冷泉系统甲烷气体渗漏的声学特征及潜在环境效应     

尉建功  吴婷婷  邓希光  于宗泽  王力峰 《海洋学报(英文版)》2020,42(5):133-144

The amount of methane leaked from deep sea cold seeps is enormous and potentially affects the global warming,ocean acidification and global carbon cycle. It is of great significance to study the methane bubble movement and dissolution process in the water column and its output to the atmosphere. Methane bubbles produce strong acoustic impedance in water bodies, and bubble strings released from deep sea cold seeps are called "gas flares"which expressed as flame-like strong backscatter in the water column. We characterized the morphology and movement of methane bubbles released into the water using multibeam water column data at two cold seeps. The result shows that methane at site I reached 920 m water depth without passing through the top of the gas hydrate stability zone(GHSZ, 850 m), while methane bubbles at site II passed through the top of the GHSZ(597 m) and entered the non-GHSZ(above 550 m). By applying two methods on the multibeam data, the bubble rising velocity in the water column at sites I and II were estimated to be 9.6 cm/s and 24 cm/s, respectively. Bubble velocity is positively associated with water depth which is inferred to be resulted from decrease of bubble size during methane ascending in the water. Combined with numerical simulation, we concluded that formation of gas hydrate shells plays an important role in helping methane bubbles entering the upper water bodies, while other factors, including water depth, bubble velocity, initial kinetic energy and bubble size, also influence the bubble residence time in the water and the possibility of methane entering the atmosphere. We estimate that methane gas flux at these two sites is 0.4×10~6–87.6×10~6 mol/a which is extremely small compared to the total amount of methane in the ocean body, however, methane leakage might exert significant impact on the ocean acidification considering the widespread distributed cold seeps. In addition, although methane entering the atmosphere is not observed, further research is still needed to understand its potential impact on increasing methane concentration in the surface seawater and gas-water interface methane exchange rate, which consequently increase the greenhouse effect.  相似文献   

中国超基性岩封存CO2的潜力研究   总被引：2，自引：0，他引：2  

盛雪芬  季峻峰  陈骏 《第四纪研究》2011,31(3):447-454

大气CO<,2>浓度上升引起的气候效应正受到国际社会的高度关注.超基性岩石与CO<,2>反应可生成稳定的碳酸盐矿物而永久性地固定CO<,2>,有效地降低人类活动排放到大气中CO<,2>浓度,从而缓解日趋严重的温室效应带来的全球气候恶化.根据各省<区域地质志>记载的超基性岩体的岩石学、地球化学资料,按照公式:T=1/3·...  相似文献   

“全球气候变化对人类活动的影响”教学过程设计     

黄琳琳 《地理教学》2011,(10):10-12

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还原CO2增多导致全球变暖的一些误读     

王家伟  段玉山 《地理教学》2010,(24):4-7

众所周知，CO2是一种温室气体。但在生活中，很多人一提到温室气体就会联想到CO2和温室效应，继而认为是人类排放的大量二氧化碳加剧了温室效应从而引起了全球变暖。在他们看来，CO2等温室气体是有害气体，是它们导致了全球变暖，进而导致了一系列因全球变暖而来的灾难。于是世界各国都在积极呼吁提倡低碳生活，主张减少碳排放，进而缓解全球变暖的趋势。事实真是如此吗？是CO2增多导致全球变暖了吗？  相似文献   

评述气候变化和温室效应     

D·E帕克 《内蒙古气象》1990,(4):40-41

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一个众说纷纭的话题     

王章敏 《湖北气象》1998,(3):41-42

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Coupled Model Simulations of Climate Changes in the 20th Century and Beyond   总被引：10，自引：1，他引：9  

YU Yongqiang  ZHI Hai  WANG Bin  WAN Hui  LI Chao  LIU Hailong  LI Wei  ZHENG Weipeng  ZHOU Tianjun 《大气科学进展》2008,25(4):641-654

