期刊文献+
共找到17篇文章
< 1 >
每页显示 20 50 100
青藏高原拉萨地块西部亚热南复式岩体年代学与地球化学 被引量:2
1
作者 于枫 侯增谦 +2 位作者 赵志丹 郑远川 段连峰 《岩石学报》 SCIE EI CAS CSCD 北大核心 2015年第5期1235-1246,共12页
青藏高原拉萨地块发育着中新世斑岩,该后碰撞时期的斑岩因与斑岩型Cu-Mo矿床有着密切关系已被前人做过大量研究。然而对于拉萨地块西部未成矿斑岩岩体的年代学、地球化学报道研究较少。本文对拉萨地块西部亚热南复式岩体识别出的两类侵... 青藏高原拉萨地块发育着中新世斑岩,该后碰撞时期的斑岩因与斑岩型Cu-Mo矿床有着密切关系已被前人做过大量研究。然而对于拉萨地块西部未成矿斑岩岩体的年代学、地球化学报道研究较少。本文对拉萨地块西部亚热南复式岩体识别出的两类侵入岩进行了锆石LA-ICP-MS U-Pb定年和岩石地球化学研究表明,亚热南复式岩体主要由始新世黑云母二长花岗岩(年龄49.4±0.9Ma)和中新世花岗斑岩(年龄16.3~16.5Ma)组成。始新世黑云母二长花岗岩属钾玄岩系列准铝质-弱过铝质,具有低的Sr/Y、(La/Yb)N值高Y、YbN值具有典型的岛弧岩浆岩性质;中新世花岗斑岩为钾玄岩系列、准铝质,具有类埃达克质特征。这两种岩性所反映的源区亦存在差别,始新世黑云母二长花岗岩源区为地幔楔混染过的中下地壳;而具有埃达克性质的花岗斑岩则可能是源于古老地壳部分熔融。结合年代学及构造背景,推论出始新世黑云母二长花岗岩的岩石成因为新特提斯洋板片断离引发混染过的中下地壳发生熔融并结晶分异形成;而中新世花岗斑岩则形成于某种动力学机制引发的古老下地壳熔融后侵位于上地壳。 展开更多
关键词 锆石U-Pb年龄 地球化学 中新世斑岩 亚热南 拉萨地块 青藏高原
下载PDF
Seed Germination and Storage of Woody Species in the Lower Subtropical Forest 被引量:5
2
作者 陈章和 彭姣凤 +1 位作者 张德明 赵建刚 《Acta Botanica Sinica》 CSCD 2002年第12期1469-1476,共8页
The dimension, water content and germination of the seeds from 90 woody species in the lower subtropical forest were analyzed in this study. Out of 90 species, germination analysis was performed in 45 species (in whic... The dimension, water content and germination of the seeds from 90 woody species in the lower subtropical forest were analyzed in this study. Out of 90 species, germination analysis was performed in 45 species (in which there were enough germinating individuals), and the effect of storage of seed and fruit on germination of seed was studied in 41 species (in which there were enough seeds and germinating individuals). Most of the species began to germinate within 60 d. Hypogeal species had longer dormancy than epigeal species. Dormancy of fleshy seeds and seeds in pulpy fruit was also longer than that of dry seeds. There were no significant differences in length of dormancy (LD, days from sowing to germination) between fleshy seeds ripening in summer and those ripening in winter and spring, and between big seeds and small seeds. Seeds in pulpy fruit or fleshy seeds had more germination than the dry seeds ( P <0.05), however, percentage germination was not significantly correlated with water content of fresh seeds. Water loss in the seeds could obviously affect percentage germination, especially during the early three days when the seeds were laid open in air in the laboratory. When water content of the seeds decreased to about 20% (fresh weight basis), percentage germination became very low, this happened when the seeds were laid open in air for 10-14 d. Percentage germination decreased with the length of storing in refrigerator ((4±1) ℃), but it was not markedly affected for one month's storage, with a decrease by 8.3% in comparison with the fresh seeds, and it was greatly affected by storing for more than three months, with values decreasing by 37%, 63%, and 81% for three months', six months' and 12 months' storage respectively. Difference in percentage germination as well as in LD was not significant for most lots after different storing periods between big seeds and small seeds, between fruit storage and seed storage, and between seeds in pulpy fruits or fleshy seeds and dry seeds. 展开更多
关键词 woody species fruit and seed GERMINATION STORAGE lower subtropical forest
下载PDF
A Study of Fructification Quantitative Characteristics of Spartina alterniflora Lossel in Mangroves 被引量:7
3
作者 覃盈盈 梁士楚 《Agricultural Science & Technology》 CAS 2009年第1期101-104,共4页
[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflo... [Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflora in Mangroves conservation zone located at Hepu of Guangxi being taken as experimental material, its morphological and quantitative characteristics, as well as the weight of 100 full seeds at maturity stage in three different growth conditions( clay, loam and sand) were studied. [ Results] The results showed that Spartina alterniflora had the best growth pattern in the loam. The morphological factors of fructification of S. altemiflora grown in sand were larger then in others. In the three growth conditions the order of quantitative characteristics of fructification of S. alterniflora was clay 〉 sand 〉 loam and the seeds in spikelet at top position were more maturity than those at the button position. [ Conclusion] In good condition, the Spartina altemiflora growth was vigor but the ratio of seed-setting was low. 展开更多
