Climate Change in the Subtropical Jetstream during 1950–2009   总被引：1，自引：0，他引：1  

B. Abish  P. V. Joseph  Ola. M. Johannessen 《大气科学进展》2015,32(1):140-148

A study of six decades(1950–2009) of reanalysis data reveals that the subtropical jetstream(STJ) of the Southern(Northern) Hemisphere between longitudes 0°E and 180°E has weakened(strengthened) during both the boreal winter(January,February) and summer(July, August) seasons. The temperature of the upper troposphere of the midlatitudes has a warming trend in the Southern Hemisphere and a cooling trend in the Northern Hemisphere. Correspondingly, the north–south temperature gradient in the upper troposphere has a decreasing trend in the Southern Hemisphere and an increasing trend in the Northern Hemisphere, which affects the strength of the STJ through the thermal wind relation. We devised a method of isotach analysis in intervals of 0.1 m s-1in vertical sections of hemispheric mean winds to study the climate change in the STJ core wind speed, and also core height and latitude. We found that the upper tropospheric cooling of the Asian mid-latitudes has a role in the strengthening of the STJ over Asia, while throughout the rest of the globe the upper troposphere has a warming trend that weakens the STJ. Available studies show that the mid-latitude cooling of the upper troposphere over Asia is caused by anthropogenic aerosols(particularly sulphate aerosols) and the warming over the rest of the global mid-latitude upper troposphere is due to increased greenhouse gases in the atmosphere.  相似文献   

Recent sudden decrease of lead in Adriatic coastal seawater during the years 2000–2004 in parallel with the phasing out of leaded gasoline in Italy     

A. Annibaldi  C. Truzzi  S. Illuminati  G. Scarponi 《Marine Chemistry》2009,113(3-4):238-249

In parallel with the process of lead removal from gasoline in Italy, a research programme was undertaken to study the lead content of Adriatic coastal seawater. In the period 2000–2004 seawater was collected systematically at three sites along the coast line close to the city of Ancona: (i) the mouth of the River Esino, (ii) an area close to the Api refinery and (iii) Portonovo beach, a less impacted zone located along the coast of Mt. Conero. All samples were analyzed by Square-Wave Anodic-Stripping Voltammetry (SWASV). The results show that dissolved Pb content in coastal seawater diminished from an overall median value of 0.25 nmol/L in 2000–2001 to 0.12 nmol/L in 2003–2004, with a decrease of about 50% (statistically significant at 95% significance level). This decrease has been correlated to the concurrent decrease of lead consumption in gasoline in Italy which led to a reduction of ~ 65% Pb emissions into the atmosphere in the same period (r = 0.8791, p < 0.05).  相似文献   

Regional study on potential CO₂ geosequestration in the Collie Basin and the Southern Perth Basin of Western Australia     

Sunil Varma  Jim Underschultz  Tess Dance  Robert Langford  Joan Esterle  Kevin Dodds  Dominique van Gent 《Marine and Petroleum Geology》2009

Coal-fired power stations in Collie, Western Australia emit 10 million tonnes of CO₂ per year. This study assesses the potential opportunities of geological storage of CO₂ both within the Collie Basin and the onshore part of the adjacent Southern Perth Basin of Western Australia within 50 km of Collie town site through a desktop evaluation of existing data. The aquifers and coal formations within both basins have been evaluated for their suitability for storage based on geological, geographical and environmental criteria related to storage capacity, injectivity, proximity to sources of CO₂, location of other natural resources and containment security. The study has concluded that there is limited scope for large-scale storage of CO₂ within the Collie Basin. In addition the potential for storage within coals of either basin is not a viable solution. This assessment is based on published criteria for CO₂ storage in sedimentary basins and coal-bearing formations.  相似文献   

Review of maritime transportation air emission pollution and policy analysis     

WANG Haifeng）  *  LIU Dahai）    DAI Guilin） ） University of Delaware  Newark  Robinson Hall DE  USA ） First Institute of Oceanography  State Oceanic Administration of China  Qingdao  P. R. China ） College of Economics  Ocean University of China  Qingdao  P. R. China 《中国海洋大学学报(英文版)》2009,8(3):283-290

The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportation have contributed to climate change and environmental degradation. Scientifically, analysts still have controversies regarding how to calculate the emissions and how to choose the baseline and methodologies. Three methods are generally used, namely the ‘bottom up’ approach, the ‘top down’ ap...  相似文献   

A Lagrangian biogeochemical study of an eddy in the Northeast Atlantic     

T.D. Jickells  P.S. Liss  S. Turner  J. Read  L.M. Cardenas  F. Carse  M. Hamren-Larssen  M. Steinke  A. Thompson  S.D. Archer  C.S. Law  P.D. Nightingale  C.E. Widdicombe  L.C. Gilpin  G. Savidge  P. Hadziabdic  R. Upstill-Goddard  R. Simó  A. Allen 《Progress in Oceanography》2008,76(3):366-398

