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Characteristics of CALIOP attenuated backscatter noise: implication for cloud/aerosol detection
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Wu D.L.; Chae J.H.; Lambert A.; et al. - Copernicus GmbH, 2011A research algorithm is developed for noise evaluation and feature detection of the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) Level 1 (L1) backscatter data with an emphasis on cloud/aerosol features in the upper troposphere and lower stratosphere (UT/LS). CALIOP measurement noise of the version v2.01 and v2.02 L1 backscatter data aggregated to (5 km) horizontal resolution is analyzed with two approaches in this study. One is to compare the observed and modeled molecular scatter profiles by scaling the modeled profile (with a fitted scaling factor α) to the observed clear-sky ba ...[article]
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Available online: http://dx.doi.org/10.5194/acp-11-2641-2011
D.L. Wu ; J.H. Chae ; A. Lambert ; F.F. Zhang
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2641-2654A research algorithm is developed for noise evaluation and feature detection of the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) Level 1 (L1) backscatter data with an emphasis on cloud/aerosol features in the upper troposphere and lower stratosphere (UT/LS). CALIOP measurement noise of the version v2.01 and v2.02 L1 backscatter data aggregated to (5 km) horizontal resolution is analyzed with two approaches in this study. One is to compare the observed and modeled molecular scatter profiles by scaling the modeled profile (with a fitted scaling factor α) to the observed clear-sky backscatter profiles. This scaling α value is sensitive to errors in the calibrated backscatter and the atmospheric model used. Most of the nighttime 532-nm α values are close to unity, as expected, but an abrupt drop occurred in October 2008 in the daytime 532-nm α, which is likely indicative of a problem in the v2.02 daytime calibrated data. The 1064-nm night α is generally close to 2 while its day α is ~3. The other approach to evaluate the lidar measurement noise is to use the calibrated lidar backscatter data at altitudes above 19 km. With this method, the 532-nm and 1064-nm measurement noises are analyzed and characterized individually for each profile in terms of the mean (μ) and standard deviation (σ), showing larger σ values in general over landmasses or bright surfaces during day and in radiation-hard regions during night. A significant increasing trend is evident in the nighttime 1064-nm σ, which is likely responsible for the increasing difference between the feature occurrence frequencies (532-nm vs. 1064-nm) derived from this study. For feature detection with the research algorithm, we apply a σ–based method to the aggregated L1 data. The derived morphology of feature occurrence frequency is in general agreement with that obtained from the Level 2 (L2) 05 km_CLAY+05 km_ALAY products at 5 km horizontal resolution. Finally, a normalized probability density function (PDF) method is employed to evaluate the day-night backscatter data in which noise levels are largely different. CALIOP observations reveal a higher probability of daytime cloud/aerosol occurrence than nighttime in the tropical UT/LS region for 532-nm total backscatters >0.01 km−1 sr−1.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Atmosphere ; Observations ; Research
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On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Fuentes E.; Coe H.; Green D.; et al. - Copernicus GmbH, 2011The effect of nanogel colloidal and dissolved organic matter[article]On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity
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Available online: http://dx.doi.org/10.5194/acp-11-2585-2011
E. Fuentes ; H. Coe ; D. Green ; G. McFiggans
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2585-2602The effect of nanogel colloidal and dissolved organic matter
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Ecosystem ; Environment and landscape ; Ocean-atmosphere interaction ; Cloud condensation nuclei (CCN) ; Oceans
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Cloud condensation nuclei in polluted air and biomass burning smoke near the mega-city Guangzhou, China – Part 2: Size-resolved aerosol chemical composition, diurnal cycles, and externally mixed weakly CCN-active soot particles
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Rose D.; Gunthe S.S.; Su H.; et al. - Copernicus GmbH, 2011Size-resolved chemical composition, mixing state, and cloud condensation nucleus (CCN) activity of aerosol particles in polluted mega-city air and biomass burning smoke were measured during the PRIDE-PRD2006 campaign near Guangzhou, China, using an aerosol mass spectrometer (AMS), a volatility tandem differential mobility analyzer (VTDMA), and a continuous-flow CCN counter (DMT-CCNC).[article]Cloud condensation nuclei in polluted air and biomass burning smoke near the mega-city Guangzhou, China – Part 2: Size-resolved aerosol chemical composition, diurnal cycles, and externally mixed weakly CCN-active soot particles
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Available online: http://dx.doi.org/10.5194/acp-11-2817-2011
D. Rose ; S.S. Gunthe ; H. Su ; R.M. Garland ; H. Yang ; M. Berghof ; Y.F. Cheng ; B. Wehner ; P. Achtert ; A. Nowak ; A. Wiedensohler ; N. Takegawa ; Y. Kondo ; M. Hu ; Y. Zhang ; M.O. Andreae ; U. Pöschl
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2817-2836Size-resolved chemical composition, mixing state, and cloud condensation nucleus (CCN) activity of aerosol particles in polluted mega-city air and biomass burning smoke were measured during the PRIDE-PRD2006 campaign near Guangzhou, China, using an aerosol mass spectrometer (AMS), a volatility tandem differential mobility analyzer (VTDMA), and a continuous-flow CCN counter (DMT-CCNC).
