نتایج جستجو برای: ozone layer

تعداد نتایج: 301828  

2009
Detlev Helmig Lana D. Cohen Florence Bocquet Samuel Oltmans Andrey Grachev William Neff

[1] Continuous surface-layer ozone flux measurements over the polar, year-round snowpack at Summit, Greenland, resulted in deposition velocities (vd) that were smaller than most previous assumptions and model inputs. Substantial seasonal differences were seen in the ozone vd behavior. Spring, daytime ozone vd values showed low variability and were consistently 0.01 cm s . During summer, ozone f...

2011
Cesare P. R. Romano

2001
M. J. Newchurch

This study examines 1211 cases of coincident ozone profiles derived from 1164 Umkehrs and 928 SAGE II profiles within 1000 km and 12 hours between October 1984 and April 1989 to study the stratospheric-aerosol effect on Umkehr ozone profiles. Because of the close correspondence of stratospheric aerosol optical depth at the SAGE II-measured 0.525 micron wavelength and the extrapolated 0.32 Umkeh...

Journal: :مهندسی بیوسیستم ایران 0
علیرضا شاه محمدی دانشگاه شهید بهشتی هادی ویسی دانشیار گروه اگرو اگولوژی پژوهشکده علوم محیطی دانشگاه شهید بهشتی کوروس خوشبخت دانشیار گروه آگرواکولوژی،پژوهشکده علوم محیطی، دانشگاه شهید بهشتی،تهران عبدالمجید مهدوی دامغانی دانشیار گروه آگرواکولوژی،پژوهشکده علوم محیطی، دانشگاه شهید بهشتی،تهران الیاس سلطانی استادیار گروه زراعت و اصلاح نباتات، پردیس ابوریحان، دانشگاه تهران

in recent years, the debate over the environmental sustainability of agricultural productions is widely increased. in this context, environmental impacts of potato production by semi-mechanized method were studied in markazi province of iran. in this research, life cycle assessment approach was used to identify and reduce environmental impacts. the environmental impacts of potato production in ...

Journal: :Eos, Transactions American Geophysical Union 2002

2017
Ryan Hossaini Martyn P Chipperfield Stephen A Montzka Amber A Leeson Sandip S Dhomse John A Pyle

It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-...

Journal: :فیزیک زمین و فضا 0
زهرا شرعی پور کارشناس ارشد هواشناسی، گروه فیزیک فضا، مؤسسه ژئوفیزیک، دانشگاه تهران، ایران عباسعلی علی اکبری بیدختی استاد گروه فیزیک فضا، مؤسسه ژئوفیزیک دانشگاه تهران، ایران

near surface ozone in urban areas can be potentially hazardous for the city dwellers. as a secondary pollutant it can also be an indicator for other air pollutants as nitrogen oxides, nox and phenol acetate nitrate (pan). in this paper time and spatial variations of near surface ozone and the effective meteorological parameters influencing it concentrations, have been investigated for tehran fo...

2014
Lanxia Cheng Xiaoye Qin Antonio T. Lucero Angelica Azcatl Jie Huang Robert M. Wallace Kyeongjae Cho Jiyoung Kim

We present an Al2O3 dielectric layer on molybdenum disulfide (MoS2), deposited using atomic layer deposition (ALD) with ozone/trimethylaluminum (TMA) and water/TMA as precursors. The results of atomic force microscopy and low-energy ion scattering spectroscopy show that using TMA and ozone as precursors leads to the formation of uniform Al2O3 layers, in contrast to the incomplete coverage we ob...

2006
Wayne Smith

Ozone is the triatomic state of oxygen, that is, it is a molecule comprising of three oxygen atoms having the chemical symbol O3. Although ozone does exist naturally, it is a relatively unstable and reactive gas. Therefore ozone exists in the lower atmosphere at low concentrations. The greatest quantities of natural ozone are found at levels of up to 6 ppm in the stratosphere, thus the term the...

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