نتایج جستجو برای: atmospheric composition

تعداد نتایج: 332625  

Journal: :PLoS ONE 2008
Rajkumar Sasidharan Andrew Smith Mark Gerstein

Recently, there was a report that explored the oxygen content of transmembrane proteins over macroevolutionary time scales where the authors observed a correlation between the geological time of appearance of compartmentalized cells with atmospheric oxygen concentration. The authors predicted, characterized and correlated the differences in the structure and composition of transmembrane protein...

Journal: :international journal of environmental research 2011
g.t. eneke s.n. ayonghe d. chandrasekharam r. ntchancho a.a. ako

douala metropolitan city loated in the littoral province of cameroon,has experienced a rapid urbaniation and industralisation. the city depends heavily on groundwater as a resource. due to ubiquitous sources of pollution, groundwater quality and contamination has become an imprtant issue for this urban groundwater supply. this study uses the major ion chemistry of groundwater together with t...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Mao-Chang Liang Geoffrey A Blake Brenton R Lewis Yuk L Yung

The isotopic composition of long-lived trace molecules provides a window into atmospheric transport and chemistry. Carbon dioxide is a particularly powerful tracer, because its abundance remains >100 parts per million by volume (ppmv) in the mesosphere. Here, we successfully reproduce the isotopic composition of CO(2) in the middle atmosphere, which has not been previously reported. The mass-in...

2014
I. Kourtchev S. J. Fuller C. Giorio R. M. Healy E. Wilson I. O’Connor J. C. Wenger M. McLeod J. Aalto T. M. Ruuskanen W. Maenhaut R. Jones D. S. Venables J. R. Sodeau M. Kulmala

Numerous laboratory experiments have been performed in an attempt to mimic atmospheric secondary organic aerosol (SOA) formation. However, it is still unclear how close the aerosol particles generated in laboratory experiments resemble atmospheric SOA with respect to their detailed chemical composition. In this study, we generated SOA in a simulation chamber from the ozonolysis of αpinene and a...

Journal: :The journal of physical chemistry. A 2015
Jesse H Kroll Christopher Y Lim Sean H Kessler Kevin R Wilson

Atmospheric oxidation reactions are known to affect the chemical composition of organic aerosol (OA) particles over timescales of several days, but the details of such oxidative aging reactions are poorly understood. In this study we examine the rates and products of a key class of aging reaction, the heterogeneous oxidation of particle-phase organic species by the gas-phase hydroxyl radical (O...

2014
J. Flemming

A representation of atmospheric chemistry has been included in the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The new chemistry modules complement the aerosol modules of the IFS for atmospheric composition, which is named C-IFS. C-IFS for chemistry supersedes a coupled system in which chemical transport model (CTM) Model for OZone and ...

Journal: :Applied and environmental microbiology 2010
Hector F Castro Aimée T Classen Emily E Austin Richard J Norby Christopher W Schadt

Researchers agree that climate change factors such as rising atmospheric [CO2] and warming will likely interact to modify ecosystem properties and processes. However, the response of the microbial communities that regulate ecosystem processes is less predictable. We measured the direct and interactive effects of climatic change on soil fungal and bacterial communities (abundance and composition...

2011
Kei Yoshimura Christian Frankenberg Jeonghoon Lee Masao Kanamitsu John Worden Thomas Röckmann

[1] We performed an intensive comparison of an isotope‐incorporated atmospheric general circulation model with vapor isotopologue ratio observation data by two quasi‐global satellite sensors in preparation for data assimilation of water isotope ratios. A global Isotope‐incorporated Global Spectral Model simulation nudged toward the reanalysis wind field, atmospheric total column data from Scann...

Journal: :Science 2017
Stella M Hurtley

sciencemag.org SCIENCE composition of an atmosphere can provide evidence for how an exoplanet formed. Wakeford et al. used the Hubble and Spitzer space telescopes to measure the spectrum of the atmosphere around HAT-P-26b, a Neptunesized exoplanet discovered in 2011. They detected signatures of water and clouds; this allowed them to constrain the atmospheric composition, which appears not to ha...

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