a third-generation wave... The growth of frequency spectra and spectral parameters of wind waves generated by cold waves, a kind of severe weather system, in the northern East China Sea is studied in this paper. Based on a third-generation wave action model(the Simulating WAves Nearshore model), simulations were developed to analyze the spatiotemporal characteristics of wind waves and to output spectral data. It is shown that the cold wave-induced spectra can be well described by the modified Joint North Sea Wave Project spectral form. The growth of wave spectra is comprehensively reflected by the evolution of the three characteristic parameters: peak frequency, spectral peak and wave energy. Besides, the approximations of dependences between spectral parameters and the three types of universal induced factors are obtained with the least squares method and compared systematically. Fetch and peak frequency turn out to be suitable parameters to describe the spectral parameters, while the dependences on the inverse wave age vary in different sea areas. In general, the derived relationships improve on results from previous studies for better practical application of the wind wave frequency spectrum in the northern East China Sea. 展开更多
关键词 cold wave frequency spectra wind wave parameters Simulating WAves Nearshore (SWAN) northern East china Sea
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A primary study of nitrous oxide emission in agriculture region of Northern China 被引量:1
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作者 Su Weihan, Song Wenzhi, Zhang Hua, Cao Meiqiu, Lu Hongrong and Zhou QuanResearch Center for Eco-Environmental Sciences,Academia Sinica,Beijing 100083,China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1990年第4期85-94,共10页
Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing ... Significance of nitrous oxide in atmospheric chemistry is reviewed briefly. Background concentration of N2O at Wudaoliang in Qinghai Province of Western China has been measured by collecting gas samples and analysing them with electron capture-gas chromatography. The atmospheric concentration fluctuates in the range of 303-315 ppb with the mean value of 308 ppb. The emission rate of N2O in agriculture region of Northern China has been studied primarily. Fertilization, rain and temperature of soil appear conductible to N2O emission. The interactions between greenhouse effect and N2O emission have been discussed. The catalytic action of N2O in stratospheric ozone depletion processes and the effect of high N2O concentration on ozone depletion in stratosphere have been considered and discussed. 展开更多
关键词 nitrous oxide agriculture region greenhouse effect northern china.
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Striking taxonomic differences in summer zooplankton in the northern South China Sea: implication of an extreme cold anomaly 被引量:2
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作者 LIAN Xiping TAN Yehui +1 位作者 HUANG Liangmin ZHOU Linbin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第10期87-96,共10页
An extreme persistent cold anomaly was prevailing in the South China Sea in February 2008. In order to understand the effect of the cold anomaly on zooplankton community, the zooplankton composition, abundance and bio... An extreme persistent cold anomaly was prevailing in the South China Sea in February 2008. In order to understand the effect of the cold anomaly on zooplankton community, the zooplankton composition, abundance and biomass were analyzed in the northern South China Sea in August 2007 and August 2008. A total of 467 zooplankton species representing 16 groups were identified, with 275 species in August 2007 and 351 in August2008. Copepods were the most dominant zooplankton group in the study area. Compared with 2007, a dramatic decline was observed in the abundance of four dominant copepod species: Subeucalanus subcrassus, Temora discaudata, Nannocalanus minor and Temora turbinata in 2008. Moreover, zooplankton abundance declined from 133.37 ind./m^3 in August 2007 to 75.49 ind./m^3 in August 2008. In contrast, the abundance of medusa, such as Diphyes chamissonis, and tunicate, such as Doliolum denticulatum and Dolioletta gegenbauri, increased during the same season. Cluster analysis showed that there was a difference in zooplankton community structure between the two years. These variations in zooplankton communities were indicative of an anomalous oceanographic condition along with the extreme cold event in 2008. 展开更多