关键词 Spartina altemiflora Different habitat FRUCTIFICATION Quantitative characteristics
下载PDF
Polycyclic Aromatic Hydrocarbons in Agricultural Soils of the Southern Subtropics,China 被引量:5
4
作者 HAO Rong WAN Hong-Fu +2 位作者 SONG Yan-Tun JIANG Hong PENG Shao-Lin 《Pedosphere》 SCIE CAS CSCD 2007年第5期673-680,共8页
The contributions of persistent organic pollutants (POPs) from the subtropical regions of China to pollution of the global environment have been paid great attention; however, little is known about the state of POPs... The contributions of persistent organic pollutants (POPs) from the subtropical regions of China to pollution of the global environment have been paid great attention; however, little is known about the state of POPs in agricultural ecosystems within these regions of China. This study primarily revealed the state of the contamination and distribution of polycyclic aromatic hydrocarbons (PAH) in agricultural soils in the subtropical regions. 115 surface soils (0-20 cm) were sampled in the breadbaskets of these regions. The concentrations and types of PAH were determined using gas chromatography linked to mass spectrometry (GC-MS). The total PAH concentrations ranged from 22.1 to 1 256.9 ng g^-1 with a mean of 318.2 ± 148.2 ng g^-1. In general terms, the current PAH concentrations were lower than most PAH levels reported in a number of investigations from different countries and regions. PAH isomer ratios indicated that pyrolytic origins, such as fossil fuel combustion related to vehicle tail gas and industrial emissions, were the dominant sources of PAH in the southern subtropical areas of China. Although PAH concentrations decreased with decreasing pollution, population, and traffic density, to a great extent PAH compositions were similar throughout subtropical soils, with naphthalene, phenanthrene, fluoranthene, and benzo(b)fluoranthene being dominant. 展开更多
关键词 agricultural soils polycyclic aromatic hydrocarbons subtropical region
下载PDF
THE SOUTH CHINA SEA SUMMER MONSOON AND THE SEASONAL MODALITY AND WEST EXTENDING OF THE NORTHERN HEMISPHERE PACIFIC SUBTROPICAL HIGH 被引量:1
5
作者 张韧 何金海 +1 位作者 董兆俊 余丹丹 《Journal of Tropical Meteorology》 SCIE 2003年第2期181-190,共10页
Based on the 4-layer dbl wavelet packet and shannon entropy decomposition /reconstruction method and the NCEP/NCAR daily reanalysis data set, the correlation between the South China Sea summer monsoon and the Northern... Based on the 4-layer dbl wavelet packet and shannon entropy decomposition /reconstruction method and the NCEP/NCAR daily reanalysis data set, the correlation between the South China Sea summer monsoon and the Northern Hemisphere Pacific subtropical high seasonal modality/shift xvas studied and discussed, and a corresponding summer monsoon frequency-band energy criterion was defined and introduced for diagnosing the Pacific subtropical high’s modality/shift. A few new phenomena and correlation between the South China Sea summer monsoon and the Northern Hemisphere Pacific subtropical high were also revealed and presented. 展开更多
关键词 Pacific subtropical high South China Sea summer monsoon wavelet packet frequency-band energy Criterion
下载PDF
Thermal contrast between the Tibetan Plateau and tropical Indian Ocean and its relationship to the South Asian summer monsoon 被引量:3
6
作者 Zhangqun Li Ziniu Xiao 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第1期7-13,共7页
The land-sea thermal contrast is an important driver for monsoon interannual variability and the monsoon onset.The thermal contrast between the Tibetan Plateau and the tropical Indian Ocean at the mid-upper tropospher... The land-sea thermal contrast is an important driver for monsoon interannual variability and the monsoon onset.The thermal contrast between the Tibetan Plateau and the tropical Indian Ocean at the mid-upper troposphere is proposed as a thermal contrast index(TCI)for South Asian monsoon.The authors investigate the TCI associated with South Asian summer monsoon(SASM)intensity and SASM onset.It is observed that the TCI considering