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81.
The radiance lights data in 2006 from the National Oceanic and Atmospheric Administration Air Force Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) and authoritative energy data distributed by the United State Energy Information Administration were applied to estimate the global distribution of anthropogenic heat flux.A strong linear relationship was found to exist between the anthropogenic heat flux and the DMSP/OLS radiance data.On a global scale,the average value of anthropogenic heat flux is approximately 0.03 W m 2 and 0.10 W m 2 for global land area.The results indicate that global anthropogenic heat flux was geographically concentrated and distributed,fundamentally correlating to the economical activities.The anthropogenic heat flux concentrated in the economically developed areas including East Asia,Europe,and eastern North America.The anthropogenic heat flux in the concentrated regions,including the northeastern United States,Central Europe,United Kingdom,Japan,India,and East and South China is much larger than global average level,reaching a large enough value that could affect regional climate.In the center of the concentrated area,the anthropogenic heat flux density may exceed 100 W m 2,according to the results of the model.In developing areas,including South America,Central and North China,India,East Europe,and Middle East,the anthropogenic heat flux can reach a level of more than 10 W m 2 ;however,the anthropogenic heat flux in a vast area,including Africa,Central and North Asia,and South America,is low.With the development of global economy and urban agglomerations,the effect on climate of anthropogenic heat is essential for the research of climate change. 相似文献
82.
Food web structure of two Mediterranean lagoons under varying degree of eutrophication 总被引:2,自引:0,他引:2
Antoine Carlier Pascal Riera Jean-Michel Amouroux Jean-Yves Bodiou Martin Desmalades Antoine Grmare 《Journal of Sea Research》2008,60(4):264-275
The food web structure and functioning of two north-western Mediterranean lagoons exhibiting contrasting degrees of eutrophication and marine influences were compared through δ13C and δ15N analysis of major potential food sources and consumers. The Lapalme Lagoon is well preserved and has kept a natural and temporary connection with the open sea. Conversely, the Canet Lagoon is heavily eutrophicated and its water exchange with the open sea has been artificially reduced. In Lapalme, all potential food sources and consumers exhibited δ15N values indicative of pristine coastal areas. Suspended particulate organic matter (POM) and sediment organic matter (SOM) pools seemed to constitute the main food sources of most primary consumers. Both primary producers and all consumers were much more 15N-enriched (by 10‰) and more 13C-depleted in Canet than in Lapalme. This reflected: (1) the assimilation of important amounts of anthropogenic nitrogen in the food web, and (2) a marked and uniform influence of 13C-depleted allochtonous sources of carbon. Based on the mean δ15N of primary consumers, we found rather similar food web lengths in both lagoons with top consumers at trophic levels 3.6 and 4.0 in Canet and Lapalme, respectively. However, the eutrophication of the Canet Lagoon resulted in a simplification of the food web structure (i.e., a single trophic pathway from a 15N-enriched fraction of the SOM pool to top predators) compared to what was observed in Lapalme Lagoon where additional 13C-enriched food sources played a significant trophic role. Moreover, some consumers of Canet tended to exploit primary producers to a larger extent (and thus to exhibit lower trophic levels) than in Lapalme. 相似文献
83.
Oxygen and hydrogen isotopic compositions of meteoric water are known to correlate with surface air temperature, except in tropical areas. This relationship has been described using a number of terms corresponding to specific observations, such as latitude, altitude and seasonal effects. However, these temperature effects do not seem to apply to precipitation in monsoonal areas of Asia. Questions have been raised as to whether the isotopic composition of meteoric water can be used to reconstruct paleomonsoon intensity. Tree rings of two modern spruce trees (Picea meyeri) and a 10,000-yr-old timber (Picea jezoensis) were analyzed for hydrogen isotopic composition. On average, the older tree is depleted in deuterium by 45‰ compared to the modern trees. We attribute this isotopic depletion to the strength of summer monsoons, which were more intense in the early Holocene than at present. Although this study is not definitive, it suggests that paleomonsoon intensity can be reconstructed by direct or proxy methods that yield the oxygen or hydrogen isotopic composition of meteoric water. 相似文献
84.