关键词 zooplankton community cold anomaly northern South china Sea
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Cold tolerance of subtropical Porites lutea from the northern South China Sea
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作者 CHEN Tianran LI Shu +1 位作者 SHI Qi CHEN Tegu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第12期58-64,共7页
Marginal scleractinian corals growing at their latitudinal limits should be quite sensitive to variations in winter sea surface temperatures(SSTs). An extreme cold event occurring in early 2008 offered a unique opport... Marginal scleractinian corals growing at their latitudinal limits should be quite sensitive to variations in winter sea surface temperatures(SSTs). An extreme cold event occurring in early 2008 offered a unique opportunity to examine the effect of cold-water anomalies on Porites lutea corals and their physiological tolerance and acclimation in the subtropical northern South China Sea(NSCS). Besides in-situ observation, a subsequent aquarium-based experiment was designed for reproducing the chilling process and a 50-year-long Sr/Ca ratio profile from two P. lutea skeletal slabs was analyzed for reconstructed the historical annual minimum SSTs which ceased Porites calcification. The 2008 low-temperature anomaly caused the minimum daily mean SSTs dropped below 13°C in the Daya Bay. The stress symptoms displayed by local P. lutea colonies included polyp retraction, reduced coloration and pale, but none showed tissue sloughing. The ability of P. lutea to survive implied its tolerance of extreme low temperatures. Here we suggest a model on the tolerance of high-latitude Porites under low-temperature stresses, which is when SSTs drop below 18°C, Porites corals contract their tentacles(losing heterotrophic capability), then cease calcification(reducing energy consumption), and meanwhile maintain relatively high levels of zooxanthellae density(sustaining host’s life via photosynthetic capacity of symbiotic zooxanthellae). This study revealed remarkable acclimatization of P. lutea corals to low temperature extremes. This acclimatization is beneficial for Porites corals in the NSCS to expand their living ranges towards the higher-latitude areas and have the potential to be the incipient reef former. 展开更多
关键词 low-temperature stress cold tolerance subtropical coral Porites lutea northern South china Sea
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Microbial diversity in cold seep sediments from the northern South China Sea 被引量:11
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作者 Yong Zhang Xin Su +5 位作者 Fang Chen Yuanyuan Wang Lu Jiao Hailiang Dong Yongyang Huang Hongchen Jiang 《Geoscience Frontiers》 SCIE CAS 2012年第3期301-316,共16页
South China Sea (SCS) is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, "SONNE" 177 cruise found two cold seep areas ... South China Sea (SCS) is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, "SONNE" 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diver- sity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abun- dance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment (wet weight). The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diver- sity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively. 展开更多
关键词 16S rRNA Microbial diversity cold seep Marine sediments northern South china Sea
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Revisit of event-based rainfall characteristics at Shapotou area in northern China 被引量:2
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作者 XinPing Wang YaFeng Zhang +5 位作者 RuiHu YanXia Pan HaoJie Xu Wei Shi YanXia Jin Hiroshi Yasuda 《Research in Cold and Arid Regions》 CSCD 2016年第6期477-484,共8页
Distribution of rainfall event sizes and interval lengths between events are important characteristics of arid and semi-arid climates. Understanding their importance will contribute to our ability to understand ecosys... Distribution of rainfall event sizes and interval lengths between events are important characteristics of arid and semi-arid climates. Understanding their importance will contribute to our ability to understand ecosystem dynamics in these regions. Rainfall event timing and magnitude are important drivers of ecosystem processes and are instrumental in creating land-scape heterogeneity in arid and semi-arid regions. Rainfall event characteristics were analyzed using an automatic