the Tibetan Plateau and tropical Indian Ocean demonstrates a stronger and closer correlation with SASM intensity(0.87)than either the Tibetan Plateau(0.42)or tropical Indian Ocean(-0.60)singly.It is implied that the TCI could preferably represent the impact of land-sea thermal condition on SASM activity.Further analysis reveals that the evolution of TCI is related to the SASM onset.The TCI is almost always larger in early onset years than it is in late onset years during the period before SASM onset.In addition,the change of the pentad-by-pentad increment of TCI leads the SASM variation.The correlation coefficient between the TCI increment and SASM index reaches a maximum when the TCI increment leads by 15 pentads.The results of this study show that the TCI plays an important role in SASM activities and is a potential indicator for SASM onset forecasting. 展开更多
关键词 Tibetan Plateau Indian Ocean Thermal contrast South Asian summer monsoon Monsoon onset
下载PDF
A DISCUSSION ON BIOGEOGRAPHICAL LINES OF THE TROPICAL SUBTROPICAL YUNNAN 被引量:6
7
作者 ZHUHua YANLi-chun 《Chinese Geographical Science》 SCIE CSCD 2002年第1期90-96,共7页
Based on comparative studies on four regional floras from northwest, west, south and southeast of Yunnan respectively, the formerly suggested two biogeographical lines, i.e. the “Tanaka Line" and the “Ecogeogra... Based on comparative studies on four regional floras from northwest, west, south and southeast of Yunnan respectively, the formerly suggested two biogeographical lines, i.e. the “Tanaka Line" and the “Ecogeographical Diagonal Line", both going from northwest to southeast of Yunnan, and their significance are discussed. In family and generic levels, similarity coefficients among the four compared floras are more than 93% and 60% separately, which indicate the close floristic affinities among them. The highest similarity coefficient, i.e. 98.7% in family level and 78.6% in generic level separately, is found between the regional flora of northwest Yunnan and the flora of southeast Yunnan although these two regions are the most distant away each other among the compared regional floras. The flora of northwest Yunnan is also the most similar to the flora of southeast Yunnan in floristic composition. These support the idea of “Ecogeographical Diagonal Line". In specific level, the relatively high similarity coefficient is between the regional flora of west Yunnan and the one of south Yunnan. The floristic affinities among these regional floras and some distribution patterns could be explained by the geological history and tectonic theory of Yunnan. 展开更多
关键词 biogeographical lines floristic affinity YUNNAN
下载PDF
Goethite Morphologies of Some Soils in South of Central China 被引量:2
8
作者 LIUFAN XUFENG-LIN 等 《Pedosphere》 SCIE CAS CSCD 1994年第3期193-200,共8页
The morphologies of goethites in latosol, red soils, yellow-brown soil and the paddy soils developed from red soils were studied in comparison with the morphology of synthetic goethite by means of the X-ray distractio... The morphologies of goethites in latosol, red soils, yellow-brown soil and the paddy soils developed from red soils were studied in comparison with the morphology of synthetic goethite by means of the X-ray distraction, transmission electron microscopy and energy dispersive X-ray analysis. The synthetic goethite displayed acicular particles elongated in the c-direction. The goethites in the latosol, red soils and yellowbrown soil were platy particles stretched in two directions or isodimensional particles, and those in the paddy soils from red soils were acicular, short columnar, platy or isodimensional particles. Various morphologies of the goethites probably suggested their different dominant crystal faces, surface charge distribution and surface adsorption characteristics. 展开更多
关键词 goethites MORPHOLOGY SOILS surface adsorption surface charge
下载PDF
Influences of tropical circulation and sea surface temperature anomalies on extreme heat over Northeast Asia in the midsummer of 2018 被引量:2
9
作者 CHEN Ruidan WEN Zhiping LU Riyu 《Atmospheric and Oceanic Science Letters》 CSCD 2019年第4期238-245,共8页
