The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
J L Palau - One of the best experts on this subject based on the ideXlab platform.
-
daily evolution of Sulphate Aerosols in a rural area northeastern spain elucidation of an atmospheric reservoir effect
Environmental Pollution, 1999Co-Authors: Xavier Querol, Andres Alastuey, A Lopezsoler, F Plana, J A Puicercus, Enrique Mantilla, J L PalauAbstract:The present work is focused on the daily evolution in the levels and composition of total suspended particles and PM10 (particulate matter <10 microns) in rural areas around the Teruel power station in northeastern Spain, with special emphasis on Sulphate Aerosols. A daily cycle in the levels of natural and Sulphate aerosol is evidenced by higher ratios of Sulphate/soil elements during the diurnal stage when compared with the nocturnal period. The origin of this cycle is probably related to higher SO2 oxidation rates and a higher frequency of plume impacts on the surface during the diurnal period. However, this trend is frequently disturbed by local atmospheric dynamics which give rise to an atmospheric reservoir of Sulphate Aerosols which increase nocturnal Sulphate levels without major SO2 plume impacts. These atmospheric dynamics are described in spring, summer and winter measurement campaigns which are characterised by different plume dispersion scenarios. The results indicate that the three following situations concerning the Sulphate levels can be present in the study area: (1) direct plume impacts inducing high Sulphate levels in short time periods; (2) a Sulphate reservoir effect leading to relatively high Sulphate background levels, homogeneously distributed at distances of 60 km from the power plant, without major SO2 impacts; and (3) a regional Sulphate background giving rise to relatively low Sulphate levels with a clear external origin and seasonal trend.
-
Daily evolution of Sulphate Aerosols in a rural area, northeastern Spain—elucidation of an atmospheric reservoir effect
Environmental Pollution, 1999Co-Authors: Xavier Querol, Andres Alastuey, F Plana, J A Puicercus, Enrique Mantilla, Angel Lopez-soler, J L PalauAbstract:The present work is focused on the daily evolution in the levels and composition of total suspended particles and PM10 (particulate matter
L A Barrie - One of the best experts on this subject based on the ideXlab platform.
-
simulating the impact of sea salt on global nss Sulphate Aerosols
Journal of Geophysical Research, 2003Co-Authors: S L Gong, L A BarrieAbstract:[1] The Canadian Aerosol Module coupled with the Canadian third generation Global Climate Model was used to simulate the global distributions of size-segregated sea salt and Sulphate Aerosols of both anthropogenic and natural origins in the atmosphere. A sectional model of 12 size bins was used to treat the size distribution of sea salt and Sulphate, which is assumed to be internally mixed in each size bin. The spatial and temporal distributions predicted by the model compare reasonably well with observations. The mixed aerosol simulations yield number and volume size distributions in the marine boundary layer (MBL) comparable with observations. Sea salt particles redistribute the mass and number distributions of Sulphate Aerosols by serving as a quenching agent to nucleation and as an additional surface area for condensation and by changing the cloud properties in the MBL. By differential simulations of global sea salt and Sulphate it is found that the presence of sea salt increases the mass mean diameter of Sulphate Aerosols by up to a factor of 2 over the MBL with high sea salt concentrations and reduces the global Sulphate aerosol mass in the surface MBL layer from 5 to 75% depending on the sea salt distributions. The high impacts are in the midlatitudes of both Northern and Southern Hemispheres with a minimum in the equatorial regions. In the polluted anthropogenic regions of North Pacific and Atlantic, sea salt reduces the Sulphate concentration from 10 to 30%. The peak reductions of 50–75% occur in the roaring 40s of the Southern Hemisphere in spring and fall. The impact of sea salt on the annual global mass and number loading is estimated to be 9.13 and 0.76%, respectively. A reduction of 20–60% in the marine cloud droplet number concentrations (CDNC) was predicted because of the presence of sea salt, with greatest reductions in the roaring 40s south (40–70%) and in the midlatitude north (20–40%) where the sea salt concentrations were high. Along the equatorial regions some enhancement of total CDNC was simulated because of the presence of sea salt Aerosols.