研究表明,在含油气岩系中,当有机质发生热演变而成熟、并逐渐向烃类转变的整个过程中,氮主要以NH+4的形式释放出来而进入孔隙流体与周围介质 (成岩矿物 )相互作用,最重要的机制是NH+4可取代粘土矿物 (如伊利石,I/S混层矿物等 )层间的K+而参与成岩作用,形成含铵矿物,这一过程中氮的地球化学性质发生了重要变化,含铵矿物中固定 -NH4的富集状况与有机质成熟度及烃类运移有关。通过研究成岩和油气生成、运移、聚集过程中氮的岩石地球化学行为及其控制因素,可将固定 -NH4作为有机质成熟度和油气运移路径的一种新的、有意义的示踪剂。 相似文献
85.
利用TRMM降水和ERA-Interim温度、比湿、环流场等再分析资料, 探讨了在1998-2018年冬季年际尺度海温变化对MJO的强度、结构和传播特征的影响。主要结论如下: 通过一种追踪MJO的方法在研究时间范围内共可挑选出50个MJO事件, 其中有14个MJO事件发生在El Ni?o期间, 25个发生在La Ni?a期间, 11个发生在ENSO正常年。El Ni?o年MJO会传播至更远的中东太平洋附近, 而La Ni?a年MJO事件趋于在西太平洋地区消亡, 这主要与东太平洋地区持续的季节内尺度的经向水汽输送有关。此外, 在印度洋和太平洋地区, El Ni?o年的MJO活动更强, 而在海洋性大陆附近, La Ni?a年的MJO活动略强一些。ENSO对MJO强度的影响主要通过影响MJO对流中心东侧水汽的输送, 水汽在异常东风气流的输送下穿过对流中心东边界进入对流中心, 进而造成MJO活动强度的差异。 相似文献
86.
The organic composition and organic‐inorganic interaction in paper mill sludge (PS) solvent extracts (hexane, ethyl acetate, acetone and ethanol) and humic fractions, humic acid (HA) and humin (HU) were studied by electron paramagnetic resonance spectroscopy (EPR), proton and carbon‐13 nuclear magnetic resonance spectroscopy (1H NMR; 13C NMR), Fourier‐transformed infrared spectroscopy (FTIR), and ultraviolet‐visible spectroscopy (UV‐vis). The strategy of fractionating the PS, sequentially, with organic solvents of increasing polarity is a reliable analytical procedure for humic substance sample separation because it results in more purified fractions. FTIR, 1H NMR and 13C NMR results showed that hexane extract consisted mainly of aliphatic hydrocarbon structures. Their contents in the extracts decreased as the polarity of the extracting solvent increased and the content of oxygen functional groups increased. Carboxylic and carboxylate functional groups were found in the acetone extract, and ester and ether functions were predominantly found in the ethanol extract. EPR spectra revealed some Fe3+ complexes with rhombic structure (g1 = 4.3; g2 = 9.0) in the humic fractions and in all solvent extracts, except hexane. Quasi‐octahedral Fe3+ complexes (g = 2.3; ΔHpp ≤ 400 G) were found in the HU fraction and in the acetone extract. The organic free radical content in the HA fraction was higher than the non‐fractionated PS sample and HU fraction. 相似文献
87.