A destructive extreme heat attacked Northeast Asia(NEA)in the midsummer of 2018,characterized by the average midsummer Tmax(daily maximum air temperature at 2 m)ranking first during the study period.The current study ... A destructive extreme heat attacked Northeast Asia(NEA)in the midsummer of 2018,characterized by the average midsummer Tmax(daily maximum air temperature at 2 m)ranking first during the study period.The current study indicates that the cyclonic anomaly over the western North Pacific(WNP)was an important cause,which presents an anomaly of two standard deviations.The cyclonic anomaly over the WNP was accompanied by anomalous convection,which favored descending and anticyclonic anomalies over NEA through a local meridional cell.The anticyclonic anomaly over NEA corresponds to the northwestward extension of the WNP subtropical high and facilitated the occurrence of extreme heat.The tropical sea surface temperature anomaly(SSTA)presents a La Ni?a decaying episode,but the SSTA over the tropical Pacific and North Indian Ocean was weak in the summer.In contrast,the southeastern tropical Indian Ocean(SETIO)was obviously cool,which was the coolest after detrending.The SETIO cooling triggered a low-level southeasterly anomaly,which turned into a southwesterly after crossing the equator,due to the Coriolis force.The southwesterly anomaly extended eastwards and favored the cyclonic anomaly over the WNP.Meanwhile,the circulation anomalies over the SETIO and WNP were connected via a local meridional cell,with the ascending branch over the WNP.Moreover,the above mechanism also operates for the climate statistics,verifying the robust in?uence of the SETIO SSTA.Considering the consistency of the SETIO SSTA,it could be a potential predictor for the climate over the WNP and NEA. 展开更多
关键词 Extreme heat Northeast Asia tropical circulation southeastern tropical Indian Ocean
下载PDF
Phosphate Adsorption and Surface Charge Characteristics and Their Relations to Mineralogy of Some Soils from Southern China
10
作者 ZHANG MINGKUI M. J. WILSON +1 位作者 HE ZHENLI L. CLARK and D. M. L. DUTHIE (Department of Soil Science and Agricultural Chemistry, Zhejiang Agricultural University, Hanyzhou 310029 China) (Soils and Soil Microbiolopy Division, Macaulay Land Use Research Institu 《Pedosphere》 SCIE CAS CSCD 1998年第4期297-304,共8页
The phosphate adsorption and surface charge characteristics of the tropical and subtropical soils derived from different parent materials in China were determined, and their relations to soil mineralogy were analysed.... The phosphate adsorption and surface charge characteristics of the tropical and subtropical soils derived from different parent materials in China were determined, and their relations to soil mineralogy were analysed.The results showed that all soil phosphate adsorption curves were well fitted by Freundlich equation and Langmuir equation. The maximum buffering capacity of P ranged from 66 to 9880 mg kg-1, with an increasing order of purple soil, skeletal soil, red soil, lateritic red soil, yellow soil and latosol; and the highest value was 149 times the lowest value, which indicated great differences among these soils in phosphate adsorption and supplying characteristics. The pHo (zero point of charge) values obtained by salt titrationpotential titration varied from 3.03 to 5.49, and the highest value was found in the latosol derived from basalt whereas the lowest value was found in the purple soil. The correlation analysis indicated that the main minerals responsible for phosphate adsorption in the soils were gibbsite, amorphous iron oxide and kaolinite; and the pHo was mainly controlled by kaolinite, gibbsite and oxides. 展开更多
关键词 MINERALOGY pH_0 phosphate adsorption tropical and subtropical soils
下载PDF
Difference in the influence of Indo-Pacific Ocean heat content on South Asian Summer Monsoon intensity before and after 1976/1977
11
作者 董玉杰 冯俊乔 胡敦欣 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第3期567-576,共10页