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Biomass ; Cloud condensation nuclei (CCN) ; Air pollution ; Research
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Photochemical processing of organic aerosol at nearby continental sites: contrast between urban plumes and regional aerosol
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Slowik J.G.; Brook J.; Chang R.Y.-W.; et al. - Copernicus GmbH, 2011As part of the BAQS-Met 2007 field campaign, Aerodyne time-of-flight aerosol mass spectrometers (ToF-AMS) were deployed at two sites in southwestern Ontario from 17 June to 11 July 2007. One instrument was located at Harrow, ON, a rural, agriculture-dominated area approximately 40 km southeast of the Detroit/Windsor/Windsor urban area and 5 km north of Lake Erie. The second instrument was located at Bear Creek, ON, a rural site approximately 70 km northeast of the Harrow site and 50 km east of Detroit/Windsor. Positive matrix factorization analysis of the combined organic mass spectral dataset ...[article]Photochemical processing of organic aerosol at nearby continental sites: contrast between urban plumes and regional aerosol
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Available online: http://dx.doi.org/10.5194/acp-11-2991-2011
J.G. Slowik ; J. Brook ; R.Y.-W. Chang ; G.J. Evans ; K. Hayden ; C.-H. Jeong ; S.-M. Li ; J. Liggio ; P.S.K. Liu ; M. McGuire ; C. Mihele ; S. Sjostedt ; A. Vlasenko ; J.P.D. Abbatt
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2991-3006As part of the BAQS-Met 2007 field campaign, Aerodyne time-of-flight aerosol mass spectrometers (ToF-AMS) were deployed at two sites in southwestern Ontario from 17 June to 11 July 2007. One instrument was located at Harrow, ON, a rural, agriculture-dominated area approximately 40 km southeast of the Detroit/Windsor/Windsor urban area and 5 km north of Lake Erie. The second instrument was located at Bear Creek, ON, a rural site approximately 70 km northeast of the Harrow site and 50 km east of Detroit/Windsor. Positive matrix factorization analysis of the combined organic mass spectral dataset yields factors related to secondary organic aerosol (SOA), direct emissions, and a factor tentatively attributed to the reactive uptake of isoprene and/or condensation of its early generation reaction products. This is the first application of PMF to simultaneous AMS measurements at different sites, an approach which allows for self-consistent, direct comparison of the datasets. Case studies are utilized to investigate processing of SOA from (1) fresh emissions from Detroit/Windsor and (2) regional aerosol during periods of inter-site flow. A strong correlation is observed between SOA/excess CO and photochemical age as represented by the NOx/NOy ratio for Detroit/Windsor outflow. Although this correlation is not evident for more aged air, measurements at the two sites during inter-site transport nevertheless show evidence of continued atmospheric processing by SOA production. However, the rate of SOA production decreases with airmass age from an initial value of ~10.1 μg m−3 ppmvCO−1 h−1 for the first ~10 h of plume processing to near-zero in an aged airmass (i.e. after several days). The initial SOA production rate is comparable to the observed rate in Mexico City over similar timescales.