The Norilsk mining district is located at the northwest margin of the Tunguska basin, in the centre of the 3,000×4,000 km Siberian continental flood basalt (CFB) province. This CFB province was formed at the Permo-Triassic boundary from a superplume that ascended into the geometric centre of the Laurasian continent, which was surrounded by subducting slabs of oceanic crust. We suggest that these slabs could have reached the core–mantle boundary, and they may have controlled the geometric focus of the superplume. The resulting voluminous magma intruded and erupted in continental rifts and related extensive flood basalt events over a 2–4 Ma period. Cu–Ni–PGE sulfide mineralization is found in olivine-bearing differentiated mafic intrusions beneath the flood basalts at the northwestern margin of the Siberian craton and also in the Taimyr Peninsula, some 300 km east of a triple junction of continental rifts, now buried beneath the Mesozoic–Cenozoic sedimentary basin of western Siberia. The Norilsk-I and Talnakh-Oktyabrsky deposits occur in the Norilsk–Kharaelakh trough of the Tunguska CFB basin. The Cu–Ni–PGE-bearing mineralized intrusions are 2–3 km-wide and 20 km-long differentiated chonoliths. Previous studies suggested that parts of the magma remained in intermediate-level crustal chambers where sulfide saturation and accumulation took place before emplacement. The 5–7-km-thick Neoproterozoic to Palaeozoic country rocks, containing sedimentary Cu mineralization and evaporites, may have contributed additional metal and sulfur to this magma. Classic tectonomagmatic models for these deposits proposed that subvertical crustal faults, such as the northeast-trending Norilsk–Kharaelakh fault, were major trough-parallel conduits providing access for magmas to the final chambers. However, geological maps of the Norilsk region show that the Norilsk–Kharaelakh fault offsets the mineralization, which was deformed into folds and offset by related reverse faults, indicating compressional deformation after mineralization in the Late Triassic to Early Jurassic. In addition, most of the intrusions are sills, not dykes as should be expected if the vertical faults were major conduits. A revised tectonic model for the Norilsk region takes into account the fold structure and sill morphology of the dominant intrusions, indicating a lateral rather than vertical emplacement direction for the magma into final chambers. Taking into account the fold structure of the country rocks, the present distribution of the differentiated intrusions hosting the Norilsk-I and Talnakh–Oktyabrsky deposits may represent the remnants of a single, >60 km long, deformed and eroded palm-shaped cluster of mineralized intrusions, which are perceived as separate intrusions at the present erosional level. The original direction of sill emplacement may have been controlled by a northeast-trending paleo-rise, which we suggest is present at the southeastern border of the Norilsk–Kharaelakh trough based on analysis of the unconformity at the base of the CFB. The mineralized intrusions extend along this rise, which we interpret as a structure that formed above the extensionally tilted block in the metamorphic basement. Geophysical data indicate the presence of an intermediate magma chamber that could be linked with the Talnakh intrusion. In turn, this T-shaped flat chamber may link with the Yenisei–Khatanga rift along the northwest-trending Pyasina transform fault, which may have served as the principal magma conduit to the intermediate chamber. It then produced the differentiated mineralized intrusions that melted through the evaporites with in situ precipitation of massive, disseminated, and copper sulfide ore. The Norilsk–Kharaelakh crustal fault may not relate to mineralization and possibly formed in response to late Mesozoic spreading in the Arctic Ocean.Editorial handling: P. Lightfoot 相似文献
88.
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90.
为研究石家庄秋季对流层内CH4垂直分布特征,2018年9月使用“空中国王350”飞机搭载Picarro温室气体在线观测仪和气象要素观测设备,对石家庄上空(600—5500 m)CH4浓度进行探测。探测期间共飞行7架次,取得7条CH4浓度廓线数据。结果表明: 石家庄上空近地面层(1000 m以下)CH4平均浓度与同时间段区域背景站上甸子站CH4浓度呈显著正相关(r=0.81,P < 0.03)。探测到的CH4浓度最小值为1898×10-9摩尔分数,最大值为2219×10-9摩尔分数,平均浓度为1981×10-9摩尔分数。观测得到的7条廓线均有较好的一致性,2000 m以上,浓度均随高度呈先增大后减小的趋势。利用后向轨迹模式(HYSPLIT)对探测时段内石家庄上空不同高度层主要气流传输路径进行统计分析表明,600 m高度输送路径较短,CH4浓度受本地排放影响较大; 3000 m受输送作用影响较大,偏西和西南路径可能将较高CH4浓度气团输送至石家庄上空; 5000 m气团传输对CH4浓度影响较小,浓度相对较稳定,对传输路径的变化不敏感。 相似文献