tip-ping-bucket rain-gauge record across the entire summer monsoon season from 2008 to 2015 at the arid desert area of Shapotou in the Tengger Desert, China. Changing the minimum inter-event time (MIT) from 30 min to 24 h alters the number of rainfall events from 64 to 25 for the event depth larger than 0.1 mm. The mean rainfall intensity declined from 0.95 mm/h to 0.53 mm/h, and the geometric mean event duration rose from 0.55 h to 4.4 h. The number of rainfall events, mean rainfall intensity, and geometric mean event duration differed under different criteria of individual rainfall depths, except that for an individual rainfall depth of 0.5, 1.0, and 5.0 mm. The aforementioned features differed only at the lowest range of the mean rainfall intensity and depth for MIT=3 and 6 h. These findings suggest that identification of event-based rainfall in this specific arid region can be better achieved by setting the MIT at six hours. The wide variation in rainfall event properties indicate the need for paying more attention to the proper selection and reporting of event criteria in studies that adopt event-based data analysis. This is especially true in quantifying effective rainfall for soil water replenishment in terms of rainfall depth and intensity with infrequent rainfall events. 展开更多
关键词 arid and semi-arid regions desert ecosystems rainfall event Shapotou area in northern china
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Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China 被引量:38
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作者 方精云 宋永昌 +1 位作者 刘鸿雁 朴世龙 《Acta Botanica Sinica》 CSCD 2002年第9期1105-1122,共18页
Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundat... Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes. 展开更多
关键词 china dynamic vegetation regionalization arid/humid climate northern limit of subtropical zone Qinling Mountain_Huaihe River line thermal climate vegetation_climate relationship vegetation regionalization vegetation zone
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Cold-region environments along the China-Russia Crude Oil Pipeline and their management 被引量:1
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作者 RuiXia He HuiJun Jin +1 位作者 LanZhi L(U) ShaoLing Wang 《Research in Cold and Arid Regions》 2010年第2期129-136,共8页
The cold-region eco-environments along the China-Russia Crude Oil Pipeline (CRCOP) in northern Northeast China are in disequilibrium due to the combined influences of pronounced climate warming and intensive anthropog... The cold-region eco-environments along the China-Russia Crude Oil Pipeline (CRCOP) in northern Northeast China are in disequilibrium due to the combined influences of pronounced climate warming and intensive anthropogenic activities.This is evidenced by the sharp areal reduction and northward shifting of the boreal forests,shrinking of wetlands,enhancing of soil erosion,accelerating degradation of permafrost and deteriorating of cold-region eco-environments.The degradation of permafrost plays an important role as an internal drive in the eco-environmental changes.Many components of the cold-region eco-environments,including frozen ground,forests,wetlands and peatlands,forest fires and 'heating island effect' of rapid urbanization,are interdependent,interactive,and integrated in the boreal ecosystems.The construction and long-term operation of the CRCOP system will inevitably disturb the cold-region environments along the pipeline.Therefore,a mandatory and carefully-elaborated environ-mental impact statement is indispensable for the proper mitigation of the ensued adverse impacts.Proper management,effective protection and practical rehabilitation of the damaged cold-region environments are a daunting,costly and long-term commitment.The recommended measures for protection and restoration of permafrost eco-environments along the pipeline route include adequate investigation,assessment and monitoring of permafrost and cold-region environments,compliance of pipeline construction and operation codes for environmental management,proper and timely re-vegetation,returning the cultivated lands to forests and grasslands,and effective mitigation of forest fire hazards. 展开更多
关键词 china-Russia Crude Oil Pipeline permafrost degradation cold-region eco-environments REHABILITATION
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Pathogenesis and preventive measures of environment-related cardiovascular disease in northern China
