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The concentration variation features of sea salt ions and non sea salt ions in a firn core recovered from Princess Elizabeth Land, East Antarctica 下载免费PDF全文
A 51.85 m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996-1997 Chinese First Antarctic Inland Expedition, has been measured for δ 18 O and major ions. Based on the high quality data of the seasonal variations of major ions, the firn core was dated with errors within ±3 years. The 51.85 m firn core record extends for 251 years (A. D. 1745-1996). The results of the glaciochemistry data of the firn core show that the mean concentrations of Cl -, Na + and Mg 2+ are similar to those reported from other coastal areas in East Antarctica. However, mean concentrations of Ca 2+ are much higher than those reported from other regions, this anomaly phenomenon may be related to the strong local terrestrial sources. It is found that the variations of three kinds of sea salt ions (Cl -, Na + and Mg 2+ ) in the past 150 years show very similarly rising trends, which may be the results the Southern Hemisphere warming in the past century. 相似文献
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Analysis of sensible heat flux(Qh),latent heat flux(Qe),Richardson number(Ri),bulk transport coefficient(Cd) and katabatic winds are presented by using the meteorological data in the near surface layer from an automatic weather station(AWS) in Princess Elizabeth Land,East Antarctica ice sheet and the data of corresponding period at Zhongshan station in 2002.It shows that annual mean air temperature at LGB69 is-25.6°C,which is 16.4°C lower than that at Zhongshan,where the elevation is lower and located on the coast.The temperature lapse rate is about 1.0°C/110 m for the initial from coast to inland.The turbulence heat flux at LGB69 displays obvious seasonal variations with the average sensible heat flux-17.9 W/m2 and latent heat flux-0.9 W/m2.The intensity(Qh+Qe) of coolling source is-18.8 W/m2 meaning the snow surface layer obtains heat from atmosphere.The near surface atmosphere is near-neutral stratified with bulk transport coefficients(Cd) around 2.8×10-3,and it is near constant when the wind speed higher than 8 m/s.The speed and the frequency of easterly Katabatic winds at LGB69 were higher than that at Zhongshan Station. 相似文献
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Preliminary research on the transmission path of nssSO_4~(2-) and NO_3~- in Antarctic ice sheet 下载免费PDF全文
The main sources of nssSO 2- 4 and NO - 3 were summarized in this paper. By analyzing the spatial distribution features of major ions in Antarctic ice sheet and studying on the different time of the same volcanic event recorded by different ice cores from different regions in Antarctica, this paper intends to study the transmission path of nssSO 2- 4 and NO - 3. Results show that nssSO 2- 4 and NO - 3 are transmitted to the ice sheet through long distance and high altitude. The procedure of the transmission is that nssSO 2- 4 and NO - 3 are transmitted to the level between the top of troposphere and the bottom of stratosphere, then subsided to the ice sheet surface and spread to other regions. 相似文献
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ZHANG Mingjun LI Zhongqin REN Jiawen XIAO Cunde QIN Dahe KANG Jiancheng LI Jun 《地理学报》2006,16(1):23-33