Monthly ocean temperature from ORAS4 datasets and atmospheric data from NCEP/NCAR Reanalysis I/II were used to analyze the relationship between the intensity of the South Asian summer monsoon(SASM) and upper ocean hea... Monthly ocean temperature from ORAS4 datasets and atmospheric data from NCEP/NCAR Reanalysis I/II were used to analyze the relationship between the intensity of the South Asian summer monsoon(SASM) and upper ocean heat content(HC) in the tropical Indo-Pacific Ocean.The monsoon was differentiated into a Southwest Asian Summer Monsoon(SWASM)(2.5°–20°N,35°–70°E) and Southeast Asian Summer Monsoon(SEASM)(2.5°–20°N,70°–110°E).Results show that before the 1976/77 climate shift,the SWASM was strongly related to HC in the southern Indian Ocean and tropical Pacific Ocean.The southern Indian Ocean affected SWASM by altering the pressure gradient between southern Africa and the northern Indian Ocean and by enhancing the Somali cross-equatorial flow.The tropical Pacific impacted the SWASM through the remote forcing of ENSO.After the 1976/77 shift,there was a close relationship between equatorial central Pacific HC and the SEASM.However,before that shift,their relationship was weak. 展开更多
关键词 South Asian summer monsoon upper ocean heat content tropical Pacific Ocean Indian Ocean
下载PDF
Rut-induced changes in the activity budgets of male tropical ungulates: Eld's deer on Hainan Island 被引量:1
12
作者 Jianhua DING Zhitao LIU +3 位作者 Yanling SONG Zhigao ZENG Qiong ZHANG Benjamin D.BRAVERY 《Current Zoology》 SCIE CAS CSCD 2012年第4期536-540,共5页
Aspects of time budgets, activity patterns and rut-related changes in behavior are well documented in temperate un-gulates; however, the application of this understanding to tropical and sub-tropical ungulate species ... Aspects of time budgets, activity patterns and rut-related changes in behavior are well documented in temperate un-gulates; however, the application of this understanding to tropical and sub-tropical ungulate species has attracted less attention and remains an area that may re-shape our knowledge of ungulate behavior. Eld's deer Cervus eldi hainanus has a tropical and sub-tropical distribution on Hainan Island, China, and males have an extended rut exceeding five months during which they do not maintain harems or defend resources. We studied males from the only remaining population on Hainan Island, and describe rut-related changes in behavior by collecting data on time budgets and activity patterns. We show that male Eld's deer do not fol- low a strict crepuscular activity pattern, do not spend the majority of their time foraging and do not increase foraging nor display rut-induced hypophagia during rut, in obvious contrast to temperate ungulates. These results are discussed in light of current hy- potheses explaining the proximate mechanisms governing feeding time in ungulates, while appreciating the need for further re-search . 展开更多
关键词 Activity Cervus eldi hainanus Eld's deer RUT Time budget Tropical ungulate
原文传递
Observational analysis and numerical simulation of the interannual variability of the boreal winter Hadley circulation over the recent 30 years 被引量:3
13
作者 SUN Yong ZHOU TianJun ZHANG LiXia 《Science China Earth Sciences》 SCIE EI CAS 2013年第4期647-661,共15页
The interannual variability of the boreal winter (DJF) Hadley Cell strength during 1979-2008 is investigated using NCEP/NCAR reanalysis data. The results of AMIP simulation of LASG/IAP AGCM GAMIL2.0 are compared aga... The interannual variability of the boreal winter (DJF) Hadley Cell strength during 1979-2008 is investigated using NCEP/NCAR reanalysis data. The results of AMIP simulation of LASG/IAP AGCM GAMIL2.0 are compared against the re- analysis data. Both the reanalysis data and the simulation show that the interannual variability of the Hadley Cell strength has a non-uniform spatial distribution, as evidenced by the 1st Empirical Orthogonal Function (EOF) mode. The change of Hadley cell strength in the tropics is opposite to that in the subtropical regions. Our analysis indicates that a positive phase of EOF1 is associated with an E1 Nifio-like warmer equatorial central and eastern Pacific and a warmer southern Indian Ocean. Above features are also seen in the results of GAMIL2.0 simulation, indicating that the interannual variability of the Hadley Cell strength is driven by the tropical ocean variability. Our analysis also demonstrates that the contribution of the warmer cen- tral-eastern Pacific to the 1st EOF mode is larger than that