A Slingo - One of the best experts on this subject based on the ideXlab platform.
-
climate model studies of Sulphate Aerosols and clouds
Philosophical Transactions of the Royal Society B, 1997Co-Authors: A Jones, A SlingoAbstract:It is generally believed that increases in the atmospheric concentrations of greenhouse gases as a result of man's activities are leading to global warming. It is also believed that the same activities lead to increasing concentrations of Sulphate aerosol, which act to cool the climate system and ameliorate the warming. The Sulphate cooling may be separated into the direct effect in cloud-free regions and the indirect effect in cloudy regions. This paper summarizes recent work at the Hadley Centre on the indirect effect. Results from two versions of the hadley Centre Climate Model are shown, using various parameterizations linking the amountof Sulphate aerosol and the number concentration of droplets in water clouds. These results illustrate the considerable uncertainties in estimating the indirect effect. It is shown that other naturally occurring components of the aerosol population, in particular sea salt, may be important in reducing the magnitude of the indirect effect.
-
Predicting cloud‐droplet effective radius and indirect Sulphate aerosol forcing using a general circulation model
Quarterly Journal of the Royal Meteorological Society, 1996Co-Authors: Alun Jones, A SlingoAbstract:Various methods for predicting cloud-droplet effective radius in the Hadley Centre general circulation model are compared with aircraft and satellite retrievals, and are used to estimate the indirect radiative forcing by anthropogenic Sulphate Aerosols since the beginning of the industrial era. The effects both of different parametrization approaches and of different input Sulphate data sets are examined; however, there is no clear evidence to prefer either of the two Sulphate data sets used in the study. Two of the parametrizations generate distributions of present-day effective radius which are similar to each other and compare favourably with observations, yet provide very different estimates of the indirect effect, ranging from −0.5 to −1.5 W m−2 in the global annual mean. A sensitivity experiment in which it is assumed that droplet concentrations are not determined by Sulphate concentrations in continental air reduces this global-mean forcing to −0.3 to −0.8 W m−2. This sensitivity demonstrates the need for a much better understanding of the link between Sulphate aerosol mass concentrations, cloud condensation nuclei, and cloud-droplet number concentrations.
-
a climate model study of indirect radiative forcing by anthropogenic Sulphate Aerosols
Nature, 1994Co-Authors: Alun Jones, D L Roberts, A SlingoAbstract:ANTHROPOGENIC Sulphate Aerosols are believed to affect the radiation budget of the Earth in two ways. Through the direct effect they scatter solar radiation back to space, producing a radiative forcing whose global annual mean has been estimated to lie in the range −0.3 to −0.9 W m−2 (refs 1–3). This is significant compared to the longwave forcing due to increases in anthropogenic trace gases since the beginning of the industrial era, estimated at +2 to +2.5 W m−2 (ref. 4). Aerosols also have an indirect effect, altering the distribution and concentration of cloud condensation nuclei (CCN) and hence the number density and size distribution of cloud droplets, thus affecting the solar radiative characteristics of clouds5,6. This is harder to quantify than the direct effect, because it depends on complex and poorly understood interactions between Aerosols, CCN and cloud properties. Here we use Sulphate aerosol data derived from a three-dimensional chemical transport model7 to estimate the indirect radiative forcing by low-level water clouds using a general circulation model. We estimate that the indirect aerosol effect at the top of the atmosphere is approximately −1.3 W m−2 in the global annual mean. Although this value is subject to a high level of uncertainty, even if the effect is only half as large it would still exceed many estimates of the direct effect, demonstrating its potential importance in climate change.
A V Eliseev - One of the best experts on this subject based on the ideXlab platform.
