检索结果-南通市图书馆

Formate and acetate records in the Muztagata ice core,Northwest Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2004年第15期49卷 1620-1624页

作者： WANGJunxia yaotandong XUBaiqing WUGuangjian XIANGShurong KeyLaboratoryofIceCoreandColdRegionsEnvironment ColdandAridRegionsEnvironmentalandEngineeringResearchInstituteChineseAcademyofSciencesLanzhou730000China InstituteofTibetanPlateauResearch ChineseAcademyofSciencesBeijing100085China

Formate and acetate concentrations are meas- ured in a 22.56 m-depth ice core recovered in Mt. Muztagata Glacier, northwest Tibetan Plateau. The mean concentrations for formate and acetate in this ice core are 186.6±160.1 and 136.4±133.9 ng/g, respectively. Study shows that there is a positive correlation between formate and nitrate, suggesting both continental origins. However, no significant relationship has been found between formate and acetate, though they both have obvious periodical variations. Because Mt. Muz- tagata lies in the mid-latitude and is correlative to the nearby human activities, formate and acetate concentrations are higher than those in Greenland and Antarctica. During re- cent decades, the increase of formate concentration in the Muztagata ice core and formaldehyde production shows a close correlation. We preliminarily presume that the high formate concentration in the Muztagata ice core is concerned with the thriving of house decoration in which excess for- maldehyde was used.

关键词：慕士塔格冰芯西藏高原北部甲酸盐记录醋酸盐记录人类活动

Comparisons on seasonal and annual variations of δ^(18)O in precipitation

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2004年第2期14卷 193-203页

作者： ZHANGXinping yaotandong CollegeofResourcesandEnvironmentSciences HunanNormalUniversityChangsha410081China ColdandAridRegionsEnvironmentalandEngineeringResearchInstitute CASLanzhou730000China

The spatial and temporal variations of stable oxygen isotope in precipitation on different time scales are analyzed according to the data from the IAEA/WMO stations with long survey series in the Northern Hemisphere. Temperature effect is mainly distributed in mid-high latitudes on seasonal scale except for Bamako and Addisababa stations. The δ 18 O/temperature slope displays the positive correlation against altitude for most of the statistical stations. Amount effect appears primarily in the region south of 30 o N and coastal areas. The δ 18 O/precipitation slope is indirectly proportional to precipitation amount. For some of the sampling stations at mid-high latitudes where their seasonal distribution of precipitation is contrary to that of temperature, coupled with temperature effect, the amount effect appears synchronistically. Either the temperature effect or the amount effect on seasonal scale, there are positive correlations to a certain extent between the annual weighted mean δ 18 O and the annual mean temperature for almost all the stations. The correlation between composite δ 18 O and temperature on spatial scale is much more marked, compared with that of individual station. There is a good agreement between 10-year moving average temperature curves I and II, with the values of the former all markedly smaller than corresponding ones of the latter, calculated by the monthly mean series group I and the annual mean series group II, respectively. However, two calculated d δ 18 O/d T curves display the distinct difference: the variation amplitude of slope series II is larger than that of slope series I. Both curves had similar ascending trend from the 1960s to the 1970s, and then, their variations display the anti-phase. Moreover, the analyses show that there is negative correlation between slope series II and temperature series II. However, the status is different for slope series I and temperature series I. Both series have contrary trend from the 1960s to th

关键词：时空变化季节性变化年变化氧同位素国际原子能组织国际气象组织温度变化

Microparticle record in the Guliya ice core and its comparison with polar records since the last interglacial

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2004年第6期49卷 607-611页

作者： WUGuangjian yaotandong L.G.Thompson LIZhongqin KeyLaboratoryofIceCoreandColdRegionsEnvironment CAREERIChineseAcademyofSciencesLanzhou730000China ByrdPolarResearchCenter DepartmentofGeologicalSciences.OhioStateUniversityColumbusOH43210USA

Based on the study of oxygen isotope and mi-croparticle in the Guliya ice core, atmospheric dust and en-vironmental changes in the northwest Tibetan Plateau since the last interglacial were revealed. The microparticle record indicates that low dust load on the Plateau in the interglacial. Particle concentration increased rapidly when the climate turned into the last glacial and reached the maximum during the MIS 4. In the Last Glacial Maximum, however, the en-hancement of microparticle concentration was slight, differ-ing to those in the Antarctic and Greenland. On the orbital timescale, both the temperature on the Tibetan Plateau and summer solar insolation in the Northern Hemisphere had their impact on the microparticle record, but the difference in phase and amplitude also existed. Though having the same dust source, microparticle records in the ice cores on the Tibetan Plateau and the Greenland seem to have different significance.