A 51.85-m firn core collected from site DT001 (accumulation rate 127 kgm-2a-1, mean annual temperature -33.1 oC) on Princess Elizabeth Land, East Antarctica, during the 1996-97 Chinese First Antarctic Inland Expedition has been analyzed for chemical composition and oxygen isotope ratio. A comparison between the seasonal variations of major ions was carried out in order to reduce the dating uncertainty, using the volcanic markers as time constrains. A deposition period of 251 years was determined. The calculated accumulation rates display an increasing trend before 1820, while after 1820, the trend of the accumulation is not obvious. Overall, temperature change in the region shows a slight increasing trend over the past 250 years. But, notably, a temperature decline of -2 oC is observed from 1860 to the present. This feature, at odds with the warming trend over the past century recorded in both hemispheres, likely reflects a regional characteristic related to the lack of a high latitude/low latitude link in the Southern Hemisphere circulation patterns. The results of the glaciochemical records of the firn core show that the mean concentrations of Cl-, Na+ and Mg2+ are similar to those reported from other sites in East Antarctica. However, the mean concentration of Ca2+ is much higher than that reported from other regions, suggesting the influence of the strong local terrestrial sources in Princess Elizabeth Land. There is no evidence of a positive correlation between NO3- concentrations and solar activity (11-year solar cycle and solar cycle length), although solar proton events may account for some of the NO3- peak values in the record. 相似文献
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1Introduction In the ongoing discussion of climate change,the mass balance of Antarctica has received increasing attention during recent decades,since its reaction to global warming will strongly influence sea-level change(Schlosser and Oerter,2002).Many … 相似文献
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通过对1996/1997年中国首次南极内陆冰盖考察获得的南极洲伊丽莎白公主地区50m 雪芯样品主要阴、阳离子浓度、通量和积累率关系的研究,揭示以下规律:1)南极洲伊丽莎白公主地区大气中各主要离子浓度足够大,足以使本地区冰雪中主要离子浓度不随积累率的变化而变化,即离子浓度不受积累率的影响。2)各主要离子干、湿沉积所占比重的计算结果表明,本地区离子沉积方式以湿沉积为主。另外,nssSO2-4 的研究结果表明火山爆发的中、短期气候效应在伊丽莎白公主地区反应不明显。 相似文献
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《盐湖研究》2017,(3)
Li~+,Na~+,K~+/Cl~-,SO_4~(2-)-H_2O五元体系相图对于硫酸钠亚型富锂卤水分离提取锂盐、锂辉石加工利用和锂盐产品的开发利用工艺制定都有指导作用。20世纪50年代曾有人研究过这一体系25℃时的相图,限于当时的科研水平,液相组成确定不准确,对平衡固相的判断,后来诸多研究结果证明也有错误。50多年来再没有人研究这一五元体系相图。利用我们提出的Li~+,Na~+,K~+,Mg~(2+)/Cl~-,SO_4~(2-)-H_2O六元体系热力学模型,对该五元体系的平衡溶液组成和正确的平衡固相进行理论预测,给出了该体系的完整相图。结合硫酸锂混盐分离、加工实例阐述了该五元体系相图的应用。 相似文献
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研究了三元体系Li~+,Mg~(2+)∥SO_4~(2-)—H_2O在25℃时的相关系和平衡液相的密度、粘度、折光率、电导等物化性质,该体系为简单共饱型,两段溶解度曲线对应于体系的两种原始组份Li_2SO_4·H_2O和MgSO_4·7H_2O的结晶区,无复盐和固溶体形成,亦无脱水作用发生,应用电解质溶液Pitzer模型检测该体系25C的溶解度,并用经验或半经验公式对平衡液相的密度和折光率进行了理论计算,计算值与实验值非常接近。 相似文献
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Mauro Guglielmin Alessandro Biasini & Claudio Smiraglia 《Geografiska Annaler: Series A, Physical Geography》1997,79(1-2):17-24
All periglacial and glacial landforms investigated in the Northern Foothills have a very thin active layer (0.1–0.3 m thickness) overlying a thin permafrost layer, characterised by electrical resistivities ranging between 13 and 50 kΩm and by different thicknesses. Below this surficial layer, different types of ground ice (with a resistivity range from 8000 to 0.1 kΩm) were detected. These different types of ground ice permitted ice-cored rock glaciers to be distinguished from ice-cemented rock glaciers, subsea permafrost to be identified in some raised beaches, and other interpretations to be suggested about a debris-covered glacier. These results have been obtained by vertical electrical soundings (VES) carried out in ice-free areas of the Northern Foothills, near Terra Nova Bay Station during the tenth national Italian expedition in Antarctica (1994–1995). In these areas on the basis of previous geomorphological research, some landforms such as rock glaciers, raised beaches with patterned ground and debris-covered glaciers were chosen to carry out the VES. The electrical prospection can be considered a good means for understanding the origins of landforms in ice-free areas of Antarctica and for making a contribution to the palaeoenvironmental reconstruction of this continent. 相似文献