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作者 Yukai Cao Xuejie Han +3 位作者 Xinbo Zhao Jiuxu Kan Yue Yuan Yue Li 《Frigid Zone Medicine》 2022年第3期140-148,共9页
Cardiovascular diseases(CVDs)have been the top-ranked cause of human death in the world for years,according to the World Health Organization.Accumulating evidence from epidemiological data supports the view that the r... Cardiovascular diseases(CVDs)have been the top-ranked cause of human death in the world for years,according to the World Health Organization.Accumulating evidence from epidemiological data supports the view that the risk of CVDs is higher in northern China than in southern area.There is no doubt that living environment has become a crucial factor contributing to the occurrence and progression of CVDs in northern region.However,there have not been any clinical guidelines for the prevention strategy of environment-related CVDs,especially for cold exposure.Thus,there is an urgent need for better understanding of the clinical characteristics and underlying mechanisms of cold-induced CVDs in order to formulate and implement proper and effective measures for minimizing the risk of CVDs for people residing in low-temperature area.Cold exposure,air pollution,lack of sunlight and irrational diet are believed to be crucial factors responsible for environment-related CVDs,and preventive measures might be carried out accordingly to decrease the high risk of CVDs in northern China. 展开更多
关键词 cold environment cardiovascular disease northern china
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Bilateral and Regional Strategic and Security Relationship Between China and the US after the Cold War
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作者 楚树龙 《Contemporary International Relations》 2000年第5期1-13,共13页
Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship bet... Sino-US relations are complex relations with multi-aspects between the two bigcountries in the world. It has three levels: the global level, the Asia-Pacificlevel and the bilateral level. The critical relationship between China and the US isembodied in the regional and bilateral levels that are more specific and essential.Beyond the field of economy and trade, their relationship is mainly embodied in thestrategic and security field. 展开更多
关键词 US Bilateral and regional Strategic and Security Relationship Between china and the US after the cold War SECURITY
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The circulation in the southern Huanghai Sea and northern East China Sea in June 1999 被引量:2
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作者 Arata Kaneko Noriaki Gohda 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2003年第3期321-332,共12页
On the basis of hydrographic data and current measurement (the mooring system, vessel-mounted ADCP and toward ADCP) data obtained in June 1999, the circulations in the southern Huanghai Sea (HS) and northern East Chin... On the basis of hydrographic data and current measurement (the mooring system, vessel-mounted ADCP and toward ADCP) data obtained in June 1999, the circulations in the southern Huanghai Sea (HS) and northern East China Sea (ECS) are computed by using the modified inverse method. The Kuroshio flows northeastward through eastern part of the investigated region and has the main core at Section PN, a northward flow at the easternmost part of Section PN, a weaker anti-cyclonic eddy between these two northward flows, and a weak cyclonic eddy at the western part of Section PN. The above current structure is one type of the current structures at Section PN in ECS. The net northward volume transport (VT) of the Kuroshio and the offshore branch of Taiwan Warm Current (TWCOB) through Section PN is about 26.2 x 10(6) m(3)/s in June 1999. The VT of the inshore branch of Taiwan Warm Current (TWCIB) through the investigated region is about 0.4 x 10(6) m(3)/s. The Taiwan Warm Current (TWC) has much effect on the currents over the continental shelf. The Huanghai Sea Coastal Current (HSCC) flows southeastward and enters into the northwestern part of investigated region, and flows to turn cyclonically, and then it flows northeastward, due to the influences of the Taiwan Warm Current and topography. There is a cyclonic eddy south of Cheju Island where the Huanghai Sea Coastal Current flows to turn cyclonically. It has the feature of high dense and cold water. The uniform and cold water is occurred in the layer from about 30 m level to the bottom between Stations C306 and C311 at the northernmost Section C3. It is a southern part of the Huanghai Sea Cold Water Mass (HSCWM). 展开更多