关键词：微粒子记录 Guliya冰核极性记录末期间冰期西藏高原大气灰尘全球气候

Change of bacterialcommunity in the Malan Ice Core and its relation toclimate and environment

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2004年第17期49卷 1869-1875页

作者： XIANGShurong yaotandong ANLizhe LIZhen WUGuangjiad WANGYouqing XUBaiqing WANGJunxia LaboratoryofIceCoreandColdRegionsEnvironment ColdandAridRegionsEnvironmentalEngineeringResearchInstituteChineseAcademyofSciencesLanzhou730000China InstituteoftheTibetanPlateau ChineseAcademyofSciencesBeijing100029China

In order to understand the relationship be- tween the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples from the Malan ice core drilled from the Tibetan Plateau. The 16S ribosomal DNA (rDNA) molecules were directly amplified from the melt water samples, and three 16S rDNA clone li- braries were established. Among 94 positive clones, eleven clones with unique restriction pattern were used for partial sequence and compared with eight reported sequences from the same ice core. The phylotypes were divided into 5 groups: alpha, beta, gamma proteobacteria; CFB, and other eubac- teria group. Among them, there were many “typical Malan glacial bacteria” pertaining to psychrophilies and new bacte- ria found in the ice core. At a longer time scale, the concen- tration distribution of “typical Malan glacial bacteria” with depth showed negative correlation with temperature varia- tions and was coincident with dirty layer. It implied the in- fluence of temperature on the microbial record through im- pact on the concentrations of the “typical Malan glacial bac- teria”. In addition, the nutrition contained in ice was another important factor controlling the distribution of microbial population in ice core section. Moreover, the result displayed an apparent layer distribution of bacterial community in the ice core section, which reflected the microbial response to the past climatic and environmental conditions at the time of deposition.

关键词：细菌群落结构冰核气候环境微生物西藏高原

Westerly moisture transport to the middle of Himalayas revealed from the high deuterium excess

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2005年第10期50卷 1026-1030页

作者： TIANLide yaotandong J.W.C.White YUWusheng WANGNinglian LaboratoryofIceCoreandColdRegionsEnvironment InstituteofTibetanPlateauResearchChineseAcademyofSciencesBeijing100085China InstituteofArcticandAlpineResearch UniversityofColoradoBoulderUSA LaboratoryofIceCoreandColdRegionsEnvironment ColdandAridRegionsEnvironmentalandEngineeringResearchInstituteChineseAcademyofSciencesLanzhou730000China LaboratoryofIceCoreandColdRegionsEnvironment ColdandAridRegionsEnvironmentalandEngineeringResearchInstituteChineseAcademyofSciencesLanzhou730000China

Previous studies found extremely high d-excess in both ice core and glacial melt water in Dasuopu glacier, Xixiabangma, middle of Himalayas. These values are much higher than the global average and those measured in southwest monsoon precipitation. The d-excess variation in over one year at Nyalam station will clarify this phenomenon. Studies show that the high d-excess is related to the seasonal variation of moisture transport to this region. The d-excess values are low during the southwest monsoon active periods, when moisture originated from the humid ocean surface. The d-excess values are higher in non-monsoon months, when moisture is derived from westerly transport. Winter and spring precipitation accounts for a substantial portion of the annual precipitation, resulting in higher d-excess in the yearly precipitation in the middle of Himalayas than other parts of the southern Tibetan Plateau. This finding reveals that the precipitation in the middle of Himalayas is not purely from southwest monsoon, but a large portion from the westerly transport, which is very important for ice core study in this area.

关键词：喜马拉雅山湿气传送器氘过剩

Oxygen-18 in different waters in Urumqi River Basin

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2003年第4期13卷 438-446页

作者： ZHANGXinping yaotandong LIUJingmiao CollegeofResourcesandEnvironment HunanNormalUniversityChangsha410081China ColdandAddRegionsEnvironmentalandEngineeringResearchInstitute CAS Lanzhou730000 China ChineseAcademyofMeteorologySciences Beijing100081Chinai

The variations of the stable oxygen isotope in different water mediums in Urumqi River Basin, China, are analyzed. The stable oxygen isotope in precipitation has marked temperature effect either under synoptic or seasonal scale at the head of Urumqi River. The linear regression equations of δ18O against temperature are δ18O=0.94T-12.38 and δ18O=1.29T-13.05 under the two time scales, respectively. The relatively large δ18O/temperature slopes show the strong sensitivity of δI8O in precipitation to temperature variation at the head of Urumqi River. According to the analyses on the δ18O in precipitation sampled at three stations with different altitudes along Urumqi River, altitude effect is notable in the drainage basin. The δ18O/altitude gradients have distinct differences: the gradient from Urumqi to Yuejinqiao is merely -0.054%c/hm, but -0.192%e/hm from Yuejinqiao to Daxigou, almost increasing by 2.6 times over the former. No altitude effect is found in surface firn in the east branch of Glacier No. 1 at the head of Urumqi River, showing that precipitation in the glacier is from the cloud cluster with the same condensation level. Influenced by strong ablation and evaporation, the δ18O in surface firn increases with increasing altitude sometimes. Survey has found that the δ18O in meltwater at the terminus of Glacier No. 1 and in stream water at Total Control have the similar change trend with the former all smaller than the latter, which displays the different runoff recharges, and all mirror the regime of temperature in the same term basically.

关键词： stable oxygen isotope temperature effect altitude effect