of the South Indian Ocean. The SST forcing enhances the local Hadley circulation strength in the central Pacific and Africa (30°S-30°N, 150°E-90°W), while it weakens the local Hadley circulation in other regions (30°S-30°N, 90°-10°W). The western Pacific anticyclone remotely driven by the E1 Nifio forcing leads to a weakened local Hadley cell in the Northern Hemisphere, while the South Indian Ocean anticyclone driven by the remote E1 Nifio forcing and the local warmer SST anomalies in the southern Indian Ocean results in a weakened local Hadley Cell in the Southern Hemisphere. The enhancement of the Pacific local Hadley Cell is stronger (weaker) than that of the Atlan- tic, the western Pacific, and the southern Indian Ocean in the tropical (subtropical) part, thus for the zonal mean condition the strength of the total Hadley Cell is stronger (weaker) in the tropical (subtropical) limb. The amplitude of the Hadley Cell change in the Northern Hemisphere is stronger than that in the Southern Hemisphere. Hence the leading interannual variability mode of boreal winter Hadley Cell exhibits a non-uniform spatial pattern. 展开更多
关键词 Hadley circulation interannual variability GAMIL2.0
原文传递
Modulation of the urban heat island by the tourism during the Chinese New Year holiday: a case study in Sanya City,Hainan Province of China 被引量:7
14
作者 Jingyong Zhang Lingyun Wu 《Science Bulletin》 SCIE EI CAS CSCD 2015年第17期1543-1546,共4页
The urban heat island (UHI) represents one of the most significant human impacts on the earth system. In recent decades, the number of the tourists has a remarkable increase in China and also other regions of the gl... The urban heat island (UHI) represents one of the most significant human impacts on the earth system. In recent decades, the number of the tourists has a remarkable increase in China and also other regions of the globe. However, it is still unclear whether or to what extent the tourism can affect the UHI. Here, we investigate the role of the tourism for the UHI during the Chinese New Year (CNY) holiday based on a case study in tropical Sanya City, which attracts many tourists for celebrating the CNY and enjoying the warm climate during the holiday. We find that the UHI effects expressed as daily mean (ATmean), maximum (ATmax), and minimum (ATmin) surface air temperature differences between urban and nearby nonurban stations averaged over the period of 1995-2004 during the CNY week were 0.48 ℃ (39 %), 0.66 ℃ (61%), and 0.42 ℃ (26 %) higher than those averaged over the background period (8 weeks including 4 weeks before and 4 weeks after the CNY week), respectively. These changes are all significant at the 99 % confidence level. Our findings highlight previously unidentified impact of the tourism on the UHI based on a case study in Sanya City, Hainan Province of China. 展开更多
关键词 Urban heat island Chinese New Yearholiday TOURISM Surface air temperature Sanya City
原文传递
The spatial distribution of archaeal lipids in a mesoscale subtropical watershed, Southeast China 被引量:1
15
作者 LI Xue Ying ZHENG FengF eng +5 位作者 CHEN Yu Fei GUO Wen Ting ZHANG TingT ing HU AnY i YU Chang Ping ZHANG Chuan Lun 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第7期1317-1328,共12页
Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community str... Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments. 展开更多
关键词 GDGT-0 Crenarchaeol Archaeol Spatial distribution Jiulong River Jiulong River Estuary
原文传递
Intraseasonal oscillation features of the South China Sea summer monsoon and its response to abnormal Madden and Julian Oscillation in the tropical Indian Ocean 被引量:2
16
作者 LI Ting YANG XiuQun JU JianHua 《Science China Earth Sciences》 SCIE EI CAS 2013年第5期866-877,共12页
