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Sensitivity of mesoscale model urban boundary layer meteorology to the scale of urban representation
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Flagg D.D.; Taylor P.A. - Copernicus GmbH, 2011Mesoscale modeling of the urban boundary layer requires careful parameterization of the surface due to its heterogeneous morphology. Model estimated meteorological quantities, including the surface energy budget and canopy layer variables, will respond accordingly to the scale of representation. This study examines the sensitivity of the surface energy balance, canopy layer and boundary layer meteorology to the scale of urban surface representation in a real urban area (Detroit-Windsor (USA-Canada)) during several dry, cloud-free summer periods. The model used is the Weather Research and Forec ...
[article]Sensitivity of mesoscale model urban boundary layer meteorology to the scale of urban representation
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Available online: http://dx.doi.org/10.5194/acp-11-2951-2011
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2951-2972Mesoscale modeling of the urban boundary layer requires careful parameterization of the surface due to its heterogeneous morphology. Model estimated meteorological quantities, including the surface energy budget and canopy layer variables, will respond accordingly to the scale of representation. This study examines the sensitivity of the surface energy balance, canopy layer and boundary layer meteorology to the scale of urban surface representation in a real urban area (Detroit-Windsor (USA-Canada)) during several dry, cloud-free summer periods. The model used is the Weather Research and Forecasting (WRF) model with its coupled single-layer urban canopy model. Some model verification is presented using measurements from the Border Air Quality and Meteorology Study (BAQS-Met) 2007 field campaign and additional sources. Case studies span from "neighborhood" (10 s ~308 m) to very coarse (120 s ~3.7 km) resolution. Small changes in scale can affect the classification of the surface, affecting both the local and grid-average meteorology. Results indicate high sensitivity in turbulent latent heat flux from the natural surface and sensible heat flux from the urban canopy. Small scale change is also shown to delay timing of a lake-breeze front passage and can affect the timing of local transition in static stability.
Language(s): English
Format: Digital (Free)Tags: Meteorology ; Modelling ; Weather forecasting ; Research
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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 ...
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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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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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Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Schneising O.; Buchwitz M.; Reuter M.; et al. - Copernicus GmbH, 2011Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases contributing to global climate change. SCIAMACHY onboard ENVISAT (launch 2002) was the first and is now with TANSO onboard GOSAT (launch 2009) one of only two satellite instruments currently in space whose measurements are sensitive to CO2 and CH4 concentration changes in the lowest atmospheric layers where the variability due to sources and sinks is largest.
[article]Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY
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Available online: http://dx.doi.org/10.5194/acp-11-2863-2011
O. Schneising ; M. Buchwitz ; M. Reuter ; J. Heymann ; H. Bovensmann ; J.P. Burrows
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 3 [03/01/2011] . - p.2863-2880Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases contributing to global climate change. SCIAMACHY onboard ENVISAT (launch 2002) was the first and is now with TANSO onboard GOSAT (launch 2009) one of only two satellite instruments currently in space whose measurements are sensitive to CO2 and CH4 concentration changes in the lowest atmospheric layers where the variability due to sources and sinks is largest.
Language(s): English
Format: Digital (Free)Tags: Carbon dioxide (CO2) ; Methane (CH4) ; Long-range weather forecasting, long-term weather forecasting, long-range meteorological forecasting ; 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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Representation of tropical deep convection in atmospheric models – Part 1: Meteorology and comparison with satellite observations
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Russo M.R.; Marécal V.; Hoyle C.R.; et al. - Copernicus GmbH, 2011Fast convective transport in the tropics can efficiently redistribute water vapour and pollutants up to the upper troposphere. In this study we compare tropical convection characteristics for the year 2005 in a range of atmospheric models, including numerical weather prediction (NWP) models, chemistry transport models (CTMs), and chemistry-climate models (CCMs). The model runs have been performed within the framework of the SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) project. The characteristics of tropical convection, such as seasonal c ...