Several scenario experiments of the IPCC 4th Assessment Report （AR4） are performed by version g1.0 of a Flexible coupled Ocean-Atmosphere-Land System Model （FGOALS） developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences （IAP/CAS）, including the ＂Climate of the 20th century experiment＂, ＂CO2 1% increase per year to doubling experiment＂ and two separate IPCC greenhouse gases emission scenarios AIB and B1 experiments. To distinguish between the different impacts of natural variations and human activities on the climate change, three-member ensemble runs are performed for each scenario experiment. The coupled model simulations show： （1） from 1900 to 2000, the global mean temper- ature increases about 0.5℃ and the major increase occurs during the later half of the 20th century, which is in consistent with the observations that highlights the coupled model＇s ability to reproduce the climate changes since the industrial revolution; （2） the global mean surface air temperature increases about 1.6℃ in the CO2 doubling experiment and 1.5℃ and 2.4℃ in the A1B and B1 scenarios, respectively. The global warming is indicated by not only the changes of the surface temperature and precipitation but also the temperature increase in the deep ocean. The thermal expansion of the sea water would induce the rise of the global mean sea level. Both the control run and the 20th century climate change run are carried out again with version g1.1 of FGOALS, in which the cold biases in the high latitudes were removed. They are then compared with those from version g1.0 of FGOALS in order to distinguish the effect of the model biases on the simulation of global warming.  相似文献   

大气中的“关卡”——约翰&#183;廷德耳和他的温室气体研究     

吴溪 《海洋世界》2009,(6)

2009年是达尔文诞辰200周年,同时也是《物种起源》出版150周年。1859年,《物种起源》横空出世,震动了全世界。其实,就在《物种起源》出版前6个月,即1859年5月,爱尔兰物理学家约翰&#183;廷德耳通过实验证明了一些气体对热辐射的显著吸收能力,为“温室效应”奠定了理论基础。当时,廷德耳的实验仅在学术界“激起几朵浪花”,并未引起更多的关注。今天,“温室效应”和“全球变暖”已成为世界性的话题,甚至被抬上了政治高度。在阐述进化论的理论之前,达尔文环游了世界,思考了20年;而廷德耳为了证明某些气体的“温室效应”,把自己关在伦敦的一间没有窗户的地下室,做了几个礼拜的实验。  相似文献   

北极上空的区域性温室效应     

汤家礼 《海洋世界》2009,(3):1-1

由美国国家航空航天局Ouikscat卫星拍摄的一组照片显示，近些年来，覆盖在北冰洋表面的冰盖正发生着剧烈的变化。早在2004年到2005年间，北极地区原先即使在夏季也不会融合的冰盖就已萎缩了14％。而今，北极地区消失的冰盖总面积已经超过72万平方千米——相当于巴基斯坦或是土耳其的国土面积。  相似文献   

Impact of land use changes on surface warming in China   总被引：29，自引：1，他引：28  

ZHANG Jingyong  DONG Wenjie  WU Lingyun  WEI Jiangfeng  CHEN Peiyan  Dong-Kyou LEE 《大气科学进展》2005,22(3):343-348

Land use changes such as urbanization, agriculture, pasturing, deforestation, desertification and irrigation can change the land surface heat flux directly, and also change the atmospheric circulation indirectly, and therefore affect the local temperature. But it is difficult to separate their effects from climate trends such as greenhouse-gas effects. Comparing the decadal trends of the observation station data with those of the NCEP/NCAR Reanalysis (NNR) data provides a good method to separate the effects because the NNR is insensitive to land surface changes. The effects of urbanization and other land use changes over China are estimated by using the difference between the station and the NNR surface temperature trends. Our results show that urbanization and other land use changes may contribute to the observed 0.12℃ (10 yr)- 1 increase for daily mean surface temperature, and the 0.20℃ (10 yr)- 1 and 0.03℃ (10 yr)-1 increases for the daily minimum and maximum surface temperatures, respectively. The urban heat island effect and the effects of other land-use changes mayalso play an important role in the diurnal temperature range change. The spatial pattern of the differences in trends shows a marked heterogeneity.The land surface degradation such as deforestation and desertification due to human activities over northern China, and rapidly-developed urbanization over southern China, may have mostly contributed to the increases at stations north of about 38°N and in Southeast China, respectively. Furthermore, the vegetation cover increase due to irrigation and fertilization may have contributed to the decreasing trend of surface temperature over the lower Yellow River Basin. The study illustrates the possible impacts of land use changes on surface temperature over China.  相似文献