关键词 Southern Huanghai Sea and northern East china Sea current structure of the Kuroshio Taiwan Warm Current and Huanghai Sea Coastal Current high dense and cold water masses
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An analysis of oasis stability in arid areas:a case study in the northern slope areas of the Tianshan Mountains 被引量:2
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作者 Luo, GePing Lu, Lei +1 位作者 Yin, ChangYing Feng, YiXing 《Journal of Arid Land》 SCIE 2009年第1期49-56,共8页
This paper discusses oasis stability at regional scale with a case study in the northern slope areas of the Tianshan Mountains (NSTM). The results showed certain significant aspects. (1) As long as water resources in ... This paper discusses oasis stability at regional scale with a case study in the northern slope areas of the Tianshan Mountains (NSTM). The results showed certain significant aspects. (1) As long as water resources in the oasis keep stable and their utilization efficiency can be maintained or gradually increased, the primary productivity could be continuously increased and the natural primary productivity keeped relatively stable. In this case, it is considered that the oasis is stable and its sustainable development can be achieved at regional scale. (2) Considering the availability of water resources in the oases, the oases on the alluvial-diluvial fans are highly stable. In the alluvial plain downstream of the groundwater overflowing zones the oases are moderately stable and in the lacustrine deltas or dry lacustrine deltas the oases are lowly stable. (3) Enlargement of oases and the increase of water resources and vegetation coverage in the oasis will certainly enhance the 'cold-island effect' of the oasis and increase the stability of oases. 展开更多
关键词 oasis stability regional scale geographical location 'cold-island effect' the northern slope areas of the Tianshan Mountains
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Abiotic and biotic drivers of species diversity in understory layers of cold temperate coniferous forests in North China 被引量:10
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作者 Hui Wang Mengtao Zhang Hongwei Nan 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第6期2213-2225,共13页
Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures,function realization,and community succession.However,little is known about how abiotic and bi... Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures,function realization,and community succession.However,little is known about how abiotic and biotic drivers affect the diversity of understory species in cold temperate coniferous forests in the semiarid climate region of North China.We hypothesized that(1)topographic factors are important environmental factors affecting the distribution and variation of understory strata,and(2)different understory strata respond differently to environmental factors;shrubs may be significantly affected by the overstory stratum,and herbs may be more affected by surface soil conditions.To test these hypotheses,we used the boosted regression tree method to analyze abiotic and biotic environmental factors that influence understory species diversity,using data from 280 subplots across 56 sites in cold temperate coniferous forests of North China.Elevation and slope aspect were the dominant and indirect abiotic drivers affecting understory species diversity,and individual tree size inequality(DBH variation)was the dominant biotic driver of understory species diversity;soil water content was the main edaphic factors affecting herb layers.Elevation,slope aspect,and DBH variation accounted for 36.4,14.5,and 12.1%,respectively,of shrub stratum diversity.Shrub diversity decreased with elevation within the range of altitude of this study,but increased with DBH variation;shrub diversity was highest on north-oriented slopes.The strongest factor affecting herb stratum species diversity was slope aspect,accounting for 25.9%of the diversity,followed by elevation(15.7%),slope(12.2%),and soil water content(10.3%).The highest herb diversity was found on southeast-oriented slopes and the lowest on northeast-oriented slopes;herb diversity decreased with elevation and soil water content,but increased with slope.The results of the study provide a reference for scientific management and biodiversity protection in cold temperate coniferous forests of North China. 展开更多