-
impact of tropospheric Sulphate Aerosols on the terrestrial carbon cycle
Global and Planetary Change, 2015Co-Authors: A V EliseevAbstract:Tropospheric Sulphate Aerosols (TSAs) may oxidise the photosynthesising tissues if they are taken up by plants. A parameterisation of this impact of tropospheric Sulphate Aerosols (TSAs) on the terrestrial gross primary production is suggested. This parameterisation is implemented into the global Earth system model developed at the A.M. Obukhov Institute of the Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM). With this coupled model, the simulations are performed which are forced by common anthropogenic and natural climate forcings based on historical reconstructions followed by the RCP 8.5 scenario. The model response to Sulphate aerosol loading is subdivided into the climatic (related to the influence of TSA on the radiative transport in the atmosphere) and ecological (related to the toxic influence of Sulphate aerosol on terrestrial plants) impacts. We found that the former basically dominates over the latter on a global scale and modifies the responses of the global vegetation and soil carbon stocks to external forcings by 10%. At a regional scale, however, ecological impact may be as much important as the climatic one.
-
climatic response to anthropogenic Sulphate Aerosols versus well mixed greenhouse gases from 1850 to 2000 ad in climber 2
Tellus B, 2008Co-Authors: Eva Bauer, Vladimir Petoukhov, Andrey Ganopolski, A V EliseevAbstract:The Earth system model CLIMBER-2 is extended by a scheme for calculating the climatic response to anthropogenic sulphur dioxide emissions. The scheme calculates the direct radiative forcing, the first indirect cloud albedo effect, and the second indirect cloud lifetime effect induced by geographically resolved Sulphate aerosol burden. The simulated anthropogenic Sulphate aerosol burden in the year 2000 amounts to 0.47 TgS. The best guesses for the radiative forcing due to the direct effect are −0.4 W m -2 and for the decrease in short-wave radiation due to all aerosol effects −0.8 W m -2 . The simulated global warming by 1 K from 1850 to 2000 caused by anthropogenic greenhouse gases reduces to 0.6 K when the Sulphate aerosol effects are included. The model's hydrological sensitivity of 4%/K is decreased by the second indirect effect to 0.8%/K. The quality of the geographically distributed climatic response to the historic emissions of sulphur dioxide and greenhouse gases makes the extended model relevant to computational efficient investigations of future climate change scenarios. DOI: 10.1111/j.1600-0889.2007.00318.x
Xavier Querol - One of the best experts on this subject based on the ideXlab platform.
-
daily evolution of Sulphate Aerosols in a rural area northeastern spain elucidation of an atmospheric reservoir effect
Environmental Pollution, 1999Co-Authors: Xavier Querol, Andres Alastuey, A Lopezsoler, F Plana, J A Puicercus, Enrique Mantilla, J L PalauAbstract:The present work is focused on the daily evolution in the levels and composition of total suspended particles and PM10 (particulate matter <10 microns) in rural areas around the Teruel power station in northeastern Spain, with special emphasis on Sulphate Aerosols. A daily cycle in the levels of natural and Sulphate aerosol is evidenced by higher ratios of Sulphate/soil elements during the diurnal stage when compared with the nocturnal period. The origin of this cycle is probably related to higher SO2 oxidation rates and a higher frequency of plume impacts on the surface during the diurnal period. However, this trend is frequently disturbed by local atmospheric dynamics which give rise to an atmospheric reservoir of Sulphate Aerosols which increase nocturnal Sulphate levels without major SO2 plume impacts. These atmospheric dynamics are described in spring, summer and winter measurement campaigns which are characterised by different plume dispersion scenarios. The results indicate that the three following situations concerning the Sulphate levels can be present in the study area: (1) direct plume impacts inducing high Sulphate levels in short time periods; (2) a Sulphate reservoir effect leading to relatively high Sulphate background levels, homogeneously distributed at distances of 60 km from the power plant, without major SO2 impacts; and (3) a regional Sulphate background giving rise to relatively low Sulphate levels with a clear external origin and seasonal trend.
-
Daily evolution of Sulphate Aerosols in a rural area, northeastern Spain—elucidation of an atmospheric reservoir effect
Environmental Pollution, 1999Co-Authors: Xavier Querol, Andres Alastuey, F Plana, J A Puicercus, Enrique Mantilla, Angel Lopez-soler, J L PalauAbstract:The present work is focused on the daily evolution in the levels and composition of total suspended particles and PM10 (particulate matter