By applying the OLR and wind data, rainfall data and the Madden and Julian Oscillation (MJO) index, the paper deals with in traseasonal oscillation features and interannual differences of the South China Sea (SCS)... By applying the OLR and wind data, rainfall data and the Madden and Julian Oscillation (MJO) index, the paper deals with in traseasonal oscillation features and interannual differences of the South China Sea (SCS) summer monsoon, distribution of its LF circulation and convection fields and rainfall, and path of summer monsoon ISO spreading, as well as impact of tropical IndoMJO on SCS summer monsoon ISO during 19792008. It is found that (1) there are three intraseasonal oscillations of the SCS summer monsoon Intraseasonal Oscillation (ISO) in summer (from May to August) in the climate normal. The SCS summer monsoon ISO goes through six phases (exclusive of weak phase) at every complete fluctuation: developing, the strongest, weakening, restraining, the weakest, and recovering. Due to tropical LC convection spreading to the east and north, the LR convection and circulation fields in the lst3rd and 4th6th phases present the antiphase in the Arabian SeaWest Pa cific latitudinal band. Its corresponding rain bands in the lst3rd and 4th6th phases als present antiphase roughly. The rain band, mainly in tropical regions in the south of 20N, moves eastward with LR convection shifting eastward, while the rain band moves northward with LR convection shifting northward in East Asia (EA) subtropical regions in the north of 20N. (2) The SCS summer monsoon ISO presents significant interannual variations in intensity. There are three stronger monsoon in traseasonal oscillations in summer in the strong SCS monsoon ISO year. The first two oscillations from the tropical Indian Ocean ISO spread northward to the Bay of Bengal first, and then to the South China Sea (SCS) along the 10-20N latitudinal band. They are strengthened there and stimulate the ISO moving to the north to form the tropical IndoISO. Finally they spread to South China (SC) by relay way in the longitudelatitude direction. Moreover, in the weaker SCS summer monsoon ISO, the oscillation weakens greatly and irregularly in intensity with the weaker ISO spreading in the longitudelatitude direction. In average conditions, the tropical Indian ISO spreads to the SCS by about 20 days (one half ISO periods). (3) MJO1 (the first modal of MJO index provided by the CPC) averaged value in the lst2nd pentads of April has the negative correlation with the SCS monsoon ISO intensity. The tropical IndoMJO is slightly stronger in the subsequent May to August when it is more ac tive in the lst2nd pentads of April, and the ISO also spreads strongly to the SCS, so that the SCS summer monsoon ISO strengthens. Conversely, the SCS summer monsoon ISO weakens. The abnormal MJO in the lst2nd pentads of April contrib utes to a certain theory basis for us to predict the subsequent SCS summer monsoon ISO intensity and analyze the related re gions' abnormal rainfall. 展开更多
关键词 South China Sea (SCS) summer monsoon (SCSSM) ISO tropical Indian Ocean MJO relay spread in the longitude-latitude direction
原文传递
First record of extinct fruit genus Chaneya in low-latitude tropic of South China
17
作者 FENG XinXin JIN JianHua 《Science China Earth Sciences》 SCIE EI CAS 2012年第5期728-732,共5页
Fossil reproductive structure from the Eocene of the Changchang Basin (Hainan Island,South China) is recognized as Chaneya hainanensis sp.nov.This new species is characterized by persistent corolla of five obovate pet... Fossil reproductive structure from the Eocene of the Changchang Basin (Hainan Island,South China) is recognized as Chaneya hainanensis sp.nov.This new species is characterized by persistent corolla of five obovate petals with three subparallel primary venation linked by arching secondary veins,circular central disk bearing two orbicular ovaries or fruit bodies.This discovery confirms the presence of the extinct fruit genus Chaneya in low-latitude tropical area,providing significant fossil evidence for investigating the origin,migration,and phytogeography of this genus and discussing the Tertiary floristic exchanges among North America,eastern Asia,and Europe.Considering the distribution of this genus and its extant relatives and the climate changes during the Cenozoic,we hypothesize that Chaneya was a widespread tropical or subtropical taxon,but,with climate cooling,became extinct in northern latitudes and evolved into Picrasma (Simaroubaceae) and Rutaceae mainly in modern tropics and subtropics. 展开更多
关键词 Chaneya EOCENE low-latitude tropic Changchang Basin South China
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部