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盆栽试验了田间持水量(45%、60%、75%)、种植模式和小麦根系分泌物丁香酚对小麦、蚕豆下土壤微生物种群结构的影响。结果表明:间作土壤中细菌、真菌和放线菌数量较单作加权平均有所减少,但间作化感促进作用和土壤微生物多样性均大于单作加权平均,且丁香酚对单作小麦和小麦间作蚕豆土壤微生物数量表现出明显的化感促进作用,在丁香酚处理下间作土壤中3种菌类数量较单作加权平均分别提高95.9%、8.8%和99.6%,但对单作蚕豆土壤微生物数量表现为化感抑制作用;随着供水水平的增加,单作小麦化感促进作用增强,单作蚕豆化感抑制作用减弱,间作化感促进作用在60%相对含水量以下随供水水平增加而增强,超过60%后随供水水平增加而减弱。丁香酚处理下间作土壤微生物多样性指数在小麦拔节期、灌浆期和成熟期比单作加权平均提高74.3%、96.1%和134.0%,且在单作小麦和间作群体下在60%相对含水量以下随供水水平增加而提高,超过60%后随供水水平增加而降低,单作蚕豆则随供水水平增加而持续降低。因此,利用间作和灌水水平的控制可充分挖掘根系分泌物对土壤微生物数量和多样性的化感促进作用。 相似文献
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Palaeomagnetic investigations and Rb–Sr dating were carried out on samples from two plutons from the Granite Harbour Intrusives of the Transantarctic Mountains inland of Terra Nova Bay. The Rb–Sr whole rock–biotite ages from Teall Nunatak (475±4, 483±4 Ma), a quartz-diorite pluton cropping out to the south of Priestley Glacier, are older than that from the Mount Keinath monzogranite (450±4 Ma), which is located to the north of the glacier. These results are consistent with the literature data, which suggest that during the last phases of the Ross Orogeny the cooling rate of the basement was significantly lower to the north than to the south of Priestley Glacier. The Teall Nunatak quartz-diorite is characterized by a stable magnetization, whose blocking-temperature spectrum ranges from 530 to 570 °C. At one site, the stable magnetization is screened by a large secondary component of opposite polarity, removed by thermal demagnetization below 300 °C. The characteristic directions after thermal demagnetization yielded a southern pole located at lat. 11°S, long. 21°E. The magnetization of Mount Keinath monzogranite consists of several components with overlapping stability spectra. A characteristic direction was isolated at one site only, obtained by demagnetizing the specimens in the temperature range from 380 to 460 °C.
Comparison with the other East Antarctica poles shows that those from Victoria Land are very well grouped and give a reliable early Ordovician palaeopole (lat. 5°S, long. 23°E, with K =196 and A95 =3.7°), whereas the poles from Wilkes, Enderby and Dronning Maud Land are dispersed. We tentatively advance the hypothesis that the dispersion reflects different magnetization ages due to the slow cooling of these regions during the last stages of the Ross Orogeny. 相似文献
Comparison with the other East Antarctica poles shows that those from Victoria Land are very well grouped and give a reliable early Ordovician palaeopole (lat. 5°S, long. 23°E, with K =196 and A
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The nutrient status of soils surrounding ten snow petrel Pagodroma nivea nests was investigated by sampling along four transects (One up-slope and three down-slope) from each nest. The highest levels for total N and P.% C. nitrite and ammonia (but not nitrate) were associated with the nest itself. Elevated levels of all nutrients still occurred at I m from the nest but dropped to levels similar to those of non-bird influenced soils at 2 m or 5 m from the nest. Highest bacterial and algal numbers were also associated with the nest. An experiment to examine the breakdown of guano showed nitrification levels to be insignificant and nutrient release levels very slow. 相似文献