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151.
Xuan Chen Masatoshi Aoki Shangxun Zhang Jinhua Zhang Susumu Nozoe Daisuke Komori Akinori Takami Shiro Hatakeyama 《Journal of Atmospheric Chemistry》2008,60(1):37-49
In order to study the concentrations of hydrogen peroxide (H2O2) and the factors controlling its concentrations, we monitored concentrations of H2O2 and other gases such as sulfur dioxide, ozone, and NO
x
as well as meteorological factors such as air temperature, relative humidity, and wind direction/speed during eight measurement
periods from 2000 to 2002 in a Japanese red pine forest in Japan. The H2O2 concentrations ranged from below 0.01 to 1.64 ppb, and analysis of the diurnal variation in H2O2 concentration showed high concentrations around noon, and low concentrations in the morning and late afternoon. The H2O2 concentrations were high in early summer, when O3 concentration, temperature, and solar radiation were high, and were low in fall, when O3 concentration, temperature, and solar radiation were low. We propose that O3 concentration affects the production of H2O2 in the monitored region during the period under study, but that high H2O2 concentrations were sometimes caused by the transport of polluted air from urban regions. H2O2 concentrations decreased remarkably when SO2 concentrations increased by transported volcanic emission on Miyake Island. In the absence of the effects of SO2, H2O2 concentrations increased with increasing O3 concentration and temperature. 相似文献
152.
153.
To assess the potential impacts of the US withdrawal from the Paris Agreement, this study applied GCAM-TU (an updated version of the Global Change Assessment Model) to simulate global and regional emission pathways of energy-related CO2, which show that US emissions in 2100 would reduce to ?2.4?Gt, ?0.7?Gt and ?0.2?Gt under scenarios of RCP2.6, RCP3.7 and RCP4.5, respectively. Two unfavourable policy scenarios were designed, assuming a temporary delay and a complete stop for US mitigation actions after 2015. Simulations by the Model for the Assessment of Greenhouse-gas Induced Climate Change (MAGICC) indicate that the temperature increase by 2100 would rise by 0.081°C–0.161°C compared to the three original RCPs (Representative Concentration Pathways) if US emissions were kept at their 2015 levels until 2100. The probability of staying below 2°C would decrease by 6–9% even if the US resumes mitigation efforts for achieving its Nationally Determined Contribution (NDC) target after 2025. It is estimated by GCAM-TU that, without US participation, increased reduction efforts are required for the rest of the world, including developing countries, in order to achieve the 2°C goal, resulting in 18% higher global cumulative mitigation costs from 2015 to 2100.Key policy insights
President Trump’s climate policies, including planned withdrawal from the Paris Agreement, cast a shadow on international climate actions, and would lower the likelihood of achieving the 2°C target.
To meet the 2°C target without the US means increased reduction efforts and mitigation costs for the rest of the world, and considerable economic burdens for major developing areas.
Active state-, city- and enterprise-level powers should be supported to keep the emission reduction gap from further widening even with reduced mitigation efforts from the US federal government.
154.
在TOGA-COAREIOP期间用涡度相关法对海气热通量进行了船载直接观测.对垂直风速、温度和湿度湍流脉动观测数据的谱分析显示它们在高频区基本满足"-2/3次方律".对船体简谐震荡影响的讨论从理论上证明该影响在热通量计算中可被忽略.根据以此方法得到的通量求出了中性层结条件下感热和潜热的整体输送系数分别为2.25×10-3和1.26×10-3.对海气边界层特性的分析表明该海域的近海层主要呈中性或弱不稳定层结.海气通量的变化与背景环流形势密切相关,潜热通量主要受海面风场强度的影响,而感热通量变化除了风场的影响外,层结变化也是一个重要因素.用整体输送法计算TOGA-COAREIOP期间以及TOGA期间8个航次的通量结果而得到的Bowen比约为0.1,显示潜热通量是暖池大气的主要热源. 相似文献
155.
薛建康 《成都信息工程学院学报》1990,(1)
本文针对冬半年高原低涡几个不同源地的低涡生成背景,着重分析500hpa环流场,指出:地形对低涡生成是非常重要的条件,但一定范围内有利的环境流场也是低涡生成不可缺少的外部条件。并给出了不同涡源区有利于低涡发生,发展的500hpa环流形势。 相似文献
156.