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The effect of H2SO4 – amine clustering on chemical ionization mass spectrometry (CIMS) measurements of gas-phase sulfuric acid
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Kurtén T.; Petäjä T.; Smith J.; et al. - Copernicus GmbH, 2011The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS) based on nitrate reagent ions. We have assessed the possible effect of the sulfuric acid molecules clustering with base molecules on CIMS measurements using computational chemistry. From the computational data, three conclusions can be drawn. First, a significant fraction of the gas-phase sulfuric acid molecules are very likely clustered with amines if the amine concentration is around or above a few ppt. Second, some fraction of these acid-amine clusters may not be cha ...
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A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Li J.; Hu Y.; Huang J.; et al. - Copernicus GmbH, 2011A method is developed based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) level 1 attenuated backscatter profile data for deriving the mean extinction coefficient of water droplets close to cloud top. The method is applicable to low level (cloud top <2 km), opaque water clouds in which the lidar signal is completely attenuated beyond about 100 m of penetration into the cloud. The photo multiplier tubes (PMTs) of the 532 nm detectors (parallel and perpendicular polarizations) of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) both exhibit a non-id ...
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Volume 89, No.1 - February 2011
is an issue of Journal of the Meteorological Society of Japan. Meteorological Society of Japan, 2011
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Anno 68 N°3 - Luglio-settembre 2008
is an issue of Rivista di Meteorologia. Organo del Servizio Meteorologico dell'Aeronautica, 2011Contiene tali:
- Il caldo anomalo del 2003 in Italia: anomalie climatiche ed
inquinamento da ozono
- HSAF - Hydrology Satellite Application Facilities: un progetto
europeo con finalità di servizio e impiego operativo
- Nuovo approccio alle previsioni stagionali: analisi
- Simulazione del Meteosat Third Generation Lightning Imager
attraverso dati reali rilevati dal satellite NASA TRMM - LIS
- Intensità delle precipitazioni: campagna internazionale di
misura a Vigna di Valle organizzata dal Ser ...
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No.10 - November 2010
is an issue of iLEAPS Newsletter. iLEAPS, 2011The latest iLEAPS Newsletter No. 10 deals with "Terrestrial feedbacks and Earth system models".
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CAWCR technical report, 43. Exploring the co-benefit of electric vehicle uptake and ozone pollution reduction in Sydney - Final report.
Given the likely pace of change in the electric vehicle market, it is important that the environmental externalities are identified and quantified. In this report we present the results of a modelling study which investigated how ozone pollution in the Greater Metropolitan Region of Sydney NSW, Australia would respond to the replacement of Sydney’s internal combustion engine (ICE) passenger vehicle fleet with a fleet of electric vehicles. A brief description of the modelling methodology is provided in the next section, and a summary of the modelling outcomes is provided in the following sectio ...
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International Polar Year (IPY). Understanding Earth's Polar challenges : International Polar Year 2007-2008 - summary by the IPY Joint Committee
The International Polar Year (IPY) 2007–2008, co-sponsored by ICSU and WMO, became the largest coordinated research program in the Earth’s polar regions, following in the footsteps of its predecessor, the first and second International Polar Years in 1881-1883 and 1932-1933 and the International Geophysical Year 1957–1958.
An estimated 50,000 researchers, local observers, educators, students, and support personnel from more than 60 nations were involved in the 228 international IPY projects (170 in science, 1 in data management, and 57 in education and outreach) and related national eff ...
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CAWCR technical report, 44. Composition of the atmosphere - abstracts of the fifth CAWCR Workshop 15 November - 17 November 2011, Melbourne, Australia
The aims of the meeting are to: 1) understand the role of atmospheric chemistry and composition in global atmospheric change as expressed in the Australasian region and internationally; and 2) to provide a forum for atmospheric composition researchers from different disciplines (in-situ observations, remote sensing observations, modelling) to share ideas, enhance collaboration and develop a coordinated regional approach to characterising atmospheric processes in Australasia.
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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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