关键词 ABIOTIC and biotic DRIVERS cold TEMPERATE CONIFEROUS forests North china SEMI-ARID region UNDERSTORY species diversity
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Research progress in cold region wetlands, China 被引量:2
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作者 YaYi Tan Xuan Wang ZhiFeng Yang YuLi Wang 《Research in Cold and Arid Regions》 2011年第5期441-447,共7页
China has some of the most abundant wetland resources in the world. Cold region wetlands cover more than 60% of the total natural wetlands in China and play an indispensable role in global climate regulation, water ho... China has some of the most abundant wetland resources in the world. Cold region wetlands cover more than 60% of the total natural wetlands in China and play an indispensable role in global climate regulation, water holding, uptake and emission of greenhouse gases, and biodiversity conservation. Because cold region wetlands are sensitive to climatic and environmental changes, it is important for ecological conservation and environmental management to summarize and analyze current research progress on these specific ecosystems. This paper reviews the focus of present studies on the typical cold region wetlands in the northeast region and the Qinghai-Tibet Plateau of China from several aspects as follows: types and distribution, responses of permafrost to climatic changes, uptake and emission of greenhouse gas, eco-hydrological processes, and vegetation succession. Our conclusions are: global wanning has a long-term and serious impact on cold region permafrost; emission of greenhouse gases has great temporal and spatial heterogeneity; and hygrophytes in the cold region wetlands have been generally replaced by xerophytes, although it is still unclear whether the vegetation diversity index has increased or decreased. Based on this review, some key topics for future study are recommended as follows: (1) the response of degeneration of cold region permafrost at various spatial and temporal scales; (2) prediction of wetland degeneration tendency by coupling weather, soil, and hydrological models; (3) evaluation of carbon storage; (4) the actual response mechanisms of greenhouse gases to climatic changes; and (5) development of water requirement calculation methods tailored to the unique ecosystems of cold region wetlands. 展开更多
关键词 cold region wetlands china PROGRESS REVIEW
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Land pressure and adaptation in the mountainous region of northern China: An empirical analysis of 21 small watersheds 被引量:1
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作者 ZHU Huiyi HE Shujin 《Journal of Geographical Sciences》 SCIE CSCD 2010年第6期913-922,共10页
Land pressure and adaptation are the main factors determining environmental degradation in most of China's mountainous regions. Little attention so far has been paid to the adaptation strategies based on evaluation o... Land pressure and adaptation are the main factors determining environmental degradation in most of China's mountainous regions. Little attention so far has been paid to the adaptation strategies based on evaluation of land pressure in these regions. We evaluated the grain production pressure and economic development pressure for 21 small watersheds undergoing soil conservation measures in the northern mountainous region of China, compared the evaluation results with actual production for each of the watersheds, and analyzed the adaptation strategies. The results imply that land pressure was spatially heterogeneous among the sample watersheds, but there was a balancing trend between land pressure and productive capacity for each watershed. Under rising pressure, these watersheds developed a variety of adaptation strategies such as labor migration, increasing fruit and nut production, and expanding rural tourism if possible. These strategies result from evolution of the market economy in China, and persistent development of the national economy determines the variation of environment in these mountainous regions. 展开更多
关键词 land pressure ADAPTATION environment restoration mountainous region northern china
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Calcium isotope fractionation and its controlling factors over authigenic carbonates in the cold seeps of the northern South China Sea 被引量:4