Analysis of ocean fronts' uncertainties indicates that they result from indiseemibility of their spatial position and fuzzi-ness of their intensity. In view of this, a flow hierarchy for uncertainty representation of ocean fronts is proposed on the basis of fuzzy-rough set theory. Firstly, raster scanning and blurring are carried out on an ocean front, and the upper and lower approximate sets, the indiscernible relation in fuzzy-rough theories and related operators in fuzzy set theories are adopted to represent its uncer-tainties, then they are classified into three sets: with members one hundred pereent belonging to the ocean front, belonging to the ocean front's edge and definitely not belonging to the ocean front. Finally, the approximate precision and roughness degree are util-ized to evaluate the ocean front's degree of uncertainties and the precision of the representation. It has been proven that the method is not only capable of representing ocean fronts' uncertainties, but also provides a new theory and method for uncertainty representation of other oceanic phenomena. 相似文献
157.
We present a new survey for Hα emission objects in the Circinus cloud complex and introduce an efficient photometric method for detecting Hα emission via observations in a narrow‐band filter. The observed flux is compared to a blackbody fit of the continuum. Our search strategy reveals 20 stars with strong Hα emission (EW > 10 Å), eight of them being new detections. All Hα stars display infrared excess corroborating their youth. On the other hand, the region contains a number of infrared excess objects that do not show Hα emission. Our results support the picture that accretion – as witnessed by Hα emission – is a highly variable phenomenon. Therefore, Hα surveys can only trace the temporarily active objects. In contrast, infrared excess is a more robust tracer that reveals most of the population of young stellar objects in a star forming region. Our analysis of the general stellar content of the region yields a reliable distance of 450 pc for the Circinus cloud. Moreover, we find a ratio of total‐to‐selective extinction of RV = 2.8 suggesting that smaller‐than‐normal dust grains may be present. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
158.
An accessible strong-motion dataset (PGA,PGV, and site vS30) of 2022 MS6.8 Luding,China Earthquake 下载免费PDF全文
Jian Zhou Nan Xi Chuanchuan Kang Li Li Kun Chen Xin Tian Chao Wang Jifeng Tian 《地震科学(英文版)》2023,36(4):309-315
A MS6.8 earthquake occurred on 5th September 2022 in Luding county, Sichuan, China, at 12: 52 Beijing Time(4:52 UTC). We complied a dataset of PGA, PGV, and site vS30 of 73 accelerometers and 791 Micro-Electro-Mechanical System(MEMS)sensors within 300 km of the epicenter. The inferred vS30 of 820 recording sites were validated. The study results show that:(1)The maximum horizontal PGA and PGV reaches 634.1 Gal and 71.1 cm/s respectively.(2) Over 80% of records ar... 相似文献
159.
福建明溪上地幔热结构及流变学特征 总被引:3,自引:0,他引:3
通过对采自福建明溪的幔源包体样品的详细研究,建立了该区上地幔的地温线,探讨其流变学特征。所获地温线高于大洋地温线,但稍低于中国东部和澳大利亚东南部地温线。由该地温线推导的壳幔边界为38km左右,但尖晶石二辉橄榄岩在32km左右即已开始出现,表明存在上地幔物质的底侵作用。同样,尖晶石二辉橄榄岩和石榴子石二辉橄榄岩包体平衡温度有所重叠,表明两者不是截然分开,其间存在有5 ̄10km的过渡带。包体的变形特 相似文献
160.
为了研究碱湖N2O释放速率及其对盐度与pH的响应,选取内蒙古大克泊碱湖的五个沉积物样点,采用15N同位素标记模拟实验,研究反硝化和厌氧氨氧化的速率、相对比例和气体产生情况,揭示高盐和高pH对碱湖氮移除的影响。发现大克泊湖潜在氮移除速率为0~16.06 n mol N mL-1 h-1,潜在反硝化速率为0~12.62 n mol N mL-1 h-1,潜在厌氧氨氧化速率为0~9.81 n mol N mL-1 h-1;当盐度34.00 g·L-1与pH 10.22时,厌氧氨氧化对氮移除贡献较大,达到43.18%~71.79%。反硝化过程气体产物以N2为主,几乎无N2O气体释出。另外,该区域潜在氮移除速率与pH呈正相关关系,与TOC、NO-3、HCO-3呈负相关关系;未发现氮移除速率与盐度之间的相关关系。因此,在研究的碱湖中,氮移除过程中主要为N2排放,而N2O低于检测水平;氮移除过程的影响因素复杂且不限于最主要的环境变量(盐度与pH)。这些结果为研究湖泊N2O排放提供了数据基础。 相似文献