Language(s): English
Format: DigitalTags: Aerosols ; Ecology ; Environment and landscape ; Research ; Canada
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Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Kuhn T.; Earle M.E.; Khalizov A.F.; et al. - Copernicus GmbH, 2011The relative roles of volume and surface nucleation were investigated for the homogeneous freezing of pure water droplets. Experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled water aerosols with maximum volume densities at radii between 1 and 3 μm. Temperature- and size-dependent values of volume- and surface-based homogeneous nucleation rates between 234.8 and 236.2 K were derived using a microphysical model and aerosol phase compositions and size distributions determined from infrared extinction measurements in the flow tube. The results show that the cont ...[article]Size dependence of volume and surface nucleation rates for homogeneous freezing of supercooled water droplets
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Available online: http://dx.doi.org/10.5194/acp-11-2853-2011
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2853-2861The relative roles of volume and surface nucleation were investigated for the homogeneous freezing of pure water droplets. Experiments were carried out in a cryogenic laminar aerosol flow tube using supercooled water aerosols with maximum volume densities at radii between 1 and 3 μm. Temperature- and size-dependent values of volume- and surface-based homogeneous nucleation rates between 234.8 and 236.2 K were derived using a microphysical model and aerosol phase compositions and size distributions determined from infrared extinction measurements in the flow tube. The results show that the contribution from nucleation at the droplet surface increases with decreasing droplet radius and dominates over nucleation in the bulk droplet volume for droplets with radii smaller than approximately 5 μm. This is interpreted in terms of a lowered free energy of ice germ formation in the surface-based process. The implications of surface nucleation for the parameterization of homogeneous ice nucleation in numerical models are considered.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Atmosphere ; Glaciology ; Air pollution ; Water pollution
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Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Zieger P.; Weingartner E.; Henzing J.; et al. - Copernicus GmbH, 2011In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RHPermalink![]()
Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Zieger P.; Weingartner E.; Henzing J.; et al. - Copernicus GmbH, 2011In the field, aerosol in-situ measurements are often performed under dry conditions (relative humidity RHPermalink![]()
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GAW Report, 200. WMO/GAW Standard Operating Procedures for In-situ Measurements of Aerosol Mass Concentration, Light Scattering and Light Absorption
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Formation and Transport of Aerosols in Tokyo in Relation to Their Physical and Chemical Properties: a Review
Journal of the Meteorological Society of Japan, Vol. 88. No 4. Kondo Yutaka; Takegawa Nobuyuki; Matsui Hitoshi - Meteorological Society of Japan, 2010Large amounts of reactive gases and aerosols are emitted from urban areas. Megacities, including the Tokyo Metropolitan Area (TMA), are very large, concentrated sources of these species affecting local, regional, and global ozone (O3) and aerosol levels. Emissions strongly influence air quality and climate on these scales. In 2003-2004, we made intensive measurements of O3 and chemical composition of aerosol particles with diameters less than 1 µm (PM1 aerosol) together with their precursors for the first time in Tokyo, Japan, as a part of the series of Integrated Measurement Program for Aeros ...Permalink![]()
Analysis of South Asian Monsoons within the Context of Increasing Regional Black Carbon Aerosols
Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Mahmood Rashed; Yao Jin-Feng - Science Press, 2010South Asian monsoons were analyzed within the context of increasing emissions of black carbon (BC) aerosols using a global atmospheric general circulation model. The BC aerosols were allowed to increase only over the south Asian domain to analyze the impacts of regional black carbon over the climatological patterns of monsoons. The black carbon significantly absorbed the incoming short wave radiation in the atmosphere, a result that is consistent with previous studies. Pre-monsoon (March-April-May) rainfall showed positive anomalies, particularly for some coastal regions of India. The summer ( ...Permalink![]()
Aerosol Indirect Effects on Warm Clouds in the Grid-Point Atmospheric Model of IAP LASG (GAMIL)
Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Shi Xiang-Jun; Wang Bin; Liu Xiao-Hong; et al. - Science Press, 2010Aerosol indirect effects on warm clouds are estimated in the Grid-point Atmospheric Model of IAP LASG (GAMIL) with a new two-moment cloud microphysics scheme using two different physically-based aerosol activation parameterizations: Abdul-Razzak and Ghan, and Nenes and Seinfeld. The annual global mean changes in shortwave cloud forcing from preindustrial times to present day (a measure of the aerosol indirect effects) estimated from these two parameterizations are remarkably similar: 0.76 W m-2 with the Abdul-Razzak and Ghan parameterization, and 0.78 W m-2 with the Nenes and Seinfeld paramete ...Permalink![]()
Volume 3 Number 4 - 16 July 2010
is an issue of Atmospheric and Oceanic Science Letters. Science Press, 2010Permalink![]()
GOES-R: Benefits of Next-Generation Environmental Monitoring
This module is an introduction to NOAA's next generation Geostationary Operational Environmental Satellite-R (GOES-R) series, focusing on the value and anticipated benefits derived from an enhanced suite of instruments for improved monitoring of meteorological, environmental, climate, and space weather phenomena and related hazards. An extensive set of visualizations highlight GOES-R and its advanced observing capabilities for providing support in thirteen key environmental application areas including air quality and visibility, climate, cloud icing, fires, hurricanes, land cover, lightning, l ...PermalinkPermalinkPermalink