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作者 WANG ShuHong YAN Wen +3 位作者 MAGALHAES H Vitor CHEN Zhong PINHEIRO M Luis GUSSONE Nikolaus 《Chinese Science Bulletin》 SCIE CAS 2012年第11期1325-1332,共8页
In this study, we analyzed stable calcium isotope results of authigenic carbonates from two cold seep areas of the Dongsha area and the Baiyun Sag in the northern South China Sea. The stable isotopes of carbon and oxy... In this study, we analyzed stable calcium isotope results of authigenic carbonates from two cold seep areas of the Dongsha area and the Baiyun Sag in the northern South China Sea. The stable isotopes of carbon and oxygen as well as the mineral composition of authigenic carbonates were used to investigate control calcium isotope fractionation. The δ44/40Ca ratios of the southwestern Dongsha area samples ranged from 1.21‰ to 1.52‰ and the ratio of the Baiyun Sag sample was 1.55‰ of the SRM915a isotope standard. X-ray diffraction analysis showed that the carbonate samples consisted of dolomite, calcite and aragonite, with small amounts of high-Mg calcite and siderite. The δ13C values of the carbonates of the southwestern Dongsha area varied between δ49.21‰ and δ16.86‰ of the Vienna PeeDee Belemnite (VPDB) standard and the δ18O values ranged from 2.25‰ to 3.72‰ VPDB. The δ13C value of the Baiyun Sag sample was 2.36‰ VPDB and the δ18O value was 0.44‰ VPDB. The δ13C values of the carbonates of the southwestern Dongsha area revealed there is methane seeping into this area, with a variable contribution of methane-derived carbon. The sampled carbonates covered a range of δ13C values suggesting a dominant methane carbon source for the light samples and mixtures of δ13C values for the heavier samples, with possibly an organic or seawater carbon source. The δ18O values indicated that there is enrichment in 18O, which is related to the larger oxygen isotope fractionation in dolomite compared to calcite. The results of the Baiyun Sag sample exhibited normal seawater carbon and oxygen isotopic values, indicating that this sample is not related to methane seepage but instead to precipitation from seawater. The relatively high δ44/40Ca values indicated either precipitation at comparatively high rates in pore-water regimes with high alkalinity, or precipitation from an evolved heavy fluid with high degrees of Ca consumption (Raleigh type fractionation). The dolomite samples from the Dongsha area revealed a clear correlation between the carbon and calcium isotope composition, indicating a link between the amount and/or rate of carbonate precipitation and methane contribution to the bicarbonate source. The results of the three stable isotope systems, mineralogy and petrography, show that mineral composition, the geochemical environment of authigenic carbonates and carbon source can control the calcium isotope fractionation. 展开更多
关键词 氧同位素分馏 碳酸盐岩 控制因素 南海北部 冷泉 中国 碳稳定同位素 X射线衍射分析
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玉米秸秆堆腐还田对黑土区土壤性状的影响 被引量:1
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作者 原韬 安琦 +4 位作者 牛彦波 孟利强 吴皓琼 樊川 曹亚彬 《中国农学通报》 2024年第5期47-52,共6页
本研究针对东北地区秋冬季节气候寒冷特点和秸秆堆腐还田的实际操作需求,开展秸秆堆腐还田试验。在秋季玉米收获之后进行田间堆腐试验,期间连续监测环境温度、降水、秸秆堆温度、秸秆失重率等指标。离田玉米秸秆经过腐熟后作为肥料还田... 本研究针对东北地区秋冬季节气候寒冷特点和秸秆堆腐还田的实际操作需求,开展秸秆堆腐还田试验。在秋季玉米收获之后进行田间堆腐试验,期间连续监测环境温度、降水、秸秆堆温度、秸秆失重率等指标。离田玉米秸秆经过腐熟后作为肥料还田,连续施用3年,检测土壤有机质、碱解氮、速效磷、速效钾、土壤孔隙度、土壤容重等指标。在基本农田和棚室保护地进行为期2年的应用试验。结果表明:120 d秸秆失重率达到31.53%。施用腐熟秸秆3年,土壤有机质提高了4.06~6.31 g/kg、土壤中碱解氮提高了15.08~27.35 mg/kg、速效磷提高了18.11~21.95 mg/kg、速效钾提高63.97~89.93 mg/kg;土壤容重降低了0.10~0.14 g/cm^(3)、土壤田间持水量提高了7.51%~9.24%(V/V)、土壤孔隙度提高了3.69%~5.27%(V/V),且差异显著(P≤0.05)。基本农田和棚室保护地应用试验中,速效养分与有机质有所增长,土壤容重与田间持水量变化显著。逐年施用腐熟秸秆对于提高土壤有机质含量、速效养分具有显著作用。同时,施用腐熟秸秆能够降低土壤容重,提高土壤孔隙度与田间持水量,改善土壤板结问题。腐熟秸秆在改良与保育黑土性质方面具有良好的作用。 展开更多
关键词 玉米秸秆 堆腐 北方寒地 还田 黑土保护 土壤性状
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1980—2016年中国北方风蚀气候侵蚀力的变化
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作者 刘伟 邹学勇 +2 位作者 刘博 王汝幸 王祖正 《地理科学》 CSSCI CSCD 北大核心 2024年第4期703-710,共8页
随着修订风蚀方程(RWEQ)的提出,采用增加了冻结因子的气候因子(WF)表达风蚀气候侵蚀力更具有科学性和必要性。基于中国北方风蚀区157个气象站1980—2016年的观测数据,逐月计算了各站点气候因子,并探讨了气候因子时空分布变化特征及影响... 随着修订风蚀方程(RWEQ)的提出,采用增加了冻结因子的气候因子(WF)表达风蚀气候侵蚀力更具有科学性和必要性。基于中国北方风蚀区157个气象站1980—2016年的观测数据,逐月计算了各站点气候因子,并探讨了气候因子时空分布变化特征及影响因素。结果表明:①1980—1997年,年气候因子值表现为快速下降,从940.46 kg/m下降到273.03 kg/m;而1998—2016年,年气候因子值表现相对稳定,在139.81~398.85 kg/m范围内波动。②春季气候因子值约占全年63%,其变化也显著高于其它季节,这也是土壤风蚀发生在春季的主要原因。③气候因子的高值区分布在新疆东部、青海西部、40°N以北的内蒙古中西部,这与气压中心和高大山体地形分布有关。 展开更多
关键词 气候因子 土壤风蚀 全球变暖 北方风蚀区
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