We report the results of an experiment in the Northeast Atlantic in which sulphur hexafluoride (SF₆) was released within an eddy and the behaviour of trace gases, nutrients and productivity followed within a Lagrangian framework over a period of 24 days. Measurements were also made in the air above the eddy in order to estimate air-sea exchange rates for some components. The physical, biological and biogeochemical properties of the eddy resemble those of other eddies studied in this area, suggesting that the results we report may be applicable beyond the specific eddy studied. During a period of low wind speed at the start of the experiment, we are able to quantitatively describe and balance the nutrient and carbon budgets for the eddy. We also report concentrations of various trace gases in the region which are similar to those observed in other studies and we estimate exchange rates for several trace gases. We show that the importance of gas exchange over other loss terms varies with time and also varies for the different gases. We show that the various trace gases considered (CO₂, dimethyl sulphide (DMS), N₂O, CH₄, non-methane-hydrocarbons, methyl bromide, methyl iodide and volatile selenium species) are all influenced by physical and biological processes, but the overall distribution and temporal variability of individual gases are different to one another. A storm disrupted the stratification in the eddy during the experiment, resulting in enhanced nutrient supply to surface waters, enhanced gas exchange rates and a change in plankton community, which we quantify, although overall productivity was little changed. Emphasis is placed on the regularity of storms in the temperate ocean and the importance of these stochastic processes in such systems.  相似文献   

确定平原地下水4He年龄方法的尝试   总被引：2，自引：0，他引：2  

蔡鹤生  鄢志华  刘存富  周爱国  张俊刚  李延河  宋鹤彬 《地球学报》2005,26(Z1):275-278

放射性衰变产生的氦组分（3H衰变质产生3He，U/Th衰变产生4He）广泛地用水地下水测年。本文分析了地下水中惰性气体的组成，采用过剩空气非分馏（UA）模型进行了单独氦组分的分离。结果表明，河北平原第三含水组（Q2）中的过剩4He是含水组内原地内原地产量和深部地壳通量的共同作用的结果。由于缺乏确定氦平衡参数的约束很好的客观分析，选择应用地下水流模型主观调节来估算迭代过程中的外部通量和流速场，然后根据这个模型所取得的4He年龄与应用其他方法包括14C测年和水文模型取得的年龄进行了对比。  相似文献   

The fate of suspended sediment and particulate organic carbon in transit through the channels of a river catchment          下载免费PDF全文

Fred Worrall  Tim P. Burt  Nicholas J.K. Howden  Gregory R. Hancock  John Wainwright 《水文研究》2018,32(1):146-159

Particulate organic matter (POM) transiting through rivers could be lost to overbank storage, stored in‐channel, added to by erosion or autochthonous production, or turned over to release greenhouse gases to the atmosphere (either while in the water column or while stored in the channel). In the UK, a net loss of POM across catchments has been recorded, and the aim here was to investigate the balances of processes acting on the POM. This study considered records of suspended sediment and POM flux in comparison to stream flow, velocity, stream power, and residence time for the River Trent (English Midlands, 8,231 km²). We show that for the lower two thirds (106 km) of the River Trent, 2% is lost to overbank storage; 10% is lost to the atmosphere in the water column; and 31% is turned over while in temporary storage. Permanent in‐channel storage is negligible, and for the lower course of the river, material stored in‐channel will have a residence time of the order of hundreds of days between the last flood hydrograph of one winter and the first winter storm of the next winter (usually in the same calendar year). When considered at the scale of the UK, 1% POM in transit would be lost to overbank sedimentation; 5% turned over in the water column, and 14% turned over while in temporary storage. In the upper third of the study river channel, there is insufficient stream power to transport sediment and so in‐channel storage or in‐channel turnover over to the atmosphere dominate. The in‐channel processes of the River Trent do not conform to that expected for river channels as the headwaters are not eroding or transporting sediment. Therefore, the source of sediment must be lower down the channel network.  相似文献   

Correlation and Prediction of the Solubility of Air Gases in Saline Solutions for Mining Processes,Using Artificial Neural Networks     

《洁净——土壤、空气、水》2017,45(2)

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Diurnal,Seasonal, and Vertical Variability in Carbon Monoxide Levels at a Semi‐Urban Site in India     

《洁净——土壤、空气、水》2017,45(5)

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The Mechanisms of High N2O Emissions from Greenhouse Vegetable Field Soils     

《洁净——土壤、空气、水》2017,45(10)

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